9th European Symposium on Martensitic Transformations ESOMAT 2012
Conference programme & Book of Abstracts
Saint-Petersburg, Russia September 9-16, 2012 9th European Symposium on Martensitic Transformations ESOMAT 2012
2 9th European Symposium on Martensitic Transformations ESOMAT 2012
Table of Contents Title Page History and Scope 4 Organizing Committee 5 Sponsors 7 General Information 8 Map of conference venue 10 Conference Scientific Programme 13 Book of Abstracts 27 Plenary lectures 29 Oral presentations 33 Poster presentation 85 Sponsor Information 139 Author Index 144 Social events 158 Accompanying person programme 161 Optional Programme 162 Access guide to Hotel “Holiday Inn – Moskovskye vorota” 163 Access guide to historical center of Saint-Petersburg 166 Important information 168
3 9th European Symposium on Martensitic Transformations ESOMAT 2012
History and Scope
The European Symposium on Martensitic Transformations is one of the important events for scientists who are interested in materials with martensitic transformation including steels, shape memory alloys, magnetic shape memory alloys and ceramics. This conference covers the different aspects of investigation of martensitic transformation from theory and modeling through experimental studies to application. Participants of ESOMAT will have a great opportunity for discussion their results with the scientists from all over the world. ESOMAT is a great chance for young scientists and students to hear lectures and reports of the world leaders in the field of martensitic transformations and to present their results for discussion. This conference is organized every three years in various European scientific centers. The previous conferences took place in Bochum, Germany (ESOMAT‟ 89) Aussois, France (ESOMAT‟ 91) Barcelona, Spain (ESOMAT‟ 94) Enschede, The Netherland (ESOMAT‟ 97) Como, Italy (ESOMAT 2000) Cirencester, England (ESOMAT 2003) Bochum, Germany (ESOMAT 2006) Prague, Czech Republic (ESOMAT 2009)
To find more information about ESOMAT community and proceedings of previous conference, please visit the website www.esomat.org
4 9th European Symposium on Martensitic Transformations ESOMAT 2012
Organizing Committee
Conference Chairs The Chairman: Prof. S. Prokoshkin (NUST “MISIS”, Moscow), Co-Chairmen: Prof. A.Volkov (St.-Petersburg State University) Dr. N.Resnina (St.-Petersburg State University) Academician V.Schastlivtsev (Institute of Metal Physics, UrB RAS, Ekaterinburg) Prof. A.Glezer (Kurdyumov Institute of Metal Physics, Moscow) Prof. Yu.Chumlyakov (Tomsk State University)
Conference Organizers Saint-Petersburg State University (Saint-Petersburg) National University of Science and Technology “MISIS” (Moscow) Ioffe Physical Technical Institute of RAS (Saint-Petersburg) Institute of Metal Physics of Ural Branch of RAS (Ekaterinburg) Kurdyumov Institute of Metal Physics (Moscow) Tomsk State University (Tomsk) Institute of Radio-Engineering and Electronics of RAS (Moscow) National Research Nuclear University “MEPhI” (Moscow) Institute of Strength Physics and Material Science of RAS (Tomsk) Ural State Forest Engineering University (Ekaterinburg) Chelyabinsk State University (Chelyabinsk) Alpha Technologies (Saint-Petersburg)
International Advisory Committee
H.K.D.H. Bhadeshia, Cambridge, UK S. Müller, Bonn, Germany E. Cesari, Palma de Malorca, Spain A. Planes, Barcelona, Spain S. Besseghini, Lecco, Italy S. Prokoshkin, Moscow, Russia G. Eggeler, Bochum, Germany D. Schryvers, Antwerp, Belgium N. Glavatska, Kiev, Ukraine P. Sittner, Prague, Czech Republic J. Van Humbeeck, Leuven, Belgium D. Stroz, Katowice, Poland Ch. Lexcellent, Besançon, France T. Waitz, Vienna, Austria
5 9th European Symposium on Martensitic Transformations ESOMAT 2012
Russian Organizing Committee Moscow: Saint-Petersburg Dr. Andreev V.A. Prof. Betekhtin V.I. Prof. Brailovski V. Dr. Belyaev S.P. Prof. Blanter M.S. Prof. Freidin A.B. Prof. Dobatkin S.V. Prof. Konopleva R.F. Prof. Estrin E.I. Prof. Kustov S. B. Prof. Ilyin A.A. Prof. Malygin G.A. Prof. Kaputkina L.M. Prof. Nikanorov S.P. Prof. Kaputkin D.E. Dr. Pulnev S.A. Dr. Khmelevskaya I.Yu. Prof. Razov A.I. Prof. Koledov V.V. Dr. Vyahhi I. E. Prof. Kollerov M.Yu. Dr. Korotitskiy A.V. Ekaterinburg Prof. Khovaylo V.V. Prof. Kashchenko M.P. Prof. Movchan A.A. Prof. Pushin V.G. Prof. Nikulin S. A. Prof. Sagaradze V.V. Prof. Prokoshkina V.G. Prof. Zeldovich V.I. Dr. Ryklina E.P. Prof. Shavrov V.G. Chelyabinsk Dr. Shelyakov A.V. Prof. Buchelnikov V.D. Prof. Shtremel M.A. Prof. Mirzaev D.A. Prof. Stolyarov V.V. Great Novgorod Ufa Prof. Khusainov M.A. Prof. Valiev R.Z. Ukhta Tomsk Prof. Andronov I.N. Prof. Gyunter V.E. Prof. Lotkov A.I. Barnaul Prof. Kulkova S.E. Prof. Plotnikov V.A.
Local Organizing Committee Prof. Volkov A. E. (Saint-Petersburg State University) Prof. Razov A.I. (Saint-Petersburg State University) Dr. Belyaev S. P. (Saint-Petersburg State University) Dr. Pulnev S.A. (Ioffe Physical Technical Institute of RAS) Dr. Vyahhi I. E. (Saint-Petersburg, Technical University)
Conference secretariat Dr. Resnina Natalia (Saint-Petersburg State University) Mr. Slesarenko Viacheslav (Saint-Petersburg State University) Mr. Sibirev Alexey (Saint-Petersburg State University) Mr. Lomakin Ivan (Saint-Petersburg State University) Mr. Zhuravlev Roman (Saint-Petersburg State University) Mrs. Drozdova Maria (Saint-Petersburg State University)
6 9th European Symposium on Martensitic Transformations ESOMAT 2012 Sponsors
ANALIT ltd St-Petersburg, 8 line 29, office 83 Tel +7812-325-4008 Fax +7812-325-5502 Mail: [email protected] www.analit-spb.ru
Shimadzu Europe GmbH (Shimadzu Moscow Representative Office) office C1301, 4th Dobryninskiy pereulok 8, Moscow 119049 Tel: +7 (495) 989-13-17, 989-13-18 Fax: +7 (495) 989-13-19 www.shimadzu.ru
Prüftechnik MT GMbH, an official distributor of Gleeble Systems within the territory of Russia and CIS countries Piskarevsky prospect 2, build. 2, office 812, Benois Business Center St. Petersburg, 195027, Russia tel.: +7 (812) 313-80-38 fax: +7 (812) 313-80-44 [email protected] www.mt-gmbh.ru
ATM GMbH (Moscow Representative Office) Leningradsky prospect, 37А, b.14, Moscow, 125167, Russia tel.: +7 (495) 783-88-12/14 fax: +7(495) 783-88-13 www.atm-mt.ru [email protected]
Zwick GMbH & Co (Saint-Petersburg Representative Office) Piskarevsky prospect 2, build. 2, office 812, Benois Business Center St. Petersburg, 195027, Russia tel.: +7 (812) 313-80-39 fax: +7 (812) 313-80-44 [email protected] www.zwick.de
7 9th European Symposium on Martensitic Transformations ESOMAT 2012 General Information Conference Venue The conference is organized in the Hotel “Holiday Inn – Moskovskye vorota”. Address: Moskovskiy avenue (prospect) 97А, St. Petersburg, 196084, Russia
Registration The registration of ESOMAT 2012 participants will take place in the Foyer of Congress- Hall “Moskovsky” in the Hotel “Holiday Inn – Moskovskye vorota” from 9:00 to 20:00 on Sunday (September 9) and from 8:00 to 18:00 on Monday (September 10).
Badge The conference badge is required for admission to all conference events (Scientific and Social). The badge contains your name, surname, city and country as well as type of your participation (Full, scientific, visiting). If you have any questions, please contact to participants with title SECRETARIAT on the badge.
Conference secretariat Conference secretariat is located at the second floor in the room “Malinary” and it is opened during all conference times since Monday (September 10) till Friday (September 14). If you have any questions, please do not hesitate to contacting us.
Guidelines to Plenary Lectures and Oral Presentations Plenary lectures and oral presentations should be prepared as PowerPoint document. Please save your presentation as ppt document. The pptx documents may not be opened. Please make sure that your presentation is uploaded well before your session starts. The total duration of a plenary lecture is 40 minutes (35 minutes for lecture and 5 minutes for questions and discussion). The total duration of an oral presentation is 20 minutes (15 minutes for presentation and 5 minutes for questions and discussion). We would like to ask all speakers to keep your lectures and presentations in time. Presenting authors should be in the hall and uploaded their presentation 15 minutes before the start of the session. In Monday (September 10) the Congress Hall “Moskovsky” will be opened since 8:00. In Tuesday, Wednesday and Friday the halls “Petrov-Vodkin” and “Stenberg” will be opened since 8:30.
8 9th European Symposium on Martensitic Transformations ESOMAT 2012 Guidelines to Poster Presentation Your poster should fit into a rectangle with a width of 841 mm (84cm) and a length of 1189mm (119cm). This size is A0 portrait format. Please, indicate your poster number (number of your presentation in the preliminary conference programme) in the upper corner of your presentation.
Size of poster
Authors with poster presentations are asked to fix their poster to the framework at 16:30 and remove at 18:30 in the day of their sessions. Please check the name of the Hall where your poster session will be in the conference programme. The reference number of your poster will be located in the upper part of the framework. Drawing pins for poster fixing will be at the side part of the framework.
9 9th European Symposium on Martensitic Transformations ESOMAT 2012
Map of the Conference Venue Hotel “Holiday Inn – Moskovskye vorota” Ground floor (in Russian – the First floor)
10 9th European Symposium on Martensitic Transformations ESOMAT 2012
Hotel “Holiday Inn – Moskovskye vorota” The first floor (in Russian – the second floor)
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Hotel “Holiday Inn – Moskovskye vorota” The second floor (in Russian – the third floor)
12 9th European Symposium on Martensitic Transformations ESOMAT 2012
Conference Scientific Programme
September 10 "Moskovsky" Congress-hall, Hotel “Holiday Inn – Moskovskye Vorota”
8:30 - 9:00 Opening the conference Prof. J. Van Humbeeck 9:00 - 9:30 Tribute to Prof. Rolf Gotthardt Chairman Prof. Sergey Prokoshkin (Moscow, Russia) 9:30 - 10:10 Plenary lecture 1. T. Kakeshita (Japan) An interpretation for kinetics of martensitic transformations Plenary lecture 2. S. Kustov (Spain) 10:10 - 10:50 Isothermal diffusionless martensitic transformations in shape memory alloys 10:50 - 11:30 Coffee break Chairman Prof. Alexander Glezer (Moscow, Russia) Plenary lecture 4. J. San Juan (Spain) 11:30 - 12:10 Copper base SMA: From macroscopic properties to nano-scale behaviour Plenary lecture 5. A. Planes (Spain) 12:10 - 12:50 Recent progress and future perspectives in magnetic shape memory Heusler alloys Plenary lecture 6. D. Schryvers (Belgium) 12:50 - 13:30 Nano- and microcrystal structure investigations of interfaces, gradient and strain fields in martensitic materials by various EM techniques. 13:30 - 15:00 Lunch
Chairman Prof. Yuriy Chumlyakov (Tomsk, Russia) Plenary lecture 7. P. Sittner (Czech Republic) 15:00 - 15:40 Revealing deformation mechanisms in SMAs by in-situ X-ray and diffraction methods Plenary lecture 8. S. Miyazaki (Japan) 15:40 - 16:20 Mechanical behaviour, shape memory effect, pseudoelasticity in Ti- based alloys Plenary lecture 9. V. Brailovski (Canada) 16:20 - 17:00 Bulk and porous metastable beta Ti-Nb-Zr(Ta) alloys for biomedical applications: processing, structure and mechanical properties. 17:00 - 17:40 Coffee break Chairman Prof. Alexander Volkov (Saint-Petersburg, Russia) Plenary lecture 10. G. Eggeler (Germany) 17:40 - 18:20 Materials science of NiTi shape memory alloys – new experimental results and directions for future work 18:20 - 19:00 Plenary lecture 11. I. Khmelevskaya (Russia) Medical and technical aspects of TiNi applications
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September 11 "Petrov-Vodkin-1" hall, Hotel “Holiday Inn – Moskovskye Vorota”
Session 12 “Mechanical behavior, shape memory effect, pseudoelasticity and other functional properties in TiNi based alloys”: Chairman Prof. Shuichi Miyazaki (Tsukuba, Japan) 9:00 - 9:20 S12-O1 M. Nishida, T. Inamura, Y. Soejima, T. Nishiura, H. Kawano, T. Hara Self-accommodation of B19’ martensite in Ti-Ni alloys: Part 1 Experimental approach 9:20 - 9:40 S12-O2 T. Inamura, T. Nishiura, H. Kawano, H. Hosoda, M. Nishida Self-accommodation of B19’ martensite in Ti-Ni alloys: Part 2 Theoretical analysis 9:40 - 10:00 S12-O3 S.E. Kulkova, A.V. Bakulin, I.V. Dudkin, Q.M Hu. Study of nickel segregation at the TiNi – Titanium oxide interface 10:00 - 10:20 S12-O4 L. Meisner, A. Lotkov, S. Meisner, Yu. Mironov, N. Sochugov, A. Solov‟ev The investigation of subsurface gradient structures in the silicon – coated TiNi alloy using EBSD and X-ray techniques 10:20 - 10:40 S12-P39 M. Rahim, J. Frenzel, M. Frotscher, R. Steegmüller, M. Wohlschlögel, G. Eggeler On the effect of particles on structural fatigue of pseudoelastic NiTi shape memory alloys. 10:40 - 11:00 S12-O6 S. Kustov, D. Salas, E. Cesari, R. Santamarta, D. Mari, J. Van Humbeeck “Strain glass: Revisited” 11:00 - 11:30 Coffee break
Chairman Prof. Gunther Eggeler (Bochum, Germany) S12-P35 B. Maass, J. Frenzel, G. Eggeler 11:30 - 11:50 New experimental results on the influence of alloy composition on phase transition temperatures in NiTiCu alloys 11:50 - 12:10 S12-O9 B. Kockar, H. Ozcan, S. Cakmak Transformation behavior of porous NiTi shape memory alloy 12:10 - 12:30 S12-P23. B. Piotrowski, Y. Chemisky, F. Meraghni, R. Echchorfi, N. Bourgeois, E. Patoor Identification and interpretation of material parameters a shape memory alloy model 12:30 - 12:50 S12-O11 B. Krevet, V. Pinneker, M. Rhode, C. Bechthold, E. Quandt and M. Kohl Evolution of temperature profiles during stress-induced transformation in NiTi thin films 12:50 - 13:10 S12-O12 A. Lotkov, Yu. Koval, V. Grishkov, G. Firstov, N. Girsova, V. Timkin, D. Zhapova Effect of the warm isothermal rolling on microstructure and martensitic transformation in TiNi-based alloys 13:10 - 13:30 S12-O13 Szurman Ivo, Miroslav Kursa, Antonín Dlouhý In-situ TEM observation of transformations in TiNiCu alloy. 13:30 - 14:50 Lunch
Chairman Prof. Jan Van Humbeeck (Leuven, Belgium) 14:50 - 15:10 S12-O14 B. Piotrowski, Y. Chemisky, F. Meraghni, R. Echchorfi, N. Bourgeois, E. Patoor Determination of transformation surface of a NiTi shape memory alloy using full field measurements and biaxial tests 15:10 - 15:30 S12-O27 I. Sen, R. Raghavan, J. Michler, M.F.-X. Wagner Small-scale deformation behavior of NiTi shape memory alloys 15:30 - 15:50 S12-O16 V.V. Rubanik, V.V. Rubanik Jr, O.A. Petrova-Burkina Peculiarities of thermoelectric force behaviour in Titanium Nickelide under unsteady heating 15:50 - 16:10 S12-O17 . V.V. Stolyarov Features of current influence during plastic deformation of TiNi alloys S8-O2 Chikosha Silethelwe and Chikwanda Hilda Kundai 16:30 – 16:30 TiPt HTSMA produced by spark plasma sintering of elemental powders
14 9th European Symposium on Martensitic Transformations ESOMAT 2012 September 11 “Stenberg-1” hall, Hotel “Holiday Inn – Moskovskye Vorota”
Session 1 “Crystal structure, texture and defects in materials with martensitic transformations” Chairman Prof. Dominique Schryvers (Antwerp, Belgium) 9:00 - 9:20 S1-O1 Yu. Koval, G. Firstov, V. Odnosum High temperature martensitic transformation and shape memory behaviour in HfIr intermetallics compound 9:20 - 9:40 S1-O2 A. Weidner , H. Berek , C. Aneziris , H. Biermann Martensitic phase transformations in composites of TRIP steel and zirconia particles 9:40 - 10:00 S1-P2 A. Settefrati, B. Appolaire, E. Aeby-Gautier Stress and strain fields associated with formation of '' in near- titanium alloys 10:00 - 10:20 S1-O4 Dos Santos Paula Andersan, Costa Cardoso Marcelo, Gonçalves Andrade Jessica, Farias Vieira Thiago, Monteiro Almeida Guilherme, Moreira Pessanha Luciano, dos Santos Freitas Maria Carolina The influence of strain-rate on textural evolution in 304L austenitic stainless steel with TRIP effect 10:20 - 10:40 S1-O5 J. Dadda, J. Lackmann, J. Monroe, I. Karaman, E. Panchenko, H. E. Karaca, T. Niendorf, H.J. Maier Tension – compression asymmetry in Co49Ni21Ga30 high-temperature shape memory alloy single crystals 10:40 - 11:00 S1-P4 Jian Zhang, Ramona Rynko, Jan Frenzel Ingot metallurgy and microstructural characterization of Ti-Ta alloys 11:00 - 11:30 Coffee break Chairman Prof. Yurii Koval (Kiev, Ukraine) 11:30 - 11:50 S1-O11 M.L. Nó, A. Ibarra, A. López-Echarri, I. Ruiz-Larrea, T. Breczewski, J. San Juan Mechanical cycling in Cu-Al-Ni single crystals: Microstructure analysis and superelastic effect 11:50 - 12:10 S1-O8 S. Dubinskiy, V. Brailovski, K. Inaekyan, S. Prokoshkin In-situ X-ray study of phase transformation in Ti-Nb-based SMA under variable stress- temperature conditions 12:10 - 12:30 S1-O9 Yu. Perlovich, M. Isaenkova, V. Fesenko, T. Dementyeva Distribution of residual elastic microstress in rolled Ti-Ni single crystals 12:30 - 12:50 S1-O10 A. Settefrati, E. Aeby-Gautier, M. Dehmas, B. Appolaire, G. Khelifati, G. Geandier Low temperature transformation in Ti5553 metastable beta titanium alloy 12:50 - 13:10 Information from sponsors – in Russian 13:10 - 14:30 Lunch Session 5 “Martensitic transformations in nanostructured alloys” Chairman Prof. Vladimir Brailovski (Montreal, Canada) 14:30 - 14:50 S5-O1 A.M. Glezer Martensite transformation in nanocrystals 14:50 - 15:10 S5-O2 C. Mangler, A. Kompatscher, N. Kucza, P. Müllner, T. Waitz Ni-Ma-Ga alloys processed by severe plastic deformation 15:10 - 15:30 S5-O3 A. Lotkov, A. Baturin, V. Grishkov, V. Kopylov Influence of equal-channel angular pressing on grain refinement and nonelastic properties of TiNi based alloys 15:30 - 15:50 S5-O5 D.V. Gunderov, A.V. Lukyanov, E.A. Prokofiev, A.A Churakova, V.G. Pushin, S.D. Prokoshkin, V.V. Stolyarov, R.Z. Valiev Microstructure and mechanical properties of the SPD-processed TiNi alloys 15:50 - 16:10 S5-O6 I. Litovchenko, A. Tyumentsev, A. Korznikov Reversible martensitic transformation produced by severe plastic deformation of metastable austenitic steel
16:10 - 16:30 S3-P17 K. A. Käfer, H. H.Bernardi, L. K. F. Naito, J.Otubo Shape memory properties of ultrafine-grained austenitic stainless steels
15 9th European Symposium on Martensitic Transformations ESOMAT 2012 September 12 "Petrov-Vodkin-1" hall, Hotel “Holiday Inn – Moskovskye Vorota”
Session 12 “Mechanical behavior, shape memory effect, pseudoelasticity and other functional properties in TiNi based alloys”
Chairman Prof. Petr Sittner (Prague, Czech Republic) 9:00 - 9:20 S12-O32 A. Pushin, A. Popov, V. Pushin Structural and phase transformations and properties of rapidly quenched Ti2NiCu based alloys 9:20 - 9:40 S12-O19 Cellard Christophe, Rio Gérard, S. Shariat Bashir, Liu Yinong, Grolleau Vincent, Delobelle Vincent, Favier Denis Experimental and numerical study of NiTi holey plates loaded in tension 9:40 - 10:00 S12-O20 D.E. Nicholson, O. Benafan, S.A. Padula II, R.D. Noebe and R. Vaidyanathan An in-situ neutron diffraction study of tension-compression cyclic deformation in polycrystalline NiTi 10:00 - 10:20 S12-O21 E. Ryklina Study of surface state influence on functional properties of Ti–Ni alloys 10:20 - 10:40 S12-O22 Y. X. Tong, B. Guo, F. Chen, B. Tian, L. Li, Y. F. Zheng, Ruslan Z. Valiev Effect of annealing on superelasticity of TiNi alloys subjected to equal channel angular pressing 10:40 - 11:00 S12-P44 X. Wang, D. Schryvers, B. Verlinden, J. Van Humbeeck Effect of annealing on the mechanical properties of a severe plastic deformed NiTi shape memory wire 11:00 - 11:30 Coffee break Chairman Prof. Alexander Razov (Saint-Petersburg, Russia) 11:30 - 11:50 S12-O24 J. Torrens-Serra, D. Salas, E. Cesari, S. Kustov, K. Sapozhnikov, J. Van Humbeeck Effect of stoichiometry on elastic and anelastic properties of NiTi-based shape memory alloys 11:50 - 12:10 S12-O25 H. Karaca , S. Saghaian, E. Acar, I. Kaya, B. Basaran, R. Noebe, Yu. Chumlyakov Ultra high strength Ni-rich NiTi-based Shape memory alloys 12:10 - 12:30 S12-O26 A. Isalgue, J. Fernandez, N. Cinca, C. Auguet, G. Carreras, V. Torra Thermomechanical fatigue behaviour of NiTi wires 12:30 - 12:50 S12-P52 M.Yu. Kollerov, E. Lukina, D. Gusev, P. Mason, P. Wagstaff Influence of the structure on the strain-controlled fatigue of NITINOL 12:50 - 13:10 S12-O29 V. Legrand, L. Saint-Sulpice, L. Pino, Sh. Arbab Chirani, S. Calloch Fatigue and self-heating of NiTi shape memory alloys 13:10 - 13:30 S12-O31 Tae-hyun Nam, Yeon-min Im, Gyu-bong Cho, Jung-pil Noh Applications of Ti-Ni alloys to current collector and electrode materials in secondary battery 13:30 - 14:50 Lunch
Session 4“Magnetic Shape memory alloys” and Session 6 “Medical applications” Chairman Prof. Antoni Planes (Barcelona, Spain) 14:50 - 15:10 S4-P21 J. Kopeček, K. Jurek, V. Kopecký, L. Fekete, I. Kratochvílová, M. Landa, H. Seiner, P. Sedlák, L. Bodnárová, P. Šittner, O. Heczko Structural changes in Co-based f-SMA 15:10 - 15:30 S4-P30 X. Chen, Y.J. He, Z. Moumni Experimental investigation on evolution of macroscopic deformation pattern in Ni-Mn-Ga magnetic shape memory alloy 15:30 - 15:50 S4-P7 J. Romberg, C. Hürrich, M. Pötschke, S. Roth, S. Kauffmann-Weiss, U. Gaitzsch, P. Müllner, L. Schultz Geometric factors on magnetically driven actuation behaviour for polycrystalline Ni-Mn-Ga and its composites 15:50 - 16:10 S6-O1 V. Legrand, S. Moyne, L. Pino, S. Arbab Chirani, S. Calloch, R. Arbab Chirani Mechanical behavior study of NiTi endodontic files taking into account anatomic shape of root canals 16:10 – 16:30 Information from sponsors
16 9th European Symposium on Martensitic Transformations ESOMAT 2012 September 12 “Stenberg-1” hall, Hotel “Holiday Inn – Moskovskye Vorota”
Session 3 “Mechanical behavior, shape memory effect, pseudoelasticity and other functional properties in Fe- based and other alloys”
Chairman Prof. Dmitry Kaputkin (Moscow, Russia) 9:00 - 9:20 S3-O1 K. Ishida Martensitic transformation from ferrite to austenite in ferrous alloys 9:20 - 9:40 S3-O2 V.V.Sagaradze, I.G.Kabanova, N.V.Kataeva, M.F.Klyukina Structural mechanism of reverse transformation and new functional properties of Fe-Ni austenitic alloys 9:40 - 10:00 S3-O3 D.P. Dunne and W. Pang Structural and hardness gradients in the heat affected zone of welded low carbon martensitic steels 10:00 - 10:20 S3-O4 I. Kireeva, Yu. Chumlyakov, A. Tverskov The affect of hydrogen on development of - - ’ martensitic transformations under loading in austenitic stainless steel single crystals 10:20 - 10:40 S3-O5 E. V. Pereloma, A. A. Gazder, I. B.Timokhina Addressing retained austenite stability in advanced high strength steels 10:40 - 11:00 S3-P8 F. Hahnenberger, M. Smaga, D. Eifler Influence of mechanical loading, temperature and chemical compositions on the deformation induced martensite formation in metastable austenitic steels 11:00 - 11:30 Coffee break Chairman Prof. Yuriy Chumlyakov (Tomsk, Russia) 11:30 - 11:50 S3-O7 Ph. Vermaut, A. Manzoni, A. Denquin, F. Prima, R. Portier Unexpected constrained twin hierarchy in Ru-based high temperature shape memory alloys martensite 11:50 - 12:10 S10-P7 H.A. Pham, T. Ohba, S. Morito, T. Hayashi Effect of titanium carbide inclusions on morphology of low-carbon steel martensite 12:10 - 12:30 S11-P2 V.I. Nikolaev, G.A. Malygin, S.A. Pulnev, P.N. Yakushev , V.M. Egorov Reactive stresses and burst character of shape memory deformation in single crystals CuAlNi and NiFeGa 12:30 - 12:50 S3-O10 V. A. Yardley, E. J. Payton Parameterization and statistical characterization of the martensite-austenite orientation relationship 12:50 - 13:10 S3-O11 M. Yaso, T. Takaiwa, Y. Minagi, T. Kanaizumi, K. Kubota, T. Hayashi, S. Morito, T. Ohba Study of metallurgy and mechanical property on JAPANESE sword 13:10 - 14:30 Lunch Session 11 “Thermodynamics and kinetics of martensitic transformations” Chairman Prof. Tomoyuki Kakeshita (Osaka, Japan) 14:30 - 14:50 S11-O2 F. Xiao, T. Fukuda, T. Kakeshita Superelastic behavior associated with second order-like martensitic transformation in a disordered Fe-31.2Pd (at.%) alloy 14:50 - 15:10 S11-O3 M. Certain, H. Zapolsky, R. Patte. Atomic density function modeling of FCC to BCC transformation 15:10 - 15:30 S11-O4 L. Saint-Sulpice, M. Lakrit, S. Arbab Chirani, S. Calloch Electric resistivity as phase volume fractions indicator in metastable alloys 15:30 - 15:50 S11-O5 M. Petrzhik On returnable accumulation of deformation at biocompatible quenched Ti-(Nb, Ta) alloys Session 6 “Medical applications” 15:50 - 16:10 S6-O2 F. Prima, F. Sun, Wafa El May, T. Gloriant, P. Laheurte, Yu. Hao Optimization of superelastic properties in TITANIUM-NIOBIUM alloys using short-time thermal treatments 16:10 - 16:30 S6-O3 V. Attari, B. Kockar Stress and deformation analysis of NiTi and TiNb shape memory alloy manipulate systems for the treatment of atrophic mandibular fractures
17 9th European Symposium on Martensitic Transformations ESOMAT 2012 September 14 "Petrov-Vodkin-1" hall, Hotel “Holiday Inn – Moskovskye Vorota”
Session 4 Magnetic Shape memory alloys
Chairman Prof. Eduard Cesari (Palma de Mallorca, Spain) 9:00 - 9:20 S4-O1 R. Santamarta, S. Kustov, E. Cesari, K. Sapozhnikov, J. Van Humbeeck. Hyperstabilization of Cu-Al-Be and Ni-Fe-Ga martensites 9:20 - 9:40 S4-O2 R .Chulist, A. Sozinov, L. Straka, N. Lanska, A. Soroka, T. Lippmann, C.-G. Oertel, W. Skrotzki Synchrotron and conventional X-ray diffraction studies of polysynthetic twins in Ni−Mn−Ga 10M martensite 9:40 - 10:00 S4-O3 N. Zárubová, Y. Ge, S.-P. Hannula Mechanism of twin variant reorientation in Ni-Mn-Ga 10:00 - 10:20 S4-O4 R. Chulist, L. Straka, N. Lanska, A. Soroka, C.-G. Oertel, W. Skrotzki, A. Sozinov EBSD characterization of highly mobile segmented interfaces of type II twins in 10M modulated Ni−Mn−Ga martensite 10:20 - 10:40 S4-P17 Ge Yanling, Zárubová Niva, Hannula Simo-Pekka Tem study of twinning in Ni-Mn-Ga alloy 10:40 - 11:00 S4-O6 V. Sánchez-Alarcos, JI. Pérez-Landazábal, V. Recarte, I. Lucia, J. Vélez, JA. Rodríguez- Velamazán Influence of long-range atomic order on the martensitic transformation of Ni-Mm-based magnetic shape memory alloys 11:00 - 11:30 Coffee break Chairman Prof. Manfred Kohl (Karlsrue, Germany) 11:30 - 11:50 S4-O7 J.A. Monroe, C. Yegin, I. Karaman, Y.I. Chumlyakov Evidence of strain glass transition linked to kinetic arrest in NiCoMnIm meta-magnetic shape memory alloys 11:50 - 12:10 S4-O8 V. Zhukova, A.M. Aliev, T. Ryba, S. Michalik, Z. Vargova, R. Varga, A. Zhukov Magnetic properties and MCE of NiMnGa glass-coated microwires 12:10 - 12:30 S4-O9 L. González, W.O. Rosa, R. Caballero-Flores, V. M. Prida, Ll. Escoda, J.J. Suñol, A. B. Batdalov, A. M. Aliev, V. V. Koledov, B. Hernando Magnetostructural phase transformation and MCE of Ni50.3Mn36.5Sn13.2 Heusler alloy ribbon 12:30 - 12:50 S4-O10 L. Mañosa, S. Yuce, B. Emre, E. Stern, A. Planes, M.Barrio, J.L. Tamarit, F. Albertini, S. Fabbrici Calorimetric study of the barocaloric and magnetocaloric effects in Ni-Co-Mn-Ga-In 12:50 - 13:10 S4-O12 Y.J. He, X. Chen, Z. Moumni Martensite reorientation in magnetic shape memory alloys under 3D magneto-mechanical loadings 13:10 - 13:30 S4-O13 Yu. Chumlyakov, I. Kireeva, I. Kretinina, V. Kirillov, O. Kuc, I. Karaman, H. Maier, E. Cesari Shape memory effect and superelasticity in FeNiCoAlTa single crystals testing - ’ martensitic transformations 13:30 - 14:50 Lunch Chairman Prof. Ibrahim Karaman (College Station, USA) 14:50 - 15:10 S4-O14 A. Likhachev Effect of magnetostatic energy of the magnetic driving forces and field induced superelastic behavior in Ni-Mn-Ga 15:10 - 15:30 S4-O15 E. Panchenko, Yu. Chumlyakov, H.J. Maier, E. Timofeeva, A. Kanaf‟eva Effect of nano-size particles on stress-induced martensitic transformation and functional properties of ferromagnetic CoNiAl, NiFeGa(Co) single crystals 15:30 - 15:50 S4-P27 S. Kauffmann-Weiss, M. E. Gruner, A. Kauffmann, P. Entel, L. Schultz, S. Fähler Adaptive nanotwinning in strained epitaxial Fe70Pd30 films S4-O17 R. Yin, V. Pinneker, A. Sozinov, Y. Ezer and M. Kohl 15:50 - 16:10 A miniature energy harvesting device using martensite variant reorientation
18 9th European Symposium on Martensitic Transformations ESOMAT 2012 September 14 “Stenberg-1” hall, Hotel “Holiday Inn – Moskovskye Vorota”
Session 9 “Theory and modeling of mechanical and functional properties” Chairman Prof. Maria Teresa Castan (Barcelona, Spain) 9:00 - 9:20 S9-O1 A. Saxena Mesoscopic modeling of shape memory and multifunctional materials 9:20 - 9:40 S9-O2 M. F. Laguna, P. Arneodo Larochette, J.L. Pelegrina Dynamic behaviour of thermal cycles in martensites 9:40 - 10:00 S9-O3 C. Lexcellent, R. Laydi and V. Taillebot What about the fracture of shape memory alloys? 10:00 - 10:20 S9-O4 Y.G. Cui, J.F. Wan, J.H. Zhang, Y.H. Rong The switching pathway and mechanism of multi-variants in Ni-Mn-Ga shape memory alloys under the external stress field: Phase-field simulation 10:20 - 10:40 S9-O5 A.E. Volkov, M.E. Evard Simulation of vibration isolation by shape memory alloy springs using a microstructural model of shape memory alloy S11-O1 E. R. Oberaigner, M. Leindl 10:40 - 11:00 Relation of the Block-Spin-Approach to the Landau- and Landau-GinZburg Model FOR Describing PolycrystalLine Shape Memory Alloys 11:00 - 11:30 Coffee break Session 10 “Theory of martensitic transformations” Chairman Prof. Alexander Volkov (Saint-Petersburg, Russia) 11:30 - 11:50 S10-O1 N.F. Viana, C.S. Nunes, H.F.G. Abreu Influence of plastic deformation and stress in variant selection in samples of Maraging-350 steel 11:50 - 12:10 S10-O2 M.P. Kashchenko and V.G. Chashchina Fundamental achievements of the dynamic theory of reconstructive martensitic transformations 12:10 - 12:30 S10-O4 M. Peigney Stress-free strains in martensite microstructures S10-O3 G. Firstov, A. Timoshevskii, Yu. Koval, S. Yablonovskii, J. Van Humbeeck 12:30 - 12:50 Phase stability and chemical bond at martensitic transformation in Zr-based shape memory intermetallics 12:50 - 13:10 S1-P14 T. Kosorukova, G. Firstov, Yu. Koval, V. Ivanchenko, J. Van Humbeeck Phase transformations and shape memory effect in alloys of Zr-Ni-Co system 13:10 - 14:30 Lunch Session 2 “Mechanical behavior, shape memory effect, pseudoelasticity and other functional properties in Cu- based alloys” Chairman Prof. Jose San Juan (Bilbao, Spain) 14:30 - 14:50 S2-O1 C.A. Biffi, A. Figini, A. Tuissi CuZr based shape memory alloys: Effect of alloying elements on the martensitic transformation 14:50 - 15:10 S2-O2 F. N. García, V. Amigó, J. Cortés, F. M. Sánchez, J.G. González, H. Flores Micromechanical analysis of stress induced martensite transformation in polycrystalline Cu- Al-Be shape memory alloy 15:10 - 15:30 S2-O3 I. López-Ferreño, T. Breczewski, I. Ruiz-Larrea, A. López-Echarri , M.L. Nó and J . San Juan Thermo-mechanical behavior of Cu-Al- Be SMA single crystals 15:30 - 15:50 S2-O4 C. Caër, E. Patoor, S. Berbenni, J.-S. Lecomte Micromechanical characterization of martensitic transformation in shape memory alloys by nanoindentation 15:50 - 16:10 S2-O5 P. Arneodo Larochette, B.A. Weiss, G. Bertolino, E.M. Castrodeza, A. Baruj, H.E. Troiani Manufacture and characterization of Cu-Zn-aL shape memory foams
19 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations
September 11 16:30 – 18:30 "Petrov-Vodkin-1" hall, Hotel “Holiday Inn – Moskovskye Vorota” Session 12 “Mechanical behavior, shape memory effect, pseudoelasticity and other functional properties in TiNi based alloys”
S12 – P1 A. Bragov, A. Galieva, V. Grigorieva, A. Danilov, A. Konstantinov, A. Lomunov, A. Motorin, E. Ostropiko, A. Razov Functional properties of TiNi shape memory alloy after high strain loading S12 – P2 D.E. Kaputkin, E.V. Esina Pseudo elastic cyclic deformation of NiTi alloy under various temperatures S12 – P4 F.M. Braz Fernandes, K. Mahesh, M. Craciunescu Corneliu, J.P. Oliveira, N. Schell, R.M. Miranda, J.L. Ocaña Structural characterization by X-ray diffraction of laser welded shape memory alloys S12 – P5 F.M. Braz Fernandes, F. Neves, K. Mahesh, A. Stark, N. Schell In-situ study of homogenization thermomechanical treatment of Ni-Ti shape memory alloysproduced by powder metallurgy S12 – P6 I.N. Andronov, R. A. Verbakhovskaya Influence of thermomechanical processing (ТМP) on deformation properties and power consumption titanium nickelide realized at thermocycling in conditions of mechanical work S12 – P7 J. Lelatko, Z. Lekston, M. Freitag, T. Wierzchoń, T. Goryczka Influence of the low temperature glow discharge nitriding and/or oxiding process on the structure and shape memory effect in NiTi alloy S12 – P8 T. Breczewski, A. López-Echarri, M.L. Nó, I. Ruiz-Larrea, and J. San Juan Temperature memory effect in a multistage martensitic transformation of TiNi alloy S12 – P10 T. Goryczka, P. Ochin, J. Lelatko Shape memory effect in NiTiCo strip produced by twin roll casting technique S12 – P12 Yeon-wook Kim and Tae-hyun Nam Shape memory characteristics of porous Ti50Ni50 alloy S12 – P13 K. Kus, T. Breczko Annealing and thermal transition cycling of NITINOL SMA S12 – P14 A. Shelyakov, N. Sitnikov, S. Saakyan, A. Menushenkov, A. Korneev Study of two-way shape memory behavior of amorphous-crystalline TiNiCu melt-spun ribbons S12 – P15 A. Korotitskiy Method for express-evaluation of shape recovery in Ti-Ni SMA S12 – P17 N. Cinca, A. Isalgué, J. Fernández, G. Fargas, S. Sampath Splat features during Vacuum Thermal Spraying of NiTi onto several substrates S12 – P18 Jong-Taek Yeom, Jae Keun Hong, Jeoung Han Kim, Chan Hee Park, Seong Woong Kim, Yong-Taek Hyun and Kee-Young Lee Hot workability analysis of as cast TiNi alloy S12 – P19 N. Resnina, S. Belyaev, A. Sibirev Strain variation during thermal cycling the TiNi alloy under constant stress through the temperature range of incomplete martensitic transformation S12 – P21 N.N. Popov, V.F. Lar‟kin, T.I. Sysoeva, A.A. Aushev, D.V. Presnyakov Study of structural peculiarities, kinetics of martensite transformation, thermo-mechanical and mechanical characteristics of shape memory alloys belonging to Ti-Ni-Nb-Zr system with the wide martensite hysteresis S12 – P26 V. Rubanik, V. Rubanik Jr., V. Dorodeiko, S. Miliukina Influence of ultrasonic treatment on shape memory effects in Ti-50,4%Ni alloy S12 – P28 A. Fabregat-Sanjuan, S. De la Flor, F. Ferrando, C. Urbina TiNiCu martensitic transformation characterization at low stress levels through thermomechanical cycling S12 – P60 R. V. Sundeev, A. V. Shalimova, A. M. Glezer Cyclical of structural and phase transformation in Ti50Ni25Cu25 alloy during severe plastic deformation S12 – P61 A. Pazgalov, M. Khusainov, A. Bondarev, S. Popov, V. Andreev The research of working ability of the activ elements of shape memory TiNi alloy
20 9th European Symposium on Martensitic Transformations ESOMAT 2012 September 11 16:30 – 18:30 “Stenberg-1” hall, Hotel “Holiday Inn – Moskovskye Vorota” Session 1 “Crystal structure, texture and defects in materials with martensitic transformations”
S1-P1 P. Ari-Gur, M.R.A.S.Bandara, V.O. Garlea, H. Cao, A. Coke, Y. Ge, I. Aaltio, S.-P. Hannula, V. Koledov Neutron diffraction study of Ni-Mn-Ga MSM alloy S1-P6 V. Pilyugin, A. Patselov, E. Сhernyshov, A. Ancharov, T. Tolmachev Influence of nanocrystalline structure of Fe on the baric phase transformations S1-P13 H. Shi, J. Van Humbeeck, D. Schryvers Study of niobium-rich precipitates in (Ni-Ti) 8.4% Nb shape memory alloy S1-O7 M. Isaenkova, Yu. Perlovich, V. Fesenko, T. Dementyeva Twinning in Ti-48%Ni-2%Fe single crystals under rolling S6-P1 Tae Suk Kim, G.C.Kim, W.W.Park, K.H.Hwang, J.K.Lee, and H.Kim Sintering and Bonding Properties of Zirconia with Veneering Ceramics S7-P1 Jong Kook Lee, Kyu Hong Hwang Crack growth by isothermal martensitic phase transformation in tetragonal zirconia polycrystals
Session 5 “Martensitic transformations in nanostructured alloys”
S5-P2 D. Stroz, J. Palka, Z. Lekston Structure and properties of NiTi shape memory alloys after severe plastic deformation S5-P3 S. Prokoshkin, V. Brailovski, M. Petrzhik, M. Filonov, V. Sheremetyev Mechanocycling and time stability of loading-unloading diagram parameters of nanostructured Ti-Nb-Ta AND Ti-Nb-Zr SMA S5-P4 G.E. Monastyrsky , V.V. Odnosum, P. Ochin , A.Yu. Pasko, V.I. Kolomytcev, Yu.N. Koval Martensitic transformation in Ni-Al-Pt high temperature shape memory alloys S5-P6 M. Zagrebin, V. Sokolovskiy, V. Buchelnikov Ab initio study of magnetic properties and phase diagram of Ni-Mn-Ga Heusler alloys S5-P10 P.O. Rusinov, Z.M. Blednova Formation nanosize blankets TiNiCu from materials with effect of memory of the form in the conditions of plasma dusting S5-P12 S. Belyaev, N. Frolova, V. Pilyugin, N. Resnina, V. Slesarenko, V. Zeldovich Structure and properties of TiNi alloy subjected to severe plastic deformation and subsequent annealing S5-P15 N. Frolova, V. Zel'dovich, V. Pilyugin, V. Gyndurev, A. Patselov Amorphization of titanium nickelide by means of shear under pressure and crystallization upon subsequent heating S5-P16 S. Belyaev, V. Pilyugin, N. Resnina, V. Slesarenko, M. Drozdova Release of energy on heating Ti-50.2 at. % Ni alloy subjected to severe plastic deformation S5-P17 N. Kuranova, V. Makarov, V. Pushin, A. Uksusnikov Thermo- and deformation induced martensitic transformations in binary TiNi-based alloys, subjected severe [plastic deformation
S5-P18 S.V. Dobatkin, R.Z. Valiev, O.V. Rybalchenko, M.N. Pankova, N. Enikeev, M.M.Abramova Structure and martensitic transformations in austenitic 0.08% C-18% Cr-10% Ni-0.7% Ti steel during severe plastic deformation S8-P8 N.N. Popov, D.V. Presnyakov, V.F. Lar‟kin, A.A. Kostyleva Study of the effect, the rate of burnishing of clutches made of shape memory alloy, belonging to Ti-Ni-Nb system, poses on labor productivity as applied to the technology of thermo-mechanical joining of conduits
21 9th European Symposium on Martensitic Transformations ESOMAT 2012 September 12 16:30 – 18:30 "Petrov-Vodkin-1" hall, Hotel “Holiday Inn – Moskovskye Vorota” Session 12 “Mechanical behavior, shape memory effect, pseudoelasticity and other functional properties in TiNi based alloys”
S12 – P29 S. Belyaev, N. Resnina, A. Sibirev Unusual multistage martensitic transformation in TiNi shape memory alloy after thermal cycling S12 – P31 G.V. Markova, A.V. Shuytsev, A.V. Kasimsev Study of martensitic transformation in TiNi intermetallics by methods of low frequency internal friction S12 – P32 A. Fedotkin, V. Stolyarov Martensitic transformations upon combined effect of tension and pulse current in nanostructured TiNi alloy S12 – P34 B.V. Senkovskiy, D.Yu. Usachov, A.V. Fyodorov, A.V. Shelyakov, V.K. Adamchuk XPS and NEXAFS investigation of electron energy structure of TiNi and TiNiCu alloys S12 – P36 D. Salas, S. Kustov, E. Cesari, J. Van Humbeeck Isothermal transformations in Ni-Ti and Ni-Ti-X (X=Fe, Cu) alloys S12 – P38 S. Belyaev, N. Resnina, V. Rubanik, V. Rubanik (jr), O. Rubanik, I.Lomakin Properties of “Ti50Ni50 – Ti49.3Ni50.7” bimetal composite produced by explosion welding S12 – P40 S. Belyaev, N. Resnina, R. Zhuravlev Influence of stress regime on work performance during thermal cycling TiNi alloy S12 – P43 Won Ki Ko, Su Ho Park, Jae Il Kim Effect of time gradient annealing on shape memory characteristic of Ti-50.4 aT.% Ni alloys S12 – P48 S. Ribeiro, P. Rodrigues, C. Marques Fontanezzi, T. Gonçalves, C. Hauegen, P.A. dos Santos, H. Bernardi, J. Otubo, K. Mahesh, F.M. Braz Fernandes The influence of aging conditions in a superelastic Ni-Ti SMA alloy S12 – P50 А.А Potapova., V.V. Stolyarov, N.N. Resnina Influence of phase composition on deformability and shape memory properties in TiNi rolled with current S12 – P53 Hande Ozcan, Sule Cakmak, Benat Kockar The effect of aging and oxidation on the phase transformation behavior of porous NiTi shape memory alloy S12 – P55 S. Belyaev, N. Resnina, K.Anshukova Work performance in Ti-52 at. % Ni alloy in temperature range of B2R martensitic transformation S12 – P58 Y. M.M. De Guzman, and A.V. Amorsolo Jr. Synthesis and characterization of TITANIUM-NICKEL shape memory alloy via electrodeposition route S5-P14 V. Kalashnikov, P. Mazaev, A. Petrov, R. Gizatullin, V. Koledov Study of termomechanical properties of Ni49,8Ti50,2 shape memory alloy after intensive plastic deformation
Session 8 “Technological applications”
S8-P1 A. Bronz, L. Kaputkina, V. Kindop, D. Kremyansky, V. Prokoshkina, A. Svyazhin Effect of nitrogen addition on martensitic transformation and ε-martensite formation in Fe-Mn- Al-С alloys S8-P2 L. Kaputkina, V. Prokoshkina, G. Khadeev Effect of nitrogen addition on tempering and strain aging processes of thermomechanically strengthened structural steels S8-P6 Z.M. Blednova, P.O. Rusinov Superficial modifying by materials with SME in engineering appendices S8-P9 Edgar Apaza Huallpa, Hélio Goldenstein, Julio Capo Sanchez, Linilson R. Padovese Analysis of the first peak of Spontaneous Magnetic Emission (SME) corresponding to the martensitic start transformation in a Fe-Ni-C alloy S8-P10 Z.M. Blednova, N.A. Procenko Structurally-mechanical control reactionary ability safe devices accumulator lithium-ionic (LIA) of space appointment with use of alloys with effect of memory of the form
22 9th European Symposium on Martensitic Transformations ESOMAT 2012 S8-P12 V.A. Zavalishin, V.V. Sagaradze, N.V. Kataeva, S.U. Mushnikova, G.U. Kalinin Formation of deformation martensite and change of magnetic properties of high-nitrogen austenitic steels S8-O1 K. Lygin, P. Labenda, T. Sadek Prediction of transformation behavior of R-phase SMA actuators by the application of fuzzy logic S8-P3 A. Irzhak, V. Koledov, V. Shavrov, V. Afonina, D. Zakharov, V. Kalashnikov, A. Mashirov, M. Bekhtina, D. Kuchin Use martensite transition in a material with shape memory effect for micromanipulator creation
September 12 16:30 – 18:30 “Stenberg-1” hall, Hotel “Holiday Inn – Moskovskye Vorota” Session 3 “Mechanical behavior, shape memory effect, pseudoelasticity and other functional properties in Fe-based and other alloys”
S3-P1 Yonghua Rong, Ke Zhang, Jiawei Dai, Hailiang Yu The microstructural design and control of ultrahigh strength-ductility martensitic steels based on a novel quenching-partitioning-tempering process S3-P2 B. Pricop, U. Söyler, B. Özkal, N. M. Lohan, A. L. Paraschiv, M. G. Suru, L.-G. Bujoreanu Influence of mechanical alloying on the behaviour of Fe-Mn-Si-Cr-Ni shape memory alloys made by powder metallurgy S3-P3 Jindal Sandeep , Chhibber Rahul and Mehta N.P. Effect of flux constituents and basicity index on mechanical properties and microstructural evolution of submerged arc welded high strength low alloy steel S3-P4 A. Druker, P. La Roca, P.Vermaut, P. Ochin, J. Malarría Shape memory effect in melt spun Fe-15Mn-5Si-9Cr-5Ni alloys S3-P5 L. Dirand, M.L. Nó , A. Denquin, J. San Juan Internal friction in high temperature Ru-Nb shape memory alloys S3-P7 H.H.Bernardi, K.A. Käfer, L.K.F. Naito, J. Otubo Shape recovery in stainless Fe-Mn-Si-Cr-Ni(-Co) SMA processed by ECAE S3-P9 M. Benke, V. Mertinger, F. Tranta Examination of TRIP/TWIP effects in FeMn(Cr) austenitic steels S3-P10 S. Farjami, Yu. Tanaka, M. Mitsuhara, M. Itakura, M. Nishida, T. Fukuda, T. Kakeshita Variant selection during disorder-order transformation under a magnetic field in Fe-Pd alloy S3-P19 S.V. Afanasev, N.V.Kataeva, V.V.Sagaradze, Deformation twinning of ε –martensite and shape memory effect in Mn-V-C austenitic steels S9-P1 T. Castán, P. Lloveras, A. Planes, A. Saxena Precursor nanoscale textures in Ferroics
Session 11 “Thermodynamics and kinetics of martensitic transformations”
S11-P1 J.I. Pérez-Landazábal, V. Recarte, V. Sánchez-Alarcos, S. Kustov, D. Salas, E. Cesari Time dependences of magnetization during isothermal transformation of a Ni-Mn-In-Co alloy S11-P4 Daróczi Lajos, El Rasasi Tarek, Beke Dezső Effect of partial thermal cycles on non-chemical free energy contributions in polycristalline Cu- Al-Be shape memory alloy S11-P5 A. Kamancev, V. Koledov, E. Morozov, R. Antonov, V. Shavrov, A. Shelyakov, N. Sitnikov, A. Zhikharev Kinetics of phase transitions and fast shape memory actuation S11-P9 Jan Frenzel, Easo George, Christoph Somsen, Martin Wagner, Antonin Dlouhy, Gunther Eggeler On the influence of the Ni-concentration on the martensitic transformation in NiTi shape memory alloys S11-P11 M.C. Gallardo, F.J. Romero, J. Manchado, J.M. Martín-Olalla, A. Planes and E.K.H. Salje Calorimetric study of avalanche criticality in the martensitic phase transition of Cu67.64Zn16.71Al15.65
Session 6 “Medical applications”
23 9th European Symposium on Martensitic Transformations ESOMAT 2012 S6-P2 A. Danilov, V. Muhonen, J. Tuukkanen, T. Jämsä Role of phase stress in variations of cell behavior on NiTi S6-P3 K. Hiramatsu, M. Tahara, T. Inamura, H. Hosoda, S. Miyazaki Effect of cold-rolling rate on texture in Ti-Mo-Al-Zr Shape memory alloy S6-P4 M. Bönisch, C. Mickel, A. Panigrahi, M. Zehetbauer, T. Waitz, A. Gebert, M. Calin, W. Skrotzki, J. Eckert Phase stability and martensitic transformations in binary Ti-Nb alloys S6-P7 Yu. Zhukova, A. Konopatsky, Yu. Pustov Investigation of electrochemical behavior of novel superelastic biomedical alloys in aimulated physiological media
September 14 16:30-17:30 "Petrov-Vodkin-1" hall, Hotel “Holiday Inn – Moskovskye Vorota” Session 4 “Magnetic Shape memory alloys”
S4-P2 R. Coll, J. Bonastre, J. Saurina, L. Escoda, J.J. Suñol Martensitic transformation in Ni-Mn-Sn alloys S4-P3 T. Breczko, V.V. Barkaline , Y.V. Douhaya Modeling of smart material properties of Heusler alloys S4-P4 Y. Kishi, T. Kubota, Z. Yajima, T. Okazaki, Y. Furuya Microstructures of Fe-Pd Alloy ribbons subjected to rapidly solidified melt-spinning S4-P8 C. Picornell, J. Pons, A. Sozinov, E. Cesari Thermomechanical behaviour of Ni-Mn-Ga and Ni-Mn-Ga-Cu high temperature shape memory alloys S4-P10 L. Fekete, J. Kopeček, L. Straka, I. Kratochvílová, O. Heczko Magnetic domains structure in 10M martensite Ni-Mn-Ga observed by magnetic force microscopy S4-P11 K. Prusik, K. Bałdys, D. Stróż, T. Goryczka, J. Lelątko Microstructure studies of NiCoMnIn magnetic shape memory ribbons S4-P13 S. Taskaev, V. Buchelnikov, I. Bychkov, A. Pelennen, U. Pastushenkov, U. Koshkidko, V. Koledov, V. Shavrov, K. Skokov, V. Khovailo Magnetocaloric effect, magnetic and mechanical properties of cold rolled Gd ribbons S4-P14 V. Zhukova, M. Ilyn, J. del Val Juan, M. Ipatov, A. Granovski, A. Zhukov Magnetic and transport properties of cu-co microwires S4-P15 V. Recarte, V. Sánchez-Alarcos, J.I. Pérez-Landazábal, J.M. Pastor, E. Rubio, A. Urdiaín Effect of ti addition on the martensitic transformation and magnetic properties of Ni-Mn-In and Ni-Mn-Sn metamagnetic shape memory alloys S4-P16 V. Khovaylo, K. Skokov, O. Gutfleisch, X. Xu, T. Omori, R. Kainuma Adiabatic temperature change in Ni(Co)-Mn-Al Heusler alloys S4-P23 R. Fayzullin, V. Buchelnikov, S. Taskaev, M. Drobosyuk Magnetic properties and magnetocaloric effect in Ni2.27-xFexMn0.73Ga (x=0.03, 0.06, 0.09) Heusler alloy S4-P24 K. Akatyeva, V. Afonina, A. Irzhak,V. Khovailo, V. Koledov, V. Shavro , S. von Gratowski, F. Albertini, S. Fabbrici Shape memory effect in microsized samples of ferromagnetic Heusler alloys S4-P31 E. Timofeeva, E. Panchenko, Yu. Chumlyakov, H.J. Maier, N. Vetoshkina Orientation dependence of stress-induced martensitic transformation in NiFeGa ferromagnetic single crystals S4-P32 Y.G. Cui, J.F. Wan, Y.H. Rong, J.H. Zhang The martensitic transformation and antiferromagnetic transition in Mn86.4Fe9.1Cu4.5 alloy
September 14 16:30-17:30 “Stenberg-1” hall, Hotel “Holiday Inn – Moskovskye Vorota” Session 9 “Theory and modeling of mechanical and functional properties”
S9-P2 Sung-Young Young, Tae-Hyun Nam Finite element calculation of B2 to R transformation of shape memory alloy
S9-P6 S. Prüger, M. Kuna Meinhar A material model for trip-steels under thermomechanical loading
24 9th European Symposium on Martensitic Transformations ESOMAT 2012 S9-P7 S. Jaeger, O. Kastner, G. Eggeler FEM simulation of transient heat transfer in SMA plates exhibiting single-step and two-step martensitic transformations S9-P8 P. Terriault, V. Brailovski Implementation of the general 3D formulation of Likhatchev’s model into a finite element program
Session 10 “Theory of martensitic transformations”
S10-P3 V. Gundyrev, V. Zel'dovich About the mechanism of deformation at martensitic transformation in the Fe-31%Ni alloy S10-P6 Yu.N. Vyunenko Evolution of the residual stress field at the realization of the shape memory effect S10-P8 Calciolari, Ribeiro Shimeni, dos Santos Paula, Andersan, da Costa Viana, C. Sérgio, Rangel Rios, Paulo Crystallographic analysis of martensitic transformation by EBSD in Fe-31.9Ni-0.02C alloy
Session 2 “Mechanical behavior, shape memory effect, pseudoelasticity and other functional properties in Cu-based alloys”
S2-P2 Y.V. Kudryavtsev, V.V. Kokorin, L.E. Kozlova, V.N. Iermolenko, S.M. Konoplyuk Effect of martensitic transformation on the optical spectra of Cu-Mn-Al alloy S2-P5 J. F. Gómez-Cortés, J. San Juan, G.A. López, M. L. Nó Obtention and characterization of Cu-Al-Ni thin films S2-P7 Y. Amiour, K. Zemmour, M. Guerioune, D. Vrel Shape memory alloy CuZnAl: Synthesis and Characterization S2-P8 N. Egido-Pérez, J. San Juan, G. A. López, M.L. Nó Characterization of Cu-Al-Ni SMA with a high ni content S2-P9 G. Markova, E. Klueva Iternal friction during reverse martensitic transformation in Mn-Cu alloy with 45 % Mn S2-P10 Almadrones, L. Emma, Espiritu, D.V. Richard, Amorsolo, V. Alberto Characterization of Cu-Zn-Al shape memory alloy fabricated via electrodeposition-annealing route
25 9th European Symposium on Martensitic Transformations ESOMAT 2012
26 9th European Symposium on Martensitic Transformations ESOMAT 2012
Book of Abstracts
27 9th European Symposium on Martensitic Transformations ESOMAT 2012
28 9th European Symposium on Martensitic Transformations ESOMAT 2012
Plenary lectures L1, L2
AN INTERPRETATION FOR KINETICS OF MARTENSITIC TRANSFORMATIONS Kakeshita Tomoyuki, Fukuda Takashi, Lee Yong-hee Department of Materials Science and Engineering, Graduate School of Engineering, Osaka University, 2-1, Yamada-oka, Suita, Osaka, 565-0871 Japan [email protected]
Martensitic transformations have been classified into two groups, athermal and isothermal ones, from the view point of kinetics. This classification may not be intrinsic because an isothermal transformation changes to an athermal one and vice versa by the application of external fields such as magnetic field and hydrostatic pressure [1]. This finding suggests that any martensitic transformation is intrinsically an isothermal one, but appears to be an athermal one in many cases because of undetectably short incubation time. In this presentation, we will demonstrate several examples of isothermal nature observed in alloys which are so far considered to exhibit an athermal transformation. That is, we will show that thermoelastic transformations in some shape memory alloys (SMAs), such as Cu-Al-Ni and Ni-Co-Mn-In alloys, proceed isothermally after some incubation time although each alloy has a so-called martensitic transformation start temperature (Ms) when it is cooled with a constant rate. In addition, we will demonstrate that the first order magnetic transition of FeRh also show clear time dependence. These results are explained by a statistical thermodynamic model derived by the authors.
[1] T. Kakeshita, T. Saburi, K. Kindo, S. Endo, Phase Transitions, 70 (1999), 65-113.
ISOTHERMAL DIFFUSIONLESS MARTENSITIC TRANSFORMATIONS IN SHAPE MEMORY ALLOYS Kustov S., Salas D., Cesari E. Universitat de les Illes Balears, Palma de Mallorca, Spain [email protected]
Recent experimental results indicate that a number of diffusionless martensitic transformations (MT) in classical shape memory alloys (SMA), like binary and ternary ones belonging to the Ni-Ti system, which were thought to be athermal actually demonstrate isothermal behaviour [1]. Similar features are found in metamagnetic SMA from the Ni-Mn-X family [2]. We present and analyze here experimental data on the kinetics of isothermal MT in conventional Ni-Ti and Ni-Ti-X (X=Fe, Cu) as well as in metamagnetic Ni-Mn-In and Ni-Mn-In-Co alloys. We found similar essential details in kinetics of isothermal diffusionless MTs in metamagnetic and conventional SMA. First, isothermal effects can be observed during both direct and reverse MTs and are restricted to the temperature range between the start and finish of the MT as detected by calorimetry. The intensity of isothermal effects is found to be essentially proportional to the heat flow. Over the major part of the MT range, isothermal effects follow a logarithmic kinetics, pointing to the existence of an energy landscape with a broad distribution of activation energies. Deviations from the logarithmic kinetics are observed close to the finish temperature of the MT and can be attributed to the appearance of a certain “incubation time”. We show that a correlation exists between the width of the transformation range and athermal or isothermal nature of the diffusionless MT. This fact, together with proportionality between the MT rate in a continuous cycle and the intensity of isothermal effects and also observations of the isothermal reverse MT, allows us to attribute isothermal features of diffusionless MTs to the thermally activated motion of interphase boundaries. The appearance of the “incubation time” in this framework can be interpreted as a depletion of the energy landscape with low activation energy configurations close to the finish temperature of the MT. Possible role of thermally activated nucleation events is discussed.
[1] S. Kustov et al. Scripta Mater. 2010;63:1240; S. Kustov et al. Acta Mater., accepted. [2] S. Kustov et al. J. Appl. Phys. 2010;107:053525.
29 9th European Symposium on Martensitic Transformations ESOMAT 2012
Plenary lectures L4, L5
COPPER BASE SMA: FROM MACROSCOPIC PROPERTIES TO NANO-SCALE BEHAVIOR Jose San Juana, Maria L. Nób aDpt. Fisica Materia Condensada, Facultad de Ciencias, Universidad del Pais Vasco, Aptdo. 644, 48080 Bilbao, SPAIN bDpt. Fisica Aplicada II, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, Aptdo 644, 48080 Bilbao, SPAIN [email protected] , [email protected]
Copper based shape memory alloys (SMA) are being developed as an alternative to the classical Ti-Ni SMA, for functional applications at low and medium temperatures, specially in between 100ºC and 200ºC, which is an important temperature range for many applications in several industrial sectors such as aeronautic, aerospace and automotive. The main drawback of Cu-based SMA is their intrinsic brittleness in polycrystalline state, being at present responsible of a lack of commercial products. However research performed along the last decades has allowed new technological solutions, from powder metallurgy to single crystal growth, offering new performances of Cu-based SMA. In the present lecture we will overview the last developments in Cu-SMA, in particular from the families of Cu-Al-Ni and Cu-Al-Be as well as more complex systems, outlining the main advantages that can be exploited from each family, in comparison with Ti-Ni SMA. Superelasticity, shape memory and damping properties will be overviewed. Another cutting-edge field for SMA is the research of their behavior at micro and nano-scale for applications as sensors and actuators in Micro Electromechanical Systems (MEMS). Recent works in this field [1,2] show that Cu-Al-Ni SMA exhibit very good superelastic and shape memory effects at micro and nano-scale, attracting a renewed interest on this system. We will also overview in the present lecture the behavior of Cu-based SMA at micro and nano-scale discussing the potentiality of such systems for practical applications.
[1] J. San Juan, M. L. Nó and C. A. Schuh, Nature Nanotechnology, 4 (2009) 415-419. [2] J. San Juan, M. L. Nó and C. A. Schuh, J. Materials Research, 26 (2011) 2461-2469.
RECENT PROGRESS AND FUTURE PERSPECTIVES IN MAGNETIC SHAPE-MEMORY HEUSLER ALLOYS Antoni Planes Departament d’Estructura i Constituents de la Matèria. Facultat de Física. Universitat de Barcelona. Diagonal 645. 08028 Barcelona. Catalonia [email protected]
The magnetic shape-memory effect was first reported in 1996 by the group of Bob O‟Handley at MIT. They proved that large deformations can be induced by application of a moderated magnetic field in the martensitic phase of a Ni2MnGa ferromagnetic Heusler alloy. At present many other materials displaying similar behaviour have been developed. In general, magnetic shape-memory properties refer to the ability of certain materials to show strong response in strain to an applied magnetic field. This strain is caused by either field inducing the martensitic transition or rearranging martensitic variants. In the first case a superelastic effect is possible, while in the second the system is able to show the shape-memory effect. The complex behavior displayed by these materials is mainly a consequence of a strong interplay between magnetism and structure which is driven by a martensitic transition. This interplay is the source of many other observed effects such as giant magneto-resistance, exhange bias and magnetocaloric effects. The investigation of magnetic shape-memory materials is an expanding field of research involving great richness of basic physics together with technologically interesting possibilities for applications of their multifunctional behavior. In my lecture, I will overview the present state of the art of the field focusing particularly on the nature of the magneto-structural interplay, phase diagrams and mechanical, magnetic and thermal properties of this class of materials. Finally, I will discuss some present challenges and outline future perspectives in the field.
30 9th European Symposium on Martensitic Transformations ESOMAT 2012
Plenary lectures L6, L9
NANO- AND MICROCRYSTAL STRUCTURE INVESTIGATIONS OF INTERFACES, GRADIENT AND STRAIN FIELDS IN MARTENSITIC MATERIALS BY VARIOUS EM TECHNIQUES Dominique Schryvers EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium [email protected]
Optimization of materials for dedicated applications through, for example, thermo-mechanical treatment typically yields micro- and/or nanostructures that need to be investigated with high-resolution instrumentation in order to elucidate and understand the chemical constituents and their exact atomic configurations inside the different components or, often more importantly, at and around the interfaces between these components. Our recent work has focused on ternary alloys based on the omnipresent Ni-Ti system, aiming for an adapted hysteresis towards low values, following the 2 = 1 concept in which a perfectly coherent untwinned martensite is formed, and on the Ni-Ti-Nb system in which large amounts of incoherent nano-precipitates are seen to hinder the transformation resulting in a slight increase of hysteresis. Samples of different compositions and with different heat treatments are investigated by DSC and various TEM and FIB/SEM methods to elucidate the relation between nano- and microstructure and the martensitic transformation behaviour.
In single crystal Co-Al-Ni samples ‟ L12 precipitates can form varying from large interdendritic shapes to smaller sheet-like ones with internal twins, both revealing the K-S orientation relationship with the austenite matrix. The occurrence of the internal twin clearly affects the outer shape of the precipitate, including facets and re-entrant grooves leading to fast growth along particular directions. When the precipitate is embedded inside a martensite matrix, a sandwiched retained austenite region is often observed between the precipitate and twinned martensite due to a strong change in local composition resulting from the Co-depletion and Al-enrichment of the matrix near to the precipitate. In order to better understand the concept of strain glass, binary Ni-Ti samples of different compositions have been investigated by quantitative high-resolution Cs-corrected TEM. First results indicate that small pockets of around 3 nm in diameter reveal strained lattice in 51.7 at.%Ni and that the lattice displacements measured at room temperature in the 51.7 at.%Ni sample are about twice as large as those measured in the 50.8 at.% sample.
BULK AND POROUS METASTABLE BETA Ti-Nb-Zr(Ta) ALLOYS FOR BIOMEDICAL APPLICATIONS: PROCESSING, STRUCTURE AND MECHANICAL PROPERTIES Brailovski Vladimira, Prokoshkin Sergeyb, Inaekyan Karinea, Dubinskiy Sergeya,b, Korotitskiy Andreyb, Petrzhik Mikhailb, Filonov Mikhailb a Ecole de Technologie Superieure, Montreal (Quebec), Canada bNational University of Science and Technology "MISIS", Moscow 119049, Russia [email protected]
In this work, TNZ: Ti-(18...22)Nb-(5...6)Zr and TNT: Ti-(19.5…21)Nb-(6.5…7)Ta (at%) ingots were manufactured by vacuum and argon arc melting. Both alloys were cold-rolled (CR) from 30 to 85% of thickness reduction, annealed in the 450 to 900oC temperature range (10‟-5h) and aged at 300oC (15‟-3h). Selected TNZ ingots were atomized using Rotating Electrode Process (REP) to produce 100 micron size powders. Both TNZ and TNT alloys subjected to CR of 30% and post-deformation annealing (TNZ: 600oC, 30‟; TNT: 500oC, 1h) possessed polygonized dislocation substructure (average subgrain size 100 nm) and manifested perfectly superelastic behavior during RT cyclic testing. Young‟s modulus of TNZ alloy was higher, while ultimate tensile strength (UTS) was lower than that of TNT alloy: 40 GPa > 30 GPa, while 400 MPa < 500 MPa. After aging treatment, Young‟s modulus of both alloys increased and reached 55 GPa, while their mechanical behavior was impacted differently: it was detrimental for TNZ and beneficial for TNT. After 300oC, 1h aging, TNZ behavior become brittle because of a decreased difference between UTS and transformation yield stress (620-550 MPa), whereas superelasticity of TNT was improved (UTS-trans.stress= 550 MPa-200 MPa). The different influence of aging on the mechanical behavior of both alloys is explained by the specificity of , and ” phases formed during aging and their effect on transformation temperatures. TNZ powder was used to manufacture open-cell foam of 45% porosity (cell size from 150 to 550 microns) using a polymer-based foaming agent. After sintering, this foam was thermally treated at the same temperature as the bulk alloy (600oC) and its tensile, compressive and flexural behaviors were compared with those of Ti-CP foam of the same porosity. For TNZ foams, the highest apparent Young‟s modulus was observed with the as-sintered material (8-12 GPa) and the lowest was observed after annealing at 600oC (5-7 GPa). As for Ti-CP foams, their Young‟s modulus remained stable regardless of the heat treatment conditions: it varied between 10 and 14 GPa depending on the deformation mode.
31 9th European Symposium on Martensitic Transformations ESOMAT 2012
Plenary lectures L11, L8
MEDICAL AND TECHNICAL ASPECTS OF TiNi APPLICATIONS Khmelevskaya Irina National University of Science and Technology “MISIS”, Moscow, Russia [email protected]
The main fields of the practical application of TiNi- based alloys with shape memory and superelasticity effects in engineering and medicine have been identified in the past decade. There are temperature-sensitive elements for the actuators, damping devices, fasteners, medical instruments and implants (correctors, clamps, stents) for trauma, spine, dentistry, soft tissues and vessels. The development of science and high technologies to produce semi-finished (thin-walled tubes, tapes and thin wire), as well as processing methods (laser cutting and welding) of TiNi-based SMA over the last 10 years contributed to the creation and implementation into clinical practice more complicated and advanced devices based on solid and porous shape-memory materials, as well as tissue (metal- textiles) and knitted (metal-jersey) implants, which led to the development of reconstructive surgery. The accumulated experience and long-term effects on the biocompatibility of installed implants permanently expands the geography of production (for example, in Russia, see Fig. 1). The annual volume of supplies of different types of implants to Europe and Asia only from Russia amounts tens of thousands of articles.
Fig.1. Location of Russian medicine centers using, SME devices and implants
This review examines the conditions which determine the mechanical and chemical biocompatibility of implants. Development and use of implants, devices and instruments for cardiovascular surgery, endoscopy and laparoscopy in urology and gastroenterology, in other areas of medicine are discussed. Special attention is paid to the description of technique of new devices creation and methods of their medical applications. Various examples of their practical application are presented.
MECHANICAL BEHAVIOR, SHAPE MEMORY EFFECT, PSEUDOELASTICITY IN Ti-BASED ALLOYS Shuichi Miyazakia,b, Hee Young Kima aDivision of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan bSchool of Materials Science and Engineering, Gyeongsang National University, Jinju, Gyeongnam 660-701, Korea [email protected]
The Ti-Ni alloys have been successfully applied as biomaterials such as orthodontic arch wires, guide wires and stents in addition to many engineering applications. However, it has been pointed out that pure Ni is a toxic element and causes Ni-hypersensitivity. Although the Ti-Ni alloys are considered as safe in the human body based on experience and scientific consideration, in order to solve the psychological problem on the risk of Ni- hypersensitivity, Ni-free -Ti SM and SE alloys have been recently developed. The Ni-free Ti-based alloys have not been used for applications yet, but will be used for medical applications in the near future. In this presentation, the history of the development of Ti-based alloys including Ti-Ni and -Ti alloys is reviewed, then the basic characteristics such as the martensitic transformation and shape memory properties of the -Ti alloys are explained in addition to recent reserch results of these alloys.
32 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 12 - O1, O2
SELF-ACCOMMODATION OF B19’ MARTENSITE IN Ti-Ni ALLOYS: PART 1 EXPERIMENTAL APPROACH M. Nishidaa, T. Inamurab, Y. Soejimaa, T. Nishiuraa, H. Kawanoa, T. Harac aDepartment of Engineering Science for Electronics and Materials, Faculty of Engineering Science, Kyushu University, Kasuga, Fukuoka, 816-8580, Japan bPrecision and Intelligence Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226- 8503, Japan cNational Institute for Materials Science, Tsukuba 305-0047, Japan [email protected]
The microstructure of the martensite in shape memory alloys is characterized by the combination of multiple habit plane variants (HPVs) to minimize the elastic strain energy upon transformation, which is so-called self- accommodation (SA). In the present study, the SA morphology of the B19' martensite in Ti-Ni alloys is systematically investigated by scanning electron microscopy (SEM), conventional transmission electron microscopy (CTEM) and scanning transmission electron microscopy (STEM). There are twelve pairs of the minimum SA unit consisting of two HPVs with V-shaped morphology connected to a {-1-11}B19' Type-I variant accommodation twin. It is found that an ideal SA morphology consists of three V-shaped units, i.e., a total of six HPVs, clustered around one of the {111}B2 traces with hexagonal shape. Triangular and rhombic SA morphologies are also observed. It is revealed that there are four kinds of characteristic HPVs interface to complete the SA morphologies. The variant selection rule and the number of possible HPV combinations in each of these self-accommodation morphologies are discussed. Three dimensional SA morphologies are also investigated by the novel SEM technique. The proposed models are rationalized by the phenomenological theory of martensite crystallography and the geometrically nonlinear theory, which will be presented in Part II of this series.
SELF-ACCOMMODATION OF B19’ MARTENSITE IN Ti-Ni ALLOYS: PART 2 THEORETICAL ANALYSIS Tomonari Inamuraa, Tomohiro Nishiurab, Hideto Kawanob, Hideki Hosodaa Minoru Nishidab aPrecision and Intelligence Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226- 8503, Japan bDepartment of Engineering Science for Electronics and Materials, Faculty of Engineering Science, Kyushu University, Kasuga, Fukuoka, 816-8580, Japan [email protected]
The competition among the invariant plane (IP) condition at the habit plane, the twin orientation relation (OR) and the kinematic compatibility (KC) at the junction plane (JP) of self-accommodated B19‟ martensite in Ti-Ni was investigated by means of geometrically nonlinear theory in order to understand the habit plane variant (HPV) clusters presented in Part I of this work. As the IP condition cannot be satisfied simultaneously with KC, an additional rotation Q is necessary to form compatible JPs for all HPV pairs; Q ≠ I, where I is identity matrix. The rotation J necessary to form the exact twin OR between the major correspondence variants (CVs) in each HPV was also examined. There is no twin OR between the major CVs in HPVs when the IP condition at the habit plane is satisfied (J ≠ I). These results mean that fully compatible HPV cluster with a JP keeping twin OR is impossible in Ti-Ni. However, there exist special pairs of HPVs that satisfy the twin OR and KC conditions at the JP simultaneously by identical rotation (Q = J). The preferentially observed HPV cluster that is coupling of two HPVs was not the cluster with the smallest Q but the one satisfying Q = J with a {-1 -1 1}B19‟ type I twin at JP. These results indicate that both Q and J are crucial to understanding the various HPV clusters in realistic transformations. The geometry of JP in the HPV clusters that are formed by three, four or six HPVs is also discussed.
33 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 12 – O3, O4
STUDY OF NICKEL SEGREGATION AT THE TiNi-TITANIUM OXIDE INTERFACE Kulkova S.E.a,b, Bakulin A.V.a, Dudkin I.V.a, Hu Q.M.c a Tomsk State University, Tomsk, Russia b Institute of Strength Physics and Material Science SB RAS, Tomsk, Russia c Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, China [email protected]
It is well-know that TiNi intermetallic alloy is covered by a thin passive layer of TiO2 that provides the biocompatibility of the alloy. In order to understand at the microscopic level the formation of the alloy-oxide interface, it is necessary to study the interaction of oxygen with the alloy surface as initial stage of this process. In the present work, we investigated the oxygen adsorption on TiNi(110) surface in dependence on the oxygen concentration, which allows us to suggest a model for the TiNi/TiO2 interface. The calculations of atomic and electronic structure of clean TiNi (110) surface and with adsorbate as well as alloy-oxide interface were carried out by using ab-initio method within density functional theory. It was shown that, the pseudo threefold-coordinated hollow site is preferable for the oxygen adsorption on the alloy surface. During relaxation, the oxygen atom shifts to this hollow position, inside a triangle formed by two Ti atoms and one Ni atom, from the initial Ti-Ni bridge position. The interaction of alloy surface with oxygen leads to the displacement of Ti surface atoms towards the vacuum whereas Ni atoms shift oppositely into the bulk. It is shown that the breaking of Ti-Ni bonds is observed upon increasing O concentration. The formation of the first oxide layers leads to depletion of Ti atoms at the interface, and as a consequence, to the formation of the Ni-rich interface. Two models of TiNi/TiO2 interface were considered. The analysis of electronic characteristics at the interface, surface and bulk were performed. The formation energies (Ef) of Ni-antisite defect, i.e., the Ni atom replacing the Ti one, in TiO and TiO2 as well as TiNi/TiO2 interface were calculated. It was shown the Ef of Ni antisites is lower in TiO (3.05 eV) in comparison with TiO2 (7.51 eV). The influence of oxygen vacancies on the defect formation energies was considered as well. Our results reveal that Ef of Ti-Ni swap defect is lower that that of Ni antisites at the alloy-oxide interface. The mechanism of the Ni atom segregation inside oxide layers is discussed. The increase of the formation energies of defects in the fully stabilized TiO2 layers indicates the increase of diffusion barriers of Ni in TiO2 as compared to TiOx, which results in the decrease of Ni segregation.
THE INVESTIGATION OF SUBSURFACE GRADIENT STRUCTURES IN THE SILICON-COATED TINI ALLOY USING EBSD AND X-RAYS TECHNIQUES Ludmila Meisnera, Alexander Lotkova, Stanislav Meisnera, Yurii Mironova, Nikolai Sochugovb, Alexander Solov’evb aInstitute of strength physics and materials science of SB RAS, Tomsk, Russia bInstitute of high-current electronics of SB RAS, Tomsk, Russia [email protected]
Today, for maintenance of certain properties on a surface of metal materials methods of ion-plasma magnetron deposition are widely used. A results of experimental study of structural conditions in layers which are formed in the coatings, intermediate zones and in the subsurface layers of a substrate material contacting to a coating are a fundamental basis for creation by these methods of coatings with high parameters of plasticity and durability, corrosion resistivity, having high adhesive properties. The purpose of this report – to present the results of the investigation of gradient structures that were formed in the subsurface area of the Si-coated TiNi alloy. The Silicon coatings by the thickness of 100–150 nm on the TiNi samples surface were formed by the ion-plasma magnetron deposition method. One part of the Silicon-coated TiNi samples was surface modified using the high dozen ion implantation regime. The study of the synthesized subsurface gradient structure was made using SEM EBSD and X-rays diffraction techniques. It was found that after deposition of the Si-coatings on the TiNi sample surface in all samples the subsurface area directly under the coating was splitted into layers differing by their substructure. Moreover, an intermediate layer by thickness in 2-3 grains of the basic B2-phase located on some excision from a surface was observed. In this layer, except B2 phase (the main phase of the TiNi substrate material) there are both R and B19‟ martensitic phases induced due to internal stress. After disappearance these phases the internal border is formed. We conclude that the typical changing of subsurface structure can be described within the limits of the multilevel approach. Level I (macroscopic) is shown at construction of the Crystal Orientation maps. Level II (mezoscopic) is shown in the form of presence disorientations in separate grains of phase B2 which can be taped using construction of Cubic Rodrigues-Frank orientation maps. Level III (microscopic) is identified by the analysis a crystalline lattice disorientations using Euler angle coloring maps.
34 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 12 – P39, O6
ON THE EFFECT OF MICROSTRUCTURES AND MARTENSITIC TRANSFORMATIONS ON STRUCTURAL FATIGUE OF NITI SHAPE MEMORY ALLOYS Mustafa Rahima, Jan Frenzela, Matthias Frotscherb, Rainer Steegmüllerc, Markus Wohlschlögelc, Gunther Eggelera a Ruhr-Universität Bochum, Bochum, Germany b Cortronik GmbH, Rostock-Warnemünde, Germany c Admedes Schuessler GmbH, Pforzheim, Germany [email protected]
In the present work, we investigate how the formation and propagation of fatigue cracks in pseudoelastic NiTi shape memory alloys (SMAs) depends on microstructures with different TiC and Ti2Ni(Ox) inclusion concentrations, and on stress induced martensitic transformations. NiTi SMA wires with different oxygen and carbon impurity levels (both ranging from 0.004 to 0.05 wt.%) were prepared by arc melting and wire drawing in combination with heat treatments. Structural fatigue testing was carried out by bending rotation fatigue using electropolished samples, and the resulting fracture surfaces were characterized through scanning electron microscopy. A special attempt was made to assess the number of cycles for both crack initiation and crack propagation by measuring fatigue striation widths. It was observed that the total number of cycles to rupture strongly decreases once the strain amplitude is high enough to trigger a stress induced martensitic transformation. During mechanical cycling at high strain amplitudes, fewer cycles are required for crack initiation as in the case of lower strain amplitudes. It was found that the formation of fatigue cracks depends on the microstructure of the material. In the case of oxygen-rich wires, Ti2Ni(Ox) particles were frequently identified as crack initiation sites.
“STRAIN GLASS”: REVISITED Kustov S. a, Salas D. a, Cesari E. a, Santamarta R. a, Mari D. b, Van Humbeeck J. c aUniversitat de les Illes Balears, Palma de Mallorca, Spain bEcole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland cKatholieke Universiteit Leuven, Leuven, Belgium [email protected]
A concept of “strain glass” in Ni-rich Ni-Ti binary alloys has been introduced [1] based on experimental observations, of a frequency-dependent minimum in the temperature dependence of the Young´s modulus (YM) together with a non-Arrhenius internal friction (IF) peak on the low-temperature side of the YM minimum. The “strain glass” concept is critically revisited here, using the results of detailed studies of elastic and anelastic properties of a series of binary Ni-Ti alloys with Ni content between 51.8 and 50.8 at% by means of 4 different acoustic techniques covering the range of frequencies from infra- to ultrasonic ones. Data on electric resistivity, calorimetry tests and high resolution transmission electron microscopy observations are used to reveal the occurrence of the martensitic transformation/premartensitic effects in the studied alloys. We show, firstly, that the position of the IF peak attributed to a transition to the “strain glass” state is not related to the position of the YM minimum: for ultrasonic frequencies, the IF peak is situated well above the temperature of the YM minimum. Secondly, even for the alloys with the highest Ni content, the transient (depending on temperature scan rate) IF component plays a significant role on the low-temperature side of the IF peak and affects its temperature. Thirdly, for the same alloy composition, the magnitude of the peak decreases strongly with temperature increase (which occurs due to the peak shift with frequency) and increases with the decrease of Ni content. These facts and a number of additional new observations evidence that the IF peak previously attributed to a transition to the strain glass state is a relaxation peak which is present in all binary alloys studied, independently of their composition, thus throwing into doubt the “strain glass” concept. Relaxation phenomena, as well as the transient IF term, can be attributed to the existence of nm-size R-phase like domains. A simple phenomenological model considering a combination of a relaxation and a frequency-independent YM temperature minimum quantitatively accounts for the experimental data observed.
[1] S. Sarkar, X. Ren, K. Otsuka, Phys. Rev. Letters, 95, 205702 (2005).
35 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations , Session 12 – P35, O9
NEW EXPERIMENTAL RESULTS ON THE INFLUENCE OF ALLOY COMPOSITION ON PHASE TRANSITION TEMPERATURES IN NITICU ALLOYS Burkhard Maass, Jan Frenzel and Gunther Eggeler Institute for Materials, Ruhr Universität, 44780 Bochum, Germany [email protected]
In the present study, we investigate the effect of Ni-content on the transformation temperatures of NiTiCu shape memory alloys (SMA). In binary NiTi SMAs, the Ni-concentration has a strong influence on the phase transformation temperatures (PTTs) of the martensitic transformation on cooling and the reverse transformation on heating. A decrease in Ni-concentration by 0.1 at.% can affect the transformation temperatures by approximately 10K [1]. Since the first studies on the effects of Cu additions to binary NiTi were published at the end of the 1970s, it has been widely believed that the addition of Cu strongly reduces the sensitivity of the transformation temperatures to the Ni-content. However, no systematic study has been published so far. In the present work, NiTiCu SMAs with different Ni and Cu levels were prepared by arc melting and subsequently homogenized in evacuated quartz tubes. The PTTs were measured using differential scanning calorimetry (DSC). Our data clearly show that the PTTs decrease with increasing Ni-content for NiTiCu SMAs with 0, 5 and 10 at.% Cu (replacing Ni). Our results confirm that Cu reduces the sensitivity of the PTT on the Ni-content. However, this effect is much smaller than implied by the work of Mercier and Melton in 1978 [2]. We discuss the obtained results in the light of the work by Liu [3], which states that the PTTs depend on the valence electron concentration cV.
[1] J. Frenzel, E.P. George, A. Dlouhy, Ch. Somsen, M.F.-X. Wagner and G. Eggeler Acta Materialia 58, (2010) pp. 3444-3458 [2] O. Mercier and K.N. Melton Metallurgical Transactions A 10A, (1979) pp. 387-389 [3] M. Zarinejad and Y. Liu: Advanced Functional Materials 18, (2008) pp. 2789-2794
TRANSFORMATION BEHAVIOR OF POROUS NiTi SHAPE MEMORY ALLOY Benat Kockar, Hande Ozcan, Sule Cakmak Department of Mechanical Engineering, Hacettepe University, 06800, Ankara, Turkey [email protected]
A great effort has been performed to produce porous Ti-based shape memory alloys using different powder metallurgy techniques for extending their applications in medical industry due to their high biomechanical compatibility. Additionally, the porous structure is suitable for the growth of bone tissue and the transport of body fluids through the interconnected pores. In this study, we aim to control the porosity level and pore size of the NiTi alloys using conventional powder metallurgy process via space holder technique. Prealloyed Ti-50.4%Ni powder having an average size of 20 micron is mixed with pure Magnesium powder. The samples are cold compacted and then sintered under argon atmosphere using a vertical furnace at 1200°C. The porosity levels of the samples are 30% and 60% and these percentages are achieved using %30 and %60 magnesium powder in the mixtures. Magnesium powders are evaporated during heating the samples from room temperature to 1200°C. Differential scanning calorimetry and Scanning Electron Microscope are utilized to characterize the transformation temperatures and microstructures of the samples, respectively. The changes in the thermomechanical response of the samples with different porosity levels, resulting from thermal cycling under constant tensile stress levels are also determined via conduction heating-cooling cycles. It is observed that the irrecoverable strain levels are very low and the shape memory behavior of the samples with two different porosity levels is stable. The transformation strain level of the sample with %30 porosity is around %4.5 and decreases with the increase in porosity percentage. However, the decrease in transformation strain level with the increase in the amount of porosity is reasonable since the amount of transforming martensite decreases. Therefore, porous NiTi alloys are possible candidates in the production of implants for certain applications in medical industry.
36 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentation, Sessions 12 – P23, O11
IDENTIFICATION AND INTERPRETATION OF MATERIAL PARAMETERS A SHAPE MEMORY ALLOY MODEL B. Piotrowski, Y. Chemisky, F. Meraghni, R. Echchorfi, N. Bourgeois, E. Patoor Laboratoire d’Etude des Microstructures et de Mécanique des Matériaux (LEM3), Paul Verlaine University, Arts et Métiers ParisTech, CNRS, 4 rue Augustin Fresnel; 57078 Metz, France [email protected]
The thermomechanical behavior of Shape Memory Alloys (SMAs) is described by many micromechanical and phenomenological models. The first ones have material parameters whose physical meaning is based on the crystallography of the phase transformation related to the studied alloy. In contrast, phenomenological models often have material parameters whose physical meaning is not obvious and that makes them difficult to identify, some of which are based on mathematical considerations. In this paper, we propose to use the formulation of the phenomenological model of Chemisky et al., and to consider the particular case of a superelastic SMA. In this case, the constitutive equation should be easily expressed analytically through the strain tensor as a function of applied load direction and material parameters. The behavior is then characterized by a complete and proportional loading. This analytical model contains 8 material parameters, 2 related to the elasticity and 6 to the phase transformation. Based on several isothermal tensile tests at various temperatures, material parameters of this model are identified using the Levenberg-Marquadt algorithm and an analytical calculation of the sensitivity matrix. Their physical meaning and their influence on the thermomechanical behavior of the alloy studied are then highlighted and discussed.
EVOLUTION OF TEMPERATURE PROFILES DURING STRESS-INDUCED TRANSFORMATION IN NiTi THIN FILMS B. Kreveta, V. Pinnekera, M. Rhodeb, C. Bechtholdc, E. Quandtc and M. Kohla aKarlsruhe Institute of Technology, IMT, P.O. Box 3640, 76021 Karlsruhe, Germany bKarlsruhe Institute of Technology, IAM, P.O. Box 3640, 76021 Karlsruhe, Germany cChristian Albrecht University Kiel, Institute for Material Science, 24143 Kiel, Germany [email protected]
This paper presents a time-resolved investigation of tensile loading induced temperature profiles in pseudoelastic NiTi thin films. The NiTi thin films have been prepared by DC magnetron sputtering and subsequent rapid thermal annealing. The chemical composition has been determined by EDX to be Ni50.4Ti49.6. Tensile specimens have been prepared by optical lithography and sacrificial layer etching. Tensile loading experiments are performed in strain control mode at room temperature. During loading, temperature profiles are monitored by infrared thermography using strain velocities up to 3.3·10-2 s-1. For increasing strain, the stress-induced forward transformation starts at the clamping jaws due to unavoidable slightly asymmetric loading conditions. The transformation front propagates to the center of the specimen and broadens due to heat conduction. A maximum temperature increase of 17 K is observed for the maximum strain rate. After sufficient holding time in strained state to allow for cooling back to room temperature, the strain is released. During the corresponding reverse transformation a maximum temperature decrease of 9 K occurs. A finite element macromodel is presented and discussed that accounts for the different effects of local generation of latent heat and heat transfer. The observed elastocaloric properties of NiTi thin films are of considerable interest to solid state cooling and heat pumping in miniature dimensions.
37 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 12 - O12, O13
EFFECT OF THE WARM ITHOTHERMAL ROLLING ON MICROSTRUCTURE AND MARTENSITIC TRANSFORMATION IN TiNi-BASED ALLOYS Lotkov Aleksandera, Koval Yuriib, Grishkov Victora, Firstov Georgiyb, Girsova Nataliaa, Timkin Victora, Zhapova Dorzhimaa aInstitute of strength Physics and Materials Science SB RAS. Tomsk. Russia bG.V. Kurdymov Institute for Metal Physics NAS of Ukraine. Kiev. Ukraine [email protected]
The experimental results about the basic mechanisms of grain structure formation in Ti49.2Ni50.8(at.%) alloy under the warm multiple pass rolling via chill-pass rolls with the square cross-section of channels and corresponding evolution of martensitic transformation (MT) temperatures are presented. The samples were rolled at 723K with the summary true deformation about e=2. The alloy are characterized by B2 structure at 295K and the average grain sizes ‹d› = 43 μm. The formation of mesoband structures and regularities of microfragmentation due to the achievement of multiple slip of dislocations in grain volumes are analyzed. It is shown that the finish alloy microstructure are appeared as the result of a competition of the dynamic recrystallization under the deformation and metadynamic recrystallization (MDR), proceeded at intermediate warm up and at cooling of deformed samples. The MDR effect make weaker with the e increase. But this factor impedes the formation of ultra-fine grain structure. The theoretical description of the experimental dependence of ‹d› versus e was carried out using the modified Johnson- Mehl-Aurami empirical formalism, fig. 1a. It is shown that the MT sequence in deformed samples is the same as one in coarse-grained samples: B2↔R↔B19 (the cubic, trigonal and monoclinic phases, correspondingly), fig. 1b. The factors caused the changes of MT temperatures will be discussed.
Fig. 1. The experimental (1) and theoretical (2) dependences ‹d› versus e (a) and the dependences of MT temperatures (s-start, f-finish) versus e:
TR (B2↔R MT), Ms→Mf (R→B19 MT) and As→Af (B19→R MT) (b).
IN-SITU TEM OBSERVATION OF TRANSFORMATIONS IN TiNiCu ALLOY Szurman Ivoa, Miroslav Kursaa, Antonín Dlouhýb a VSB-TU Ostrava, Ostrava, Czech Republic b) ÚFM AV ČR, Brno, Czech Republic [email protected]
Alloys from the system Ni-Ti-Cu, which are usually prepared by alloying by Cu to the expense of Ni in volumes up to approx. 30 at. %, show shape memory phenomena, similarly as binary Ni-Ti alloys. Addition of Cu also reduces high influence of composition on transformation temperature, transformation hysteresis and flow stress in martensitic state. Amount of added copper also influences significantly manner of transformation. Addition of copper (more than 7 %) causes forming of martensite B19. Observation of microstructure should be realized by optical microscopy, but more effective is use of electron microscopy, such as SEM and TEM respectively. TEM technique makes it possible to combine morphological information obtained from the image, which is formed in light or dark field, with information from diffraction photos taken by the method of selective (SAD) or convergent (CBED) diffraction. Experimental alloy was prepared by melting in a graphite crucible in high-frequency induction vacuum furnace. The alloy was cast into a graphite ingot-mould. In this manner a round ingot with diameter of 10 mm and height of 300 mm was obtained. After metallurgical preparation of the alloy it was formed – by combinations of swaging at the temperature of 850°C followed by drawing. A wire with diameter of 2.3 mm was prepared by this technology. Samples for TEM were taken from the component volume by electro-spark Fig. 1 Dislocation density in residual phase B2 found in majority phase cutting. Fig 1 shows dislocation density in residual phase B2 found in majority B19. phase B19. This article deals with observation of microstructural characteristics of NiTiCu shape memory alloy, after different types of thermal treating by transmission electron microscopy. 38 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 12 - O14, O27 DETERMINATION OF TRANSFORMATION SURFACE OF A NITI SHAPE MEMORY ALLOY USING FULL FIELD MEASUREMENTS AND BIAXIAL TESTS Y. Chemisky, R. Echchorfi, F. Meraghni, N. Bourgeois, B. Piotrowski, E. Patoor Laboratoire d’Etude des Microstructures et de Mécanique des Matériaux (LEM3), Paul Verlaine University, Arts et Métiers ParisTech, CNRS, 4 rue Augustin Fresnel; 57078 Metz France [email protected]
With the design of new complex devices in shape memory alloys (SMAs) and to take advantage of their large recoverable strains, SMA components are more and more subjected to multiaxial loadings. It has been shown that the transformation surface of shape memory alloys exhibit specificities, such as tension-compression asymmetry for the critical stress and the maximum transformation strain. To determine the importance of such features and to define the transformation surface for NiTi shape memory alloys, but also the dependence of the maximum transformation strain according to the loading direction, biaxial isothermal tests on NiTi cruciform specimens are conducted. Different isothermal solicitations (traction-traction, traction-compression) are therefore conducted on the same type of plate samples. This has the advantage to ensure that the specimens subjected to different loading have the same thermomechanical history. DIC technique is employed to obtain the strain fields at the surface of the specimen. Finite Element simulations are carried out using thermodynamical constitutive model, which takes into accounts the tension-compression asymmetry. The strain fields computed numerically are compared with the strain fields obtained from DIC to find the material parameters, notably those that are describing the asymmetry, which best matches experimental measurements. The procedure to obtain these material parameters is based on an inverse identification procedure, which consists on the minimization of the cost function built in terms of the strain components on the surface of the specimen. Transformation surfaces are obtained for different temperatures, as well as the dependence of the maximum transformation strain with the loading direction.
SMALL-SCALE DEFORMATION BEHAVIOR OF NiTi SHAPE MEMORY ALLOYS Indrani Sena, R. Raghavanb, J. Michlerb and M.F.-X. Wagnera aChemnitz University of Technology, Institute of Materials Science and Engineering, D-09107 Chemnitz, Germany bEMPA Materials Science and Technology, Feuerwerkerstrasse 39, 3602 Thun, Switzerland [email protected]
The unique characteristics of pseudoelastic NiTi have been successfully deployed into various small scale applications such as biological stents or actuator devices. However, a thorough understanding of the microstructure- property correlation at the micro-scale is still missing. In this study, we combine nanoindentation and micro-pillar compression testing to probe the mechanical and transformation behavior of NiTi in small volumes. Systematic nanoindentation was performed using spherical indenter tips with radii (R) varying from 5 up to 50 µm as well as indentation depths (h) varying between 100 and 900 nm. With the variation of R and h, the pseudoelastic characteristics of the alloy can be quantified by the remnant depth ratio (RDR, Fig. 1). A value of RDR ≤ 10% signifies pseudoelasticity [1] which can be achieved for R ≥ 20 µm. We show how the indentation load- displacement data can be utilised to estimate the indentation stress-strain curves. This approach leads to a simple way of estimating the stress-strain behavior from multi-axial stress-state nanoindentation tests. In addition, the uniaxial deformation behavior of the alloy has also been characterised by in-situ SEM micro-pillar compression tests. These were performed over a wide strain range, covering the pseudoelastic regime as well as the plastic deformation regime of stress-induced martensite. Our in-situ observations during micro-pilar testing reveal unique information on the evolution of stress-induced martensite plates (Fig. 2) and highlight the complex interaction between growth of martensite, the shape change of the pillar and (reversible) buckling type deformation during nominally uniaxial loading.
Fig. 1: Typical load-displacement (nanoindentation) Fig. 2: Branching of martensite plates near the curve for NiTi top of a micro-pillar during compression
[1] J. Pfetzing, M.F.-X. Wagner, T. Simon, A. Schaefer, Ch. Somsen, G. Eggeler, ESOMAT 06027
39 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 12 - O16, O17
PECULIARITIES OF THERMOELECTRIC FORCE BEHAVIOUR IN NIKELIDE TITANE UNDER UNSTEADY HEATING V.V. Rubanik a,b, V.V. Rubanik Jr a,b, O.A. Petrova-Burkina a aInstitute of Technical Acoustics of NAS of Belarus, Belarus, Vitebsk bVitebsk State Technological University, Belarus, Vitebsk [email protected]
The phenomenon of thermoelectric force under unsteady heating (thermokinetic emf) in nickelide titanium undergoing thermoelastic phase transformations has been studied. It is established that the movement of the heating zone in the extended samples of TiNi wire causes the appearance of thermo-emf which is constant in value and direction and equaled to 0.22 mV. Changing in the direction of the heating zone leads to the polarity change of thermo-emf. The appearance of thermo-emf in TiNi is related to the thermoelastic phase transformation in the heating zone, the contact potential difference between the areas of TiNi material that is in different phase states, the non-linear dependence of resistance on temperature. Cycling the sample under conditions of unsteady heating leads to the decrease in the thermo-emf value and resistance, and their nature change is the same.
FEATURES OF CURRENT INFLUENCE DURING PLASTIC DEFORMATION OF TiNi ALLOYS Stolyarov V.V. Moscow Engineering Research Institute of Russian Academy of Sciences, Moscow, Russia [email protected]
Sequential or simultaneous action of plastic deformation and current in different alloys, including shape memory TiNi - alloys, leads to a number of the features representing scientific and practical interest. The raised deformability, suppression or intensification of phase transformations, formation of nano- or ultrafine-grained structure, accompanied improvement of mechanical and functional properties can be observed during simultaneous current and deformation [1]. Influence of the combined action severe deformation and a pulse current on a microstructure and mechanical behavior of long-size rods and strips with thin section out of Ti50Ni50 and Ti49.3Ni50.7 alloys is presented. Dependence of electroplastic effect on the grains size and phase structure of the initial alloys is shown in occurrence multidirectional stress jumps on the stress-strain curve (fig.1). It is established, that electropulse postdeformation processing promotes acceleration of a stress relaxation at stages of recovery, polygonization and recrystallization alloys. The method can be considered as alternative to a heat treatment.
Fig.1 Deformation behavior at tension of coarse-grain Ti49.3Ni50.7: without current (a); with current (b).
[1] V.V. Stolyarov, Mater. Sci. Forum, V. 683 (2011) 137-148
40 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 1 - O1, O2
HIGH TEMPERATURE MARTENSITIC TRANSFORMATION AND SHAPE MEMORY BEHAVIOUR IN HfIr INTERMETALLIC COMPOUND Yuri Koval, Georgiy Firstov, Valeriy Odnosum G.V. Kurdyumov Institute for Metal Physics, National Academy of Sciences, Kiev, Ukraine [email protected]
The present report is dedicated to the first observation of the martensitic transformation (MT) and associated shape memory effect (SME) in HfIr equiatomic intermetallic compound. Differential scanning calorimetry allowed to determine MT temperatures: Ms=970 K, Mf=650°C, As=850°C, Af=970°C. It was also shown that MT taking place at such high temperatures is associated with SME measured in 3 point bending. MT temperatures and crystal structure changes in the homogeneity range of HfIr compound were also studied. SME behavior changes in the homogeneity range of HfIr compound will be discussed.
MARTENSITIC PHASE TRANSFORMATIONS IN COMPOSITES OF TRIP STEEL AND ZIRCONIA PARTICLES A. Weidner a, H. Berek b, C. Aneziris b, H. Biermann a a) Institute of Materials Engineering, TU Bergakademie Freiberg, Freiberg, Germany b) Institute of Ceramic, Glass and Construction Materials, TU Bergakademie Freiberg, Freiberg, Germany [email protected]
Composite material on the basis of a TRIP (transformation induced plasticity) steel with zirconia particles as reinforcement was produced by powder metallurgical technology and conventional sinter process. The goal of such type of material is to obtain exceptional mechanical properties like high energy absorption due to the combination of martensitic phase transformations both in steel and ceramic. The steel matrix was made of AISI 304, which shows a deformation-induced martensitic phase transformation from the austenitic phase (fcc) into the ‟-martensite (bcc). The zirconia particles were partially stabilized with MgO and show stress-assisted martensitic phase transformation from the tetragonal to the monocline phase. Flat specimens with gauge length of 12 mm and a rectangular cross section of 5 × 2 mm² were tensile deformed. The deformation was carried out in-situ in a scanning electron microscope in order to follow the damage behaviour of the material. Some zirconia particles were characterized before and after tensile testing both by backscattered electron contrast as well as by electron backscatter diffraction (EBSD) in combination with energy dispersive X-ray spectroscopy (EDS). During tensile deformation different damage mechanisms were observed in the composite material. In the steel matrix, pronounced deformation bands develop which are preferred sites of nucleation of ‟-martensite. The damage behaviour of the zirconia particles can be distinguished in three groups: (1) fracture of particles, (2) decohesion of zirconia particles from the steel matrix and (3) coalescence of cracks starting from debonded particles or from pores. Furthermore, the combined EBSD and EDS investigations revealed the monoclinic phase to some extent already in the initial state. This can be explained by the diffusion of the Mg out of the MgO stabilized zirconia which leads to a destabilization resulting in the formation of precipitates along the interface between steel and zirconia particle. Nevertheless, zirconia particles with a tetragonal central part were monitored before and after tensile deformation in order to follow the martensitic phase transformation.
41 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 1 – P2, O4
STRESS AND STRAIN FIELDS ASSOCIATED WITH FORMATION OF '' IN NEAR- TITANIUM ALLOYS Amico Settefratia,b, Benoît Appolairec, Elisabeth Aeby-Gautiera a LSG2M INPL/CNRS, Ecole des Mines, Parc de Saurupt, 54042 Nancy Cedex, France b AIRBUS Operations SAS, 316 route de Bayonne, 31060 Toulouse Cedex, France c LEM ONERA/CNRS, 29 av. De la Division Leclerc, 92322 Châtillon, France [email protected]
In near- titanium alloys, it has recently been observed experimentally [1] that an orthorhombic phase '' is forming during isothermal tempering between 300°C and 400°C from the metastable bcc beta phase obtained by quenching from high temperatures. It has also been mentioned in the literature that '' martensite can be viewed as an hcp phase deformed in the hcp basal plane, with strains related to the content in alloying elements (e.g. [2]). Hence, to examine whether the difference between and '' (through the orthorhombicity parameter) could be attributed to misfit generated stresses, the local stress-strain fields arising from the lattice cell parameters mismatch between / '' and , have been computed using fast Fourier transforms following the efficient algorithm of Suquet and co-workers [3]. The calculations assume that the Burgers orientation relationships hold between hcp plates and bcc matrix, and take into account the differences in anisotropic elastic constants between both phases. A particular attention is paid to the eigenstrain attributed to the / '' phase: its influence on the lattice parameters is discussed with respect to the recent experimental results in [1]. Finally, the influence of the shapes and spatial arrangement of the /'' plates on orthorhombicity is also investigated.
[1] E. Aeby-Gautier, A. Settefrati, F. Bruneseaux, B. Appolaire, B. Denand, M. Dehmas, G. Geandier, P. Boulet, accepted in J. Alloy Comp. [2] A.V. Dobromyslov, V.A. Elkin, Mat. Sci. Eng. A 438–440 (2006) 324–326. [3] J.C. Michel, M. Moulinec, P. Suquet, Comp. Meth. Appl. Mech. Engng 172 (1999)109-143.
THE INFLUENCE OF STRAIN-RATE ON TEXTURAL EVOLUTION IN 304L AUSTENITIC STAINLESS STEEL WITH TRIP EFFECT dos Santos Paula, Andersana, Costa Cardoso, Marceloa, Gonçalves Andrade, Jessicaa, Farias Vieira, Thiagoa, Monteiro Almeida, Guilhermea, Moreira Pessanha, Lucianoa, dos Santos Freitas, Maria Carolinaa,b aUniversidade Federal Fluminense, Volta Redonda, Brazil bCentro Universitário de Volta Redonda - UniFOA, Volta Redonda, Brazil [email protected]
Transformation induced by plasticity (TRIP) can be present in some austenitic stainless steels when it deformed at room and low temperatures. Austenitic stainless steels with TRIP effect are an option to attend the market in order to increase the mechanical resistance during final forming process as a function of the temperature and strain-rate, contributing to obtain pieces with higher resistance and reduced weight. The aim of the present study was to analyze the influence of deformation level and the strain-rate in uniaxial tensile stress at room temperature upon the mechanical properties of a the metastable 304L austenitic stainless steel 1 mm sheet. The mechanical properties and martensitic phase transformation evolution were evaluated in-situ during tensile tests using a ferritscope coupled on the sample surface in the middle of gauge length. The textural results were obtained by Electron Backscattering Diffraction (EBSD) on Scanning Electronic Microscopic (SEM) in as- received and deformed samples at room temperature, associated with microstructural characterization by secondary electron (SE) on SEM and microhardness test maps. The results of present the study make it possible to estimate of the effect of deformation on martensitic transformation, microstructural and textural evolution on the metastable 304L austenitic stainless steel under uniaxial tensile loading at room temperature.
42 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 1 – O5, P4
TENSION - COMPRESSION ASYMMETRY IN CO49NI21GA30 HIGH-TEMPERATURE SHAPE MEMORY ALLOY SINGLE CRYSTALS J. Daddaa J. Lackmanna J. Monroeb I. Karamanb E. Panchenkoc H. E. Karacad T. Niendorfa H.J. Maiera aLehrstuhl für Werkstoffkunde (Materials Science),University of Paderborn, Pohlweg 47-49, 33098 Paderborn, Germany bDepartment of Mechanical Engineering, Texas A&M University, College Station, TX 77843, U.S.A. cSiberian Physical-Technical Institute, Tomsk 634050, Russia dDepartment of Mechanical Engineering, University of Kentucky, Lexington, KY 40506-0503, U.S.A [email protected]
This paper reports on the tension-compression asymmetry of [001]-oriented Co49Ni21Ga30 single crystals at elevated temperatures. The temperature and stress-state dependences of the material response under pseudoelastic loading conditions as well as iso-stress cooling-heating are mainly dictated by the type of active martensite variants and their detwinning behavior. The resulting transformation strains indicate that the short axis of the martensite is parallel to the loading axis under compression, while the longer axis is aligned with the loading direction in tension. This resulted in maximum strains of -4.8 % and 8.6 % in compression and tension, respectively. A linear Clausius- Clapeyron relationship was observed for both stress-states where the smaller slope in tension resulted in a significant increase of the martensite start temperature, which reached 180 °C under a constant stress level of 150 MPa. In addition, the material demonstrated a large pseudoelastic temperature range of about 300 °C under both stress state conditions. The results in this study unequivocally indicate the potential of these alloys for applications where elevated temperatures and stress levels prevail.
INGOT METALLURGY AND MICROSTRUCTURAL CHARACTERIZATION OF TI-TA ALLOYS Jian Zhang, Ramona Rynko, Jan Frenzel Institute for Materials, Ruhr University Bochum, Bochum, Germany [email protected]
Due to the demand of the applications in hot environment, the development of shape memory alloys are required to have a martensitic transformation temperature above 373K, which has attracted more attention in the past decade. Among them, the Ti-Ta alloys, confirmed with shape memory effect in Ti-(30~40)Ta, exhibit excellent cold workability (>90% thickness reduction at room temperature), which facilitates the manufacturing of wires or thin sheets for practical applications. The origin of their shape memory behavior is the reversible martensitic transformation between the (body centered cubic) parent phase and the α (orthorhombic) martensite phase. So far, there is no systematic study on the ingot metallurgy and the effect of which on the microstructure and transformation behaviors. In the present study, we systematically investigated the annealing temperature and time on the composition homogeneity of the Ti-Ta alloys, as well as the effect of various annealing conditions on the microstructure and the martensitic transformation behaviors.
43 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 1 – O7, O8
TWINNING IN Ti-48%Ni-2%Fe SINGLE CRYSTALS UNDER ROLLING Isaenkova Margarita, Perlovich Yuriy, Fesenko Vladimir, Dementyeva Tatyana National Research Nuclear University “Moscow Engineering Physics Institute”, Moscow, Russia [email protected]
Under rolling of Ti-48%Ni-2%Fe single crystals in the phase B2 at 350oC the twinning is the main mechanism of plastic deformation by many initial orientations of these single crystals, as texture data show clearly. Splitting of initial maxima in the stereographic projection of single crystal into several new ones is an evident manifestation of twinning. At that, the reproducible arrangement of these maxima in pole figures indicates to homogeneous formation of twins in any microvolume of the initial single crystal. This mode of reorientation is observed only at initial stages of rolling, when deformation degrees do not exceed ~10-15%. A geometrical analysis of pole figures for all rolled single crystals was undertaken by use of the known procedure [1] in order to reveal, whether the twinning could be really responsible for the observed reorientation, and to determine the concrete operating twinning system. It was recognized, that the main planes of twinning in the phase B2 are {114} and (118}. Earlier there were TEM observations of the twinning by planes {114} in Ti-Ni alloys [2], but the twinning by planes {118} was revealed for the first time. While twinning by {114} planes reorients the axes <001> at an angular distance of 39o, twinning by {118} planes reorients them at a distance of 21o only. When comparing evidences of twinning in single crystals with different initial orientations, characterized by different values of the Schmidt factor for possible slip and twinning systems, one can conclude, that the critical shear stress increases in the following succession: slip systems {011}<001>, twinning systems {118}<441>, twinning systems {114}<221>. Depending on the initial orientation of the single crystal, some slip or twinning systems prove to be more or less preferred. For example, the single crystal in the initial orientation {115}<011> shows the predominant twinning by systems {114}<221>, single crystal in the initial orientation {013}<123> - by systems {118}<441>, while single crystals in stable initial orientations become deformed mainly by the slip.
[1] Vishnyakov Ya., Babareko A., Vladimirov S., Egiz I. (1979) Theory of Texture Formation in Metals and Alloys, Nauka, Moscow (in Russian). [2] Moberly W.J., Proft J.L., Duerig T.W. and Sinclair R. (1990) Acta Metal. Mater., 38, 12, 2601.
IN-SITU X-RAY STUDY OF PHASE TRANSFORMATION IN TI-NB-BASED SMA UNDER VARIABLE STRESS-TEMPERATURE CONDITIONS Dubinskiy Sergeya,b, Brailovski Vladimira, Inaekyan Karinea, Prokoshkin Sergeyb aEcole de technologie superieure, Montreal (Quebec), Canada bNational University of Science and Technology "MISIS", Moscow, Russia [email protected]
X-ray phase analysis is a commonly used technique to study phase transformation in shape memory alloys. This technique allows determination of the phase structure and the lattice parameters of each phase, and therefore evaluation of the theoretically reachable recovery strain in untextured polycrystalline material. Some commercially available add-on devices (thermal chambers) allow carrying out X-ray phase analysis in a certain temperature range, whereas the others can be used for in-situ analyses under action of external force (tensile stages). Since martensitic transformation can be induced by both the temperature and stress variations, it could be interesting to combine in one device mechanical loading and temperature control capabilities and that in a wide temperature range, more specifically under negative temperatures. This work addresses the design, manufacturing and validation of an original tensile stage fit within TTK450 thermal chamber of PANalytical X‟Pert PRO diffractometer and powered by Ti-Ni SMA active elements. Results obtained during X-ray analysis of the phase transformation in the newly developed Ti-Nb-based SMA for biomedical application are also presented.
44 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 1 – O9, O10
DISTRIBUTION OF RESIDUAL ELASTIC MICROSTRESS IN ROLLED Ti-Ni SINGLE CRYSALS Perlovich Yuriy, Isaenkova Margarita, Fesenko Vladimir, Dementyeva Tatyana National Research Nuclear University “Moscow Engineering Physics Institute”, Moscow, Russia [email protected]
Development of martensitic transformations (MT) is controlled by the field of residual elastic microstress, formed in the sample as a result of its treatment. It is shown experimentally, that a distribution of residual microstress in rolled Ti-48%Ni-2%Fe single crystals varies depending on features of their deformation textures. Among these features there are the character of symmetry, the number and the scattering degree of main components, operated plastic deformation mechanisms, responsible for observed reorientation of the crystalline lattice. Typical modes of the microstress distribution were found by X-ray study of Ti-Ni rolled single crystals using the method of Generalized Pole Figures (GPF) [1]. The method consists in successive measurements of profiles for the same X-ray line of B2 phase by all possible positions of the sample in the course of diffractometric study of its texture. Values of the peak position 2θ002 are recalculated into values of the interplanar spacing d001 and then into values of the relative lattice strain ε001= (d–dav)/dav, where dav – the weighted average level of d001, corresponding to operation of the actual macrostress. GPF ε001 shows the distribution of lattice elastic microstrains in stereographic projection of the sample. At that, these microstrains are conditioned by operation of elastic residual microstress, 3 equilibrated within a volume of ~0,1 mm , as it follows from X-ray data. The value ε001 at the point of GPF with angular coordinates (ψ, υ) indicates the lattice strain along axis <001> in the case of its coincidence with this direction. In rolled single crystals, due to the specific character of their textures, cubic axes can be aligned only along some external directions in the limits of texture maxima scattering. In cases of simplest rolling textures, containing the single component, texture maxima break into halves with opposite signs of elastic deformation, whereas by two-component rolling textures the one-sign elastic strain dominates within different maxima. Corresponding distributions of residual microstress are responsible for the non- uniform development of MT by cooling of rolled single crystals.
[1] Perlovich Yu., Bunge H.J., Isaenkova M., Fesenko V. Text. & Microstr. (1999) 33, 303.
LOW TEMPERATURE TRANSFORMATION IN TI5553 METASTABLE BETA TITANIUM ALLOY A. Settefratia,b, E. Aeby-Gautiera, M. Dehmasa B. Appolairec, G. Khelifatib, G. Geandiera a IJL-SI2M CNRS 7198 Université de Lorraine Nancy, France b AIRBUS Operations, Materials and Proceses, Toulouse, F. cLEM, Unité Mixte CNRS ONERA [email protected]
The transformation processes in the beta metastable titanium alloy Ti5553 is investigated for two different thermal paths, both leading to metastable ”. On one hand (A), transformation has been characterized during an isothermal transformation temperature of 325°C after direct cooling from the solution treatment in the beta temperature range. On another hand (B), the transformation has been characterized after cooling to room temperature from the solution treatment in the beta temperature range, and further isothermal ageing at 325°C. Transformations have been studied using continuous High Energy X Ray Diffraction (HEXRD) and electrical resistivity. The transformation kinetics has been determined as well as the crystallographic structure of the phases, and their cell parameters. Results obtained by HEXRD show that isothermal transformation after the direct treatment (A) leads to formation of an orthorhombic phase (”). The transformation during ageing (B) presents a more complex sequence. At first the hexagonal isothermal is characterized as generally mentioned in the literature. Additional peaks are also observed that could be indexed as peaks of a CFC structure (2 phase). Increasing the holding time, peaks corresponding to the orthorhombic phase (”) appear while those corresponding to isothermal and 2 vanish. It is worth to mention that we clearly identify the presence of the orthorhombic phase (”), although the HCP phase is generally mentioned in the literature. The content of ” increases while the content of and 2 decrease. In addition to the transformation sequence, we characterized the cell parameters of each phase. The obtained results are analysed as well as the effect of the thermal path on the kinetics of transformation.
45 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 1 - O11
MECHANICAL CYCLING IN CU-AL-NI SINGLE CRYSTALS: MICROSTRUCTURE ANALYSIS AND SUPERELASTIC EFFECT M.L. Nóa, A. Ibarraa, A. López-Echarrib, I. Ruiz-Larreaa, T. Breczewskia, J. San Juanb a Dpt. de Física Aplicada II, Facultad de Ciencia y Tecnología, Universidad del Pais Vasco, Aptdo 644, 48080- Bilbao, Spain b Dpt. de Física Materia Condensada, Facultad de Ciencia y Tecnología, Universidad del Pais Vasco, Aptdo 644, 48080-Bilbao, Spain [email protected]
The transformation behaviour of shape memory alloys (SMA) depends on the nucleation and growing conditions of martensite, which is strongly influenced by the microstructure of the material. However, during martensitic transformation local internal stresses are generated, which can be high enough as for creating dislocations by local plastic deformation. Then, an evolution of the microstructure is expected on cycling and its knowledge is very important from a technological point of view in order to guarantee the reliability of the material behaviour in service conditions. The aim of this work is to establish the relationship between the macroscopic behaviour during tensile superelastic cycling in Cu-Al-Ni SMA single crystals, and the associate evolution of the microstructure. The analysis has been carried out as a function of the testing temperature, the maximum reached strain and the number of cycles. Tensile superelastic cycles were performed in two samples with different compositions, which thermally transform to different kinds of martensite β‟3 and γ‟3. A further calorimetric study was carried out on these superelastic cycled samples in order to determine the evolution of thermal transformation. Moreover a Transmission Electron Microscopy (TEM) analysis, by post mortem and in situ observations, was performed and the results from in situ (TEM) superelastic tests [1] were discussed and compared with those obtained by tensile superelastic cycling. Finally the results obtained by tensile superelastic cycling are also discussed and compared with the previously obtained results, on the same single crystal alloys, by compression superelastic tests [2].
[1] A. Ibarra, J. San Juan, E.H. Bocanegra, M.L. Nó; Acta Materialia 55 (2007) 4789-4798 [2] M.L. Nó, A. Ibarra, D. Caillard, J. San Juan; Acta Materialia 58 (2010) 6181-6193
PREDICTION OF TRANSFORMATION BEHAVIOR OF R-PHASE SMA ACTUATORS BY THE APPLICATION OF FUZZY LOGIC Konstantin Lygin, Patrick Labenda and Tim Sadek Ruhr-Universität Bochum, Bochum, Germany [email protected]
The “rhombohedral” R-phase is an intermediate phase during the transformation form “cubic” austenite (B2) to “monoclinic” martensite (B19‟). The R-phase transformation (B2 > R) in NiTi based shape memory alloys (SMA) has a lot of advantages, compared to the martensitic transformation (B2 > B19‟). The main advantages of the R-phase transformation are the very small temperature hysteresis (2-5K) and the high durability (> 100.000 cycles). The main disadvantage of actuators based on R-phase transformation is the small SMA effect (approx. 0,8%). Due to the small temperature hysteresis, the R-phase actuators are usable for temperature sensitive applications in heating technology or in air conditioning. The R-phase transformation doesn‟t appear in each SMA alloy and needs a special thermo mechanical treatment to be induced. Fuzzy logic is an approach to computing based on "degrees of truth" rather than the usual "true or false" (1 or 0) Boolean logic. It includes 0 and 1 as extreme cases of truth but also includes the various states of truth in between so that, for example, the result of a comparison between two things could be not "tall" or "short" but "70% tall". The objective of this paper is to show the applicability of the approach of fuzzy logic in the field of shape memory alloys. With this approach, it should be possible to define the thermo mechanical heat treatment parameters for a SMA alloy to achieve the required R-phase transformation behavior, without having detailed information of all possible influence parameters. To have the basic knowledge about influence parameters, a binary NiTi alloy with 50,9at.-%Ni was investigated. The parameters degree of cold forming, annealing temperature and annealing time were varied and their influence on the transformation behavior of the R-phase noted. Additional data to further influence parameters, like N-content, were researched in scientific papers and added to the knowledge basis.
46 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 5 - O1, O2
MARTENSITE TRANSFORMATION IN NANOCRYSTALS A.M. Glezer I.P.Bardin State Scince Center for Ferrous Metallufgy. Moscow, Russia [email protected]
The size effect of parent phase for different types of martensite transformation has been investigated. It was established that the -Fe-Ni nanocrystals with (28-29)%Ni located in amorphous matrix did not undergo martensite transformation on cooling to 77K, but the martensite transformation occurred in the nanocrystals of the greatest size fraction (100-130 nm) on cooling to 4.2 K. It was found that the B2-(Ni-Ti-Cu) nanocrystals located in amorphous matrix underwent the thermoelastic martensite transformation B2→B19 so that when the nanocrystal size ranged from 10 to 50 nm all nanocrystals of size over 25 nm transformed fully to martensite whereas nanocrystals of size 15-25 nm transformed partially and the smaller the nanocrystal size the smaller the transformed volume of nanocrystal. It was shown that thermoelastic martensite transformation as well as the non-thermoelastic type occurred starting with the greatest size fraction of the nanocrystals located in amorphous matrix in Ni-Ti-Cu and Fe- Ni-B alloys. A critical size at which martensite transformation was suppressed was found to exist on cooling. The experimental results are in good agreement with theoretical predictions. It should be noted that the concrete value of the size parameter depends, first of all, on chemical composition and on cooling conditions. As our experiments show, the value of the critical size obtained in Fe-Ni-B alloy (110-120 nm) is higher than that in the Ni-Ti-Cu alloy (15-16 nm). This is related to several factors: a different temperature interval of martensite transformation and different conditions of elastic accommodation. But it is essentially due to the other type of martensite transformation. It was suggested that the essential difference between the critical size for Ni-Ti-Cu and Fe-Ni-B alloys is due to different type of martensite transformation (thermoelastic and non-thermoelastic (athermal), respectively). Also the accommodation behaviour is an important parameter. For example, the critical size of pure Fe powders to suppress the martensite transformation was found to be 10 nm because of a facilitation of the accommodation processes. By cryogenic (77 K) deformation the martensite nanoparticles in Fe-Ni-Cr-Al alloys has been prepared. It was shown that for alloy compositions for which no martensite transformation at the room - temperature rolling and at the low - temperature cooling (up to 77 K) occurred if these factors have been applied together (cryogenic rolling) the martensite nanoscale lamellas were appeared. It was detected that such a cryogenic deformation caused the essential hardening (3,5 times) of material.
Ni-Ma-Ga ALLOYS PROCESSED BY SEVERE PLASTIC DEFORMATION Clemens Manglera,b, Arno Kompatschera, Nikki Kuczac, Peter Müllnerc, Thomas Waitza aPhysics of Nanostructured Materials, Faculty of Physics, University of Vienna, Austria bMaterials Center Leoben Forschung GmbH, Leoben, Austria cDepartment of Materials and Engineering, Boise State University, Boise, Idaho, USA [email protected]
Grain size can strongly affect the thermomechanical properties of shape memory alloys [1]. The grain size might be optimized to achieve a tailored combination of functional properties and enhanced mechanical strength. In the present work, ferromagnetic high temperature Ni54-Mn25-Ga21 shape memory alloys containing tetragonal martensite at room temperature were subjected to severe plastic deformation using high pressure torsion (HPT). The severe plastic deformation is driving the material far from its equilibrium yielding strong grain fragmentation concomitant with defect accumulation, chemical disordering and deformation induced formation of metastable fct, fcc and bcc phases. Caused by the disordering, both the martensitic phase transformation and the ferromagnetism of the severely plastically deformed alloys are suppressed. Upon isochronal heating of the alloys subjected to HPT, in a first step both fct and fcc transform to bcc; finally ordering yields the ferromagnetic L21 Heusler austenite at a temperature lower than that required for significant grain growth. Using a suitable combination of the HPT and heat treatment, bulk Ni-Mn-Ga alloys were processed containing grains that are almost defect free and have an average size of about 150 nm. In the small grains both the forward and the martensitic phase transformation occur at a temperature that is about 100°C lower than that observed in the coarse grained material. Whereas tetragonal martensite is encountered in the coarse grains, constraints imposed by the boundaries of the small grains favour the formation of the 14M martensite. The morphology of the martensite is analysed and its formation is explained applying the general thermodynamic theory of the martensitic phase transformation including the effects of grain size [2] and considering the concept of the formation of an adaptive martensitic structure [3].
[1] T. Waitz, K. Tsuchiya, T. Antretter, F.D. Fischer, MRS Bulletin 34: 814, 2009. [2] M. Peterlechner, T. Waitz. C. Gammer, T. Antretter, Int. J. Mater. Res. 102: 634, 2011. [3] S. Kaufmann et al., Phys. Rev. Lett. 104: 145702, 2010.
47 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 5 – O3, O5
INFLUENCE OF EQUAL-CHANNEL ANGULAR PRESSING ON GRAIN REFINEMENT AND NONELASTIC PROPERTIES OF TiNi BASED ALLOYS. aLotkov Aleksander, aBaturin Anatoly, aGrishkov Victor, bKopylov Vladimir aInstitute of strength Physics and Materials Science SB RAS. Tomsk. Russia bPhysiko-Technical Institute NAS Belarus, Minsk, Belarus [email protected]
On the basis of own results and literary data in the given work the review of regularities and possible mechanisms of grain refinement in TiNi based alloys under the equal-channel angular pressing (ECAP) is made. It is shown, that the fragmentation process in this alloys occurs at different scale levels in which different deformation mechanisms and dynamic recrystallization play an important role. It is shown, that the regularities of grain refinement in isothermal conditions ECAP have the general character irrespective of alloy composition and an initial structure-phase condition. The description of dependence of the size of grain from value of the saved up deformation within the limits of model dynamic recrystallization is given. The existing representations about factors defining a limiting fragmentation in metals and their applicability for definition of the minimum size of grains in on TiNi based alloys are considered. The results of experimental researches of ECAP influence on functional properties of TiNi based alloys are presented.
MICROSTRUCTURE AND MECHANICAL PROPERTIES OF THE SPD-PROCESSED TiNi ALLOYS D.V. Gunderova,, A.V. Lukyanova, E.A. Prokofieva, A.A Churakovaa, V.G. Pushinb, S.D. Prokoshkinc, V.V. Stolyarovd, R.Z. Valieva a Ufa State Aviation Technical University, Ufa, Russia b Institute of Physics of Metals UB RAS, Ekaterinburg, Russia c Moscow Institute of Steel and Alloys, Moscow, Russia dMechanical Research Engineering Institute of RAS, Moscow, Russia [email protected]
Strength and functional characteristics of TiNi-based alloys with shape memory effect (SME) can be significantly enhanced due to formation of ultrafine-grained (UFG) and nanocrystalline (NC) structures by severe plastic deformation (SPD). The UFG TiNi alloy with the grain size (D) 300 nm can be produced by equal channel angular pressing (ECAP). Amorphised and NC states of the TiNi alloys can be produced by high pressure torsion (HPT) and annealing. Our HPT technique enables producing relatively large samples with a diameter of 20 mm and thickness of 1mm [1]. Besides, an amorphous- nanocrystalline structure was formed in TiNi alloys by combining ECAP and subsequent cold rolling. As a result of formation of amorphous and NC structures with D 20 nm the ultimate tensile strength (UTS) and yield stress (YS) of the TiNi alloy increase over 2000 MPa (from initial UTS 1000 MPa and YS 500 MPa) [1,2]. But the ductility in this state is low (about 10%). There is no phase pseudoplasticity plateau on the tensile curve of the amorphous TiNi alloys. A pseudoplasticity plateau can be observed in TiNi with D≥20 nm. High YS values in SPD TiNi alloy allow achieving superior values of the reactive stress. The UFG TiNi alloy (produced by ECAP or by HPT and annealing) with D about 300 nm at room temperature has UTS 1400 MPa and high ductility up to 60 %, which is unusual for other UFG materials. However, increasing deformation temperature up to 400 – 500°C leads to decreasing of plasticity in UFG TiNi. В тоже время ductility of NC TiNi with D 50 nm achieves 70 % at Т = 500ºС. Recent investigations have shown that a combination of ECAP and thermal cycling provides an opportunity to achieve an additional increase of the dislocation density and structure refinement in bulk samples of TiNi, and the strength increases almost to 2000 MPa. Presently, in USATU development a Equal channel angular pressure-Conform (ECAP-C) method, that is a perspective technique for industrial fabrication of UFG TiNi alloys.
48 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Secssion 5 - O6, Session 3 - P
REVERSIBLE MARTENSITIC TRANSFORMATION PRODUCED BY SEVERE PLASTIC DEFORMATION OF METASTABLE AUSTENITIC STEEL Litovchenko Igora, Tyumentsev Alexandera, Korznikov Alexanderb a Institute of Strength Physics and Materials Science SB RAS, Tomsk, Russia b Institute for Metals Superplasticity Problems RAS, Ufa, Russia [email protected]
The feature of nanostructured states formation produced by severe plastic deformation of metastable austenitic steels is participation of martensitic transformations in plastic deformation. The phase composition of the steel after severe plastic deformation depends on the phase stability, the conditions and the degree of deformation. In this paper transmission electron microscopy, X-ray phase analysis and measurements of the specific magnetization were used to investigate the structural and phase transformations in metastable austenitic steel (Fe-18Cr-8Ni-Ti) after severe plastic deformation by high pressure torsion. It is shown that plastic deformation leads to the formation of α' and ε martensitic phases. In this case ε - martensite is an intermediate phase, which undergoes ε → α' martensitic transformation. Volume content of α'- martensite depends on the rate and the degree of deformation. At the initial stages of deformation volume content of α '- martensite increases and reaches more than 70%, then decreases to ≈ 50% (at e ≈ 6, e – true logarithmic strain) with a subsequent increase to 80%. Increase of strain rate reduces the volume fraction of martensite at e ≈ 6 significantly. Similar degree of deformation dependence of the volume content of martensite during severe plastic deformation by torsion suggests that not only the direct (γ → α΄), but also reverse (α΄ → γ) martensitic transformations take place in this case. The defect structure of steel after high pressure torsion consists mainly of fragmented banded nano-sized structures, containing fragments of the austenite and α '- martensite distributed by volume of specimen inhomogeneously. The misorientations of crystal lattice between fragments of austenite, which can be obtained as a result of direct and reverse martensitic transformations, were found. Martensitic fragments are formed by the action of one or more different systems of martensitic transformation. Based on the obtained results, the mechanisms of phase transformations and nanostructured states formation in metastable austenitic steel produced by severe plastic deformation are discussed.
SHAPE MEMORY PROPERTIES OF ULTRAFINE-GRAINED AUSTENITIC STAINLESS STEELS Käfer, K. A., Bernardi, H. H., Naito, L. K. F., Otubo, J. Instituto Tecnologico da Aeronautica, Sao Jose dos Campos, SP, Brazil [email protected]
Recent works have shown that the grain size reduction contributes to the increase of the shape recovery and decrease the stress to induce the ↔ martensitic transformation of shape memory stainless steels. Another parameter to improve shape memory performance in ferrous alloys is the chemical composition. It has been reported that the addition of strong carbide-forming elements such as Nb, Ti, V and Ta, could increase the amount of stress- induced martensite. The production of fine coherent precipitates in austenite will provide a preferential nucleation site for the stress-induced martensite. Considering these two important principles, the present study aims to investigate the combined effect of grain refinement and particles precipitation on a Fe-Mn-Si-Cr-Ni-Co-Ti shape memory stainless steel. To achieve this goal, it will be used the technique of Equal Channel Angular Extrusion (ECAE) to obtain ultrafine grain in bulk material. The extrusion is carried out in a die with square cross-section of 7x7 mm2 and internal die angle of 120°. The samples are processed using multiple passes of ECAE (1, 2 and 3 passes) using the route Bc. After ECAE deformation, samples are annealed for 1 hour at several temperatures from 450°C to 1050°C. Deformed and annealed samples are characterized using scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and X-ray diffraction. Preliminary results show that the heat treatments leads to the formation of intermetallic precipitates uniformly distributed in the austenitic matrix. The volume fraction of precipitates increases as the deformation increases, and these particles promote a significant increment in the hardness of samples after the heat treatment at temperatures from 650°C to 850°C. The grain size reduction could be observed only after 2 passes of ECAE and the average grain size at this stage of processing is about 4 m. Recrystallization of the grains is observed from 750°C. Shape memory properties are being evaluated using differential scanning calorimeter (DSC), and compression tests.
[1] Z. Wei, J. Laizhua, L. Ning, W. Yuhua, J Mater Process Tech, 130-134, 208 (2008). [2] J. Otubo, F. C. Nascimento, P. R. Mei, L. P. Cardoso, M. J. Kaufman, Materials Transactions, The Japan Institute of Metals, 916-919, 43 (2002). [3] F. C. Nascimento, P. R. Mei, L. P. Cardoso, J. Otubo, Materials Research, 63-67, 11 (2008). [4] N. Stanford, D.P. Dunne, Journal of Materials Science, 4883-4891, 41(2006).
49 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 12 – O32, O19
STRUCTURAL AND PHASE TRANSFORMATIONS AND PROPERTIES OF RAPIDLY QUENCHED Ti2NiCu BASED ALLOYS Pushin Artema, b, Popov Artemyb, Vladimir Pushina, b aInstitute of Metal Physics, Ural Branch, Russian Academy of Sciences, Ekaterinburg, Russia bThe First President of Russia B.N.Yeltsin Ural Federal University, Ekaterinburg, Russia [email protected]
Methods of X-ray diffraction, transmission and scanning electron microscopy have been used to study phase composition and structure of an almost stoichiometric alloy Ti50Ni25Cu25. The alloys of the quasi-binary section TiNi–TiCu, which exhibit in the initial as-cast state thermoelastic martensitic transformations B2 ↔ B19 and related shape memory effects, have been produced by rapid quenching of the melt (melt spinning technique). The chemical composition of the Ti2NiCu alloys was varied with respect to titanium and nickel, titanium and copper, nickel and copper within ±1%. It has been shown that the rapid quenching from the melt at a cooling rate of 106 K/s leads to the amorphization of all the studied alloys. The heating to 723 K or higher temperatures leads to their devitrification via the polymorphic, primary, or eutectic mechanisms without changes or with changes in the chemical composition and the formation of a polycrystalline structure of the В2 austenite. The nonstoichiometric Ti50+xNi25–xCu25 alloys form homogeneous solid solutions, undergo decomposition, and become precipitation-hardening, depending on the extent of nonstoichiometry. The crystallization and subsequent recrystallization of the stoichiometric Ti2NiCu alloy occur practically without change in the chemical composition. The mechanical properties of the alloys have been measured in the initial amorphous state and after subsequent heat treatment. The ultimate strength σu changes in the limits of 850–1380 MPa; the yield stress σ0.2 - in the limits of 680–1160 MPa; the relative elongation - 9–12%; with the retention of high values of the reactive stress equal to 620–1060 MPa and of the recovery strain equal to 3–5%. The characteristic temperatures of the start and finish of the process of crystallization from the amorphous and amorphous-crystalline states and the critical temperatures of the start and finish of the forward (Ms, Mf) and reverse (As, Af) thermoelastic martensitic transformations have been determined by measuring temperature dependences of the electrical resistivity of the alloys. The diagrams of the dependence of the critical temperatures on the chemical composition of the alloys have been constructed.
EXPERIMENTAL AND NUMERICAL STUDY OF NITI HOLEY PLATES LOADED IN TENSION Cellard Christophea, Rio Gérarda, S. Shariat Bashir b, Liu Yinongb, Grolleau Vincenta, Delobelle Vincentc, Favier Denisc aUniversité de Bretagne Sud, Université Européenne de Bretagne, Lorient cedex, France bSchool of Mechanical and Chemical Engineering, The University of Western Australia, Crawley, Australia, cUniversité de Grenoble (UJF, G-INP), CNRS UMR 5521, Grenoble, CEDEX, France, [email protected]
We present results of experiments and numerical modeling of superelastic deformation of NiTi holey plates. Ti-50.8at% rectangular plates of 110 mm x 29.5 mm in dimension and 0.1 mm and 1.5 mm in thickness are used for tensile testing and for simulation. Electrical discharge machining (EDM) was used to machine tensile specimens and to cut circular holes of different diameters in the plates. The holey plate samples were loaded in uniaxial tension along the length direction at room temperature. A special apparatus was applied to confine out-of plane displacements in order to avoid buckling. The rate of deformation is sufficiently low to avoid thermal effect due to the release of latent heat. The 3D displacement field on the sample surface was recorded by means of 3D digital image correlation method (Aramis software), which also calculates the associated in-plane strain fields. Material property parameters for the simulation are extracted from tensile, shear and bulge test experiments. Other remaining parameters required are selected from previous experiments or the literature. Simulation of the tensile deformation behaviour of the holey plates was conducted by means of finite element simulation based on a elasto-hysteretic tensorial model. Findings of the simulation were validated by comparison with the experimental data. The objective of the work is firstly to get the whole data needed for a benchmark about a non-homogeneous test on NiTi, and secondly to investigate the capability of our numerical model [1]. In particular we compare the experimental and simulated results, for the global evolution of the structure «holey plate» and for the local evolution in non homogeneous area.
Example of comparison between experiment data (on the left) and simulation (on the right) for the same level of global vertical displacement.
[1]Gérard Rio, Denis Favier and Yinong Liu DOI: http://dx.doi.org/10.1051/esomat/200908005
50 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 12 – O20, O21
AN IN SITU NEUTRON DIFFRACTION STUDY OF TENSION-COMPRESSION CYCLIC DEFORMATION IN POLYCRYSTALLINE NiTi D.E. Nicholsona, O. Benafana,b, S.A. Padula IIb, R.D. Noebeb and R. Vaidyanathana aAdvanced Materials Processing and Analysis Center (AMPAC); Mechanical, Materials, and Aerospace Engineering Department; University of Central Florida, Orlando, Florida 32816, USA b NASA Glenn Research Center, Cleveland, Ohio 44135, USA [email protected]
Isothermal cyclic deformation of a monoclinic martensitic NiTi (49.9 at.% Ni) shape memory alloy was studied in situ using the Spectrometer for Materials Research at Temperature and Stress (SMARTS) at Los Alamos Neutron Science Center. Diffraction patterns were acquired at stress by time-of-flight (TOF) neutron diffraction. All experiments were performed at room temperature. Evolution of texture and plane specific lattice strains were followed during isothermal tension-compression cyclic deformation to ±0.4, ±2 and ±4% strain, for 10, 12 and 10 cycles, respectively. Neutron data was collected during the first, second and final cycle of each case. Macroscopic results showed an asymmetrical stress-strain response with the maximum stresses under tension and compression increasing at maximum strain. The results also showed decreasing stresses at intermediate strains, bounded by unique crossing-points, and decreasing energy dissipation with each cycle. Finally, the observed asymmetry increased as the strain range was increased. The objective of these experiments was to investigate microstructural changes responsible for the macroscopic cyclic stress-strain response of the NiTi. Towards this goal, texture was systematically analyzed using inverse pole figures. Results showed tension-compression asymmetry in the texture evolution, which was dependent on strain, and independent of stress and cycle. Emphasis was placed on decoupling contributions of preferred variant selection during variant reorientation and detwinning to asymmetry and evolution of stresses observed in the macroscopic response. Preferred variant orientation, which occurred in tension, was partially maintained when going into compression, as the tensile direction was loaded first. This observation of maintaining variants selected in tension became more dominant as the strain range was increased.
STUDY OF SURFACE STATE INFLUENCE ON FUNCTIONAL PROPERTIES OF Ti–Ni ALLOYS Ryklina Elena National University of Science and Technology “MISIS”, Moscow, Russia [email protected]
Binary TiNi alloys containing 50.0 at.% Ni and 50.7 at.% Ni were tested under bending. Shape memory effect (SME) and two-way SME (TWSME) parameters were measured. Low-temperature thermomechanical treatment (LTMT) by drawing with true strain e ≈ 0.6 and post-deformation annealing (PDA) was performed in the temperature range 300600С for 0.5 1 hr permitted obtaining different types of initial austenite structure. A homogenizing annealing at 700С for 20 minutes served as a reference heat treatment (recrystallized structure of austenite). The wires with 0.3 and 0.45 mm in diameter were studied. Element composition of surface oxide film formed during PDA was studied using scanning electron microscope «CamScan−4», equipped with «Inca Energy 300» adaptor. Characteristic temperatures of martensitic transformations were determined by measuring of electrical resistivity. Thickness of the oxide film was determined using an optical microscope “Union”. The curves of element distribution through the surface layer were graphed. The SME training procedure was carried out in bending under load at 0C for Ti 50.0 at.% Ni and at 10C for Ti 50.7 at.% Ni with the constrained strain εt in the range of 0.7 8 %. Thickness, structure and element composition of the oxide film strongly depend on PDA regimes. In all cases titanium quantity in the boundary layer correlates with the oxygen quantity, diffused from the surface. Evidently, it is caused by their chemical reaction and oxide formation. Nickel atoms remain in uncombined state, and their migration is directed from the surface deep into the sample. LTMT permits decreasing the film thickness more than by 10 times. Surface state strongly affects all studied parameters: characteristic temperatures, recovery strain and TWSME value. Increasing of wire diameter from 0.3 to 0.45 mm leads to significant changes of studied parameters. Forecasting of said influence is difficult because of its ambiguity. Therefore, the oxide film must be eliminated by etching in order to obtain the reliable results.
51 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 12 – O22, P44
EFFECT OF ANNEALING ON SUPERELASTICITY OF TINI ALLOYS SUBJECTED TO EQUAL CHANNEAL ANGULAR PRESSING Y. X. Tonga, B. Guoa, F. Chena, B. Tiana, L. Lia, Y. F. Zhenga,b, Ruslan Z. Valievc aCenter for Biomedical Materials and Engineering, Harbin Engineering University, Harbin 150001, China bDepartment of Materials Science and Engineering, Peking University, Beijing 100871, China cInstitute of Physics of Advanced Materials, Ufa State Aviation Technical University, Ufa, 450000, Russia [email protected]
TiNi shape memory alloys (SMAs) have been widely used in the engineering applications due to their excellent functional properties, such as shape memory effect, superelasticity and high damping property. Thermomechanical processing has been proven to be an effective method to improve the mechanical and functional properties. Recently, equal channel angular pressing (ECAP) was used to prepare bulk ultrafine-grained (UFG) TiNi SMAs [1]. To date, several important aspects of TiNi alloys subjected ECAP have been reported, including microstructure, phase transformation, mechanical properties and shape memory effect [2] etc. However, the dependence of superelasticity on annealing temperature in the ECAPed TiNi SMAs remains unknown. In the present work, Ti49.2Ni50.8 alloy was cessed by ECAP and annealed at different temperatures from 300 to 600 °C for 30 min with a temperature interval of 100 °C. The effect of annealing temperature, deformation strain and temperature, deformation cycling on the supererelasticity was investigated. Figure 1 shows the effect of annealing temperature on the residual strain. The deformation strain was 6%. It is seen that with increasing annealing temperature from 300 to 400°C, the residual strain decreases. Further increase of annealing temperature leads to the increase of residual strain. After mechanical cycling for up to 40 times, the sample annealed at 400 °C shows the smallest residual strain, indicating that the annealing at 400°C for 30 min is beneficial to improve the superelasticity. This can be understood from the grain size evolution with annealing temperature.
Figure 1 Effect of heat treatment temperature on the residual strain of Ti49.2Ni50.8 alloy deformed to 6%.
[1] R.Z. Valiev, D.V. Gunderov, E.A. Prokofiev, V.G. Pushin, Y. Zhu, Mater. Trans. 2008, 49, 97. [2] E. Prokofiev, D. Gunderov, S. Prokoshkin and R. Valiev, in ESOMAT 2009 - The 8th European Symposium on Martensitic Transformations, EDP Sciences (www.esomat.org), 2009, 06028, 1.
EFFECT OF ANNEALING ON THE MECHANICAL PROPERTIES OF A SEVERE PLASTIC DEFORMED NITI SHAPE MEMROY WIRE Wang Xiebina, Schryvers Dominiqueb, Verlinden Berta, Van Humbeeck Jana a Department of Metallurgy and Materials Engineering, Katholieke Universiteit Leuven, Leuven, Belgium b EMAT, Department of Physics, University of Antwerp, Antwerp, Belgium [email protected]
Severe plastic deformation and post-deformation annealing is a powerful way to refine the microstructure of NiTi shape memory alloys. A co-drawing process can lead to severe plastic deformation. In this study, a co-drawing process and post-deformation annealing (300°C-600°C, 30min) were applied to a binary NiTi shape memory wire. The evolution of microstructure, transformation behavior and mechanical response with respect to annealing temperature were studied by using transmission electron microscopy (TEM), differential scanning calorimetry (DSC) and a dynamic mechanical analyzer (DMA). The preliminary experiments indicated that fine grains with a diameter of 30nm-90nm can be obtained by using the co-drawing method. The 300°C annealed wires showed near- linear superelasticity, while the 400°C annealed wires exhibited a superelastic plateau strain of 4.25%. Compared with the as received cold drawn wires, there was not much difference in total elongation, superelastic plateau strain and recoverable strain, when annealed at 400°C-600°C. However, the tensile stress and plateau stress at room temperature of the co-drawn wires were much higher than that of as received wires, e.g. a plateau stress of 738MPa for co-drawn wires and 558MPa for as received wires. The relationship between the evolution of microstructure and mechanical behavior at different annealing temperatures will be discussed in light of the experimental observations. Apart from the annihilation of dislocations and recrystallization during annealing, particular attention is given to the precipitation behavior and texture evolution with respect to the annealing temperature.
52 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 12 – O24, O26
EFFECT OF STOICHIOMETRY ON ELASTIC AND ANELASTIC PROPERTIES OF NiTi-BASED SHAPE MEMORY ALLOYS Torrens-Serra, J.a , Salas, D.a, Cesari E.a, Kustov S. a, Sapozhnikov K.b, Van Humbeeck J.c aUniversitat de les Illes Balears, Palma de Mallorca, Spain bA.F. Ioffe Physico-Technical Institute, St.Petersburg, Russia cKatholieke Universiteit Leuven, Leuven, Belgium [email protected]
Structural changes occurring in different Ni-Ti and Ni-Ti-Fe alloys over the temperature range from 13 to 300 K are monitored by investigations of elastic and anelastic properties, calorimetry and electrical resistivity measurements. Several binary and ternary alloys were used with different thermomechanical history, which demonstrate distinct transformation paths: B2-B19‟, B2-R and B2-R-B19‟. The most important result obtained is that elastic and anelastic properties strongly depend on the deviation from the stoichiometric composition. In alloys with the excess of Ni, in addition to the martensitic (B2-R, B2-B19´) and intermartensitic (R-B19´) transformation peaks, a new relaxation internal friction (IF) peak is observed at about 90 K (for a frequency of about 100 kHz). No peculiarity is detected in electrical resistivity at this temperature, indicating that the IF peak is not related to any structural transition. Experimental data on the non-linear (strain amplitude-dependent) IF evidence that above the IF peak temperature an intense dynamic strain ageing sets in, likely pointing to the occurrence of diffusion of point defects, assisted by dislocations/interfaces. This relaxation is not detected in alloys with the excess of Ti. In that case the strain amplitude dependent IF decreases monotonously for decreasing temperatures and demonstrates a strong anomalous increase at temperatures below approximately 50 K. This observation points to a strong enhancement of the mobility of twin boundaries at very low temperatures in the alloys with excess of Ti. The effect of deviation from stoichiometry on elastic and anelastic properties in NiTi family of alloys is probably related with the different types of defects formed on opposite sides of the stoichiometric composition.
THERMOMECHANICAL FATIGUE BEHAVIOUR OF NiTi WIRES Antonio Isalguea, Javier Fernandezb, Nuria Cincab, Carlota Augueta, Guillem Carrerasa, Vicenç Torraa aDep. Física Aplicada, Univ. Politècnica Catalunya (UPC),Pla Palau 18, E-08003, Barcelona; Spain bCPT, Dep. CMEM, Facultat Química, Universitat Barcelona, Diagonal 649, E-08028, Barcelona; Spain [email protected];
Shape Memory Alloys are considered smart materials because of its singular thermomechanical properties, due to the thermoelastic martensitic transformation, enabling possible uses as dampers (because of its hysteresis) and as actuators (because of its mechanical recovery induced from temperature changes). Many applications of SMA need a careful evaluation of the fatigue life. Working of SMA devices often implies temperature and stress changes. Then, thermal and mechanical fatigue should be considered. The failure of a given device made of SMA can be classified as structural failure (fracture of the specimen after successive loading-unloading cycles) or as functional fatigue, incapacity to do the expected task, or perform the expected path in stress-strain-temperature, even if fracture does not occur. Structural fatigue failure in metallic NiTi usually comes from a surface defect inducing crack growth, and this means that fatigue has to be studied for concrete applications, with the correct samples, as the state of the material presents size effects. Testing machine experiments on Ni-rich pseudoelastic wires indicate that the main parameter controlling the fatigue life in the traction-traction experiments is the effective stress on the NiTi wire. Long wire life (in the million cycle regime) can be achieved under limited stresses (around or under 200 MPa) in traction-traction tests. Also, experiments have been done on thermal actuation of NiTi wire under traction at constant load. Long actuator life (larger than 300000 cycles) can be achieved at low stresses (around 100 MPa), coherently with the results from the mechanical cycling, but the thermally actuated wires had relatively high macroscopic strains (around 2.5 %) at these stresses.
53 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 12 – O25, P52
ULTRA HIGH STRENGTH NI-RICH NITI-BASED SHAPE MEMORY ALLOYS Karaca Haluka, Saghaian Sayeda, Acar Emrea, Kaya Irfana, Basaran Buraka, Noebe Ronaldb, Chumlyakov Yuriyc aUniversity of Kentucky, Dept. of Mechanical Engr., Lexington, KY, 40504, USA bNASA Glenn Research Center, 21000 Brookpark Rd, Cleveland, OH 44135, USA cSiberian Physical-Technical Institute, Tomsk, 634050, Russia [email protected]
In this study, the mechanical and shape memory properties of the Ni-rich NiTi, NiTiHf and NiTiHfPd single and polycrystalline alloys are investigated. Extensive microstructural and mechanical characterization studies have been conducted to determine their shape memory behavior as functions of aging temperature and time. Effects of heat treatments, crystallographic orientation, application of external stress and test temperature on transformation strain, stress and hysteresis as well as cyclic stability are revealed. It has been determined that precipitation hardening is a very effective tool to increase the material‟s strength resulting in stable superelastic and shape memory behavior of selected alloys. Perfect superelasticity in NiTiHf polycrystalline alloys at temperatures above 200C is achieved. Moreover, it is revealed that stable shape memory effect can be observed in these alloys under ultra high stress levels (>1500 MPa). The thermal hysteresis of Ni-rich NiTi alloys is found to be highly applied stress dependent and can be as low as 5C under 1500 MPa. Ultra high strength NiTi-based alloys provided an opportunity to study the shape memory behavior under high stress levels without the complications stem from extensive dislocation formation.
INFLUENCE OF THE STRUCTURE ON THE STRAIN-CONTROLLED FATIGUE OF NITINOL Kollerov M.Yu. a, Lukina E. b, Gusev D. a, Mason P. b, Wagstaff P. b a“MATI”-Russian State Technological University, Moscow, Russia bKingston University London, London, United Kingdom [email protected]
Many researches believe that the fatigue behavior of nitinol is greatly influenced by its structure [1-2]. It is assumed [2] that, the improving of the nitinol fatigue resistance in the strain-controlled conditions can be achieved by the creation of the microstructure which provides M/slipminimum, where M is the stress of the martensite twinning or its stress-induced formation and slip is the stress at which slip mechanism starts. However evaluation of strain-controlled fatigue resistance of the material like nitinol, which has non-elastic mechanical behavior, by 0. 2 measuring these stresses is almost impossible. It‟s more reasonable to use εc r (critical strain) introduced in [3]. Critical strain characterizes the transition from the martensite twinning or its stress-induced formation mechanism to the slip deformation mechanism. Strains lower that critical are realized by the described martinsite mechanism and the amount of the thermally or mechanically irreversible defects is neglible. Our work considers the influence of the structure parameters (increased dislocation density, volume fraction and dispersity of Ni-rich (Ti3Ni4 and Ti2Ni3) and Ti-rich (Ti2Ni) particles) on the low- and high-cycle fatigue resistance of nitinol and the attempt was made to explain this influence by taking into consideration 0. 2 εc r parameter. The fatigue tests were performed on nitinol wire samples (55.7 wt. Ni) at a temperature of 21 ± 1°C by bending and the rotation of the samples. The rotation frequency was 1.5 Hz. Strain amplitude (a) was in the range of 0.2-8% (mean strain is zero). Resistance to low-cycle and high-cycle fatigue was evaluated by the strain 3 3 6 amplitude which the samples withstood without failure on the base of 10 ( 10 ) and 10 ( 106 ) cycles a a 3 correspondingly. It was found that in low-cycle fatigue conditions (N10 ,a3%) fatigue resistance of nitinol 0. 2 0. 2 depends on εc r . It was revealed that being dependent on (M-slip) difference, εc r is the temperature (since M is determined by the difference in the temperatures of the fatigue tests and the martensite transformation, for ex. Af) and 0. 2 structure dependent parameter. Essential thing is that εc r can reflect the complex influence of the structure, since its modifying often results both in slip and M change (rising of dislocation density or dispersity of Ni-rich particles increases both slip and M, whereas volume fraction of Ni-rich particles governs M by changing its Af). It was 0. 2 found, the higher εc r , the better nitinol low-cycle fatigue resistance. It was revealed that in high-cycle fatigue 6 conditions (N10 , (a0.5%) the substructure of nitinol predominantly determine its fatigue resistance, which is being the best in samples that had high dislocation density or high dispersity of Ni-rich particles. It could be assumed that slip and localization of micro-plastic deformation play the main role this case. It was found that the increasing of Ti-rich particles volume fraction decreases high-cycle fatigue resistance of nitinol. Localization of the micro-plastic deformation on these particles which were not less than 1 micron in size was supposed to be the reason for that.
[1] Wagner M., Dey S., Gugel H., Frenzel G., Somsen C., Eggeler G. (2010). Intermetallics. Vol.18, pp. 1172-1179. [2] Heckmann, A. & Hornbogen, E. (2002) Mat. Science Forum. Vol. 394-5, pp. 325-328. [3] Kollerov M. Yu. et.al. Proc. of the Int. Con. «Ti-2008 in CIS» 2008, p. 407.
54 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 12 – O29, O31
FATIGUE AND SELF -HEATING OF NITI SHAPE MEMORY ALLOYS Vincent Legranda,c, Luc Saint-Sulpiceb, Laurent Pinoa, Shabnam Arbab Chirania,c, Sylvain Callochc aLBMS - ENIB; bLAMI - IUT de Montluçon; cLBMS -ENSTA Bretagne; France [email protected]
Shape memory alloys are materials which are able to recover a large inelastic deformation (up to 8%) under thermomechanical loadings. It is due to a solid-solid diffusionless phase transformation called martensitic transformation. This interesting property makes these alloys suitable for the development of original applications in various domains like biomedical, transport, etc. The thermomechanical behavior of these alloys has been studied more and more since last years. These materials can generate different types of behavior. Superelasticity is one of these behaviors which is obtained under isothermal mechanical loading. This effect is widely used in applications. In recent years, many models have been developed to describe the behavior of these materials. But their fatigue is still a relatively unexplored area. Currently in the design phase of structures based on these materials, fatigue is not considered. In this study, we focus on superelastic NiTi fatigue and also the self-heating phenomena. This study begins with a primary phase based on fatigue tests at low and high number of cycles. By this way, Wöhler curves are obtained by conventional techniques for the studied alloy. These tests permit to determine the fatigue mechanisms in these alloys and also to determine the phase transformation effects on the fatigue properties. A model for the fatigue of superelastic NiTi is proposed and validated. In parallel, self-heating tests are carried out to determine the fatigue properties of these materials by these fast techniques. In this study, we also propose an explanatory model to justify the relationship between self-heating and fatigue properties of superelastic NiTi. The adopted approach in this study allows the development of well-adapted fatigue criteria for these materials. ______
APPLICATIONS OF TI-NI ALLOYS TO CURRENT COLLECTOR AND ELECTRODE MATERIALS IN SECONDARY BATTERY Tae-hyun Nam, Yeon-min Im, Gyu-bong Cho, Jung-pil Noh School of Materials Science and Engineering, Gyeongsang National University, Jinju, Korea [email protected]
Ti-Ni alloys have many advantages for fabricating secondary battery with high flexibility and high cycle performance which are required for mobile electrical appliances such as wearable computer. The superelasticity of Ti-Ni alloys is very useful for realizing secondary battery with high flexibility. The stress induced martensitic transformation in Ti-Ni alloys is useful for improving cycle performance. Moreover, Ti-Ni alloys simplify the process for fabricating secondary battery because electrode materials such as Ti and Ni sulfides, which are typical cathode materials in Li battery, are easily formed on the surface of Ti-Ni alloys by annealing under sulfur atmosphere, while multi-step fabrication processes such as mixing, pasting, drying are necessary in conventional secondary battery without Ti-Ni alloys. In this study we will introduce various electrode system using Ti-Ni alloys, such as sulfide/Ti-Ni, LiNiTiO2/Ti-Ni and Si/Ti-Ni electrodes. In the sulfide/Ti-Ni electrode, Ti and Ni sulfides act as a cathode and Ti-Ni substrates act as a current collector. In the silicon/Ti-Ni electrode, Si act as an anode and Ti-Ni substrates act as a current collector. In the LiNiTiO2/Ti-Ni electrode, LiNiTiO2 act as a cathode and Ti-Ni substrates act as a current collector. The electrodes show a clear charge-discharge behavior with high capacity. The superelasticity of Ti-Ni alloys improve electrochemical properties of the battery by accommodating large volume change during electrochemical reaction.
LiNiTiO2/Ti-Ni Sulfide/Ti-Ni Si/Ti-Ni
55 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 4 – P21, P30
STRUCTURAL CHANGES IN Co-BASED F-SMA Kopeček Jaromíra, Jurek Karela, Kopecký Víta, Fekete Ladislava, Kratochvílová Irenaa, Landa Michalb, Seiner Hanušb, Sedlák Petrb, Bodnárová Lucieb, Šittner Petra, Heczko Olega a Institute of Physics of the AS CR, Praha, Czech Republic b Institute of Thermomechanics of the AS CR, Praha, Czech Republic [email protected]
The alloys in Co-Ni-Al system and even their shape memory properties have been studied for decades as the cobalt based alloys were supposed to have the higher transformation stresses and the wider interval of superelasticity than other shape memory alloys (SMA). Moreover the ferromagnetic shape memory effect is expected. Nevertheless, the published data are controversial as alloy preparation and its thermomechanical treatment are complicated and material is very sensitive to slight changes. The two-phase structure in high-temperature austenitic state is certain exception between SMA. It contains B2 ordered (Co,Ni)Al matrix and A1 fcc solid solution particles. Such microstructure helps compensate transformation stresses and generally improve brittleness. The B2 phase transforms into the L10 martensitic phase, while particles remains unchanged in the A1 structure. To investigate martensitic transformation in these alloys the unidirectional solidified samples were prepared by Bridgman method. The material had to be annealed and quenched as the martensitic transformation is apparently suppressed in the as-grown samples. We examine the effect of different annealing temperatures on microstructure, phase composition and functional properties. To observe phase evolution by the diffraction methods the powders were prepared from the bulk single-crystalline samples. We found peculiar discrepancy in transformation behavior depending on the experimental methods used. The diffraction and magnetic methods (neutron diffraction, electron back-scattered method, and magnetic measurements) established clearly the martensitic transformation close to -70 °C, while resonant ultrasound spectroscopy and microscopy methods (optical, magnetic force and scanning electron microscopy) indicate the change of microstructure already around room temperature. Such behavior points to the instability of the cubic lattice and it can be explained by the overlap of thermal and stress-induced martensitic transformation, which is difficult to distinguish due to stress induced by the particles in microstructure after annealing and subsequent quenching.
EXPERIMENTAL INVESTIGATION ON EVOLUTION OF MACROSCOPIC DEFORMATION PATTERN IN NI-MN-GA MAGNETIC SHAPE MEMORY ALLOY X. Chen, Y.J. He, and Z. Moumni ENSTA-ParisTech, Paris, France [email protected]
Magnetic shape memory alloys (MSMA) such as Ni-Mn-Ga are promising candidates for sensors and actuators for their high-frequency response and large recoverable strain. The large strain of MSMA is due to martensite reorientation driven by mechanical stresses and/or magnetic fields. Considerable theoretical and experimental efforts have been done on the investigation of martensite reorientation in MSMA1−3. However, the deformation instability and the resulted domain pattern evolution of the material during martensite reorientation are seldom reported. By using the in situ optical technique known as digital image correlation (DIC)4, this paper reports the experimental results on the deformation pattern evolution during martensite reorientation in Ni-Mn-Ga single crystal under uniaxial and biaxial compressions. It is found that the strain inside the localized bands does not saturate when the bands nucleate. Moreover, crossing deformation pattern is observed in biaxial compression test.
Fig.1. Nominal horizontal-stress − horizontal-strain curves with corresponding DIC images: (a) uniaxial compression test; (b) biaxial compression test with constant vertical compression of 9 MPa. The values of stresses and strains are positive for compression.
[1] O. Heczko, J. Magn. Magn. Mater. 290-291, 787 (2005) [2] H. E. Karaca, I. Karaman, B. Basaran, Y. I. Chumlyakov, and H. J. Maier, Acta Mater. 54, 233 (2006). [3] B. Kiefer and D. C. Lagoudas, J. Intell. Mater. Systems Struct. 20, 143 (2009). [4] S. Daly, G. Ravichandran, and K. Bhattacharya, Acta Mater. 55, 3593 (2007).
56 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 4 – P7, Session 6 - O1
GEOMETRIC FACTORS ON MAGNETICALLY DRIVEN ACTUATION BEHAVIOUR FOR POLYCRYSTALLINE Ni-Mn-Ga AND ITS COMPOSITES Jan Romberga,b, Claudia Hürricha,b, Martin Pötschkea,b, Stefan Rotha, Sandra Kauffmann-Weissa,b, Uwe Gaitzscha, Peter Müllnerc and Ludwig Schultza,b aIFW-Dresden, Institute for Metallic Materials, Dresden, D-01069, Germany bDresden Technical University, Dresden, D-01069, Germany cBoise State University, Boise, Idaho, USA [email protected]
Ni-Mn-Ga ferromagnetic shape memory alloys (FSMAs) show up to 10% strain in magnetic field due to the motion of twin boundaries. But the large strain is only observed for single crystals. For technical application, polycrystals are of great interest because they are easier to produce und cheaper. But in polycrystals the grain boundaries can hinder twin boundary motion. It is known that in textured polycrystals magnetically induced reorientation is possible. The thermo-mechanical behaviour of polycrystalline Ni-Mn-Ga depends on microstructure and several geometric sample properties. The interdependence of microstructure and shape is more pronounced in plate-shaped specimens and therefore a significantly increase of the magnetic field induced strain may be expected. We used an alloy of the composition Ni50Mn29Ga21 was produced by induction melting. This alloy has a 10 M modulated structure at room temperature and a martensite transition temperature of 65 °C. It was found that in thinner plates the MFIS and the mechanical stability are reduced. Furthermore, it was found that larger grains do not result in higher MFIS in every case because the elastically stored energy is distributed on less grain boundaries. Thus, the instability of grain boundaries against cracks is grater than in the case of fine grained samples. Our aim is to reduce the impact of grain boundaries. We considered the size of grains in order to explain the discovered dependence of plate thickness on strain. There are several approaches to reduce the inhibiting in‼uence of the grain boundaries. For example Ni-Mn-Ga ※bers have been embedded in polymers. Ni-Mn-Ga composites with Ni-Mn-Ga particles are produced by crushing of ingots, ribbons or ※bers The particles are aligned by a magnetic ※eld, while the polymer matrix cures. The particles form chains within the matrix. Thus the brittleness of these composites increases and requires lower ※lling fraction then the theoretical maximum for spherical particles. For Ni-Mn-Ga composites of differently shaped particles ※lling fraction of 20 % and up to 50 % are published. For a maximum strain of the composite a matrix material with stiffness matched and a high ※lling fraction is necessary. The so far known composites with Ni-Mn-Ga particles or ※bers show magnetically induced strains of approximately 0.1 %. The Findings were used to design new composites of Ni-Mn-Ga and polyurethane which show up to 1 % MFIS and are stable over one million cycles of strain. Since the production of composite material relies on the production of simple polycrystals, it is simple and producible with low energy consumption and therefore inexpensive to manufacture.
MECHANICAL BEHAVIOR STUDY OF NITI ENDODONTIC FILES TAKING INTO ACCOUNT ANATOMIC SHAPE OF ROOT CANALS V. Legranda,b, S. Moyneb, L. Pinoa, S. Arbab Chirania,b, S. Callochb and R. Arbab Chiranic aLBMS – ENIB ; bLBMS -ENSTA Bretagne; cLATIM – UFR d’Odontologie– UBO; France [email protected]
Nickel-Titanium (Ni-Ti) rotary instruments, which are much more flexible than traditional stainless steel instruments, have been used since the 90s to improve the effectiveness and the speed of endodontic preparation even in curved root canals. This extreme flexibility is due to the superelasticity Ni-Ti Shape Memory Alloys (SMA). An increasing number of Ni-Ti instrument systems are currently available1. These files have unique design properties in terms of cross-sectional shape with „radial lands‟ or sharp cutting edges, constant or variable pitch, progressive or constant taper, etc1. However, whatever the instrument may be, intracanal separation can occur2. Some authors relate it mainly to fatigue caused by repetition of bending stresses in curved canals. Other authors point out torsion as a primary mechanism responsible for fracture. In this paper, we proposed to study the mechanical behavior of NiTi files taking into account the real form of root canals. This study is based on finite elements simulations using a well adapted model describing the superelasticity of NiTi alloys3. For this simulations ABAQUS finite elements software developed by Simulia-USA is used. The real shape of root canals obtained by microtomography of teeth4, are applied as limit conditions in numerical simulations. The complete sequences of root canal preparation using Revos files made by MicroMega-France are simulated. This study permits to identify the real loading path under which the NiTi files are used. This is very important for the design of future files or for the fatigue study of these structures. [1] Hülsmann M, Peters OA, Dummer PMH. Endod Topics,10:30-76, 2005. [2] Parashos P, Messer HH. J Endod, 32:1031-43, 2006. [3] Saint-Sulpice L, Arbab Chirani S, Calloch S. Mechanics of Materials, 41(1):12-26, 2009. [4] Arbab Chirani R, Chevalier V, Jacq JJ, Calas P., (Abs) Int. Endod. J., 40:993-4, 2007.
57 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 3 - O1, O4
MARTENSITIC TRANSFORMATION FROM FERRITE TO AUSTENITE IN FERROUS ALLOYS K. Ishida Department of Materials Science, Graduate School of Engineering, Tohoku University, Sendai, Japan [email protected]
The fcc austenite γ phase in ferrous alloys undergoes two types of martensitic transformations, namely, (1) to the bcc or the bct α‟ phase and (2) to the hcp ε phase. However, a very rare case of transformation from the ferrite α phase to the γ phase has been reported in Fe-Cr-Ni- base stainless steels [1] and duplex Fe-Mn-Al-C alloys [2]. This kind of transformation has been confirmed in the Fe-Mn-Ga [3] and Fe-Mn-Al [4] systems. This peculiar transformation is caused by the temperature dependence of the partial molar free energy change of Mn, Ni, Cr, etc., between the α and γ phases due to the magnetic effect [5-6]. The martensitic transformation of the Fe-Mn-Al alloy [4] is non-thermoelastic, while that of the Fe-Mn-Al- Ni alloy is thermoelastic, which shows a small temperature dependence of superelastic stress over a wide temperature range due to a small entropy change between the α and γ phases [7]. The characteristic features of the α → γ‟ martensitic transformation are presented.
[1] T. Tomida, Y. Maehara and Y. Omori, Mater. Trans. JIM, 30 (1989) 326. [2] S. K. Chen, K. H. Hwang, C. M. Wan and J. G. Byrne, Scripta Metall., 23 (1989) 1919. [3] T. Omori, K. Watanabe, R. Y. Umetsu, R. Kainuma, and K. Ishida, Appl. Phys. Lett. 95 (2009) 082508. [4] K. Ando, T. Omori, I. Ohnuma, R. Kainuma and K. Ishida, Appl. Phys. Lett. 95 (2009) 212504. [5] K. Ishida, K. Shibuya and T. Nishizawa, J. Jap. Inst. Met., 37 (1973) 1305. [6] K. Ishida and T. Nishizawa, Trans. JIM, 15 (1974) 217. [7] T. Omori, K. Ando, M. Okano, X. Xu, Y. Tanaka, I. Ohnuma, R. Kainuma, K. Ishida, Science, 333 (2011) 68.
THE EFFECT OF HYDROGEN ON DEVELOPMENT OF - - MARTENSITIC TRANSFORMATIONS UNDER LOADING IN AUSTENITIC STAINLESS STEEL SINGLE CRYSTALS Kireeva Irina, Chumlyakov Yuriy, Tverskov Anton Siberian Physical Technical Institute of the Tomsk State University, Tomsk, Russia [email protected]
The effect of hydrogen on development of - - martensitic transformations (MT) during tensile deformation have been investigated in single crystal orientations [-111] - [-123] - [001] of austenitic stainless steel 2 (ASS) Fe-18%Cr-12%Ni-2%Mo (wt.%) with low stacking fault energy sf=0.025 J/m in dependence on the crystal axis orientation and the test temperature using transmission electron microscopy and X-ray diffraction analysis. It is shown, that in a condition without hydrogen - - MT in single crystals of ASS develops during plastic deformation at Т <173 K. The amount of slip deformation at T=77 K prior to - - MT is established to be dependent on the crystal axis orientation. - - MT in [- 111] - crystals starts from the beginning of the plastic flow 3%, whereas in [-123]- crystals - - MT is observed after significant amount of slip deformation =16% and in [001] - crystals - - MT do not develop. Alloying with hydrogen (for 10 hours at 50 mA/cm2 at a temperature of 300 K) of ASS [-111] - [-123] - [001] – single crystals leads to development - - MT at Т=300 K from the beginning of a plastic deformation. Development of - - MT at Т=300 K proves to be true researches transmission electron microscopy and X-ray diffraction analysis and temperature dependence of critical resolved shear stress cr (T). At simultaneous alloying with nitrogen to CN=0.25 wt. % and hydrogen at t2 hours of ASS [-111] - [-123] - [001] – single crystals - - MT under loading in them develops at Т=77К. It is shown, that at alloying with hydrogen of ASS [-111] - [-123] -
[001] – single crystals orientation dependence cr is observed and cr [001]>cr [-111]>cr [-123]. The physical reason of development - - MT at Т=300 K at alloying with hydrogen is connected with influence of hydrogen on value of stacking fault energy and as consequence of it on thin structure of a dislocation.
58 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 3 – O2, O3
STRUCTURAL MECHANISM OF REVERSE αγ TRANSFORMATION AND NEW FUNCTIONAL PROPERTIES OF Fe-Ni AUSTENITIC ALLOYS V.V.Sagaradze, I.G.Kabanova, N.V.Kataeva, and M.F.Klyukina Institute of Metal Physics, Ural Branch, Russian Academy of Science [email protected]
The analysis of structural peculiarities of the reverse martensitic α-γ transformation during the heating is of great importance for understanding the reasons of formation of the nanocrystalline austenite as a result of realization of direct and reverse γ-α and α-γ transformations in the massive samples of metastable austenitic steels. Structural mechanism of formation of the nanocrystalline austenite upon 500 transformation in massive items of any size has been defined. The structure of нм the metastable austenite Fe–32%Ni alloy quenched for martensite and subjected to the transformation at slow heating (to 430–500ºС) with the formation of a nanocrystalline austenite (fig.1) of different orientation was investigated by methods of electron microscopy. Electron diffraction analysis has revealed that the L10 superstructure is characteristic of a nickel-enriched disperse phase both after slow heating of Fig 1 Structure of nanocrystalline the alloy to 430°С and after its subsequent additional annealing at 280°С for austenite in Fe–32%Ni alloy. 120 h (fig. 2a). Together with the phase, there was detected the disperse ε martensite with a hexagonal close-packed (hcp) lattice, whose volume fraction increased with rising the temperature of slow heating (fig.2b). Along with the realization of ordinary orientation relationships (ORs) of Kurdjumov – Sachs, between a matrix phase and an ordered phase in the sample of Fe–32%Ni alloy after slow heating to 500°С there have been established Headley–Brooks Ors (fig.2c). Such cyclic transformation promotes the improvement of many functional properties of steels (strength properties, coercive force, swelling resistance under irradiation and others).
111ε 010ε 141α 210ε 020 222α εεε 110 111γ 110α 110ε γ 220γ 222α 112α 110γ 100ε 110γ 220γ 001γ 101ε 001γ 111γ 002α 002γ 002γ 200 a b c Fig. 2. Reflections of superstructure L1o (a), ε-phase (b) и Headley–Brooks Ors (c) в in Fe-32%Ni alloy after α→γ transformation during slow heating to 430°С (a,b) and to 500°С (c).
STRUCTURAL AND HARDNESS GRADIENTS IN THE HEAT AFFECTED ZONE OF WELDED LOW CARBON MARTENSITIC STEELS D.P. Dunne a and W. Pang b a Faculty of Engineering, University of Wollongong, Wollongong, NSW, Australia, 2522. b Bisalloy Steels, Unanderra, NSW, Australia, 2526. [email protected]
Welding of low carbon martensitic steels with yield strengths above 690 MPa requires careful attention to the welding procedure to avoid hydrogen assisted cold cracking (HACC) and to minimise degradation of the mechanical properties of the weldment. Investigations of the microstructural and hardness gradients in the heat affected zone (HAZ) of these types of steels revealed that the peak hardness does not occur in the grain coarsened heat affected zone (GCHAZ) adjacent to the fusion boundary, as normally observed for ferritic steels, but is displaced towards the grain refined region (GRHAZ). This phenomenon, referred to as the displaced hardness peak (DHP) effect, is considered to arise when the hardenability of the steel is sufficiently high to produce the same microstructure in the both the GC and GR heat affected zones, but refinement of the austenite grains and the martensitic/bainitic transformation product in the GRHAZ increases the hardness and strength above that of the GCHAZ. Implications relative to the susceptibility of the weldments to HACC are discussed.
59 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 3 – O5, P8
ADDRESSING RETAINED AUSTENITE STABILITY IN ADVANCED HIGH STRENGTH STEELS Elena V. Pereloma,a, Azdiar A. Gazder,b and Ilana B.Timokhinab , aSchool of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, NSW 2522, Australia bCentre for Material and Fibre Innovation, Deakin University, Geelong, VIC 3217, Australia [email protected]
Advances in the development of new high strength steels resulted in the microstructures containing a significant amount of retained austenite. The transformation of retained austenite to martensite on straining contributes to improved ductility. However, in order to achieve this beneficial effect not only the amount, but size, morphology and distribution of the retained austenite should be controlled. It is well known that carbon concentration in the retained austenite is responsible for its chemical stability, whereas size and morphology determines its mechanical stability. Thus, to achieve the required mechanical properties control of the processing parameters affecting the microstructure development is essential. In this paper we present the examples of various microstructures produced in Transformation-Induced Plasticity (TRIP) steels and bainitic steels as a function of processing parameters. The stability of retained austenite during tensile testing was evaluated, as well as contribution of the TRIP effect to mechanical properties. Transmission electron microscopy and atom probe tomography were utilised for detailed characterisation of composition, morphology and location of retained austenite. It has been shown that chemical overstabilisation of the retained austenite, which prevents TRIP effect, leads to lower ductility of studied steels.
INFLUENCE OF MECHANICAL LOADING, TEMEPARTURE AND CHEMICAL COMPOSITIONS ON THE DEFORMATION INDUCED MARTENSITE FORMATION IN METASTABLE AUSTENITIC STEELS Hahnenberger Frank, Smaga Marek, Eifler Dietmar Institute of Materials Science and Engineering, University of Kaiserslautern, D-67653 Kaiserslautern, Germany [email protected]
The deformation induced martensite formation in the metastable austenitic steels AISI 304, 321 and 348 was investigated in tensile and in low cycle fatigue tests at ambient and low temperature. By means of stress-strain and magnetic measurements, the mechanical behavior and phase transformation were characterized. The susceptibility of deformation induced martensite depends on the chemical composition, the temperature and the degree of plastic deformation. The investigated steels show differences in austenite stability, which lead to significant differences in the amount of deformation induced martensite and their mechanical behavior. Dependent on the type of steel and the testing temperature similar martensite fractions but different strengths developed.
Fig. 1: Development of ‟-martensite content versus the accumulated plastic strain at different temperatures in low cycle fatigue tests with a constant total strain amplitude of 1 %
The development of the martensitic phase during fatigue loading shows a sigmoidal shape, leading to different plateau values for certain combinations of austenite stability and testing temperature (Fig. 1). On the basis of comprehensive experimental data for fatigue tests a new mathematical model was developed to describe and predict the martensite formation under cyclic loading in the temperature range from -60°C to 25°C.
60 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 3 – O7, O10
UNEXPECTED CONSTRAINED TWIN HIERARCHY IN RU-BASED HIGH TEMPERATURE SHAPE MEMORY ALLOYS MARTENSITE Philippe Vermauta,b, Anna Manzonic, Anne Denquinc, Frédéric Primaa and Richard Portiera a Groupe de Métallurgie Structurale LPCS UMR-CNRS 7045, Chimie Paristech, 11 rue P et M Curie 75231 Paris, France b Université Pierre et Marie Curie, 4 Place Jussieu 75231 Paris, France c ONERA 29 Avenue de la Division Leclerc, Châtillon 92260, France [email protected]
As a consequence of a structural phase transformation with a decrease of the symmetry between the parent austenitic phase and the martensite, a finite number of variants is generated in each grain of the parent phase. They can be counted using simple group theory argument and each of them has the same probability of nucleation. Each lost symmetry operation of the parent phase transforms one martensite variant into another one. In the case of martensitic transformation, because of the unit cell transformation, the self accommodation of the variants is necessary for minimizing the deformation but the equiprobability of nucleation of the variants will lead to an equiprobability of the production of the self-accommodated group of martensite in each grain of the austenite grains (Ni-Ti, Cu-Al-Ni alloys). The situation can be different when the martensitic transformation is constrained by some structural features. RuNb and RuTa alloys exhibit martensitic transformations above 1000K providing them an interesting high temperature shape memory effect. If equiatomic compounds undergo two successive martensitic transformations, β (B2) β‟ (tetragonal) β‟‟ (monoclinic), out of stoechiometry alloys exhibit a single transition from cubic to tetragonal. In the case of two successive martensitic transformations, we expect to have a finer microstructure of the second martensite because it is supposed to develop inside the smallest twin elements of the former one. In equiatomic Ru-based alloys, if the first martensitic transformation is “normal”, the second one gives unexpected microstructures with twins with a thickness which is larger than the smallest spacing between twin variants of the first martensite. In fact, the second martensitic transformation takes place in special conditions and it is: geometrically constrained (twin variant with a few nanometers thickness for the first martensite), elastically constrained (with a large evolution of the tetragonal martensite on cooling in the temperature range of its existence domain, the stored elastic increases and acts as a trigger for the second transformation), crystallographically constrained (twins planes of the tetragonal martensite are inherited by the monoclinic martensite).TEM and EBSD, have permitted to understand this unexpected microstructure and allowed explaining some unexpected aspects of the shape recovery behaviour of equiatomic alloys.
PARAMETERIZATION AND STATISTICAL CHARACTERIZATION OF THE MARTENSITE- AUSTENITE ORIENTATION RELATIONSHIP Yardley V. A.a, Payton E. J.a,b aInstitut für Werkstoffe, Ruhr-Universität Bochum, Bochum, Germany bBundesanstalt für Materialforschung und -prüfung, Berlin, Germany [email protected]
Orientation relationships (OR) between parent and product phases in martensitic transformations have been represented in a number of ways, for example by orientation matrices, Euler angles or by comparisons to named orientation relationships such as those of Kurdjumov and Sachs (KS) [1] and Nishiyama and Wassermann (NW) [2,3]. Since the OR between martensite and ferrite in steels does deviate significantly from both KS and NW, the first two of these options allow more flexibility in manipulation than the third. However, they have the disadvantage that the martensitic transformation generates either 12 or 24 variants, each of which can be described in one of 24 crystallographically equivalent ways, such that for a precise determination of ORs and their variation from experimental data, all data points must be mapped on to some chosen representative variant. An alternative approach is to use a notation that separates out the material-specific part of the OR from the part arising from the crystal symmetry of the parent and product phases. In the article by Kurdjumov and Sachs in which they proposed the OR that now bears their names [1], they also listed three angular parameters describing the deviation between the {001} planes in martensite from the {001} planes of the nearest Bain correspondence unit cell (although they did not denote this as such). These small deviations are the same in magnitude for each variant and, as three independent parameters, provide a sufficient description of the rotational part of the OR. They can be used to calculate the full set of variants given the set of Bain correspondence matrices. In addition, this representation provides a relatively straightforward and computationally light way of extracting the OR from experimental orientation data obtained using electron backscatter diffraction (EBSD) and allows a more thorough statistical treatment of the OR than was previously possible. [1] G. Kurdjumow and G. Sachs, Z. Physik 64 (1930) 325-343 [2] Z. Nishiyama, Science Reports of the Tôhoku Imperial University 23 (1934) 637-664 [3] G. Wassermann, Mitteilungen aus dem Kaiser-Wilhelm Institut für Eisenforschung zu Düsseldorf 17 (1935) 149-155
61 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 11 - P, Session 3 - O11
EFFECT OF TITANIUM CARBIDE INCLUSIONS ON MORPHOLOGY OF LOW-CARBON STEEL MARTENSITE H.A. Pham, Takuya OHBA, Shigekazu MORITO, Taisuke HAYASHI Department of Materials Science, Shimane University 1060 Nishikawatsu-cho, Matsue-shi, Shimane 690-8504, Japan [email protected]
Recently many crystallographic features of martensite in low-carbon steels have been extensively studied. However the effect of inclusion particles in austenite on transformation kinetics of martensite and its morphology has not been systematically investigated. Fine dispersive inclusions, such as titanium carbide (TiC) and vanadium carbide which strengthen the austenite by a particle-strengthening mechanism, may have a strong effect on nucleation and growth of martensite. In this study the effect of TiC inclusions on morphology of martensite in two low carbon steels with composition of Fe-0.23C-0.92Mn- 1.0Ti (mass %) - steel 1 and Fe-0.15C-2.89Mn 0.45Ti – steel 2, was investigated.
Microstructure was examined by using optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscope Figure 1. Lath martensite in steel 1 after heating at 1300oC for 105s, followed by (TEM). The crystallographic features of martensite were studied by high water-quenching (prior austenite grain resolution electron backscatter diffraction (EBSD). The main inclusion phase in boundaries were made-up by white line) hot-rolled specimens of both two steels is TiC which has morphology of coarse micro-size particles and dispersive fine nano-size particles aligned in rows. The microstructure of heat-treated specimens observed by optical microscope is as- quenched lath martensite with micro-size particles of TiC dispersed inside the packets and at prior-austenite grain boundaries. Although the heat treatment was performed at high temperature (1300oC) for a long time (105s), the obtained microstructure is very inhomogeneous with the simultaneous existence of large and small prior austenite grains (Fig.1). EBSD analyses showed the dispersive distribution of many minor blocks (blue and red) within a large block (yellow) Figure 2. Steel 2 after heating at 1300oC 5 in a martensite packet (Fig.2). The preferential direction and irregular shape of for 10 s, followed by water-quenching – block map of a lath martensite packet blocks were also remarked. The results of fine morphology observation obtained by EBSD. investigated by high resolution EBSD and TEM will be discussed in detailed to reveal the effect of dispersive TiC particles on transformation kinetics and morphology of martensite in two studied steels.
STUDY OF METALLURGY AND MECHANICAL PROPERTY ON JAPANESE SWORD aM. Yaso, aT. Takaiwa, aY. Minagi, bT. Kanaizumi, bK. Kubota, cT. Hayashi, cS. Morito, cT. Ohba aYasugi municipal Wakoh Museum, Yasugi, Japan bMetallurgical Research Laboratory in Yasugi Works, Hitachi Metals, Ltd., Yasugi, Japan cDepartment of Materials Science, Shimane University, Matsue, Japan [email protected]
From recent metallurgical studies on Japanese sword, lath martensite recognized in modern tool steel is observed in the area of its cutting edge. Functionally graded structure changes lath martensite to fine pearlite while observation point goes away from the cutting edge and hamon (in Japanese, like wavy pattern) which enhances one of many artistic values is formed on the surface due to this structural transition. Though Japanese sword has quite long history more than one thousand years, regrettably actual strength and toughness of its sword has never been investigated scientifically up to now. In this research, two Japanese swords which are modern sword and old sword, were prepared respectively and specially polished for evaluation of those mechanical properties. After observation of microstructure, residual stress on the surface was measured by XRD. Moreover, four-points bending test has been performed to estimate actual strength of sharp edge. As a result of this series of investigation, it is found that magintude of the strength of sharp edge and tendency of the crack propagation in bending fracture mode are mainly dependent on the microstructure distribution and the grain size in cross section of Japanese sword. The old sword-specimen after bending test is shown in Fig.1 and Fig.2 indicates its fracture surface.
62 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 11 – P2, O3
REACTIVE STRESSES AND BURST CHARACTER OF SHAPE MEMORY DEFORMATION IN SINGLE CRYSTALS CuAlNi AND NiFeGa V.I. Nikolaev, G.A. Malygin, S.A. Pulnev, P.N. Yakushev , V.M. Egorov Ioffe Physico-Technical Institute of RAN, St.Petersburg, Russia [email protected]
Two effects have been studied in present work. One of them is influence of reactive stresses on kinetic and thermodynamic of martensitic transformation [1], the another is high rate (burst) recovery deformation due to shape memory effect (SME) [2]. It has been revealed that there was an essential difference in specific heat of identical monocrystalline strip specimens of CuAlNi alloy tested in DSC2, Perkin-Elmer: 1) as-grown , 2) unloaded after deformation, 3) deformed and clamped in a stainless ring. The clamping leads to generation of elastic stresses in the specimen at heating. In-situ experiments show essential decrease of specific heat in the case of the clamping crystals. The effect strongly depends on a value of reactive stresses which were varied by changing the thickness of strip specimens. The obtained result means that in conditions of constrained SM deformation a part of thermal energy of martensitic transformation is spent on a creation of the reactive stresses in the strip. The stress-strain curves and the behavior of SM deformation near transformation temperature have been studied in NiFeGa crystals compressed along [100] and [110]. In the case of [100] orientation we observed smooth stress-deformation curves but in the second case they contained two smooth stress drops which the crystal exhibited only elastic deformation. The rate of SM deformation recovery was measured by optical laser interferometer and video control system. Strong orientation effect was observed in NiFeGa single crystals in the course of their subsequent heating. The crystal compressed along [110] axis revealed a burst character of the SM deformation at temperature of 361 K. As a result, the specimen with an additional load of 400 g jumped on a height of 66 mm under the hard base. Calculations showed that this hight corresponds to a work of W =0.26 J and the initial velocity 1.2 m/s for the sample with 400 g additional load, and 22 m/s in the absence of it, in contrast to crystal deformed in [100] direction. This crystal was undergone martensitic transition at ordinary temperature 288 K and had a smooth character of SM deformation recovery. This temperature difference is indication of a significant hysteresis of the transition, that is, of a strong resistance of deformed [110] crystal to motion of interphase boundaries. The observed difference in deformation behavior of [110] and [100] crystals may be explained by low values of tangential stresses operative in the {110} twinning planes in the case of crystal compression along [110] axis. This circumstance is a probable reason of unstable character of deformation behaviour and stress drops on deformation curves of [110] crystal. These drops may be caused twin massive reorientation of crystal lattice near stress concentrators or be possible the result of formation of an orthorhombic martensite phase. The total energy stored during unstable deformation becomes free at heating and, as calculations show, is completely spent on an elevation of crystal with the addihional load 400 g on the hight 66 mm. [1] V.I. Nikolaev, V.M. Egorov, G.A. Malygin. S.A. Pul‟nev. Phys. Solid State 52, 2419 (2010). [2] V.I. Nikolaev, P.N. Yakyshev, G.A. Malygin, S.A. Pul‟nev. Techn. Phys. Lett. 36, 914 (2010).
ATOMIC DENSITY FUNCTION MODELING OF FCC TO BCC TRANSFORMATION Maryline Certain, Helena Zapolsky and Renaud Patte. GPM, UMR 6634, CNRS, University of Rouen, Saint-Etienne du Rouvray, France [email protected]
Although the present understanding of atomic systems in thermodynamic equilibrium is rather satisfactory and is based on well established theoretical methods, the dynamic theory of atomic-scale evolution during phase transformation is far from completion in spite of extensive experimental and theoretical investigations. Recently, the continuum version of atomic function density (ADF) theory has been proposed to model atomic-scale evolution of crystalline patterns at [1,2]. It was shown that, in fact, the continuum version of the ADF kinetic theory is a particular case of the previously developed atomic density theory based on underlying Ising lattice. A small parameter determining the limit transition to continuum is the ratio of the underlying Ising lattice parameter to the atomic interaction radius. A theoretical foundation of the ADF method is based on the non-equilibrium Helmholtz free energy of a system that is a functional F[ρ] of an arbitrary distribution of atomic density function, ρ(r). The ADF kinetic equation is based on assumption that the relaxation rate, (,)/r t t where t is time is linear proportional to the transformation driving force, Fr[]/() . The purpose of this paper is to demonstrate that the ADF approach has a sufficient versatility to describe the different crystallographic structures and can give an insight on the atomic rearrangement during martensitic transformation.
[1] Y. Jin, A. G. Khachaturyan, J. Appl. Phys. 100, 013519 (2006) [2] M. Certain, H. Zapolsky, A.G. Khachaturyan, Solid State Phenomena, 172-174,1234(2011)
63 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 11 – O2, O4
SUPERELASITC BEHAVIOR ASSOCIATED WITH SECOND ORDER-LIKE MARTENSITIC TRANSFORMATION IN A DISORDERED FE-31.2PD (AT.%) ALLOY Xiao Fei, Fukuda Takashi, Kakeshita Tomoyuki Department of Materials Science and Engineering, Graduate School of Engineering, Osaka University, Osaka, Japan [email protected]
The disordered Fe-31.2Pd (at.%) alloy exhibits a weak first order (second order-like) martensitic transformation from the A1-type parent phase to the so-called FCT martensite at about TM = 230 K. This transformation is characterized by a small latent heat of about 0.3 J/g. The jump in lattice parameters at TM is also small (about 1%), and the lattice parameters of the FCT martensite change gradually below TM. Such transformation characteristics are largely different from those of conventional shape memory alloys such as Ti-Ni and Cu-Al-Ni alloys. Consequently, we may expect different superelastic behavior in the Fe-31.2Pd alloy from that of conventional shape memory alloys. However, mechanical behavior of the alloys exhibiting second order-like transformation has been hardly investigated until now. In this study, therefore, we have investigated superelastic behavior of the Fe-31.2Pd alloy by using a single crystal. A compressive stress was applied in the [001] direction, which corresponds to the c-axis (short axis) of the martensite, and the strain was measured in the [001] direction by attaching a strain gage on the specimen. The Young‟s modulus of the parent phase decreases almost linearly on approaching TM, and the value at 240 K is about 1GPa, being the same order as that of polycarbonates. At this temperature, a large elastic-like strain of 6.5% is obtained; the strain of 6.5% perfectly recovers in the stress removing process with negligibly small hysteresis. The specimen start to yield when the strain exceeds 7.3% at 240 K, and the yield stress is about 285 MPa. The yielded specimen shows traces of slip plane. On the other hand, when the same experiment is made by using a polycrystalline specimen, the Young‟s modulus at 240 K is 24 GPa, and the elastic limit is below 1%.
ELECTRIC RESISTIVITY AS PHASES VOLUME FRACTIONS INDICATOR IN METASTABLE ALLOYS Luc Saint-Sulpicea, Mohamed Lakritb, Shabnam Arbab Chiranic, Sylvain Callochb a Insitut Pascal – IUT d'Allier, Montluçon, France b LBMS – ENSIETA, Brest, France c LBMS - ENIB, Brest, France [email protected]
The microstructure of metastable alloys varies with the thermomechanical history of the material. During a thermomechanical loading, different phases can be present in the material simultaneously. They can be at the origin of macroscopic stress and strain. Consequently, it is important to determine the proportion of each phase to understand the transformation kinetic. However, the techniques usually used to carry out these measures such as magnetic properties measurments, neutron or X-ray diffraction (Šittner and Novák, 2004), are heavy and require a lot of ressources. This study, thanks to experimental tests based on electric resistance measurements, permits to determine the volume fraction of the different states present in the material. These measurements were realised on a copper based shape memory alloy in order to determine the volume fraction of the three possible state of the alloy which are austenite, stress induced martensite and twinned martensite. The method is also effective on stainless steel as it takes into account the effects of elasticty, transformation and plasticity, and then permits to determine the volume fraction of the different phases of the material during transformation coupled with plasticity. This method is simple, low cost and easy to implement on any testing machine. The results of the tests were qualitatively compared with other methods. The next step of the study is to fully validate this method by comparing quantitatively the results with usual methods such as magnetic properties measurments, or neutron diffraction.
[1] P. Šittner and V. Novák, Scripta Materialia", 51/4, 2004, pp 321-326
64 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 11 – O5
ON RETURNABLE ACCUMULATION OF DEFORMATION AT BIOCOMPATIBLE QUENCHED Ti-(Nb, Ta) ALLOYS Mikhail Petrzhik National University of Science and Technology “MISIS”, Moscow, Russian Federation [email protected]
Ternary and quaternary Ti–Nb-based alloys have been extensively investigated during the last several years and the results confirm the possibility of producing Ni-free, Ti-based solid solution alloys with superelasticity thanks to reversible β to α″ martensitic transformation [1,2]. In this work products of martensitic transformation of biocompatible quenched Ti-(Nb, Ta) alloys have been studied by elastic E and G moduli determination, thermal analysis, tensile tests and nanoindentation. The experimental results were analyzed taking into account XRD data on phase composition, as well as on degree of distortion R=√3a/b of orthorhombic alfa”-martensite (Cmcm space group) according to Yu.A. Bagariatskii‟s diagram of transition [2,3]. It was found that experimental realization of superelasticity (up to 2,5 % of returnable deformation) was closed to its theoretical limit [3] and it was observed at alloys having extremely low Young‟s modulus (about 60 GPa and less) and the largest rhombic distortion (about R=1.16) of unit cell. Also it was noted a high thermal stability of the martensitic structure against thermal cycling [4]. So, the alloys are attractive for medical applications as metallic implant materials combining superelasticity with biocompatibility comparable to that of pure titanium.
[1] S. Miyazaki, H.Y. Kim, H. Hosoda, Mater. Sci. Eng., A 438–440 (2006) 18. [2] M.I. Petrzhik, S.G. Fedotov., Proc. XVI Conf. on Applied Crystallography,1995, World Sci.Pbl., р. 273. [3] Yu.S. Zhukova, M.I. Petrzhik, S.D. Prokoshkin. Russian Metallurgy (Metally), 2010, No.11, p. 1056 [4] Petrzhik M.I.; Fedotov, S.G.; Kovneristyj, Yu.K.; Zhebyneva, N.F. Metall Science and Heat Treatment No. 3 Mar 1992 p.
65 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 6 –O2, O3
OPTIMIZATION OF SUPERELASTIC PROPERTIES IN TITANIUM-NIOBIUM ALLOYS USING SHORT-TIME THERMAL TREATMENTS Frédéric Primaa, Fan Suna, Wafa El Mayb, Thierry Gloriantc, Pascal Laheurteb, Yulin Haod a Laboratoire de Physico-Chimie des Surfaces, (CNRS-UMR 7045) Groupe de Métallurgie Structurale, ENSCP Paris, France. b Laboratoire d’Etude des Textures et Application aux Matériaux LETAM (CNRS-FRE 3143), Université de Metz, France c Laboratoire de Science Chimique SCR/CM (CNRS-UMR 6226) Groupe Chimie Métallurgie, INSA Rennes, France. d Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, China [email protected]
The short-time thermal treatment strategy has been proved to be very efficient in improving the mechanical properties of various titanium based alloys. The mechanical properties of alloys such as Ti-Nb, Ti-Nb-Zr and Ti-Nb- Zr-Sn based alloys, are extremely sensitive to the beta phase stability, microstructure and phase constitution. The concept of the short-time treatment is designed to control precisely the material structure (phase precipitation, etc…) without extensive modification of the distribution of alloying elements. This results in reliable optimizations regarding the balance between elastic modulus, pseudo- (super-) elasticity and strength. For orthopedic applications, a low modulus (< 60 GPa) could be obtained after short-time thermal treatments resulting in micronic grains size and nanostructured phase precipitation of alpha and/or omega phases. Recent results on Ti-20Nb-6Zr (at%) and Ti-Nb-Zr-Sn (Ti2448) confirms that a balance among relatively low modulus (45 - 55 GPa), high strength (800-1000 MPa) and stable recovery strain (~ 2.6%) can be achieved by the studied treatment through very good control of micro- and nanostructuration. Excellent fatigue endurance can be expected, due to the associated suppression of stress induced martensitic (SIM) transformation. On the other hand, short-time thermal treated materials (Ti-Nb and Ti-Nb-Zr) exhibit superior super- elasticity, an important mechanical behavior required by orthodontic applications, which is optimized (complete recovery till 3.4% and maximum recovery of about 3.8%) with high critical resolved shear stress (CRSS) for martensitic transformation at about 400 MPa and a yield stress for dislocations slip at around 900 MPa. The corresponding microstructures on the treated material display a fine grain size (> 500 nm) and a well-dispersed nano-scale omega precipitation, both of which benefit in improving both mechanical strength and large and stable superelasticity. Currently, the structural evolution mechanisms involved in the short time treatments are under systematic investigations in the aim of achieving accurate control of the microstructures and optimized balance of mechanical properties.
STRESS AND DEFORMATION ANALYSIS ON NiTi AND TINB SHAPE MEMORY ALLOY MINIPLATE SYSTEMS FOR THE TREATMENT OF ATROPHIC MANDIBULAR FRACTURES Vahid Attari , Benat Kockar Department of Mechanical Engineering, Hacettepe University, 06800, Ankara, Turkey [email protected]
The purpose of this study is to investigate the Ti-based shape memory alloys which are prospective candidate materials in the production of miniplates for the treatment of atrophic mandibular fractures. Miniplate fixation of fractured atrophic mandibles is sometimes not sufficient therefore; reconstruction plates or two miniplates have been recommended for the treatment. However, fixation of these fractures using two miniplates or one reconstruction plate has created so many problems in patients such as violation of the inferior alveolar nerve. Additionally, using single miniplate in some treatments may also have some disadvantages such as fracture of the bone and/or miniplate due to high external loads, biting forces and/or stress shielding effect. A mandible model is constructed from the Computer Tomography (CT) scan images of a 74 year old female patient. The mandible of the patient together with the miniplate and screws are integrated and the whole model which is to be investigated by finite element modelling is established. The model is supported by three constraint points. Anterior and posterior types of loadings are applied at different magnitudes to fully understand the stress sharing and stress bearing behavior of the miniplate and mandible. Maximum Principal Stress levels on the bone and Von-Mises Stress levels on the miniplates and screws and deformation magnitudes are determined via running the finite element analysis using NiTi and TiNb. The reason of choosing NiTi and TiNb is that these alloys show excellent biomechanical compatibility, corrosion resistance and very high superelasticity. The results of the FE analysis have shown that the anterior loading is deforming the mandible relatively higher than that of posterior loading due to location of load application point. The aforementioned shape memory alloys investigated in this study lead to a considerable decrease in the stress levels on the bone and as well as on the miniplates. The results are very promising in terms of using NiTi and TiNb alloys instead of rigid pure Titanium and some other rigid materials used in biomedical industry conventionally. 66 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 4 –O1, O2
HYPERSTABILIZATION OF Cu-Al-Be AND Ni-Fe-Ga MARTENSITES a Santamarta R., a Kustov S., a Cesari E., b Sapozhnikov K., c Van Humbeeck J. aUniversitat de les Illes Balears, Palma de Mallorca, Spain bA.F.Ioffe Physical-Technical Institute, St.Petersburg, Russia cKatholieke Universiteit Leuven, Leuven, Belgium [email protected]
The martensite is hyperstabilized when only a small volume fraction retransforms upon heating into the parent phase over a temperature range slightly higher than the nominal reverse transformation temperature, whereas the rest of martensite retransforms through a re-nucleation of the parent phase. This full retransformation requires a strong overheating (which can be about 250-300 K) with respect to the nominal transformation temperatures. In the present contribution new results obtained by differential scanning calorimetry, internal friction and transmission electron microscopy in Ni-Fe-Ga and Cu-Al-Be are discussed and compared to the ones obtained previously in the latter system [1], in order to draw a generic image of this phenomenon. According to the results, the hyperstabilization can be attributed to a severe blocking of the motion of interphase boundaries during the reverse transformation, which is revealed by extremely low levels of internal friction. Either a high concentration of highly mobile quenched-in defects (“sweeping” of defects during the reverse transformation) or the creation of obstacles by preliminary plastic deformation can be responsible for this blocking. In addition to that, the renucleation of the parent phase inside variants of hyperstabilized martensite is preceded by a relaxation internal friction peak; a possible origin and role of this relaxation will be also discussed. On the other hand, in situ TEM observations show that the parent phase is renucleated in the form of fine lamellae. The renucleation is associated with important changes in the thermoelastic balance of the martensitic transformation. The elastic energy in the hyperestabilized martensites probably plays a key role in the nucleation of parent phase, and its value could be notably different as compared to the conventional reverse thermoelastic martensitic transformations.
[1] S. Kustov, J. Pons, E. Cesari, M. Morin; Scripta Materialia 46, 817-822 (2002).
SYNCHROTRON AND CONVENTIONAL X-RAY DIFFRACTION STUDIES OF POLYSynthetic TWINS in Ni−Mn−Ga 10M martensite Chulist Roberta, Sozinov Alexeib, Straka Ladislavc, Lanska Nataliyab, Soroka Aleksandrb, Lippmann Thomasd, Oertel Carl-Georga, Skrotzki Wernera a Institut für Strukturphysik, Technische Universität Dresden, Dresden, Germany b AdaptaMat Ltd., Helsinki, Finland c Aalto University School of Science and Technology, Espoo, Finland d Institut für Werkstoffforschung, GKSS Forschungszentrum, Geesthacht, Germany [email protected]
Magnetic shape memory materials, such as Ni−Mn−Ga alloys, are promising for applications in actuators, sensors, and energy harvesting devices. The twinning stress TW as a key property of MSM materials determines the required level of an applied stress or magnetic field for twin variant rearrangement. Recently, it was shown that in Ni−Mn−Ga five-layered (10M) martensite the reorientation of the short c-axis can be realized by the motion of type
I as well as type II twin boundaries (TBs). Type II TBs show very low TW of about 0.1 MPa, in contrast to 1 MPa for type I TBs [1]. This suggests that designing a laminated twin microstructure (polysynthetic twins) mainly containing type II TBs is preferable for practical applications. The laminated twin microstructure created by bending exhibits TW of about 0.8 MPa [2, 3] (see also [4, 5] for details of the bending method). In the current work we performed detailed X-ray diffraction studies to understand the reason for the high TWin the laminated twin microstructure. The samples studied were Ni−Mn−Ga single crystals with the dimension of 3×3×20 mm3 and with a laminated twin microstructure. This two-variant twin microstructure had parallel TBs with a spacing of 10-40 μm. The diffraction experiments were performed with a conventional X-ray diffractometer X‟Pert MRD and with high- energy synchrotron radiation (100 keV) using the GKSS materials science beam line HARWI-II at DESY in Hamburg, Germany. The high penetration depth of synchrotron radiation (approximately 10 mm) allows the investigation of representative large sample volumes in transmission geometry. It was found that the polysynthetic twins created by bending consist of type I twin boundaries. This explains the high TW measured for this microstructure in the current work and before [2, 3]. As bending does not result in a microstructure with type II twin boundaries, other methods have to be developed to create a laminated twin microstructure mainly containing type II
TBs with a low TW.
[1] A. Sozinov, N. Lanska, A. Soroka, and L. Straka, Appl. Phys. Lett. 99 (2011) 124103 [2] L. Straka, N. Lanska, K. Ullakko, and A. Sozinov, Appl. Phys. Lett. 96 (2010) 131903 [3] L. Straka, H. Hänninen, A. Soroka, A. Sozinov, J. Phys.: Conf. Series 303 (2011) 012079 [4] Z.S. Basinski, and J.W. Christian, Acta Metall. 2 (1954) 101 [5] H.D. Chopra, C. Bailly, and M. Wuttig, Acta Mater. 44 (1996) 747 67 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 4 –O3, P17
MECHANISM OF TWIN VARIANT REORIENTATION IN Ni-Mn-Ga Zárubová Nivaa, Ge Yanlingb, Hannula Simo-Pekkab a Institute of Physics, ASCR v.v.i., Na Slovance 2, Prague 8, 182 21, Czech Republic bAalto University School of Chemical Technology, POB 16200, FI-00076, Aalto, Finland [email protected]
The magnetic-field-induced-strain in Ni-Mn-Ga is directly related to the reorientation of martensite variants. In the present study, straining inside a transmission electron microscope (TEM) was performed to follow the reorientation processes in the non-modulated as well as modulated martensites. The tensile in-situ TEM straining was carried out in a JEM 1200EX microscope. The tetragonal structure of the non-modulated martensitic before straining consisted of thermally induced self-accommodated multi-variants. During straining, reorientation processes were observed and video-recorded. A detailed structural study of the strained samples was made in the JEM and in a Tecnai F20 G2 200kV FEG microscope [1]. Fig.1a illustrates the reorientation process in a partly detwinned region of the non-modulated (NM) martensite. The strong, periodically repeating contrast on the plates of the disappearing variant indicates that the reorientation occurs by movement of twinning dislocations. An analysis of the contrast [2] showed that the twin dislocations glide in the successive {202} twin planes and their Burgers vector is 1/12 <101>, in agreement with Ref. 3. Similar situation is depicted in Fig. 1b for 7-layered (14M) martensite. However, no periodical contrast is observed on the disappearing plates which behave as stacking faults [4]. A detailed investigation of the reorientation processes in the 7-layered and 5-layered martensites is in progress.
[1] Y. Ge et al., Proc. ESOMAT 2009, 04007 (2009) DOI: 10.1051/esomat/200904007 [2] N. Zárubová et al., Functional Material Letters, in press [3] B. Muntifering, R.C. Pond, P. Müllner, Proc. 3rd ICFSMA, Dresden 2011, p. 159-160 [4] M. Han, F.F. Kong, J. Alloys and Compounds 458 (2008) 218-222
Fig.1.Reorientation processes in non-modulated (a) and 7-layered (b) martensites.
TEM STUDY OF TWINNING IN Ni-Mn-Ga ALLOY Ge Yanlinga Zárubová Nivab, Hannula Simo-Pekkaa aAalto University School of Chemical Technology, POB 16200, FI-00076, Aalto, Finland b Institute of Physics, ASCR v.v.i., Na Slovance 2, Prague 8, 182 21, Czech Republic [email protected]
More than 10% strain can be induced in Ni-Mn-Ga alloy either by magnetic field or by stress via reorientation of the martensitic twin variants. In-situ tensile straining was carried out in a JEM 1200EX transmission electron microscope (TEM) both on non-modulated (NM) and seven-layered modulated (14M) martensites. The strained twinning structure was studied in detail with high resolution TEM (HRTEM). In both materials the twinning reorientation occurs by propagation of stacking faults with leading twinning dislocations gliding in the twinning planes. The twinning plane and Burgers vector together with the twin boundary structure were investigated.
68 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 4 –O4, O6
EBSD CHARACTERIZATION OF HIGHLY MOBILE SEGMENTED INTERFACES OF TYPE II TWINS IN 10M MODULATED NI−MN−GA MARTENSITE Chulist Roberta, Straka Ladislavb, Lanska Nataliyac, Soroka Aleksandrc, Oertel Carl-Georga, Skrotzki Wernera, Sozinov Alexeic a Institut für Strukturphysik, Technische Universität Dresden, Dresden, Germany b Aalto University School of Science and Technology, Espoo, Finland c AdaptaMat Ltd., Helsinki, Finland [email protected]
In magnetic shape memory alloys, the high mobility of twin boundaries is the key parameter for efficient actuation using magnetic field induced reorientation (MIR) of martensitic variants. So far, the highest mobility, i.e. the lowest twinning stress has been demonstrated in the Ni−Mn−Ga martensite with 10M crystal structure. A very low twinning stress of 0.05-0.3 MPa is only observed for type II twin boundaries or for twinned interfaces consisting of type II twin boundary segments [1]. Thus, for successful practical applications of this material a thorough understanding of type II twin-based interfaces is of great interest. Previous optical and XRD investigations revealed a complex twin microstructure associated with segmented interfaces: type II twin boundaries, modulation domains and a/b-laminate [1]. However, due to the geometrical constraints, the XRD techniques do not provide a complete analysis. This can be performed by electron backscatter diffraction (EBSD), which allows combining microstructural analysis and orientation information. The pioneering works done in this field on Ni-Mn-Ga only used a simple non-modulated tetragonal crystal lattice. In contrast, Li et al. suggested a monoclinic approach [2]. Here, additionally we also include the direction of modulation and the difference between the a- and b-axis. This new approach opens the possibility for direct experimental identification of all 12 possible twin variants [1]. In this presentation, we show the results of an EBSD study performed on the highly mobile interfaces consisting of type II twin boundary segments, similar to that presented in [1]. Fig. 1 depicts the domain configuration of such an arrangement indicating type II and modulation (compound) twin boundaries. In contrast to the previous XRD investigations, the modulation twins are directly confirmed not only on one side but on both sides of the highly mobile segmented interface. Moreover, various examples of other twin configurations studied using EBSD will be presented and discussed.
Fig. 1: Schematic diagram and EBSD map showing a highly mobile twinned interface consisting of type II twin boundary segments and modulation twins in a Ni-Mn-Ga alloy
[1] L. Straka, O. Heczko, H. Seiner, et al., Acta Mater. 59 (2011) 7450. [2] Z. Li, Y. Zhang, C. Esling, X. Zhao, and L. Zuo, Acta Mater. 59 (2011) 2762.
INFLUENCE OF LONG-RANGE ATOMIC ORDER ON THE MARTENSITIC TRANSFORMATION OF Ni-Mn-BASED MAGNETIC SHAPE MEMORY ALLOYS Sánchez-Alarcos Va, Pérez-Landazábal JIa, Recarte Va, Lucia Ia, Vélez Ja, Rodríguez-Velamazán JAb,c aDepartamento de Física – Universidad Pública de Navarra, Campus de Arrosadía 31006 Pamplona, Spain bInstituto de Ciencia de Materiales de Aragón, CSIC - Universidad de Zaragoza, Zaragoza, Spain cInstitut Laue-Langevin, CRG’s D1B ¬ D15, F-38042 Grenoble, France [email protected]
The effect of long-range atomic order on the martensitic transformation and the magnetic properties of Ni- Mn-X alloys (X=Ga, In, Sn and Sb) has been analyzed from the evolution of both the L21 atomic order degree and the transformation temperatures under high-temperature quenching and post-quench annealing thermal treatments. It is found that, in all cases, the Curie temperature and the saturation magnetization increases with the increasing atomic order degree as a consequence of the increase of the ferromagnetic exchange coupling. On the contrary, the martensitic transformation temperature increases in Ni-Mn-Ga alloys whereas it decreases in the metamagnetic Ni- Mn-In, Ni-Mn-Sn and Ni-Mn-Sb alloys. Furthermore, regardless of composition, the atomic order variations associated to the thermal treatments only affect the martensitic transformation temperature in those alloys in which at least one of the structural phases show magnetic order at the transformation temperature. The different observed behaviors are explained as a consequence of the effect of the magnetic exchange coupling variations brought by atomic ordering on the free energy difference between austenite and martensite. In particular, it is proposed that the atomic ordering stabilizes the structural phase showing higher magnetic moment, in the same way as an external magnetic field does, thus pointing out the key role of magnetism in the martensitic transformation.
69 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 4 –O7, O8
EVIDENCE OF STRAIN GLASS TRANSITION LINKED TO KINETIC ARREST IN NICOMNIN META- MAGNETIC SHAPE MEMORY ALLOYS J.A. Monroea, C. Yeginb, I. Karamana,b, Y.I. Chumlyakovc aDepartment of Mechanical Engineering, Texas A&M University, MS 3123, College Station, TX 77843, USA bMaterials Science and Engineering Program, Texas A&M University, College Station, Texas 77843-3003, USA cSiberian Physical Technical Institute, Novosobornaya sq. 1, Tomsk, 634050, Russia [email protected]
NiMn based metamagnetic shape memory alloys (MMSMAs) show great promise for sensing, energy harvesting and actuation applications because they undergo magnetic field induced martensitic phase transformation due to differences between the austenitic and martensitic magnetic saturation levels. A phenomena that inhibits the austenite to martensite transformation at low temperatures, described in the literature as kinetic arrest, has been shown in several alloy systems including NiMnIn, NiCoMnIn, NiCoMnSn and NiCoMnAl. While arrest of the martensitic transformation has been theoretically attributed to the entropy difference between the austenite and martensite phases going to zero, a satisfactory explanation and experimentally derived origin of this arrest has not been presented. This study explores strain glass transitions in NiCoMnIn MMSMAs and their interaction with the martensitic-type structural transition. Strong evidence for the cause of arrest of the austenite to martensite transformation due to a strain glass transition in austenite is shown.
MAGNETIC PROPERTIES AND MCE OF NIMNGA GLASS-COATED MICROWIRES Zhukova V.a, Aliev A.M.b, Ryba T.c, Michalik S.c, Vargova Z.c, Varga R.c, Zhukov A.a,d aDpto. de Fís. Mater., UPV/EHU San Sebastián 20018, Spain bAmirkhanov Institute of Physics of Daghestan Scientific Center, RAS, Makhachkala, Russia cInst. Phys., Fac.Sci., UPJS, Park Angelinum 9, Kosice, Slovakia dIKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain [email protected]
Recently studies of magnetic shape-memory alloys (MSMAs) attracted growing attention owing to significant magnetic-field-induced strain (MFIS), originated from the coupling between magnetic and structural ordering. From point of view of technological applications, miniaturizing of MSMA-based devices based on small- size MSMA particles, wires, ribbons, films, bi- and multilayers, pillars is quite important [1]. Thus, recently we reported on first fabrication and magnetic characterization of long Ni2MnGa glass-coated microwires [2] Here we report on effect of annealing on magnetic properties of Heusler-type Ni2MnGa glass-coated microwires with metallic nucleus with diameters, d, 13, 31 and 44 m surrounded by glass coating with total diameters, D, of 20, 65 and 80 m prepared using Taylor-Ulitovsky technique. The samples were annealed up to 790 K. The magnetocaloric effect, MCE has been measured directly by recently introduced precise method allowing the detection of a change in the temperature, ΔT, with an accuracy of below 10–3 K [3]. As-prepared microwires did not showed ferromagnetic ordering at least near room temperature. Samples annealed above 773 K show magnetization versus temperature dependence typical for ferromagnetic behaviour with Curie temperature about 315 K. We measured directly the MCE, ΔT, in samples with d ≈13 (wire 1) and 31 (wire 2) m after annealing at 723 K. Before glass removal we observed ΔT 0,06 K for sample 1 and 0,08 K for sample 2 at magnetic field change ΔH=18 kOe. After glass removal of sample 1 ΔT increase to 0,22 K. Specific heat for both microwires exhibit a maximum at about 315 K, indicating existence of magnetic transformation. Observed MCE is associated with magnetic (paramagnetic-ferromagnetic) and probably structural (austenite- martensite) phase transitions. Observed MCE is almost one order higher (in microwires after glass coating removal) than previously observed MCE for Fe3P microwires [4]. Analysis of the X-ray diffraction allows us to identify, that crystalline structure is polycrystalline L21 structure with a lattice parameters a = 3.75 Ǻ and c = 6.78Ǻ. From point of view of future technological applications existence of glass-coating allows improvement of mechanical properties of such composite Ni2MnGa microwires. Prepared glass coated microwires are flexible with the sample length of few meters. Therefore these studies might be important for a new development in the field of the magnetocaloric materials.
[1] D C. Dunand and P. Müllner, Adv. Mater., 23(2011) 216. [2] R.Varga et. al, Scripta Materialia, 65, 8, (2011) 703 [3]A. M. Aliev, A. B. Batdalov, and V. S. Kalitka, JETP Letters, 90 (2009)663. [4] M. I. Ilyn et. al., Phys. Stat. Sol. (a), 205 No 6 (2008 ) 1378
70 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 4 –O9, O10
MAGNETOSTRUCTURAL PHASE TRANSFORMATION AND MCE OF NI50.3MN36.5SN13.2 HEUSLER ALLOY RIBBON. L. Gonzáleza, W.O. Rosab, R. Caballero-Floresa, V. M. Pridaa, Ll. Escodac, J.J. Suñolc, A. B. Batdalovd, A. M. Alievd, V. V. Koledove, B. Hernandoa. a Dpto. de Física, Universidad de Oviedo, Calvo Sotelo s/n, 33007-Oviedo, Spain. b Centro Brasileiro de Pesquisas Físicas, Rio de Janeiro – RJ, Brasil. c Girona University, Campus Montilivi, ed. PII, Lluís Santaló s/n, 17003 Girona, Spain. d Amirkhanov Institute of Physics of Daghestan Scientific Center, RAS, Makhachkala, Russia. e Kotelnikov Institute of Radio Engineering and Electronics, RAS, Moscow, Russia. [email protected]
We report the dependence of Martensitic Transition (MT) and Magnetocaloric Effect (MCE) in Ni50Mn37Sn13 Heusler alloy ribbon, produced as single-phase microcrystalline material using melt-spinning technique, at different applied magnetic fields. The crystal structure was determined by X-ray diffraction (Diamond, UK) and its microstructure, as well as, elemental chemical composition analyses were performed by means of Scanning Electron Microscopy (SEM, JEOL 6100) equipped with an Energy Dispersive X-ray microanalysis system (EDX, Inca Energy 200). From these analyses we obtain an average-composition of Ni50.3Mn36.5Sn13.2 (e/a = 8.11), with an accuracy of 0.1%. The magnetic properties were measured on a Quantum Desing VersaLab VSM in the temperature range of 50 - 400 K and up to 3 T applied field. MT was characterized from the thermomagnetic measurements, Zero Field Cooling (ZFC), Field Cooling (FC) and Field Heating (FH) protocols, at different applied magnetic fields. Thermomagnetic measurements show clearly how the unusual structural transition is affected by the magnetic field in Ni50.3Mn36.5Sn13.2 ribbon. It can be observed at 50 Oe, three different austenite and martensite temperatures. Such feature is lost when the applied field reaches the value of 10 kOe. MCE has been studied by direct method, specific heat and thermomagnetic measurements. Direct and inverse magnetocaloric effects near Curie point and martensitic transformation temperature respectively have been clearly revealed. 50 55 50 Oe M = 251 K 30 kOe 50 S 45 10 kOe A = 274 K 40 45 F 35 FC 40 30 35 M = 245 K 25 30 F 20 ZFC-FC-FH 25 15 ZFC-FH 20
m(emu/g) FC-FH A = 268 K FC S 10 m(emu/g) 15 5 10 0 5 T = 23 K ZFC -5 0 100 200 300 400 150 200 250 300 350 400 T (K) T (K) Thermomagnetic curves for Ni50.3Mn36.5Sn13.2 alloy.
CALORIMETRIC STUDY OF THE BAROCALORIC AND MAGNETOCALORIC EFFECTS IN Ni-Co- Mn-Ga-In L. Mañosaa, S. Yucea,e, B. Emrea,f, E. Sterna, A. Planesa, M.Barriob, J.L. Tamaritb, F. Albertinic, S. Fabbricic,d a Dept. ECM. Ftat. Física. Universitat de Barcelona, 08028 Barcelona, Catalonia. b Dept. Física. ETSEIB. Universitat Politècnica de Ctalunya., 08028 Barcelona, Catalonia. cIMEM. CNR., 43124 Parma, Italy. dMIST-ER. Lab., 40129 Bologna, Italy. eOndokuz Mayis University, Dept. Phys., 55139 Samsun, Turkey. fAnkara University, Dept. Eng. Phys., 06100 Ankara, Turkey. [email protected]
Differential scanning calorimetry under magnetic field and under hydrostatic pressure has been used to determine the magnetic-field and pressure induced entropy changes. Data enable to quantify the barocaloric and magnetocaloric effects for this magnetic shape memory alloy system. It is found that the barocaloric effect is conventional (heating with applying pressure) while the magnetocaloric effect is inverse (cooling on applyig magnetic field). A comparative discussion of the different caloric effects in this material will be presented.
71 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 4 –O11, O14 AN OPTIMIZATION OF THE MAGNETOCALORIC EFFECT IN NI-MN-IN ALLOYS Buchelnikov V.D.a, Sokolovskiy V.V.a, Entel P.b aChelyabinsk State University, Department of Physics, 454001, Chelyabinsk, Russia bUniversity of Duisburg-Essen, Faculty of Physics and CeNIDE, Duisburg, 47048, Germany [email protected]
Magnetic cooling is attracting worldwide attention due to its potential use in solid state and environmentally friendly refrigeration technology as compared to the conventional gas refrigeration technique [1]. Crucial for the success of magnetic cooling is the availability of materials showing a large magnetocaloric effect (MCE), which is related to the adiabatic temperature change ΔTad under application (removal) of a magnetic field [1]. Recent experiments have shown that in Ni-Mn-In Heusler alloys the sign of ΔTad can be negative at a first-order magnetostructural (MS) martensitic transition (Tm) and positive at the conventional magnetic phase transition (TC) [2, 3]. Moreover, the absolute value of the inverse MCE (ΔTad < 0) at the MS transition is larger than the correponding value of the convetnional MCE (ΔTad > 0) at the Curie point. In this work we investigate theoretically the influence of the magnetic exchange interactions on the value of the inverse MCE at MS martensitic transition. In a recent paper (see Ref. [4]), we have performed Monte Carlo simulations of the conventional (ΔTad > 0) and inverse (ΔTad < 0) MCE of the Ni50Mn34In16 Heusler alloy, whereby the magnetic exchange parameters have been obtained from ab initio calculations using the SPR-KKR code [5] which combines the Korringa-Kohn- Rostoker (KKR) method with the (single-site) coherent potential approximation (CPA). Corresponding results for the magnetic exchange parameters were obtained for th cubic phase of the stoichiometric (Ni50Mn25In25), off- stoichiometric (Ni50Mn34In16) and martensitic phase with tetragonality c/a = 0.94. In this work we are tried to optimize the value of MCE in Ni50Mn34In16 by the changing of the magnetic exchange parameters. Our simulations show that a decrease of the magnetic exchange interactions leads to increasing values of the MCE. We obtained that if the values of the exchange parameters are taken to be twice as small compared to the original ab initio exchange parameters, then the value of the inverse MCE (ΔTad < 0) increases by almost a factor of three, whereas the increase of exchange constants leads to lower the inverse MCE. So, we suppose that a reduction of the exchange interactions (Mn1-Mn2, Mn1-Ni and Mn2-Ni) in Ni-Mn-In alloy can be realized by the doping with nonmagnetic atoms such as B, Si, V, Ti etc. In our opinion the quartenary Ni-Mn-In-X Heusler alloys (X = B, Si, V, Ti etc) are good candidates for refrigerants of magnetic cooling technology. [1] V.K. Pecharsky and K.A. Gschneidner Jr. J. Magn. Magn. Mater. 200, 44 (1999). [2] S. Aksoy, T. Krenke, M. Acet, E.F. Wassermann, X. Moya, L. Mañosa, and A. Planes, Appl. Phys. Lett. 91, 241916 (2007). [3] X. Moya, L. Mañosa, A. Planes, S. Aksoy, E. F. Wassermann, and T. Krenke, Phys. Rev. B 75, 9184412 (2007). [4] V.D. Buchelnikov, V.V. Sokolovskiy, S.V. Taskaev, V.V. Khovaylo, A.A. Aliev, L.N. Khanov, A.B. Batdalov, P. Entel, H. Miki, and T. Takagi, J. Phys. D: Appl. Phys. 44, 064012 (2011). [5] H. Ebert, D. Ködderitzsch, and J. Minár, Rep.Progr. Phys. 74, 096501 (2011).
EFFECT OF MAGNETOSTATIC ENERGY ON THE MAGNETIC DRIVING FORCES AND FIELD INDUCED SUPERELASTIC BEHAVIOR IN Ni-Mn-Ga Likhachev Alexander Institute for Metal Physics, N.A.S.U. 36 Vernadsky Boulevard, Kyiv 03142, Ukraine [email protected]
Different ideas were suggested concerning the possible effects of the magnetic field on the martensitic transformations and shape memory behavior in some ferromagnetic shape memory alloys. One of them has been first clearly formulated in 1995 by Ullakko and suggested the mechanism based on the martensite-martensite twin boundary motion driven by magnetic field in martensitic state. During the few past years, a significant progress based on this general idea in designing of a new class of magnetic shape memory alloys (MSMA) has been achieved. By now, the largest magneto-strain effects were found in Ni-Mn-Ga ferromagnetic shape memory alloys. The main thermodynamic driving forces have in this case magnetic nature and connected with high magnetization anisotropy and significant differences in magnetization free energies for different twin variants of martensite. Present publication gives a general theoretical concept and also presents the relevant experimental results concerning the effect of the magnetostatic coupling between the twin layers on the magnetic-field-controlled superelastic behavior during the mechanical cycling in magnetic field in Ni-Mn-Ga. We also discuss the physical mechanism of this effect using our latest magnetic free energy model developments. We specially emphasize the fact that the main magnetic and magneto-mechanical properties of MSMA_s are strictly dependent on the details of twin and also fine internal magnetic domain microstructure within the twin bands. These magnetic domains was not expected and usually not taken into account in many early models of MSMA‟s. Here we show that their presence may essentially modify the magnetization behavior and field dependence of magnetic driving forces acting at the twin boundaries in these materials.
72 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 4 –O12, O13
MARTENSITE REORIENTATION IN MAGNETIC SHAPE MEMORY ALLOYS UNDER 3D MAGNETO-MECHANICAL LOADINGS He Y.J., Chen X. Moumni Z. Department of Mechanical Engineering, ENSTA-ParisTech Chemin de la Huniere, 91761 Palaiseau Cedex, France [email protected]
Investigation on the behaviours of Magnetic Shape Memory Alloys (MSMA) includes multiphysics problems: temperature-induced martensite phase transition and ferromagnetic phase transition; stress- and magnetic- induced martensite reoreientation, magneto-caloric effects, etc [1-3]. Being the candidate for high-frequency actuators and sensors, MSMA can transfer magnetic energy to mechanical energy or vice versa, through the mechanism of martensite reorientation [2,3]. However, due to the anisotropic magnetic energy of the materials, the output (or input) mechanical energy for the one-dimensional configuration (uniaxial stress) is limited to a small value (the stress triggering the reorientation is less than 3MPa) [2]. Recent theoretical analysis [3] and 2D experiments [4] show that MSMA can work at higher stresses in 2D configurations. In this paper, we perform a three-dimensional magneto- mechanical energy analysis and plot phase diagrams (with/without hysteresis) to study the martenste reorientation in MSMA (Ni-Mn-Ga) under general magneto-mechanical loadings.
Figure 1: Phase diagram of the three martensite variants in terms of deviatoric stresses Si (including deviatoric mechanical stresses and deviatoric magneto-stresses) without hysteresis. The switching between the three martensite variatnts can be triggered by mechanical stresses or magnetic fields.
[1] O. Heczko and L. Straka. J. Appl. Phys. 94: 7139, 2003. [2] S. J. Murray, M. Marioni, S. M. Allen, R. C. O‟Handley, and T. A. Lograsso, Appl. Phys. Lett. 77: 886-888, 2000. [3] Y. J. He, X. Chen, and Z. Moumni, J. Appl. Phys. 110: 063905, 2011. [4] X. Chen, Y. J. He, and Z. Moumni, (in preparation).
SHAPE MEMORY EFFECT AND SUPERELASTICITY IN FeNiCoAlTa SINGLE CRYSTALS TESTING - ’ MARTENSITIC TRANSFORMATIONS Chumlyakov Yuriya, Kireeva Irinaa, Kretinina Irinaа, Kirillov Vladimira, Kuc Olgaa, Karaman Ibrahimb, Maier Hansc, Cesari Eduardd aSiberian Physical Technical Institute of the Tomsk State University», Tomsk, Russia bDepartment of Mechanical Engineering, Texas A&M University, College Station, USA cUniversityof Paderborn,Lehrstuhl fur Werstoffkunde, Paderborn, Germany dUniversitat deles Illes Balears, Departament de Fisica, Palma de Mallorca, Spain [email protected]
The effect of disperse particles and crystals orientation on development of thermoelastic martensitic transformations (MT) from high-temperature FCC phase () to tetragonal BCT () martensite have been investigated in single crystals of Fe-28%Ni-17%Co-11.5%Al-2.5%Ta (at. %) alloy. The use of single crystals allows to investigate for ageing more higher temperature (Т=973 K) and smaller times of ageing (t=1-10 h) in comparison with polycrystals at the expense of suppression of processes of discontinuous reaction and to receive the new experimental data. It is shown, that thermoelastic - MT take place only after ageing at Т=973К, from1 h till 7 h. At t> 7 h of perfect reversible - MT are not observed. By method of transmission electron microscopy it is shown, that ageing at Т=973К and t=1-7 h leads to precipitation of disperse particles '-phase with the size of particles d from 2 nm to 5 nm. Growth of particles d > 5 nm leads to irreversibility occurrence of MT. It is established, that temperatures MT, values of a thermal and mechanical hysteresis depend on the size of disperse particles. Ageing at t=1 h leads to fall Ms <77 K, the temperature interval of superelasticity is observed in the range of temperatures from 77 K to 323 K and the minimum values of a mechanical hysteresis =50 MPa are found out. To growth of ageing time there is an increase in temperatures of MT and values and at t=7 h Ms =160 K and =130 MPa and thermal hysteresis T=Af-Ms=25 K. The maximum values of shape memory effect and superelasticity are observed in [001] crystals at deformation by tension that is in the consent with theoretical estimations.
73 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 4 –O15, P27
EFFECTS OF NANO-SIZE PARTICLES ON STRESS-INDUCED MARTENSITIC TRANSFORMATION AND FUNCTIONAL PROPERTIES OF FERROMAGNETIC CoNiAl, NiFeGa(Co) SINGLE CRYSTALS Panchenko Elenaa , Chumlyakov Yuriya, Maier Hans Jürgenb, Timofeeva Ekaterinaa Kanaf’eva Annaa aSiberian Physical Technical Institute of Tomsk State University, Tomsk, 634050, Russia bLehrstuhl f. Werkstoffkunde, University Paderborn, 33095 Paderborn, Germany [email protected]
In the present study the effects of disperse particles on stress-induced martensitic transformation (MT), shape memory effect (SME), superelasticity (SE), stress hysteresis in the single crystals of ferromagnetic Co35Ni35Al30, Ni49Fe18Ga27Co6 (at.%) alloys are investigated. It is shown that in the aged single crystals the thermoelastic MT, SME, SE are controlled by the different mechanisms of interaction between the nano-size (<50 nm) and large (> 200 nm) particles and the austenite/martensite matrix. These mechanisms do not depend on the type of thermoelastic MT (B2-L10 in CoNiAl and L21(B2)-10M-14M-L10 in NiFeGaCo) and the atomic structure of the dispersed particles which do not undergo MT. The precipitation of nano-size particles leads to a formation of high-strength state in the austenite and high density of "geometrically-necessary" twins in the martensite which appear to accommodate the martensitic deformation of matrix and elastic deformation of particles. It is established that such mechanism of interaction between nano-size particles and austenite/martensite matrix determines the size reduction of martensite lamellae, the decreasing of the transformation temperatures by 20-100 K and a 2 to 8-fold growth in the temperature range for the forward and reverse MT in comparison with monophase state and single crystals containing the large (> 200 nm) particles. High-temperature SE up to 473 K, good cyclic stability of the SE response and reduction of the stress hysteresis with increasing test temperature are observed in crystals contained nano-size particles. It is established that oriented growth of not spherical nano-size particles by stress-assisted aging along the [123], [011] direction under compressive stress of 100MPa leads to improvement of functional properties of ferromagnetic of CoNiAl and NiFeGaCo single crystals. For the first time it was found that due to stress-assisted aging it is possible to obtain the two-way SME at cooling/heating, to increase the martensite start temperature and the yield strength of the high-temperature phase, to reduce the critical stress level for stress-induced MT and the stress hysteresis as compared to stress-free aged crystals.
ADAPTIVE NANOTWINNING IN STRAINED EPITAXIAL Fe70Pd30 FILMS Sandra Kauffmann-Weissa,b, Markus Ernst Grunerc, Alexander Kauffmanna,b, Peter Entelc, Ludwig Schultza,b, and Sebastian Fählera a IFW Dresden, P.O. Box 270116, 01171 Dresden, Germany b Dresden University of Technology, Institute for Materials Science, 01062 Dresden, Germany c University of Duisburg-Essen, Theoretical Physics, 47048 Duisburg, Germany [email protected]
Magnetic shape memory (MSM) alloys are a class of multi functional materials which is rich in physical effects which originate from different ways of the coupling between magnetic and crystal order. Fe70Pd30 as the second MSM alloy discovered is of particular interest for thin films and microsensors. In quenched, disordered Fe- Pd bulks the phases fcc, fct, bct and bcc are observed close to room temperature. This makes Fe-Pd a prototype system for the Bain transformation path. In thin epitaxial Fe70Pd30 films, this transformation can be frozen by depositing films at room temperature on substrates with different lattice parameters with DC magnetron sputtering [1,2]. By varying the lattice parameters of the substrates, a coherent epitaxial straining by 54% is possible. When straining films beyond the Bain path, a lattice relaxation mechanism is observed, which is not expected for stable materials. An adaptive nanotwinned structure similar to the modulation in Ni-Mn-Ga is observed [3]. The combination of thin film experiments and large-scale first-principles calculations allows identifying the underlying mechanism. A low twin boundary energy compared to a high elastic energy is the key precondition for adaptive nanotwinning in the Fe-Pd system. With this, one can control both, the microstructure and magnetic properties. This work was funded by DFG through SPP 1239.
[1] S. Kauffmann-Weiss, M. E. Gruner, A. Backen, L. Schultz, P. Entel, S. Fähler, Phys. Rev. Lett. 107 206105 (2011). [2] J. Buschbeck, I. Opahle, M. Richter, U. K. Rößler, P. Klaer, M. Kallmayer, H. J. Elmers, G. Jakob, L. Schultz, S. Fähler, Phys. Rev. Lett. 103 216101 (2009). [3] S. Kaufmann, U. K. Rößler, O. Heczko, M. Wuttig, J. Buschbeck, L. Schultz, and S. Fähler, Phys. Rev. Lett. 104 145702 (2010).
74 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 4 –O17
A MINIATURE ENERGY HARVESTING DEVICE USING MARTENSITE VARIANT REORIENTATION R. Yina, V. Pinnekera, A. Sozinovb, Y. Ezerb and M. Kohla aKarlsruhe Institute of Technology, IMT, P.O. Box 3640, 76021 Karlsruhe, Germany bAdaptaMat Ltd. , Yrityspiha 5, FIN-00390 Helsinki, Finland [email protected]
This paper presents a miniature energy harvesting device that makes use of stress-induced cyclic martensite variant reorientation in a Ni-Mn-Ga single crystal of 0.3x2x2 mm³ size. Ni-Mn-Ga is a ferromagnetic shape memory alloy (FSMA) showing the unique property of giant magnetic field-induced strain (MFIS) up to 10 %, which is due to the reorientation of martensite variants. The inverse effect of strain-induced change of magnetization has a high potential for power generation. In particular, the development of miniaturized energy harvesting systems is of large interest to self-sustaining systems in mobile or remote applications. In this work, we study the stress- and magnetic field-induced reorientation of single crystalline Ni50.2Mn28.4Ga21.4 samples of 0.3 mm thickness that are cut along (100) direction and subjected to uniaxial compressive loading. A demonstrator is presented consisting of the FSMA sample placed in the gap of a magnetic circuit to guide and enhance the field of a permanent magnet. External vibrations generated by a piezoelectric motor are used to mechanically load the FSMA sample. The corresponding change of magnetic flux induces an electrical voltage in a copper pick-up coil (N=2000 turns). The effects of biasing magnetic field, strain amplitude and strain velocity are investigated. An optimum external magnetic field of 0.6 T is found, where the output voltage shows a maximum. For a strain velocity of 0.5% ms-1, an output voltage of 120 mV is obtained.
75 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 9 –O1, O2
MESOSCOPIC MODELING OF SHAPE MEMORY AND MULTIFUNCTIONAL MATERIALS Avadh Saxena Los Alamos National Lab, Los Alamos, USA [email protected]
Strain based perspectives on the modeling of shape memory alloys and multifunctional materials such as multiferoics will be presented. This involves a free energy that is based on the symmetry-adapted strain tensor components as order parameter for the phase transformation. A crystal group-subgroup relationship between the parent and product phase is required in addition to the elastic compatibility constraint. The latter leads to a long- range elastic interaction between the order parameter strains and determines the type of microstructure that is likely to emerge during the phase transformation. Coupling of strain to other functionalities such as magnetism (e.g. in magnetic shape memory alloys) will be considered. Additional focus will be on ferroics: materials which possess two or more orientation states (domains) that can be switched by an external field and show hysteresis. Examples include ferromagnets, ferroelectrics and ferroelastics which occur as a result of a phase transition with the onset of spontaneous magnetization (M), polarization (P) and strain, respectively. Materials displaying two or more ferroic properties simultaneously are called multiferroics, e.g. magnetoelectrics (simultaneous P and M). Another recently discovered class of ferroic materials is that of ferrotoroidics. The mesoscale modeling and microstructure resulting from the transitions in these multiferroic materials will be described in some detail. The role of (polar and magnetic) dipolar interactions in determining the microstructuire will also be discussed.
DYNAMICAL BEHAVIOUR OF TERMAL CYCLES IN MARTENSITES Laguna M F, Arneodo Larochette P, Pelegrina J L CONICET-Centro Atómico Bariloche, Bariloche, Río Negro, Argentina [email protected]
The dynamical behavior of the reverse martensitic transformation has been numerically simulated with an atomistic model and compared with the experiments in a Cu-Zn-Al alloy. For the calculations a model based on a classical isotropic two-body potential [1] has been used. The samples for dilatometry, electrical resistance measurements and mechanical experiments were prepared from austenitic single crystals. First, the samples were cooled at different speeds to obtain an initial configuration of martensitic variants that differ in size and shape. Then, the dynamics of the transformation to austenite was studied as a function of this initial variant configuration and the velocity at which the temperature was increased. The behavior of the martensitic phase fraction as a function of the temperature has been found to be strongly influenced by the intervariant boundaries. Additionally, a single martensitic variant specimen was obtained by inducing the transformation under stress. This new initial configuration was then subjected to a similar set of heating speeds as previously and the reverse transformation path was followed using electrical resistance measurements and dilatometry. In this way, it was possible to study the transition in the absence of intervariant boundaries. This allowed isolating and characterizing the influence of the initial variant configuration and the heating speed on the transformation characteristics.
[1] M.F. Laguna, E.A. Jagla, J. Stat. Mech. P09002 (2009).
76 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 9 –O3, O4
WHAT ABOUT THE FRACTURE OF SHAPE MEMORY ALLOYS? C. Lexcellent, R. Laydi and V. Taillebot Département Mécanique Appliquée, Institut FEMTO-ST, 25000 Besançon, France [email protected]
With an as “plasticity SMA model” around the fracture tip , the phase transformation surfaces can be predicted whatever the chosen mode and the curvature of the tip.[1] Some experiments on Ni-Ti cantilever beams linked with displacement measurements allows a qualitative agreement with the model prediction [2] . The final aim is to describe the transformation toughening behavior of a static crack along an interface between a shape memory alloy and a linear elastic isotropic material.[3]. With a model integrating the asymmetry between tension and compression , we determine the initiation (ending) phase transformation yield surfaces in term of the local phase angle introduced by Rice et al.[4]
[1] C. Lexcellent, M.R. Laydi, V. Taillebot INT.JOURNAL OF FRACTURE 169,pp1-13 2011 [2] V.Taillebot, C. Lexcellent and P. Vacher To appear in “Functional materials letters” [3]R.Laydi C. Lexcellent J.R. Rice to appear in Archive for Rational Mechanics and Analysis [4] J.R.Rice, Z. Suo, J.S. Wang In :Ruhle, M.Evans, A.C., Ashby M.F., Hirth J.P.(eds) Metal Ceramic Interfaces, Pergamon Press, New York, 269-294 (1990).
THE SWITCHING PATHWAY AND MECHANISM OF MULTI-VARIANTS IN NI-MN-GA SHAPE MEMORY ALLOYS UNDER THE EXTERNAL STRESS FIELD: PHASE-FIELD SIMULATION Y.G. Cui, J.F. Wan, J.H. Zhang, Y.H. Rong School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China [email protected]
The mechanism of reorientation of martensitic variants under the continuous stress field along different directions in NiMnGa alloys have been investigated by using Phase-field method. The tensile or compressive stress along the [100], [110] or [111] direction, respectively was applied to the system for the same initial martensitic state(shown in Fig.1). The simulated results revealed that the type and the direction of the external stress will have different influence in the final evolutional micro-structure such as two variants, single variant or the complete parent . The related switching mechanism of the structural conversion and the phase transition was proposed to explain the inner physical nature. The twinning or detwinning stress was calculated for different directions and also discussed, which were close to the experimental measurements. The pseudo-elasticity related to the structural conversion as well as phase transition was also studied. The reversibility of structural evolution between two variants and three variants was simulated and discussed.
Fig. 1. The morphology of the system varying with the reduced time, t=100, (b) t=300, (c) t=1000, (d) t=10000.
77 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 9 - O5, Session 11 - O1
SIMULATION OF VIBRATION ISOLATION BY SHAPE MEMORY ALLOY SPRINGS USING A MICROSTRUCTURAL MODEL OF SHAPE MEMORY ALLOY Volkov Aleksandr E., Evard Margarita E. Saint-Petersburg State University, Saint-Petersburg, Russia [email protected]
Vibroisolation is an approved method of protection of different devices (useful loads) from external sources of vibration. The isolator does not let pass to a useful load the vibrations with frequencies higher than some characteristic “cut-off” frequency, its value depending on the stiffness of the isolator. At the same time vibrations with lower frequencies (especially the resonant one) easily penetrate to the isolated body, whose vibrations in this case are stronger than without any isolation. The use of shape memory alloys (SMA) in a vibroisolator makes possible to change its stiffness and respectively the cut-off and the resonant frequencies. Besides, wide mechanical hysteresis and high damping ability of SMA decreases the displacement of a useful load in the case of a shock or resonant excitation. The considered vibroisolation system consists of an inertial body fixed by two helical SMA isolators to a frame, which can experience vibrations or shocks. To simulate the vibrations of the body the equations of motion and the constitutive equations of SMA based on the microstructural model [1] are considered. This model describes all the main features of SMA mechanical behavior: reversible and irreversible deformation on cooling, strain recovery and force generation. The forces of external and internal friction in the system are taken into account. It is shown that the resonant frequency and the vibration and acceleration amplitudes are less for the two-phase and martensitic state of the SMA. When the exciting vibration frequency is near the resonance the SMA elements undergo not only elastic but also unelastic phase deformations. The preliminary tension of elements in pseudoelastic state decreases their effective stiffness and increases the energy dissipation thus leading to a decrease of the mass vibration amplitude especially near the resonance. A change of the operating temperature of functional SMA elements permits to escape from the resonance.
[1] A.Volkov, F.Casciati. Shape memory alloys. Advances in modeling and applications (eds. F.Auricchio, L.Faravelli, G.Magonette, V.Torra), 2001, p.88 – 104.
RELATION OF THE BLOCK-SPIN-APPROACH TO THE LANDAU- AND LANDAU-GINZBURG MODEL FOR DESCRIBING POLYCRYSTALLINE SHAPE MEMORY ALLOYS Oberaigner Eduard Romana,b Leindl Marioa,b aInstitute of Mechanics, University of Leoben, Leoben, Austria bMaterials Center Leoben Forschung GmbH, Leoben, Austria [email protected]
The understanding of Shape Memory Alloys (SMAs) is of major importance in many areas of applications. Those are, e.g., aerospace engineering, damping devices in buildings, medical applications, etc. Many models exist so far to describe one or more aspects of the SMA behavior. Common to all the models is, that they belong to a few classes of description, e.g., matching assumptions on the internal variables or on the driving forces. Another model class is along the scheme of the Landau approach to describe ferromagnetic phase transitions as the Landau- Ginzburg approach to describe superconductivity. The authors of the present study developed together with colleagues an approach which is similar to block-spin-approach of Kadanoff used to describe the critical behavior of ferromagnets. Going along this way, one is able to derive analytical formulas for the internal variables and their rates, as well as to derive the hysteretical behavior. One can explain the self-accommodation and the compression- tension asymmetry, and several more properties of SMAs. In the present study, a link is established to both, the Landau- and the Landau-Ginzburg approach to describe critical phenomena. Examples are given for a transformation with two martensitic variants and with three martensitic variants, showing how within the block- spin-approach of the authors, a non convex free energy can be derived. Similar to magnetic or fluid systems, critical exponents are derived, which allow to quantify the kind of near singularity, e.g., in the pseudo-elastic behavior. Those exponents are also compared to that derived via Landau- resp. Landau-Ginzburg. The block-spin-approach of the authors takes as input only the properties of the pure martensite and austenite single crystals, such as their elastic constants, specific heats and mole densities. There are no free parameters for matching. Despite of this, the qualitative and quantitative agreement with experiments is very good. Examples for technical applicability are prepared.
78 9th European Symposium on Martensitic Transformations ESOMAT 2012
Oral presentations, Session 10 –O1, O2
INFLUENCE OF PLASTIC DEFORMATION AND STRESS IN VARIANT SELECTION IN SAMPLES OF MARAGING-350 STEEL Viana, N.F., Nunes, C.S., Abreu, H.F.G. Federal University of Ceará, Fortaleza, Brazil [email protected]
Experiments have been conducted to study the variant selection phenomenon in the transformation from austenite to martensite in Maraging-350 steel. The transformation of austenite to martensite in Maraging steels occurs at temperatures below 300 C varying according to the alloy chemical composition. The Maraging 350 whose chemical composition is (18Ni, 12Co, 5Mo,1.3Ti, Fe bal) shows Ms temperature of 190oC. The transformation to martensite in these steels occurs regardless of the cooling rate. Samples of Maraging-350 were austenitized at 860oC inside a furnace attached to a tension test machine and then cooled in the furnace until the temperature of 300oC. At this temperature the samples were deformed by compression with reductions below 10%. After deformation the force was removed and samples were cooled to room temperature in air. A second group of samples was subjected to the same austenitization and cooling process until the temperature of 300oC when it was applied a compressive stress with magnitude below the yield strength. With the force applied, the samples were air cooled to room temperature. EBSD analysis was performed in cross-section of samples to determine the influence of plastic deformation before the transformation and also the influence of a stress in the elastic regime in the selection of variants of martensite. Measured pole figures were compared with calculated ones using the phenomenological martensite transformation concept associated with Patel-Cohen model.
FUNDAMENTAL ACHIEVEMENTS OF THE DYNAMIC THEORY OF RECONSTRUCTIVE MARTENSITIC TRANSFORMATIONS aKashchenko M.P. and bChashchina V.G. aUral State Forestry University, Ekaterinburg, Russia bUral Federal University, Ekaterinburg, Russia [email protected]
In recent years, the dynamic theory [1] of reconstructive martensitic transformations (MTs) has received a significant progress [2]. The transition from the threshold strains to the finish strains was carried out [3]. An axiomatics of the theory has been refined. In this report the solutions of several important problems are reviewed using the fcc-bcc (bct) transformation in iron alloys as an example. 1. The dynamic model of the twinning of martensite crystals, which is compatible with supersonic speed of growth of martensite crystals is developed. An analysis of the distribution of primary and secondary components is carried out [4]. 2. Analytical formula for the critical size of austenite grains Dc (Ms (Dc) = 0) was obtained [2,5]. The dependence of Dc on significant physical parameters was analyzed. 3. Dependence of Dc on the energy of d-electrons allowed to explain as strong magnetic field H operates size Dc. The action of a field H is most expressed near the singular concentration C* (for C → C*, Ms → 0, Dc → ∞). A strong field can sharply reduce a size Dc till a size DcH < [1] Kashchenko M.P. The wave model of martensite growth for the FCC-BCC transformation of iron-based alloys // arXiv: cond-mat/0601569 v3. [2] Kashchenko M.P., Chashchina V.G. Physics – Uspekhi. 2011. V. 54. № 4. P. 331 – 349. [3] Kashchenko M.P., Chashchina V.G. Russian Physics Journal. 2008. V. 51. № 11. P. 1161-1167. [4] Kashchenko M.P., Chashchina V.G. arXiv: cond-mat/1007.0094 v3. [5] Kashchenko M.P., Chashchina V.G. Physical Mesomechanics. 2010. V. 13, № 3-4. P. 195-202. [6] Kashchenko M.P., Chashchina V.G. and Konovalov S.V. Metal science and heat treatment. 2010.V. 52. № 9-10. P. 446-450. 79 9th European Symposium on Martensitic Transformations ESOMAT 2012 Oral presentations, Session 10 –O3, O4 PHASE STABILITY AND CHEMICAL BOND AT MARTENSITIC TRANSFORMATION IN Zr-BASED SHAPE MEMORY INTERMETALLICS Georgiy Firstova, Andrei Timoshevskiib, Yuri Kovala, Sergey Yablonovskiib, Jan Van Humbeeckc aG.V. Kurdyumov Institute for Metal Physics, National Academy of Sciences, Kiev, Ukraine bInstitute of Magnetism, National Academy of Sciences, Kiev, Ukraine cDepartment MTM of the Catholic university of Leuven, Heverlee, Belgium [email protected] ZrCu-based intermetallic compounds are known as perspective high temperature shape memory alloys [1, 2]. They, as well as the binary ZrCu, undergo the martensitic transformation from high temperature B2 austenite into two monoclinic martensites belonging to Cm and P21/m space groups [3]. Yet, their application is hindered because of the significant plastic deformation resulting from the crystallographic scheme of the B2→B19` martensitic transformation. The stability of B2 austenite to martensitic transformation can be enhanced by the additions of Co instead of Cu up to binary ZrCo, which possesses B2 type of structure upon cooling to the temperature of liquid helium. The replacement of Cu by Ni destabilizes B2 phase to such extent that binary ZrNi crystallizes from the liquid into B33 phase. In other words, the competition between B2 austenite (Pm3m) and B19` (P21/m), B33 (Cmcm) martensites and martensite belonging to Cm space group is taking place for multi-component quasi-binary shape memory intermetallics based upon compounds of ZrCu-ZrNi-ZrCo row. The present paper is dedicated to the analysis of influence of the chemical bond in these intermetallics onto relative stability of the crystalline phases competing in the process of martensitic transformation. To do so, the high precision FLAPW and LCAO methods were used to calculate atomic structure and total energies of model structures mentioned above. Structural instability of the martensitic character for the real ZrCu, ZrNi and ZrCo intermetallics was modeled with the help of these structures. The comparison between the results of modeling and experimental data allows discussing the perspectives of the purposeful design of Zr-based high temperature shape memory alloys with the required type of martensitic transformation, which in its own turn will ensure their optimal functional properties. [1] G. Firstov, J. Van Humbeeck and Yu. Koval: J. Intell. Mater. Syst. Struct., 2006, 17, 1041. [2] J. Ma, I. Karaman and R.D. Noebe, Int. Mat. Rev., 2010, 55, No 5, 257. [3] G. Firstov, J. Van Humbeeck and Yu. Koval, J.Physique IV, 2001, Pr8, No 11, 481. STRESS-FREE STRAINS IN MARTENSITE MICROSTRUCTURES Michaël Peigney Université Paris-Est, Paris, France [email protected] The peculiar properties of shape-memory alloys are the result of a solid/solid phase transformation between different crystallographic structures, known as austenite (stable at high temperature) and martensite (stable at low temperature). In terms of crystallographic structure, the austenite has a higher symmetry than the martensite. Therefore, the martensite actually exists in the form of several variants, corresponding to different orientations of the martensitic lattice with respect to the austenitic lattice. Accordingly, to each martensitic variant is attached a transformation strain, describing the deformation between the crystallographic structures of the austenite and the martensite. The number of martensitic variants as well as the corresponding transformation strains depend on the alloy considered, through the structure of the austenite and martensite lattices. Some common examples include the cubic to tetragonal transformation (MnCu, MnNi), the cubic to orthorombic transformation (CuAlNi) and the cubic to monoclinic transformations (NiTi), corresponding respectively to 3, 6 and 12 martensitic variants. This paper is concerned with the theoretical prediction of the set of strains that minimize the effective (or macroscopic) energy. Those strains, classically refered to as recoverable strains, play a central role in shape memory effect displayed by alloys such as NiTi or CuAlNi. They correspond to macroscopic strains that can be achieved in stress-free states. The macroscopic energy is defined as the quasiconvexification (or relaxation) of a multi-well energy function that models the behaviour of the material at a microscopic level. The relaxation procedure essentially consists in finding the austenite/martensite microstructures which minimize the global energy. Closed-form solutions have been obtained only for two phases in the geometrically nonlinear setting, and up to three phases in the geometrically linear setting. This paper aims at complementing existing results on that problem, essentially by deriving bounds on the set of energy-minimizing strains. Upper bounds are obtained using distinctive properties of Young measures. Lower bounds are constructed using lamination techniques. Special emphasis is put on the study of the twelve-well problems corresponding to cubic to monoclinic transformations. 80 9th European Symposium on Martensitic Transformations ESOMAT 2012 Oral presentations, Session 1 –P14 PHASE TRANSFORMATIONS AND SHAPE MEMORY EFFECT IN ALLOYS OF Zr-Ni-Co SYSTEM Kоsоrukоvа Tatianaa, Firstov Georgiya, Koval Yuria, Ivanchenko Volodymyra, Jan Van Humbeeckb aG.V. Kurdyumov Institute for Metal Physics, National Academy of Sciences, Kiev, Ukraine bDepartment MTM of the Catholic university of Leuven, Heverlee, Belgium [email protected] A systematic study of the alloys of Zr-Ni-Cо system with the help of X-ray diffractometry, differential thermal analysis, optical metallography and shape memory effect measurements was carried out. It was shown that the formation of the low symmetry B33 structure in Ni-rich Zr50Cо50-xNix (0 < x < 50) intermetallics is taking place by diffusion at temperatures higher than 0.8Tmelt. The phase formation changes into diffusionless martensitic transformation in intermetallics with Ni content below 30 at.% and occurs at the lower temperatures. In the latter case, B2 austenitic phase is formed by diffusion. It is transforming on cooling below 0.8Tmelt into two martensitic phases ordered by B33 and B19` structure types. Martensitic transformation is also taking place in one of the eutectic components for the alloys of CoZr-CoZr2-NiZr2-NiZr region. Shape memory behavior associated with the mentioned martensitic transformation in the alloys of Zr-Ni-Cо system will be presented. The perspectives of these materials as high temperature shape memory alloys will be discussed. 81 9th European Symposium on Martensitic Transformations ESOMAT 2012 Oral presentations, Session 2 –O1, O2 CuZr BASED SHAPE MEMORY ALLOYS: EFFECT OF ALLOYING ELEMENTS ON THE MARTENSITIC TRANSFORMATION C.A. Biffia, A. Figinib, A. Tuissia aCNR-IENI Institute for Energetics and Interphases, Lecco Unit C.so Promessi Sposi, 23900 Lecco, Italy. b Edison SpA, R&D Division Foro Buonaparte 31, 20121 Milano, Italy. [email protected] In the present work an investigation on CuZr based shape memory alloys is proposed. In particular, the study addresses the effect of the addition of some elements, such as Cr and Co, on the martensitic transformation behaviour. The characterization is performed using DSC in terms of evolution of characteristic temperatures. The analysis of the proposed alloys is completed with the evaluation of the mechanical properties (i.e. microhardness) and the microstructure, observed by means of a scanning electron (SEM) and optical microscopy (OM).Moreover, X-raysdiffraction (XRD) analysis is also carried out at room temperature to confirm the observed microstructures in the different alloys. Finally, a comparison between the stability of the martensitic transformation of the considered alloys after the first thermal cycles is also taken into account. Advantages and disadvantages of the proposed alloys in comparison with the binary CuZr system are presented and discussed, too. MICROMECHANICAL ANALYSIS OF STRESS INDUCED MARTENSITE TRANSFORMATION IN POLYCRYSTALLINE CU-AL-BE SHAPE MEMORY ALLOY aGarcía F. N., bAmigó V., aCortés J., cSánchez F. M., cGonzález J. G., dFlores H. a Centro Tecnológico Aragón, FES Argón, UNAM. Av. Rancho Seco s/n, Col. Impulsora, Cd. Nezahualcóyotl, Edo. de México, México, C.P. 57130. b Universidad Politécnica de Valencia, Instituto de Tecnología de Materiales, Camino de Vera s/n, C.P. 46022. c Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México Apdo. Postal 70-186, Cd. Universitaria, México, D. F. C.P. 04510. d División de Materiales Avanzados, Camino a la Presa San José 2055, Col. Lomas 4a. sección C.P. 78216, San Luis Potosí, San Luis Potosí, México. [email protected]. The mechanical behavior of polycrystalline shape memory materials is characterized by the apparition of martensite variants. Recently it was reported that the first criteria of the martensite variant apparition is the maximum Schmid factor, nevertheless some dispersion could be appear when the materials don‟t has been strained or when the relative grain size change hardly. On the other hand as is well known, that in samples obtained of casting ingots the grain size and shape the mechanical behavior can be change so hard respect from these ones which were hot or cold worked. In fact it is well known the typical inter-grain failure in casting samples. Also it well know that more regular behavior is found in polycrystalline samples with smalls and equiaxed grains, microstructure which is obtained before hot or cold work and re-crystallization treatment. The shape memory materials can be a powerful tool for the study of the mechanical behavior of polycrystalline materials and the influence of the micro-structural parameters as: a) the grain size, b) the grain shape and c) the plastic strain percent between others. In the present paper, a set of single crystal and polycrystalline samples were subject to a simple tension and three points bending test. During the test the micro-structural change are observed through an optical microscopy. The crystalline orientation of every single crystal and each grain of each polycrystalline sample were measured using the Electron Backscatter Diffraction (EBSD) techniques. Using the maximum Schmid Factor criteria and rests of the information available for Cu-Al-Be shape memory alloy as: a) The elastic constants of cubic austenitic structure. b) The transformational systems for the Cu- Al-Be alloys. c) The stress ratio and d) The transformation temperatures. It was generate a simulation of the mechanical behavior of each single crystal and each grain of the polycrystalline samples which consist in the calculation of the distortion during the test before and after the test of martensite transformation. A post assembly of each grain of the polycrystalline samples was made and possible incompatibilities were observed. Also the new variants in each grain were evaluated and the state of stress was estimated. 82 9th European Symposium on Martensitic Transformations ESOMAT 2012 Oral presentations, Session 2 –O3, O4 THERMO-MECHANICAL BEHAVIOR OF CU-AL- BE SMA SINGLE CRYSTALS I. López-Ferreñoa, T. Breczewskib, I. Ruiz-Larreab, A. López-Echarria , M.L. Nób and J . San Juana a Dept. de Física de la Materia Condensada, Facultad de Ciencia y Tecnología Universidad del País Vasco, Aptdo 644, 48080- Bilbao, SPAIN b Dept. de Física Aplicada II, Facultad de Ciencia y Tecnología Universidad del País Vasco, Aptdo 644, 48080 Bilbao, SPAIN [email protected] Among the different Cu-based shape memory alloys (SMA), the Cu-Al-Be family exhibit a particular interest for low and intermediate temperatures applications as these alloys show a low thermal hysteresis in a wide range of temperatures maintaining a good thermal stability against overheating. In the present work we study the influence of several thermal treatments on the thermo-mechanical properties of three different concentration Cu-Al-Be single crystals. Superelastic tests and thermal cycles under different loads have been carried out on the different single crystals with the aim of establishing the Clausius-Clapeyron line and characterising the one-way shape memory effect. The different thermal treatments were studied by differential scanning calorimetry and internal friction measurements. The analysis of the transformation behavior after each thermal treatment allows us to optimise the treatment in order to avoid precipitation and stabilization of martensite and to find the right process to be useful for all the alloys transforming between 200 K and 400 K. In addition, internal friction measurements were performed in order to study the short range diffusion mechanism associated to a relaxation observed around 520 K for a frequency of 1 Hz. Finally, the influence of thermo-mechanical cycling on the transformation temperatures has been also studied. MICROMECHANICAL CHARACTERIZATION OF MARTENSITIC TRANSFORMATION IN SHAPE MEMORY ALLOYS BY NANOINDENTATION C. Caër, E. Patoor, S. Berbenni, J.-S. Lecomte LEM3, Arts et Métiers ParisTech, CNRS, 4 rue Augustin Fresnel, Metz, France [email protected] Micromechanical approaches used to model shape memory alloys behavior neglect several phenomenon such as the influence of grain size on martensitic transformation. This is due to a micro-homogenization of intra-granular mechanisms. This study aims at characterizing and modeling mechanisms of martensitic transformation and reorientation in these alloys at intra-granular scale. The characterization of these discrete mechanisms is done by nanoindentation and atomic force microscopy. A discrete variant activation mechanism, characterized by the presence of events such as “pop-in” and “pop-out” on the plot resulting from nanoindentation is observed and analyzed. 83 9th European Symposium on Martensitic Transformations ESOMAT 2012 Oral presentations, Session 2 – O5, Session 8 - O2 MANUFACTURE AND CHARACTERIZATION OF Cu-Zn-aL shape memory foams P. Arneodo Larochettea, B.A. Weissb, G. Bertolinoa, E.M. Castrodezac, A. Baruja, H.E. Troiania aCentro Atómico Bariloche - Instituto Balseiro (U.N. Cuyo / CNEA) and CONICET, Bariloche, Argentina. bFacultad de Ingeniería, Universidad Nacional de Entre Ríos, Oro Verde, Argentina. cDepartment of Metallurgical and Materials Engineering, COPPE-UFRJ, Rio de Janeiro, Brazil [email protected] The low cost Cu-Zn-Al foams present, in specific composition ranges, good pseudo-elastic properties associated with interesting damping capacities, which establish these materials as attractive from the point of view of structural applications. For this work the possibility of manufacturing Cu-Zn-Al foams with compositions in the pseudo-elastic range by using two different synthesis methods has been studied. The purpose of this study was to determine the quality of each synthesis method remembering that small departures in local chemical composition would result in strong variations in the martensitic transformation temperature, Ms. The foams where manufactured by infiltrating the molten alloys with SiO2 small spheres under pressure in two different ways. In process A the alloys were molten by using a resistive furnace, while in process B the alloys were molten in an inductive furnace. In both cases, the alloy was molten in an open crucible and the SiO2 spheres were infiltrated while the alloy was in the molten state. Afterwards the SiO2 spheres were removed by immersing the material in a solution of water and hydrofluoric acid. As a consequence, we obtained polycrystalline foams with grains in the millimeter range and a 3 mm pore size, in accordance with the size of the SiO2 spheres used. The paper details both the local physico-chemical and mechanical characterization of the foams synthesized with the two different methods. Strong differences were found in the transformation profile and mechanical behavior between these the materials. This fact is due to two factors. In first place, in the case of the inductive furnace the melting time is shorter. Then, in the inductive process there is a lower zinc loss during alloy preparation in comparison to the resistive process. And second, during inductive melting there is a strong stirring of the molten alloy, which results in better homogeneity. The main conclusion is that the correct method to synthesize Cu-Zn-Al foams is the one which uses the inductive furnace. Additionally, the pseudo-elastic behaviors of foams produced with both methods were investigated at different temperatures. The temperature dependence of the transformation stress is lower than 0.3 MPa/K, while this value is 2.7 MPa/K for policrystals of the same composition. TIPT HTSMA PRODUCED BY SPARK PLASMA SINTERING OF ELEMENTAL POWDERS Chikosha Silethelwe and Chikwanda Hilda Kundai CSIR, Pretoria, South Africa [email protected] Titanium-platinum (Ti50Pt50) alloy has been identified as a potential candidate for high temperature shape memory alloy (HTSMA) applications such as actuators in jet engines. However, this alloy has not yet found industry application due to challenges associated with its processing, because most research carried out thus far has been based on using conventional casting for producing the alloy. Inherent to this method is the high costs associated with the high temperatures required for melting and composition inhomogeneity resulting from oxidation during melting. Furthermore, the behaviour of this alloy is not well understood due to the limited research work that has been carried out on it. This work evaluates powder metallurgy as an alternative processing route with the added benefit that near net shaped components can be formed. Spark plasma sintering (SPS) of blended elemental titanium and platinum powders was carried out. This method was chosen as it was expected to form fully dense parts under minimal conditions of temperature and time. The sintering conditions used were: temperatures ranging from 1200 to 1400 °C and sintering times ranging from 10 to 30 minutes. SEM with EDS, XRD and DSC was carried out to study the results. Results showed that SPS only achieved full densification, but not homogenisation of the alloys. All sintering conditions resulted in formation of the martensitic TiPt phase of interest, together with some or all of the following phases: Ti, Ti3Pt, Ti4Pt3, Ti3Pt5 and Pt. Post sintering annealing treatments were carried out to homoginise the alloys at 1300 °C for times ranging from 5 to 15 hours. With sufficient annealing times a two phase microstructure was produced with TiPt as the majority matrix phase and Ti3Pt5 as the precipitate phase. It was concluded that TiPt can be formed by sintering and homogenization of blended elemental powders and that strict control of the processing environment, i.e. eliminating oxidation, carburization, nitridation, etc. is required if a single phase structure is to be obtained. 84 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 12 – P1, P2 FUNCTIONAL PROPERTIES OF TINI SHAPE MEMORY ALLOY AFTER HIGH STRAIN LOADING Bragov Anatolyb, Galieva Alesiaa, Grigorieva Viktoriaa, Danilov Anatolya, Konstantinov Alexandrb, Lomunov Andreyb, Motorin Alexandera, Ostropiko Eugenia, Razov Alexandera aSaint-Petersburg University, Saint-Petersburg, Russia bLobachevsky State University of Nizhni Novgorod, Nizhni Novgorod, Russia [email protected] Use of shape memory alloys (SMA) in engineering currently receives a new pulse by discovery of new alloys, a considerable progress in the production of semi-finished products and technologies in their processing, overcoming conservatism of engineers and designers [1]. However, many modern application developments are aimed to miniaturization and reducing the response time of devices. Therefore a great importance has the study of thermo-mechanical and functional properties of SMAs at high strain loading. The results of such studies may also be useful in developing technologies and in the manufacturing of SMAs. In addition high strain rate loading can be used for surface treatment, which is important for implants to improve their biological compatibility [2]. The object of study was equiatomic TiNi shape memory alloy. The samples were tensioned at the rate of about 103 s-1 at various temperatures in martensitic, austenitic and two-phase state using split Hopkinson pressure bar technique. One way and two-way shape memory effects were investigated. Effect of high strain rate on functional properties of TiNi-shape memory alloys is presented. It is shown, that high strain rate loading of TiNi alloys at various temperatures can lead both to an increase in functional properties as well as to their suppression. [1] A.I. Razov. The Physics of Metals and Metallography. 2004. V.97, Suppl.1. P.97-126, [2] T. Jamsa, V. Muhonen, A. Danilov, J. Tuukkanen. Material Science Forum. 2010. V.631-632. P. 175-179. PSEUDO ELASTIC CYCLIC DEFORMATION OF NITI ALLOY UNDER VARIOUS TEMPERATURES Dmitry E. Kaputkin, Elena V. Esina National University of Science and Technology “MISiS”, Moscow,Russian Federation [email protected] 0 0 Scheme of pseudo elastic cyclic deformation of Ti49.4Ni50.6 wire (Ms=(0±2) C) at temperatures up to 700 C included loading up to 4.3% elongation and unloading. It was shown that the parameters of the strain/stress patterns are strongly resulting from numbers of preliminary deformation cycles (NoPDC). For all testing temperatures some changes were fixed. 1. An increase of NoPDC up to 5-15 results in 40-60% decrease of the stress, necessary to start of the direct martensitic transformation. These stresses for all next NoPDC‟s are almost constant. 2. The maximal stress of the cycle is near the constant for any NoPDC.. 3. An increase of NoPDC up to 5-10 results in 10-20% increase of the stress during unloading, necessary to start of the reverse martensitic transformation. These stresses for all next NoPDC‟s are almost constant too. 4. An increase of NoPDC up to 50 results in 30-50% increase of the stress during unloading, necessary to finish of the reverse martensitic transformation. 5. An increase of NoPDC results in monotonous decrease of the energy, which disappears during one cycle. Thus, preliminary deformation facilitates both the direct, and the return martensitic transformations. Temperature dependences of all above-mentioned stresses for equal number of cycles of previous deformation are monotonously (near-linear) increasing. This fact corresponds to the martensitic nature of pseudo elastic deformation. Thus it is possible to evaluate the important temperatures of the martensitic transformations by extrapolation of the stress/temperature lines onto the zero stress. For the studied alloy after the quenching at 5500C 0 0 0 these points are: Ms = +5±2 C, As = –2±4 C, Af = +13±2 C. A very interesting fact was established: these critical temperatures (calculated for any constant NoPDC) are the same. Thus, the preliminary deformation significantly influences on the phase transformation realization under the external stress but don‟t effects on the temperature intervals of the phase transformations without a stress. 85 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 12 – P4, P5 STRUCTURAL CHARACTERIZATION BY X-RAY DIFFRACTION OF LASER WELDED SHAPE MEMORY ALLOYS Braz Fernandes Francisco M.a, Mahesh Karimbia, Craciunescu Corneliu M.a, Oliveira João Pedroa, Schell Norbertb, Miranda Rosa M.c, Ocaña J.L.d a CENIMAT/I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal b Institute of Materials Research, Helmholtz-Zentrum Geesthacht, Geesthacht, Germany, c UNIDEMI, Departamento de Engenharia Mecânica e Industrial, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal, d Centro Láser UPM, Universidad Politécnica de Madrid, Edificio “La Arboleda”, Madrid, Spain [email protected] The demand of emerging joining techniques for shape memory alloys (SMA) has become of great importance, as their functional properties namely shape memory effect (SME) and superelasticity (SE) present unique solutions for state-of-the-art applications. Literature shows that significant efforts have been conducted on laser-welding of these alloys, although very limited results concerning mechanical properties are repeatedly achieved. A better understanding of the mechanical behaviour of these welded joints may be got through a detailed analysis of the structural characteristics of the material from the base metal to the weld bead. Such studies have been carried out on a series of Ni-rich Ni-Ti SMA laser welded plates using synchrotron radiation. Specimens were cut-off from as-received plates to 30x30 mm2 for butt welding. A Nd:YAG laser power source operating in continuous wave mode was used with a gas protection of argon on top and helium in the. Butt welds were performed in a special chamber built in-house using heat input of 396, 660, 742.5 J/cm. The beam diameter on focus was 0.45 mm and the focal point was positioned at the upper surface, evaluated by a beam profilometer. Butt welding was performed with zero gap between opposite plates, XRD analysis was performed at the beamline P07 of the PETRA III (DESY, Hamburg), using a 2D detector MAR-3450. Radiation was tuned to 87 keV. Line scans (3 mm long) across the base material, heat affected zone and weld bead were performed using a beam spot of 0.1x0.1 mm, spaced by 0.2 mm in order to identify the phases at different positions. The results obtained for the different welding parameters are discussed. IN-SITU STUDY OF HOMOGENIZATION THERMOMECHANICAL TREATMENT OF Ni-Ti SHAPE MEMORY ALLOYS PRODUCED BY POWDER METALLURGY Braz Fernandes Francisco M.a, Neves Filipea, Mahesh Karimbia, Stark Andreasb, Schell Norbertb a CENIMAT/I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal b Institute of Materials Research, Helmholtz-Zentrum Geesthacht, Max-Planck-Str. 1, D-21502 Geesthacht, Germany [email protected] Recently, two promising approaches to produce nanostructured NiTi alloys via PM have been proposed. Those processes, involving mechanical activation of elemental powder mixtures and densification through extrusion or forging, were named Mechanically Activated Reactive Extrusion Synthesis (MARES) and Mechanically Activated Reactive FOrging Synthesis (MARFOS). MARES and MARFOS combine a short duration ball milling and a relatively low temperature densification process. The intimate mixture of the reactants was achieved within each elemental phase minimizing the diffusion path lengths. Also, smaller activation energy for reaction was detected after mechanical activation, allowing a controlled reactive synthesis. Densification resulted in the development of multiphase products with a high density. Afterward, multiple-step martensitic transformations could be observed in aged materials. The phase constitution is common to materials produced via PM route and can be explained by the thermodynamic characteristics of the Ni–Ti system and also by composition fluctuations in the MA powder particles. These were presumably responsible for the formation of different secondary phases during the densification process. The work that was carried out has revealed the necessity of having a detailed knowledge of what happens in relation to the phase transformation during the homogenization heat treatments, in particular to the relation between the newly formed intermetallic phases and the solid solutions. In this study, in situ analysis of dynamic processes is carried out, by combining dilatometric and XRD data during thermomechanical cycles. For this purpose, a dilatometer DIL 805, working under compression was mounted on P-07 beamline (PETRA-III, DESY). Thermomechanical cycles comprising heating to 500, 700 and 950ºC, followed by holding times from 30 min to 8h and applied loads of 500, 1000 and 2000 N. X-ray beam tuned to 100 keV and a 2D detector MARS-3450 have been used. The kinetics of the different operating conditions are discussed. 86 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 12 – P6, P7 INFLUENCE OF THERMOMECHANICAL PROCESSING (ТМP) ON DEFORMATION PROPERTIES AND POWER CONSUMPTION TITANUIM NICKELIDE REALIZED AT THERMOCYCLING IN CONDITIONS OF MECHANICAL WORK Andronov I.N., Verbakhovskaya R. A. Russia, Ukhta, Ukhra state technical university [email protected] We executed regular researches of ТМP influence on memory property deformations and specific working capacity of titanium nickelide realized at thermocycling in conditions of mechanical work. Thermocycling modes are found at which the effect of form memory deformation increase at the expense of ТМP reaches 9, and power consumption is 7.5. The experimental part of this work is executed on the special installation designed and made at Ukhta state technical university [1]. Experiences were carried out in a torsion mode on continuous, cylindrical samples with length and diameter of working part 33 and 4 mm accordingly, as follows. As an experimental object we used continuous cylindrical samples from equiatomic alloy of titanium nickelide, mark ТН-1, with temperatures of martensite transitions. Thermocycling loading at the stage of heating and cooling had values h и с accordingly, under condition of conducting τh/τc = k > 1. Thermocycling under the specified loading was carried out within 10 cycles. In a consequence within 10 cycles we carried out TMP thermocycling samples TMO 011 011 011 under loading h and с under condition of parities performance h / с k . Then we came back to an initial mode of thermocycling under loading and . Effect of power consumption memory deformation increase and at the expense of ТМP were defined as the relation 011 / and ATMO / A for each set of working loading and TMP loading. It is shown that ТМP effect essentially depends on the relation of maximum ТМP loading and working pressure at a parity h /c 4 reaches 9 on deformation and 7.5 on specific working capacity. The named approach allows to form the demanded functionally – mechanical properties of materials with memory. Vlasiv, V. P. A.S. 1809356 USSR. Installation for materials samples test at difficult tension [Text] / V.P.Vlasov, I.N.Andronov, J.B.Kakuliya//Discoveries. Inventions. 1993. №14. INFLUENCE OF THE LOW TEMPERATURE GLOW DISCHARGE NITRIDING AND/OR OXIDING PROCESS ON THE STRUCTURE AND SHAPE MEMORY EFFECT IN NiTi ALLOY Lelatko Jozefa, Lekston Zdzislawa, Freitag Marlenaa, Wierzchoń Tadeuszb, Goryczka Tomasza a University of Silesia, Institute of Material Science, Bankowa 12, 40-007 Katowice, Poland b Warsaw University of Technology, Faculty of Materials Science and Engineering, Wołowska 141, 02-507 Warsaw, Poland [email protected] The NiTi alloys with shape memory effect and the superelasticity effect are frequently used for medical implants. Apart from their good biocompatibility there still exists an occurrence of side effect during medium and long term use. It is related to contact with human tissue. In order to increase corrosion resistivity the surface of NiTi alloy is covered by layers. Layers can be made from titanium nitrides or oxides as well as their mixture. Recently, a glow discharge technique have been applied for coatings formation. However, the deposition process requires to be done at elevated temperature. Therefore, it may take a negative effect on the structure, which is responsible for the shape memory phenomena. The results obtained from studies, done over the influence of the glow discharge nitriding and combination of nitride and oxidizing process on: - the structure, - the kinetics of martensitic transformation, - the one-way shape memory effect and the superelasticity effect of the NiTi alloys will be reported. The results showed that during deposition process, curried out at temperatures above 250°C and time up to 30 minutes, the precipitation of dispersive particles of Ni4Ti3 phase already starts and take a positive effect on the superelasticity phenomena. Moreover, the particles generated the stress field, which changed the martensitic transformation course from one-step to two- steps with occurrence of the R-phase. Applied deposition technique do not affect negatively the shape memory effect. 87 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 12 – P8, P10 TEMPERATURE MEMORY EFFECT IN A MULTISTAGE MARTENSITIC TRANSFORMATION OF TiNi ALLOY T. Breczewskia, A. López-Echarrib, M.L. Nóa, I. Ruiz-Larreaa, and J. San Juanb a Departamento Fisica Aplicada II, Universidad del País Vasco, Bilbao, Vizcaya, Spain b Departamento de Fisica Condensada, Universidad del País Vasco, Bilbao, Vizcaya, Spain [email protected] DSC Calorimetric measurements have been performed in a polycrystalline TiNi shape memory alloy (Ti-50.3 at.%Ni). After thermal treatment (950ºC+Ice Quenching+400ºC+Ice Quenching), the TiNi wires present the characteristic multi-stage martensitic 1.6 Ti Ni transformation mainly due to the intermediate R-phase 49.7 50.3 1.4 transformation. The kinetics of the transformation has been fully characterized by means of several heating and 1.2 cooling runs. The temperature memory effect (TME) B19ґ R B2 shown by shape memory alloys, has been also studied 1 around the martensitic (B19´) → intermediate (R) → (J/(gєC) Cp austenitic phase (B2). This effect is characterized by the 0.8 shift of the martensitic transformation up to higher 0.6 T T temperatures after partial transformation cycles [1]. As a a2 a1 consequence, additional peaks are found in the 0.4 calorimetric curves. The figure shows experimental -10 0 10 20 30 40 50 60 70 evidence of this effect in both phase transformations. The T (єC) calorimetric curves before (□: black) and after (o: red) two independent partial transformation cycles to Ta1 and Ta2 are compared. Thermodynamic models based on the martensitic variant elastic relaxation during the re-nucleation processes have provided a convincing description of this phenomenon in Cu-Al-Ni single crystals [2] but are found not able to account for this effect on quantitative grounds in powder or polycrystalline samples. [1] G. Airoldi, A. Corsi, G. Riva. Scripta Mater 36 (1997) 1273. [2] J. Rodríguez-Aseguinolaza, I. Ruiz-Larrea, M. L. Nó, A. López-Echarri, J. San Juan. Acta Materialia 56 (2008) 6283 SHAPE MEMORY EFFECT IN NiTiCo STRIP PRODUCED BY TWIN ROLL CASTING TECHNIQUE Goryczka Tomasza, Patrick Ochinb, Lelatko Jozefa aUniversity of Silesia, Institute of Materials Science, Bankowa 12, 40-007 Katowice, Poland bICMPE Institut de Chimie et des Matériaux Paris Est, CNRS-Université Paris-Est, France [email protected] It has been known that the highest value of the shape memory effect (SME) can be achieved in properly oriented single crystals. In practice single crystals have been rarely applied due to the high cost and difficulties during their production. This is the point, why attention was paid to receiving highly textured polycrystalline shape memory alloys (SMA). Unconventional methods of the alloy production, which give possibility of the grain texturing, have been adopted for the SMA. One of them is twin roll casting. The ternary Ni47Ti50Co3 alloy was produced using twin roll casting technique. The strip showed presence of the reversible martensitic transformation, in which the parent phase transformed to the B19‟monoclinic martensite via the R-phase. The main condition for appearance of the shape memory effect was satisfied. The strip was highly textured. It revealed presence of the axial component <100> and the sheet component {100}<001>. Moreover, calculation of the total amount of grains, which were oriented along the identified texture components, was higher than 80%. The [001] direction in the texture {100}<001> was parallel to length of the strips. Measured value of the on-way shape memory effect (as an elongation versus temperature under constant load) along the strip was lower than 2%. In order to increase value of the SME, the sample was oriented along [011] direction. For such orientation the SME was 6.3%. Theoretical calculation revealed that in this direction SME can reach 6.8% for single crystal. Such oriented sample was trained in order to receive two-way shape memory effect. This effect was induced after 30 cycles. 88 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 12 – P12, P13 SHAPE MEMORY CHARACTERISTICS OF POROUS Ti50Ni50 ALLOY aYeon-wook Kim and bTae-hyun Nam aDepartment of Advanced Materials Engineering, Keimyung UniversityDalseo-gu, Daegu South Korea bSchool of Materials Science and engineering & ERI, Gyeongsang National University 900 Gazwa-dong, Jinju 600-701, Republic of Korea [email protected] TiNi shape memory alloys combine attractive functional properties, high mechanical strength and good corrosion resistance. For the fabrication of bulk near-net-shape shape memory alloys and porous metallic biomaterials, consolidation of TiNi alloy powders are more useful than that of elemental powders of Ti and Ni. In the present study, Ti50Ni50 shape memory alloy powders were prepared by inert gas atomization, and martensitic transformation temperatures and microstructures of those powders were investigated as a function of powder size. XRD analysis showed that the B2-B19‟ martensitic transformation occurred in the powders smaller than 200m. In DSC curves of the as-atomized Ti50Ni50 powders as a function of powder size, that only one clear peak was found on each cooling and heating curve. The martensitic transformation starting temperature (Ms) of the 10-20 m powders o was 22.9 C. Ms continued to decrease inconsiderably with increasing powder size, and the difference of Ms between 10-20 m powders and 150-200 m powders is only 1oC This study also presents a synthesis method for obtaining porous TiNi from the atomized alloy powders using a spark plasma sintering (SPS). It was found that no significant difference in Ms is detected for the sintered materials. Evaluation of powder microstructures was based on SEM examination of the surface and the polished and etched powder cross sections and the typical images of the rapidly solidified Ti50Ni50 powders showed cellular morphology. Fig. 1 SEM images of (a) as-atomized Ti50Ni50 powders and (b) spark plasma sintered bulk. ANNEALING AND THERMAL TRANSITION CYCLING OF NITINOL SMA Krzysztof Kusa, Teodor Breczkob aFaculty of Technical Sciences, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland bFaculty of Mathematics and Computer Science, University of Bialystok, Bialystok, Poland [email protected] The transition phase behaviours of nitinol SMA in relation to various annealing conditions and thermal cycling were investigated. Note that the as-received material had no exactly known the processing history, and in this state revealed the two-stage transition behaviour covering fairly wide temperature range (-67 to + 45°C). As indicated by DSC, the thermal characteristics for studied alloy were sensitive to the annealing executed under different parameters (temperature, time, cooling rate). A nitinol sample for which the one-stage reaction was recognized after annealing was chosen for thermal cycling test through the martensitic transition temperature range (below Mf and above Af). According to DSC results, the successive temperature cycles changed the transition temperatures resulting in the two-stage behaviour on cooling. Despite the fact that there are already many publications devoted to these issues, the findings collected in the present work may be viewed as a supplement to the wealth of literature being useful in modifying and tailoring the thermal properties of SMA for specific applications. Moreover, it is believed that such data are significant and helpful in experiments where the effect of thermo- mechanical cycling conducted under different loading profiles on the shape memory behaviour is investigated using nitinol SMA heat-treated at various conditions. 89 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 12 – P14, P17 STUDY OF TWO-WAY SHAPE MEMORY BEHAVIOR OF AMORPHOUS-CRYSTALLINE TiNiCu MELT-SPUN RIBBONS Shelyakov Alexander, Sitnikov Nikolay, Saakyan Sergey, Menushenkov Alexey, Korneev Alexander National Research Nuclear University MEPhI, 115409, Moscow, Russia [email protected] Recently we reported on the Ti50Ni25Cu25 (at.%) alloy melt-spun ribbon exhibiting reversible shape memory effect. It was established that from the “contact” side of the ribbon, solidification of the melt occurred with the generation of an amorphous phase, but on the opposite side of the ribbon, a crystalline layer was formed (Fig.1). This laminated rapidly quenched amorphous-crystalline composite realized two-way shape memory behavior in bending without any additional thermomechanical treatments. Upon heating above As the ribbon began to bend, taking the form of a ring at the temperature higher than Аf, and upon cooling below Mf the ribbon returned to its initial straight shape. In this study a ribbon with a crystalline layer thickness of 10 μm was chosen as starting material. The total thickness of the ribbon was varied from 42 to 12 µm due to removal of the amorphous layer by means of electrochemical polishing. As a result the radius of the ring decreased from 10 mm to 2 mm. The typical temperature dependence of the bending deformation of the amorphous-crystalline composite ribbon is presented in Fig.2. Structural investigations were performed by means of X-ray analysis. Martensitic transformation intervals were determined by plotting resistance versus temperature curves. The reasons why the amorphous-crystalline ribbon can exhibit a two-way shape memory behavior are discussed. Fig.1. SEM micrographs of an amorphous- Fig.2. Bending strain vs. temperature curves of the crystalline Ti50Ni25Cu25 ribbon at an initial state composite ribbon with different thickness SPLAT FEATURES DURING VACUUM THERMAL SPRAYING OF NiTi ONTO SEVERAL SUBSTRATES N. Cincaa, A. Isalguéb, J. Fernándeza, G. Fargasc, S. Sampathd aCentre de Projecció Tèrmica, Fac. Química, Universitat de Barcelona, Diagonal 649 E-08028, Barcelona; Spain bDep. Física Aplicada, Universitat Politècnica Catalunya, Pla Palau 18 E-08003, Barcelona; Spain c Dep CMEM Univ. Politècnica Catalunya, Comte d’Urgell 187, Barcelona; Spain dCenter for Thermal Spray Research, Stony Brook, New York; USA [email protected] NiTi alloys have been proposed as alternative protective coatings because of bulk NiTi relevant wear resistance and corrosion near the martensitic transformation temperature. Different processing methods for surface modification have been used to make a NiTi coating such as overlaying welding, vacuum plasma spraying or laser- assisted plasma spraying. Each technology produces different microstructures and performace. Vacuum Plasma Spraying has been used to produce coatings onto steel substrates. This work deals with the study of splat morphology, adhesion, interfacial features and metastable phases formation of the NiTi alloy sprayed by VPS onto different substrates (aluminium, copper, stainless steel, glass and alumina). All the previous characteristics are discussed in terms of wettability and thermal conductivities regarding the rapid cooling involved in the process. Although identical conditions were used during thermal spraying, a wide variety of splat formations were observed; mainly, slushy or splash/disc splats are formed depending on whether the particles have partially or fully melted. Considering the low pressure conditions, the reduced amount of adsorbed gases is an important factor for the improvement of adhesion. The thermal effusivity of the substrate material, which is a measure of its ability to exchange thermal energy with its surroundings, seems to play an important role promoting more or less spreading. The higher the thermal effusivity is, the more rapidly the splats are cooled, thus starting the solidification before they come to rest and, changing their morphology. 90 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 12 – P15, P18 METOD FOR EXPRESS-EVALUATION OF SHAPE RECOVERY IN Ti-Ni SMA Korotitskiy Andrey National University of Science and Technology “MISiS”, Moscow, Russia [email protected] For shape memory alloys (SMA) as for other metallic materials the full deformation can be divided into components corresponding to different deformation processes (mechanisms) that can be attributed to the recoverable (elastic, thermal expansion, phase transformation, …) and non-recoverable (dislocation plastic deformation, diffusion, and other parts). In most cases, the SMA are used in conditions where the role of non-recoverable deformation mechanisms is small, that makes it possible to exclude them from consideration in the evaluation of thermomechanical behavior of structures and elements which are based on SMA. Therefore, the most important aspect for developers using SMA is the precise knowledge of the limiting value of the recovery (full recovery) strain which is the main functional property of SMA determining their operational capacity. Since all the functional properties of SMA are structure-sensitive, then the practical task of the handler is to establish the optimal regimes of thermomechanical treatment (TMT) as an effective method of producing extremely high or desired value for the complex functional properties of SMA (for example: a combination of recovery stress and recovery strain). Therefore, it is actual to decrease the test time, reducing the metal content and complexity of verification tests for SMA, subjected to TMT, in combination with the high reliability of the test results. The regular method of evaluation of recovery strain (εr) is based on the bending of long specimens around cylindrical mandrels. But, this method has some significant drawbacks. The proposed procedure is based on the precise analysis of real profile of sample in three states: initial (undeformed), after deformation (according to the scheme of the three point bending) and after shape recovery, and thereby significant improvement the reliability of the results: in addition, after only one act of deformation, the experimental dependence was obtained: η = f(εi) – the shape recovery rate (η) vs the strain-induced (εi), and, in the broad and the meaningful strain-induced range. Practical application this method for express-evaluation of shape recovery was obtained for testing of Ti-Ni alloys (near the equiatomic composition) subjected to TMT (including the moderate plastic deformation and post- deformation annealing).Good correlation between the predicted and experimental data was showed the following relation as an approximation function for η = f(εi): r 1 where: α, a, n - numerical coefficients. n ; i 1 exp( a i ) This analytical expression for η = f(εi) was obtained in the framework of the model which describes the plastic deformation of SMA through the competition implementation of the recoverable and non-recoverable deformation mechanisms (considering the probability of overcoming the potential barriers with different "effective height"). HOT WORKABILITY ANALYSIS OF AS CAST TINI ALLOY Jong-Taek Yeoma, Jae Keun Honga, Jeoung Han Kima, Chan Hee Parka, Seong Woong Kima, Yong-Taek Hyuna and Kee-Young Leeb aTitanium Research Group, Korea Institute of Materials Science (KIMS), Changwon, Korea bKPCM Corp., Gyeongsan, Korea [email protected] Ingot breakdown is the most important process for achieving good-quality wrought materials. The ingot breakdown of NiTi shape memory alloy is mainly performed by the hot working process such as forging, rolling, etc. However, the study on hot workability of as cast NiTi alloy during ingot breakdown process was not accomplished yet. Hot workability of as cast NiTi shape memory alloy was investigated by considering processing maps and the dynamic material deformation behavior. The NiTi alloy samples used in this study were made from a vacuum plasma arc melting process. In order to analyze the microstructural change and flow behavior of as cast NiTi alloy during ingot breakdown process, high temperature compression tests were carried out at the different temperatures and strain rates up to true strain of 0.7. Processing maps were generated using the dynamic materials model (DMM) initially proposed by Prasad et. al. [1] Also, the flow instability criterion proposed by Ziegler [2] was utilized to evaluate unstable deformation region in the processing map. In high temperature deformation of NiTi alloy, the main microstructural change is grain refinement by the recrystallization behavior. The effects of hot deformation parameters on the recrystallization behavior were analyzed in this work. [1] Y.V.R.K. Prasad, et. al., Metall. Trans. A, Vol. 15A(1984), pp.1883. [2]H. Ziegler, in Prog. Solid Mech. Edited by I.N. Sneddon and R. Hill, Vol.4, Jonn Willey and Sons, New York (1965) 91 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 12 – P19, P26 STRAIN VARIATION DURING THERMAL CYCLING THE TiNi ALLOY UNDER CONSTANT STRESS THROUGH THE TEMPERATURE RANGE OF INCOMPLETE MARTENSITIC TRANSFORMATION Resnina Natalia, Belyaev Sergey, Sibirev Alexey Saint-Petesburg State University, Saint-Petersburg, Russia [email protected] Strain variation on thermal cycling the TiNi alloy under a constant stress of 50 MPa through the temperature range of complete as well as incomplete forward martensitic transformation was studied. Thermal cycling the alloy through the temperature range of incomplete forward martensitic transformation was carried out to realize 25, 50 or 75 % of temperature range of forward phase transition. As expected, thermal cycling the TiNi alloy through the temperature range of complete forward martensitic transformation resulted in observation of “training effect” (an increase in values of transformation plasticity and shape memory effects strain) and accumulation in residual plastic strain. So, the value of shape memory effect increased of 0.6% in the first cycle to 2.5% in the 30th cycle. At the same time a residual strain increased of 0.45% in the first cycle to 0.6% in the 30th cycle. It was shown that observation of “training effect” as well as accumulation of residual strain depended on the completeness of the forward martensitic transformation. It was found that if less than 50 % of temperature range of forward martensitic transformation took place on cooling than the values of shape memory effects were stable during thermal cycling. Moreover, accumulation of residual plastic strain was found only in the first and second cycles and its value was very small (approximately 0.1%). At the same time, if more than 50 % of temperature range of forward martensitic transformation was realized on cooling than accumulation of residual strain were observed on thermal cycling the TiNi alloy under a constant stress of 50 MPa. As higher the fraction of temperature range of forward martensitic transformations as stronger variation in values of shape memory effects and higher the accumulated strain on thermal cycling the TiNi alloy. These phenomena were due to that the martensite accommodation process was elastically in the early stage of forward martensitic transformation. The plastic accommodation of martensite took place on the final stage of forward phase transition. INFLUENCE OF ULTRASONIC TREATMENT ON SHAPE MEMORY EFFECTS IN TI-50,4%NI ALLOY V. Rubanika, V. Rubanik Jr.b, V. Dorodeikoc, S. Miliukinab a Institute of Technical Acoustic, Vitebsk, Belarus b Vitebsk State Technological University, Vitebsk, Belarus c Medical Enterprise “Simurg” [email protected] Here we present the results of a study aimed at the effects of an ultrasound treatment on the properties of nitinol. The wire samples of Ti-50,4%Ni were deformed by bending to various deformation rates (up to 10%) in martensitic state, rigidly fixed and treated by ultrasonic vibrations with the frequency of 22 kHz. The samples were thermocycled in a free state after sonication, and shape memory effects (straight and reversible) were measured. Also the transformation temperatures were determined by differential scanning calorimetry. The results of experiments suggest that deformation effects in the investigated alloy depend on both: preliminary deformation ratio and ultrasonic power. After the minor (up to 3%) induced deformations, the ultrasonic treatment of the fixed samples results in a significant decrease of restoring deformation during the following thermocycling – in some cases practically to zero. At higher induced deformations (3% - 10%) we have observed the dependence of restoring deformation on the amplitude of injecting ultrasonic vibrations. So, after the ultrasonic treatment with amplitudes up to 10 μm at the temperature Т Мf is applied, the shape memory effect grows with rising of induced deformation, but always stays below that in a not treated sample. At the same time the reversible shape memory increases and reaches 2% at maximal preliminary deformation. After a more powerful ultrasonic treatment, the restoring deformation stays at the values less than 3-3,5% instead of common 7-8% for this material. The reversible shape memory stays within 1-1,5%. The thermography experiments show that during the ultrasonic treatment the sample temperature does not exceed Аf. We have not detected any changes of transformation temperatures or kinetics of martensite transitions after sonication. 92 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 12 – P21 STUDY OF STRUCTURAL PECULIARITIES, KINETICS OF MARTENSITE TRANSFORMATION, THERMO-MECHANICAL AND MECHANICAL CHARACTERISTICS OF SHAPE MEMORY ALLOYS BELONGING TO TI-NI-NB-ZR SYSTEM WITH THE WIDE MARTENSITE HYSTERESIS N.N. Popov, V.F. Lar’kin, T.I. Sysoeva, A.A. Aushev, D.V. Presnyakov The Russian Federal Nuclear Center – (FSUE RFNC-VNIIEF), Sarov, Russia. [email protected] The traditional technology of thermo-mechanical joining (TMJ) of conduits uses the shape memory alloys belonging to Ti-Ni-Fe system. However, the clutches made of these alloys are to be initially deformed, stored and mounted at cryogenic temperatures. To do away with this drawback the authors have patented the new progressive alloy belonging to Ti-Ni-Nb-Zr system with the wide temperature hysteresis of martensite transformations [1]. This alloy makes it possible to develop the advantageous TMJ technology, according to which the clutches made of Ti- Ni-Nb-Zr alloy can be stored at the room temperature prior to putting them into operation. The present paper describes the study of the effect posed by alternating initial state (casted and extruded) and the type of thermal processing (hardening and vacuum annealing) on the structure and kinetics of martensite transformations and mechanical and thermo-mechanical characteristics of the alloys belonging to Ti-Ni-Nb-Zr system. To study thermo- mechanical characteristics of shaped memory alloys in the wide temperature range as well as deformation rate and labor rent of TMJ technology a special experimental and methodological source was developed [2].Using the above source the chemical and phase composition of the alloys under study were studied and their microstructure was revealed. The kinetics of martensite transformations was examined. Parameters of sub-structure and micro-stresses were calculated. The values of mechanic and thermo-mechanic characteristics were identified. The effects of alternating initial state of the alloys and of the type of thermal processing on the above properties were determined.As it was stated, the extruded initial state of the alloys (resulting from extrusion of the casted alloy) belonging to Ti-Ni-Nb-Zr system is advantageous as compared to the casted initial state, since it leads to the expressed changes in its structure: lower number of inclusions of parasite Ti2Ni phase and carbides; eliminated porous defects; grinded down to 10 nm grains and clusters; lower macro-stresses; improved complex of mechanical and thermo-mechanical properties. It was revealed, that after thermal processing of the samples made of Ti-Ni-Nb- Zr according to vacuum annealing mode, the average values of the most important thermo-mechanical characteristics, such as the initial and the final temperature of form rebuilding when shape memory effect and reversible shape memory effect are exibited, the value of the induced deformation, the coefficient of form rebuilding, hysteresis of martensite transformation reach the higher values as compared to the annealing and the initial extruded state.The above studies proved, that the alloys belonging to Ti-Ni-Nb-Zr system in the extruded initial state are perspective as they are used to produce clutches and structural elements within TMJ technology. Noteworthy is that the clutches made according to this technology can be stored at the temperatures up to +40 C prior to putting them into assembly process. [1] Popov N.N., Prokoshkin S.D., Abramov V.Ya, Makushev S.Yu. An Alloy with the Shape Memory Effect. Patent of RF №2327753, MPK S 22 S 14/00, S 22 S 19/03. – 2008. – Issue № 18. (in Russian). [2] Popov N.N. Development of Progressive Technologies on the Basis of Materials with the Shape Memory Effect. Monograph. – Sarov: FSUE "RFNC-VNIIEF". – 2008. – 315 p. (in Russian). 93 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 12 – P27, P28 ANNEALING EFFECTS IN MARTENSITIC TRANSFORMATION TEMPERATURE OF THE Ni-Ti SHAPE MEMORY ALLOY RAPIDLY SOLIDIFIED Anselmo, G. C. S., de Castro, W. B. ; de Araújo, C. J. Universidade Federal de Campina Grande, Campina Grande - PB – Brazil [email protected] One important challenge of microsystems design is the implementation of miniaturized actuation principles efficient at the micro-scale. Shape memory alloys (SMAs) have early on been considered as a potential solution to this problem as these materials offer attractive properties like a high-power to weight ratio, large deformation and the capability to be processed at the micro-scale. Ti44,8Ni55,2 shape memory alloy was prepared by melt spinning technique at different wheel speed. The effect of annealing at different temperatures on a rapidly solidified/melt- spun Ni-Ti alloy has been investigated in depth. The analysis of these treatments was made by means of DSC. Changes on martensitic transformation temperatures in Ti44,8Ni55,2 melt spun ribbons were observed with the increase of the wheel speed and variation of annealing temperature and time. In NiTi alloy parent phase B2 usually transforms to a monoclinic B19´ structure. But sometimes it can occur as two-step transformation from the B2 phase to a trigonal R-phase and then to the B19´ structure [1]. This phenomena is very sensitive to the fine structure of the parent phase. The as spun ribbons of grain-size mixed Ti44,8Ni55,2 SMA have most of the large and small grains at the free surface and copper roller surface of the ribbons, respectively. The as-spun ribbons have intrinsic multiple martensitic transformations with two peaks appearing in the cooling DSC curves, B2 to R-phase and R-phase to B19´. This is typical behavior of the as-quenched ribbons. Decrease of martensitic transformation temperature caused by increasing numbers of vacancies is being progressively recovered as the alloy stays in parent phase during thermal treatment. Due to the high quenching rate, this effect is enhanced in the rapidly solidified ribbons. For the annealed ribbons a progressive increase of reversible and forward martensitic transformation temperature with respect to the thermal treatment temperature was observed. The as-spun annealed ribbons have martensitic transformations with only one peak appearing in the cooling DSC curves, B2 to B19´. [1] L. Wu, S. Chang and S. Wu, Journal of Alloys and Compounds, vol. 505, pp.76–80, 2010. TiNiCu MARTENSITIC TRANSFORMATION CHARACTERIZATION AT LOW STRESS LEVELS THROUGH THERMOMECHANICAL CYCLING Fabregat-Sanjuan, Albert; De la Flor, Silvia; Ferrando, Francesc; Urbina, Cristina Department of Mechanical Engineering. Universitat Rovira i Virgili, Tarragona, Spain [email protected] According to the current literature, different macroscopic constitutive models based on the stress-temperature diagram have been built to model SMA behaviour [1], where SMA show a constant ratio stress/temperature following the equation of Clausius-Clapeyron. However, this relationship is not applicable for all stress values. Therefore, it is not valid for values under the critical stress for the martensitic transformation below Ms (σCR). Below this stress level, there are differences in the aforementioned models, because depending on the load level, martensitic transformation (MT) can occur by a transformation to self-accommodated twinned martensite or by a transformation to detwinned or reoriented martensita in which a specific variant is dominant [2]. Moreover, σCR is different with thermomechanical cycling (TC) and also is affected by heat treatment temperature (HTT) [3]. The main objective of this study is the characterization of MT at low stress levels through TC in order to evaluate its behaviour below σCR for different HTT, and evaluate the critical stress to obtain orientation (σOR). To carry out this characterization Ti44.6Ni5Cu (at.%) 1mm wire specimens with different HTT (400, 450, 500 and 550ºC) have been used. Constant stress tests were conducted within the various ranges of critical stresses and by varying the temperature from a lower temperature than Mf, to a higher temperature than Af. Furthermore, a home- made extensometer and a programmed multimeter with 4-wires configuration have been used to evaluate MT through deformation evolution and electrical resistance variations. Experimental results have shown that σOR is different for each HTT, showing a tendency towards lower σOR with higher HTT. Moreover, it has been proved that if TC is conducted under σOR, transformation temperatures (TT) are not affected and deformation stabilizes. On the other hand, once σOR is reached, TC strongly affects TT and deformation behaviour. [1] De la Flor S, Urbina C, Ferrando F. Materials science engineering.A, Structural materials 2006;427:112. [2] Duerig TW. Engineering aspects of shape memory alloys. London; Boston: Butterworth-Heinemann, 1990. [3] Nespoli A. Journal of thermal analysis and calorimetry 2011;103:821. 94 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 12 – P60, P61 CYCLICAL OF STRUCTURAL AND PHASE TRANSFORMATION IN ALLOY Ti50Ni25Cu25 DURING SEVERE PLACTIC DEFORMATION Roman V. Sundeev, Anna V. Shalimova, Alexander M. Glezer I.P.Bardin Central Research Institute for Ferrous Metallurgy [email protected] The report presents the results of research of structural phase transformations in the initially amorphous and initially crystalline Ti50Ni25Cu25 alloy during sever plastic deformation in a Bridgman chamber. An amorphous ribbon (50 μm thickness; 8 mm width) obtained by melt spinning in the argon atmosphere was used. A crystalline state was obtained by annealing the initial amorphous ribbon. Severe deformation was carried out in the Bridgman chamber at room temperature under hydrostatic pressure P = 4 GPa. The number of turns of the mobile anvil, n, 1 varied as follows: /8, µ, ´, 1, 2, 3, 4, 5, 6, 7, 8 and 9. The initial stages of the severe deformation of the amorphous 1 state (n = /8 - 1) were characterized by the appearance of crystalline phases (the volume fraction of the crystalline phase at n = ´ is ~ 80%). Then the volume fraction of the crystalline phase decreased with the increasing strain, and at n = 4 the alloy was completely amorphized. However, for n = 6, a two-phase amorphous-crystalline structure was revealed through the X-ray and electro-microscope investigations. Further increase in the severe deformation up to n = 8 led to the amorphization of the alloy again. The initial structure of the crystalline state of alloy Ti50Ni25Cu25 was characterized by lamellar martensite B19. With the increase in the strain, degradation and destruction of the initial lamellar martensite structure and the transformation into an amorphous state through the deformation dissolution of the crystalline phase fragments was observed. Under the deformation corresponding to n=4 the original crystalline structure became completely X-ray amorphous. The subsequent deformation was structurally observed through the repetition of the "crystallization – amorphization” cycle. Thus, the study has demonstrated that three cycles of direct and reverse structural phase transitions are realized through a successively increasing deformation of both initially amorphous and initially crystalline states. The nanocrystallization of the amorphous state has been determined by the superposition of different channels of the dissipation of the elastic energy injected into the material in the course of severe deformation. It has been concluded that the development of individual shear bands and their branching, the accumulation of an excess free volume, and the presence of direct and reverse thermoelastic martensitic transformations are among the most probable ways of dissipation. THE RESEARCH OF WORKING ABILITY OF THE ACTIV ELEMENTS OF SHAPE MEMORY TINI ALLOY Pazgalov Aleksandra, Khusainov Mikhaila, Bondarev Andreyb, Popov Stanislava, Andreev Vladimirb aYaroslav the Wise Novgorod State University, Veliky Novgorod, Russia, bIndustrial centre MATEKS Ltd., Moscow, Russia [email protected] The paper considers the data on working ability of the spherical segments as active elements which are used in thermoresponsive switches and shut-off thermo-valves. Previously it was found out that the spherical segments deformed (bent) in martensite inversely to initial shape show an explosive behavior: they recover the initial shape with a clap and if there is an obstacle on the shape recovery way they do with an impact. This phenomenon was used for the energy-efficient shut-off valves designing in which the spherical segment is a shut-off and thermosensitive element. In this work we investigated working ability of the spherical segments after overheatings above austenite finish temperature (Af). In the temperature region is always the shape recovery with a clap. The spherical segment force of the impact (Pimp) on the obstacle, the height of jump (Hjump) from a heated surface and the force impulse (F·t) are the main force parameters of the object. According to these parameters‟ changes we could estimate their working ability. In particular it is shown that the overheatings above 200°С cause a significant decrease in these parameters. Cyclic tests on the segment by the scheme bend in martensiteheating with an impact and overheating up to 150°С do not decrease the forces generated in the material after stabilizing thermo-mechanical treatment with the annealing at 420°С in constrained state. Experiments on the ladling hop are the evidence for this. The ladlings were placed on the spherical segments and stably hopped at particular height depending on the ladling weight at multiple cycling in the interval of the phase transition martensiteaustenite. The segment‟s energy input for lifting the ladling at the pre-set height is estimated. The ladling weight critical value at which one the energy input for lifting the ladling reached the maximum value is found out. Approximating function in the form of up-bulge parabola testifies that decrease or increase in the ladling weight either causes the energy input decreasing. The found regularities are connected to geometrical shape of the investigated object and to peculiarities of the shape memory effect. 95 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 1 – P1, P6 NEUTRON DIFFRACTION STUDY OF Ni-Mn-Ga MSM ALLOY Pnina Ari-Gura, Amila SB Madiligamaa, V. Ovidiu Garleab, Huibo Caob, Ashley Cokeb, Yangling Gec, Ilkka Aaltioc, Simo-Pekka Hannulac, and Victor Koledovd aWestern Michigan University, Kalamazoo, MI, USA b Neutron Sciences Directorate, Oak Ridge National Lab, Oak Ridge, TN 37831, USA cDepartment of Materials Science and Engineering, Aalto University, Espoo, Finland dRussian Academy of Sciences, Moscow, Russia [email protected] Magnetic shape memory (MSM) alloys attracted much attention; non-stoichiometric Ni-Mn-Ga alloys, specifically, are considered promising for numerous applications [1]. Their performance is sensitive to variations in their composition and crystal structure [1]. Substantial amount of work was focused on the crystal structure of Ni- Mn-Ga alloys [2], however more information is still needed about their chemical order. The order (or lack of it) is critical, as it affects the distance between Mn atoms and the magnetic properties. In the current work, neutron diffraction has been used to investigate the crystal and magnetic phase transformations and chemical order of a Ni-Mn-Ga material in single-crystal, polycrystalline, and powder forms. Overall, the results show no dependence of the structural and magnetic phase diagram on the sample morphology. Above 330 K the results reveal an L21 Heusler phase. The refinement indicates a stoichiometry of Ni48Mn32Ga20, in good agreement with chemical analysis. Below the martensitic transformation, at 330K, the structure has been described by a 7-fold modulated structure with the monoclinic space group P2/m. In this supercell each atomic species occupies six non-equivalent positions. A long-range magnetic order is found to occur below 380 K. Both the cubic (L21) and the low temperature monoclinic phases are ferromagnetic with all the ordered moment confined to the sites with full Mn occupation. The refined value of the Mn moment at 300 K is ~ 2.9(2)μB. [1] K. Rolf, A. Mecklenburg, J.-M. Guldbakke, R.C. Wimpory, A. Raatz, J. Hesselback, R. Schneider, J. Mag. and Mag. Mat., 321 (2009) 1063. [2] Y. Ge, O. Söderberg, N. Lanska, A. Sozinov, K. Ullakko, V.K. Lindros, J. Phys. IV 112 (2003) 921. INFLUENCE OF NANOCRYSTALLINE STRUCTURE OF Fe ON THE BARIC PHASE TRANSFORMATIONS Pilyugin Vitalya,b, Patselov Alexandera, Сhernyshov Eugenye, Ancharov Alexeyc, Tolmachev Timofeya a Institute of Metal Physics, Ekaterinburg, Russia bUral Federal University, Ekaterinburg, Russia cNovosibirsk State University, Novosibirsk, Russia [email protected] The influence of high pressure and the combined action of pressure and large deformation caused by pressure on the α → ε transition in iron is studied. High pressure causes a reversible martensitic transition (α-bcc→ε-hcp). Hysteresis of one increases with increasing of nonhomogeneity (nonhydrostatic) of the high pressure cell. The main purpose was to determine the effect of the nanocrystalline state of Fe in the hysteresis of α ↔ ε transition. Samples of Fe in coarse-grain and nanocrystalline (n-Fe) structure studied in situ under pressure by methods of NGR – spectroscopy and synchrotron radiation on с-BN Bridgmen`s anvils. n-Fe condition was obtained by severe plastic deformation under high pressure torsion (HPT) techniques. Hysteresis of transistion was founded to increase symmetrically at 4 GPa of pressure scale. The increase in hysteresis for n-Fe is associated with an increase in restraining force of the martensitic transformation, which is characteristic of the physical yield point. Strain hardening causes an increase in yield strength and the restraining force of transformation. This is the reason for the increase of hysteresis α → ε transformation in n-Fe on the pressure scale. The slope of quantity of -phase - pressure curve reflects that the range of direct transition ( Pк Pн ) for both types of samples (coarse-grained Fe and n-Fe) remains the same. The observed effect is determined by the stabilization of the -phase high-pressure by nanocrystalline structure formed at severe plastic deformation - HPT. The detailed study of structural transformations of Fe at cold- and cryodeformations under pressure was conducted. 96 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 1 – P13, Session 6 – P1 STUDY OF NIOBIUM-RICH PRECIPITATES IN (NI-TI) 8.4% Nb SHAPE MEMORY ALLOY Hui Shia, Jan Van Humbeeckb and Dominique Schryversa aEMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium bMTM, KULeuven, Kasteelpark Arenberg 44, B-3001 Leuven, Belgium [email protected] The purpose of this work is to clarify the composition and microstructure aspects of Nb-rich precipitates and their relation with the large hysteresis of the MT in Ni-Ti-Nb SMAs and their respective phase diagram. Small and large Nb-rich precipitates have been found in the material by SEM and TEM. The large precipitates have two distinct shapes, some elongated some more rounded. The small nanoscale precipitates disperse in the Ni-Ti (B2) matrix. All of these structures, matrix as well as precipitates, are bcc based. Average composition obtained from 20 measurements (each) by TEM EDX shows that the Nb concentration in the large precipitates and the matrix equals 88.1±0.1 (at.%) and 2.1%±0.7% (at.%), respectively, while the small nanoscale precipitates are found to be almost pure Nb. Also, small Ni-Ti residual areas can be found inside the large Nb-rich precipitate by STEM. The angle between the (110) planes of the matrix and large precipitate is about 30°. Diffraction patterns reveal a cube-on-cube orientation relationship between a small precipitate and the matrix. The geometric phase analysis (GPA) reveals no elastic strain field surrounding the small precipitate in the B2 matrix. The lattice mismatch of about 10% between the small precipitate and the B2 matrix and is relieved by a string of dislocations along the interface. Microstructure changes during a thermal MT have been characterized by in-situ cooling TEM. It is found that the small precipitate prohibits the continued growth of the incoming martensite plate. The interaction results in a strain field around the precipitate, and induces the nucleation of another martensite variant in another direction. This stop-and-go process could be part of the reason for the increased hysteresis of this ternary alloy when compared to binary Ni-Ti. SINTERING AND BONDING PROPERTIES OF ZIRCONIA WITH VENEERING CERAMICS Tae Suk Kim, G.C.Kim, W.W.Park, K.H.Hwang, J.K.Lee, and H.Kim Eng. Res. Inst., I-Cube Center, Gyeongsang National University, S.Korea Chosun University, Seoul National University, S.Korea [email protected] Densification and mechanical properties of dental zirconia ceramics were evaluated by different sintering methods. Microwave sintering was very effective so that considerable mechanical properties such as flexural strength and bulk density were drastically increased than conventional electric heating method. And the effect of thermo-cycling treatment on the bond strength and flexural strength of ceramic veneered zirconia was evaluated. After thermo-cycling treatment between 5 oC to 55 oC ceramic-zirconia bond strength and zirconia flexural strength was not affected. In the phase analyses using XRD, after thermo-cycling treatment, however both the experimental group and the control group were tetragonal phase without any martensitic transformation. That is, the ceramic- zirconia bond strength and zirconia flexural strength were unaffected by low temperature degradation. So low temperature aging treatment did not reduce the flexural strength and the temperature applied to the aging treatment was relatively low. 97 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 7 – P1, Session 5 – P2 CRACK GROWTH BY ISOTHERMAL MARTENSITIC PHASE TRANSFORMATION IN TETRAGONAL ZIRCONIA POLYCRYSTALS Jong Kook Leea,b and Kyu Hong Hwangc aDepartment of Advanced Materials Engineering, Chosun University, Gwangju 501-759, Korea bBK21 Education Center of Mould Technology for Advanced Materials & Parts, Chosun University, Gwangju 501- 759, Korea cSchool of Materials Engineering, Gyeongsang National University, 660-701, Jinju, Korea [email protected] Yttria –stabilized tetragonal zirconia polycrystals(Y-TZP) have many of advantages as an implant material, because of its strong, tough, wear-resistant and osseoconductive properties, which is suitable for stress-bearing implantable applications. But, it also has a disadvantage of low temperature degradation, which is induced by the o martensitic transformation of tetragonal to monoclinic ZrO2 phase during heat treatment at range of 100-500 C and associated with severe failure of implants materials. In this study, we investigated the crack nucleation and growth and propagation on the surface of Y-TZP during isothermal phase transformation by low temperature aging. Crack initiation and growth on the surface of Y-TZP specimen was dependent on the yttria content and sintered microstructure. In the case of 2Y-TZP with low yttria content, phase transformation induced an abrupt fracture of specimen at the initial stage of low temperature aging, but slow crack growth was observed in 3Y-TZP specimen. Most of cracks in TZP by low temperature aging were nucleated on the surface of specimens (free surface, near pore, etc), and grew into the bulk interior through the pore, crack and grainboundaries. Isothermal martensitic phase transformation was enhanced by water vapor, open pores of the sintered body and microcracks. Sintered Y-TZP specimens show the intra-granular fracture mode under the load, but fracture surfaces by isothermal martensitic phase transformation show the inter-granular fracture mode. STRUCTURE AND PROPERTIES OF NITI SHAPE MEMORY ALLOYS AFTER SEVERE PLASTIC DEFORMATION Danuta Stroz, Jakub Palka, Zdzislaw Lekston Institute of Materials Science, University of Silesia, Katowice, Poland [email protected] One of the possibility of tailoring the NiTi alloy properties to the application requirements is the formation of nanocrystalline structure from amorphous material subjected to severe plastic deformation. The hitherto carried out studies [1-5] indicate that strong structural refinement is achieved by severe plastic deformation methods such as high-pressure torsion. This treatment results in considerable changes of the mechanical and functional properties of the alloys. The results presented here concern two NiTi alloys (near-equiatomic NiTi and Ni-rich alloy) subjected to plastic deformation by compression combined with reversion oscillating torsion. The maximal strain obtained was c = 6.20. Some samples were deformed with the use of still other method i.e. cold rolling combined with transverse movement of the rolls. Finally the alloys were annealed at the temperature range 300 – 500oC for 1 hour. The structure of the as-prepared alloys was studied with the use of temperature X-ray diffraction and TEM observations. Also the DSC and bend and free recovery ASTM tests were carried out. It was found that the structure consists of a mixture of highly deformed B2 parent phase and B19‟ martensite. The strain distribution after the applied plastic deformation was not uniform, the highest strain region was in the middle of the cylinder sample. In these regions small amount of the Ni2Ti phase was indentified. The TEM studies revealed some amorphous areas in the most strained region of the samples. Annealing at lower temperatures caused formation of nanocrystalline structure that grew to the microcrystalline and finally well-defined polygonized structure in annealed at 500oC specimens. Multi-stage transformation was observed in the annealed at lower temperatures samples. Nanomegas TEM attachment ASTAR allowing determination of the orientation of grains in nanoareas was applied to determine the grain orientation distribution and the grain disorientation angles (an example shown below). [1] M. Peterlechner, T. Waitz, H.P. Karnthaler, Scripta Mater. 59 (2008), 566 [2] T. Waitz, W. Pranger, T. Antretter, F.D. Fisher, H.P. Karnthaler, Mat. Sci. & Eng.A 481-482 (2008), 479 [3] M. Peterlechner, T. Waitz, H.P. Karnthaler, Scripta Mater. 60 (2009), 1137 [4] F. M. Braz Fernandes, K. K. Mahesh, R.J.C. Silva, C. Gurau, G. Gurau, Figure: High angle boundaries in the studied NiTi alloy, the Phys.Status Solidi C 7, No. 5, (2010), 1348 angle between the grains is about 25-30o 98 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 5 – P3, P4 MECHANOCYCLIC AND TIME STABILITY OF LOADING-UNLOADING DIAGRAM PARAMETERS OF NANOSTRUCTURED Ti-Nb-Ta AND Ti-Nb-Zr SMA Prokoshkin Sergeya, Brailovski Vladimirb, Petrzhik Mikhaila, Filonov Mikhaila, Sheremetyev Vadima a National University of Science and Technology “MISIS”, Moscow, Russia b Ecole de technologie superieure, Monreal, Canada [email protected] The Ti-21.8Nb-6Zr and Ti-19.7Nb-5.8Ta (in at. %) shape memory alloys (SMA) were thermomechanically treated by cold drawing and post-deformation annealing at 550-600°C. As a result, a nanosubgrained structure was formed in the β-phase. Cyclic mechanical testing using “loading-unloading” mode with 2% tensile strain in each half-cycle reveals non-perfect superelastic behavior of both alloys during the very first cycles of testing, which becomes perfect during further mechanocycling. The Young‟s modulus of thermomechanically treated alloys is low, and it decreases during mechanocycling (n=10 cycles) down to (25-35 GPa) approaching the Young‟s modulus of a cortical bone tissue (Fig. 1). The Young‟s modulus of Ti-Nb-Ta alloy is systematically lower than that of Ti-Nb-Zr alloy. Thus, thermomechanically treated Ti-Nb-Zr and Ti-Nb-Ta shape memory alloys in the nanostructured and ultrafine grained states possess high biomechanical compatibility with the bone tissues. The Young‟s modulus obtained in the 10th cycle is stable or slightly changes during furthers 40-days keeping at room temperature and then during repeated mechanocycling. The other parameters of loading-unloading diagrams: residual strain per cycle, transformation yield stress and mechanical hysteresis, - decrease during mechanocycling. Then, after 40-days keeping at room Fig.1. Example of changes of Young‟s modulus of annealed at 600°C, 30 min Ti- temperature, they restore their initial values. Nb-Ta alloy during mechanocycling, keeping for 40 days at RT and repeated The repeated mechanocycling is accompanied mechanocycling. by the repeated decrease of these parameters. MARTENSITIC TRANSFORMATION IN NI-AL-PT HIGH TEMPERATURE SHAPE MEMORY ALLOYS Monastyrsky G.E. a,b, Odnosum V.V. b, Ochin P. c, Pasko A.Yu. c, Kolomytcev V.I.b, Koval Yu.N.b a NTUU “KPI”, 37 Peremogy av, UA-03506 Kyiv, Ukraine bIMP of NASU, 36 Vernadsky av., UA-03142, Kyiv, Ukraine cICMPE-CNRS2-8, rue Henri Dunant-94320, Thiais, France [email protected] As a potential alloy for high temperature applications, Ni-Al alloys have several disadvantages: a) the brittleness in polycrystalline state, b) precipitating of Ni3Al phase mainly appearing along the boundaries and c) Ni5Al3 precipitate both from austenitic (B2) and martensitic (L12) phase. The solution to these problems can be achieved by the appropriate alloying with third elements. In this study alloys with the nominal compositions Ni– 39(40)Al–xPt (x = 5,10,15,20 at.%) were examined primarily using X-ray diffraction, SEM and thermal analysis. The alloying by Pt instead of Ni shifts the composition of the alloys in the direction off the area of Ni5Al3 as well as Ni3Al stoichiometric compositions, provided that the total content of Ni and Pt is less than 60-61 at.%. It was found that Pt addition strongly increases the Ms point however there is no direct proportionality between the at.% of Pt and the Ms point increasing. No traces of Ni3Al were found after homogenization. The precipitating of Ni5Al3 was observed in Ni–Al–Pt alloys with the Pt content below 15at.% after the cycling through the wide temperature interval between the room temperature and 800oC. The effect of Pt alloying on the martensitic transformation and Ni5Al3 precipitation as well as high temperature martensitic transformation stability is governed by the competition between the martensitic transformation and alloy decomposition processes. Addition the Pt influences the L10B2‟+Ni5Al3 decomposition processes doubly. Firstly (thermodynamic reason), the Pt addition shifts the composition of alloy out of the area of precipitating of Ni5Al3 phase on phase diagram. Extra atoms of Pt destroy the ordering of Ni5Al3 structure, thus (Ni,Pt)5Al3 formation is becoming unfavorable from thermodynamically point of view. Secondly (kinetic reason), the Pt alloying makes it difficult the diffusion processes and consequently the decomposition processes. 99 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 5 – P10, P12 FORMATION NANOSIZE BLANKETS TINICU FROM MATERIALS WITH EFFECT OF MEMORY OF THE FORM IN THE CONDITIONS OF PLASMA DUSTING P.O. Rusinov, Z.M. Blednova Kuban state university of technology, Krasnodar, Russia [email protected], [email protected] The complex method of formation nano size blankets from a material with shape memory effect (SME) TiNiCu, including a plasma dusting of mechanically activated powder on the basis of TiNiCu is developed, the subsequent thermal both thermomechanical processing and allowing to receive in blankets nanostructure a condition providing high level of is functional-mechanical and operational properties. It is shown, that preliminary mechanical activation of powders allows to lower porosity of coverings and to raise durability of coupling of a covering with a basis. Operating parameters of superficial modifying are established became a material with SME TiNiCu, supervising a structural condition of material on a stage of plasma dusting, and the subsequent combined processing, and allowing purposefully to influence functional properties of a blanket with SME. The technology of superficial modifying of the constructional and alloyed steels by a material with SME on the basis of TiNiCu is developed, and the statistical model of technological process establishing connection between technological parameters (structure plasma gas, an arrangement corner plasmatron) and exit parameters (adhesive durability, porosity) is made. The formation mechanism nano dimensional condition in the course of mechanical activation of powders from materials with SME as a result of intensive plastic deformation is described at repeated high-speed influence of a working body on a processed material, polygonization and recrystallization. It is shown, that at a plasma dusting of mechanically activated powder there is an allocation of the energy reserved in the course of processing in the form of a various sort of defects that leads to the best connection evaporated particles among themselves and with a basis, provides good adhesive properties and smaller porosity, and the taking place high gradient of temperatures between a substrate and a powder particle creates additional conditions nanostructure.The received experimental data about influence of superficial modifying by a material with SME on mechanical properties have shown: wear resistance of a steel 45 with blanket TiNiCu raises in 2-2,5 times; high corrosion properties of blankets TiNiCu in sea water are experimentally confirmed. STRUCTURE AND PROPERTIES OF TiNi ALLOY SUBJECTED TO SEVERE PLASTIC DEFORMATION AND SUBSEQUENT ANNEALING Belyaev Sergeya, Frolova Nataliab, Pilyugin Vitalyb, Resnina Nataliaa, Slesarenko Viacheslava, Zeldovich Vitalib aSaint-Petersburg State University, Saint-Petersburg, Russia bInstitute of Metal Physic, the Ural branch of RAS, Ekaterinburg, Russia [email protected] The structure and martensitic transformation in the Ti – 50.2 at. %Ni shape memory alloy subjected to high pressure torsion (HPT) and subsequent annealing were studied. HPT was carried out at a room temperature under a pressure of 8 GPa up to different angles from 15 degree to 5 turns. The annealing was performed in two different ways: dynamic heating up to 550 oC with different heating rates and isothermal holding at different temperatures. The structure of the alloys was studied by transmission electron microscopy (TEM) and X-ray diffraction analysis (XRD) after different steps of deformation and annealing. The heat release during annealing as well as martensitic transformation after deformation and annealing were studied by differential scanning calorimetry (DSC). The TEM and XRD data have shown that the structure of the alloy, subjected to HPT with angle lower than 90 degree was nanocrystalline or amorphous-nanocrystalline. An increase in value of angle resulted in almost full amorphization of the alloy structure. DSC data have demonstrated that no any martensitic transformations were found in the samples subjected to HPT even after deformation up to 15 degree. It was found that three peaks of heat release took place on heating the deformed sample up to 550 oC. An increase in angle of torsion resulted in an increase in temperatures of heat release peaks. It was suggested that on heating the amorphous sample the first calorimetric peak was due to structural relaxation, the second peak was crystallization of amorphous phase and the third peak was due to the recrystallization and grain growth. It was found that value of angle of torsion influenced the kinetics of martensitic transformation observed in the deformed alloy after annealing. So, in the samples deformed up to 90 degree and heated up to 550 oC two-stage forward martensite transformation was observed on cooling and one-stage phase transition was found on heating. Whereas, in the samples subjected to deformation up to one and more turns and heated up to 550 oC three-stage forward transformation was observed on cooling and two- stage transition was found on heating. Probably, it was due to the formation of bimodal crystalline structure in the alloy during deformation and subsequent heating. 100 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 5 – P15, P16 AMORPHIZATION OF TITANIUM NICKELIDE BY MEANS OF SHEAR UNDER PRESSURE AND CRYSTALLIZATION UPON SUBSEQUENT HEATING Frolova Natalya, Zel'dovich Vitaly, Pilyugin Vitaly, Gyndurev Vyacheslav, Patselov Alexander Institute of Metals Physics of the Ural Division of the RAS, Ekaterinburg,Rassia [email protected] By transmission electron microscopy and X-ray analysis the structural changes in the alloy Ti-50.5 atm.% Ni during deformation by shear under pressure at room temperature and subsequent heating are investigated. It is shown that the deformation occurs first direct B2-B19' martensitic transformation, and then, with increasing degree of deformation, the reverse B19'-B2. Reverse transformation begins at the stage of deformation of martensite structure when deformation twinning and slip are exhausted, and rotational deformation mode are include. At this stage amorphization is begin. The formation of a martensitic structure with a large number of crystal boundaries and increasing of the total length of boundaries during deformation leads to the rapid dispersion of the structure as compared with the deformation of non transformated B2 phase. The resulting nanocrystalline structure is transformed into an amorphous with further deformation. It is possible that amorphization begins at the boundaries of the nanocrystals, rotating in the deformation process. It is assumed that the amorphization of titanium nickelide during deformation associated with large mean-square displacements of atoms, leading to instability of the crystal lattice. The amorphous state of titanium nickelide obtained by intensive plastic deformation is described by the model of Bernal-Finney. The scheme for the formation of the amorphous structure of the alloy during deformation is represented. The crystallization of the amorphous structure during the heating begins at 470 K, but is going slowly up to 570 K (at exposition of 0.5 hours). After aging at 620 K crystallization occurs completely and formed nanocrystalline structure with grain sizes of 20-70 nm. This work was supported by Ural Division of RAS ( grant № 12-U-2-1022). RELEASE OF ENERGY ON HEATING Ti-50.2 at. % Ni ALLOY SUBJECTED TO SEVERE PLASTIC DEFORMATION Belyaev Sergeya, Pilyugin Vitalyb, Resnina Nataliaa, Slesarenko Viacheslava, Drozdova Mariaa aSaint-Petersburg State University, Saint-Petersburg, Russia bInstitute of Metal Physics, the Ural branch of RAS, Ekaterinburg, Russia [email protected] The processes of heat release on heating the Ti – 50.2 at. % Ni alloy, subjected to high-pressure torsion up to 3.5 turns were studied by differential scanning calorimetry (DSC). The X-ray analysis had shown that the structure of the deformed alloy was amorphous. The deformed samples were heated up to 550 oC at different heating rate of 10 to 40 K/min in the chamber of DSC. It was found that three calorimetric peaks of heat release were observed on heating the deform sample at all heating rates. It was assumed that the first peak was due to the structural relaxation of amorphous matrix, the second peak was associated with crystallization of amorphous phase and the third peak was due to the grain growth. It was observed that increase in heating rate resulted in an increase in temperatures of calorimetric peaks. The values of energy estimated as a square under a calorimetric peak were measured. It was shown that an increase in heating rate led to decrease in crystallization energy (the second calorimetric peak), at the same time, the energy of structural relaxation (the first calorimetric peak) increased. The Kissinger analysis was applied to estimate the values of activation energy of the first and second calorimetric peaks. It was found that the relaxation process was characterized by activation energy equal to 5.5 kJ/mol and the crystallization process was characterized by the 220 kJ/mol. Additionally the kinetics of martensitic transformation in the deformed samples subjected to heating up to 550 oC at different heating rate was studied by DSC. It was shown that three stages of forward martensitic transformation were observed on cooling and two stages of reverse martensitic transition were found on heating. It was found that the one part of volume of the alloy underwent B2 B19‟ martensitic transformation. At the same time, the other part of the sample underwent B2 R B19‟ transitions on cooling and B19‟ B2 – on heating. The temperature range of different transformations strongly depended on the value of rate of heating the deformed sample up to 550 oC. 101 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 5 – P17, P18 THERMO- AND DEFORMATION INDUCED MARTENSITIC TRANSFORMATIONS IN BINARY TiNi- BASED ALLOYS, SUBJECTED SEVERE PLASTIC DEFORMATION Kuranova Natalia, Makarov Vladimir, Pushin Vladimir, Uksusnikov Alexsey Institute of Metal Physics, Ural Branch of Russian Academy of Science, Ekaterinburg, Russia [email protected] Among the materials with thermoelastic martensitic transformations and shape memory effects, binary titanium nickelide based alloys exhibit the best physical, chemical, and mechanical properties and, therefore, show adequate service characteristics. In this work the effect of high pressure torsion (HPT) and annealing on the peculiarities of the phase and structural transformations in Ti50.5Ni49.5, Ti50Ni50, Ti49.7Ni50.3, Ti49.5Ni50.5 alloys has been investigated. Structure of alloys have been studied by methods of transmission and scanning electron microscopy, x-ray and neutron diffraction. Principal stages of the evolution of microstructure and phase composition were for the first time determined for alloys of various stability (controlled by the chemical composition and temperature), applied pressure, and degree of severe plastic deformation by HPT, regimes of thermotreatment. It is shown that HPT results in the amorphization of the TiNi-based alloys characterized by the metastable austenitic state. In this case, first the martensitic B2→B19' transformation induced by the applied pressure occurs and, subsequently, during the megaplastic deformation under HPT, the multipacket morphology of the B19' martensite transforms into the fragmented grain–subgrain bimodal nano- and submicrocrystalline, single modal nanocrystalline, and finally amorphized structure with nanocrystalline inclusions. High resolution electron microscopic studies showed that the amorphous matrix, which is predominant in the alloy volume (more than 97 wt %), after HPT with 5 and 10 revolutions is characterized by the high density of uniformly distributed nanocrystalline inclusions less than 3–5 nm in size, which have a distorted crystal structure typical of partly or completely ordered В2-austenite structure. It was found that the TiNi-based alloys consisting of the В2 austenite, which is stable with respect to deformation induced martensitic transformations, almost are not amorphized during HPT but can be prepared in the nanocrystalline state with an average nanograin size from 10 to 100 nm. A size baroeffect of reverse thermoelastic martensitic transformations in the nanocrystalline titanium nickelide based alloys was revealed. Work is partially supported by the Russian Foundation for Basic Research 11-02-00021. STRUCTURE AND MARTENSITIC TRANSFORMATIONS IN AUSTENITIC 0.08% C-18% Cr- 10% Ni-0.7% Ti STEEL DURING SEVERE PLASTIC DEFORMATION a,b c a d c c Dobatkin S.V. , Valiev R.Z. , Rybalchenko O.V. , Pankova M.N. , Enikeev N. , Abramova M.M. aA.A. Baikov Institute of Metallurgy and Materials Science of RAS, Moscow, Russia bNational University of Science and Technology "MISIS", Moscow,Russia cUfa State Aviation Technical University, Ufa, Russia dI.P.Bardin Central Research Institute for Ferrous Metallurgy, Moscow,Russia [email protected] It is known that severe plastic deformation (SPD) of some austenitic steels at room temperature initiates martensitic transformations. The martensitic transformation increases hardening, but reduces the corrosion resistance. The purpose of the present work was to study the opportunity of the nano- and submicrocrystalline (SMC) structure formation in the 0.08%C-18%Cr-10%Ni-0.7%Ti steel during high pressure torsion (HPT) in the fully austenitic state after deformation. The HPT under the pressure of 6 GPa was carried out at the temperatures 20°C, 300°C and 500°C, and also on step-regimes with increasing 20°C→500°C and decreasing 500°C→300°C→20°C of the temperature. In all regimes there was total strain N=10 turns that corresponds to true strain in the middle of radius of the sample about 5.7. X-ray phase analysis revealed the presence of a fully martensitic phase after HPT at 20°C in steel, and only the austenite phase after deformation by another regimes. In our case, the deformation temperature of 300 and 500°C lie above the temperature of formation of deformation martensite Md. With increasing deformation temperature from 20оС to 500оС in step-regime, probably, martensite formed at room temperature turns into austenite during HPT at 500°C. Under the step-regime of HPT with decreasing deformation temperature from 500°C to 20°C a small fraction of martensite (<3%) is available. It seems that the stepwise decreasing of HPT temperature with decreasing grain size reduced Md to subcritical. TEM analysis of the steel after deformation at all regimes revealed the formation of nano-and SMC structure. After HPT at 20°C, 300°C and 500°C structure with an average grain size of 60, 85 and 125 nm, respectively, was observed. Thus it is shown that it is possible to obtain nano-and SMC structures in a fully austenitic matrix in austenitic steel after HPT by increasing the deformation temperature above Md and at room temperature by reducing Md due to reduction of the grain size during step-regime of HPT (500°C → 300°C → 20°C). 102 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 12 – P29, P31 UNUSUAL MULTISTAGE MARTENSITIC TRANSFORMATION IN TiNi SHAPE MEMORY ALLOY AFTER THERMAL CYCLING Belyaev Sergey, Resnina Natalia, Sibirev Alexey Saint-Petesburg State University, Saint-Petersburg, Russia [email protected] Variation in martensitic transformation in equiatomic TiNi shape memory alloy during thermal cycles was investigated. Samples annealed at 500 C for 1 hour were subjected to repeated thermal cycles through the temperature range of martensitic transformation. Differential scanning calorimetric analysis had shown that sample underwent one stage phase transformation in the first thermal cycle. It was found that thermal cycling in the temperature range of 300 † 373 K resulted in variation in sequence and temperatures of martensitic transformations. The sample subjected to 20 thermal cycles demonstrated unusual sequence of phase transitions. Three stage of martensitic transformation were observed on cooling: B2→R, B2→B19'1, R→B19'2 and 2 stage of martensitic transformation on heating: B19'2→B2, B19'1→B2. Moreover, it was observed that characteristics of calorimetric peaks depended on heating history. Kinetics of martensitic transformation depended on the temperature at which cooling started (maximum temperature). If maximum temperature was 373 K than three peaks were observed on cooling. An increase in maximum temperature resulted in shift of heat peaks temperatures and additional calorimetric peak was found. So in the cycle where the cooling started from 473K four calorimetric peaks were found on cooling: B2→R, B2→B19'1, B2→B19‟3, R→B19'2. It is necessary to note that variation in martensitic transformation kinetics was reversible. If maximum temperature had exceeded 513K the kinetics of martensitic transformation did not depend on the temperature of cooling start. Hence, one may assume that the thermal cycling the equiatomic TiNi alloy in the temperature range of 300†513 K should not influence the martensitic transformation kinetics. To verify this assumption TiNi alloy was subjected to thermal cycles from 300K to 513K. It was observed that thermal cycling at this temperature range influenced less the kinetics of martensitic transformation and the variation of parameters of calorimetric peaks did not depend on maximum temperature in the cycle. Probably unusual kinetics of martensitic transformation may be caused by reversible defects appearing at forward martensitic transformation. STUDY OF MARTENSITIC TRANSFORMATION IN TiNi INTERMETALLIC BY METHODS OF LOW FREQUENCY INTERNAL FRICTION Markova G.V., Shuytsev A.V., Kasimsev A.V. Tula State University, Tula, Russia [email protected] It is known that TiNi production on an industrial scale is a difficult task because even small deviations from the stoichiometric composition lead to a drastic change of the intermetallic compounds properties. Powdered materials are an alternative way to produce intermetallic compounds (TiNi, in particular). They are deprived of the shortcomings of cast materials. Powder technology allows to obtain homogeneous fine powders. Compaction operations of products do not allow their melting [1, 2]. The temperature dependence of internal friction (TDIF) and the resonance frequency on the wire sample TiNi were measured. The temperature of the beginning and the end of the forward and reverse martensitic transformation was determined. The dependence of the value of the martensitic transformation Figure 1. The dependence of the Figure 2. The dependence of the peak of internal friction on the heating martensitic transformation peak area martensitic transformation peak rate (Fig.1) and the frequency (Fig.2) of the internal friction on the heating height of internal friction on the was determined. Transition, the phase rate frequency transformation and the background parts of internal friction were measured and calculated (Grimaud model) [3]. The temperature dependence of internal friction in alloys of Ti-Ni with 100% content of intermetallic phase TiNi obtained by powder metallurgy was measured. The influence of the other phases (Ti2Ni and TiNi3) on the martensitic transformation course was also examined. [1] Kornilov I.I., Belousov O.K., Kachur E.V. Nickelide titanium and other alloys with the effect of "memory". - M.: Nauka. 1977. - 180. [2] Kasimtsev A.V. dis. Dr. techn. Science / A.V. Kasimtsev, "National Science and Technology University" MISA ". - M, 2010. - 44. [3]. Markova G.V. Izv. Tula State University. Ser. Materials Science. -2000. Number 1. -p. 20-31. 103 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 12 – P32, P34 MARTENSITIC TRANSFORMATIONS UPON COMBINED EFFECT OF TENSION AND PULSE CURRENT IN NANOSTRUCTURED TiNi ALLOY Fedotkin Alexeya,b, Stolyarov Vladimira,b aIMASH RAS, Moscow, Russian Federatation bMoscow state industrial university, Moscow, Russian Federatation [email protected] At present a great interest of scientists appears to issue a joint or successive action of the deformation and current [1]. This phenomenon was observed in a stress jumps in tension coarse-grained crystals or monocrystals of pure metals [2]. At the same structure - phase dependence of electroplastic effect (EPE) has not been investigated. The first results in this area were obtained in [3], where the stress jumps were observed in tension with the pulse current in the austenite at room temperature for TiNi alloy with a grain size <100 nm. Of particular relevance is the comparison of EPE in the austenitic and martensitic nanostructured shape memory TiNi alloy. The studies were conducted on samples of Ti-Ni alloy in two different phase states at the room temperature: austenitic Ti49.3Ni50.7 and martensitic Ti50Ni50. Investigated two structure states: coarse-grained (CG), obtained by quenching or annealing and nanostructured (NS) processed by electroplastic rolling and subsequent annealing. Selection structural states due to the absence of experimental data on the effect of electric current on display EPE and shape memory effect (SME) in the NS-materials and their comparison with CG. The influence of structural-phase state and the parameters of the pulse current to display EPE in TiNi was shown. Pulse current leads to a stress jumps in tension diagram associated with the appearance EPE or phase transformation (Fig. 1). It is shown that the structural-phase state of alloys and the parameters of the pulse current effect on the amplitude and direction Fig. 1. Stress-strain curve of course-grained of the jumps. It is shown that EPE is a structure-sensitive property of alloys. TiNi alloy with a single pulse current Grains refinement from tens microns to tens nanometers affects the amplitude of stress jumps down for both alloys. [1] Okazaki, K. Kagawa, M. Conrad, H. Scripta MET., 1978. - Vol. 12. - P. 1063-1068. [2] Troitskii, O.A. Zh. Eksp. Teor. Fiz., 1969. - 10 (1). - P. 18-22. [3[ Stolyarov, VV Ugurchiev, U.H. Fizika i technika vysokikh davlenii, 19, 1 (2009) 92-96 (in Russian). XPS AND NEXAFS INVESTIGATION OF ELECTRON ENERGY STRUCTURE OF TiNi AND TiNiCu ALLOYS Senkovskiy B.V. a, Usachov D.Yu. a, Fyodorov A.V. a, Shelyakov A.V. b, Adamchuk V.K. a a Saint-Petersburg State University, Saint-Petersburg, Russia b National Research Nuclear University “MEPhI”, Moscow, Russia [email protected] Electronic structure of the series of Ti(100-x)Nix (x = 45, 50, 55 at. %) and Ti50Ni(50-х)Cuх (х = 0, 10, 15, 25, 38, 50 at. %) alloys has been investigated by X-ray photoelectron spectroscopy (XPS) and near edge X-ray absorption fine structure spectroscopy (NEXAFS). We present our schematic model of the Ni electronic density of d-states (d- DOS) redistribution in the area of unoccupied and occupied states under Ti-Ni alloys formation. It is found that Ni d-DOS under the Ti-Ni alloys formation shift to higher binding energy and the shift is larger when the alloy has a larger concentration of titanium. Unoccupied Ni d-states are found to be shifted below the Fermi level in Ti-Ni alloys, and the Ni d-states contribution to the DOS at the Fermi level is decreased. Relative changes in the Ni, Ti and Cu 3d-bands occupancy upon Ti(100-x)Nix and Ti50Ni(50-х)Cuх alloys formation have been investigated using NEXAFS spectroscopy. The obtained depletion of the Ni 3d-band in the Ti(100-x)Nix alloys is only 0.13 electrons/atom relative to the pure metal. The Ni 3d-band occupancy does not depend on the chemical composition of the Ti(100-x)Nix alloy. In contrast, the Ti 3d-band occupancy in alloys is determined by its chemical composition and reaches a minimum value in the alloy of equiatomic composition. We have demonstrated that the charge transfer between Ti and Ni atoms in the alloys is negligible, thus the changes in the Ti and Ni d-bands occupancies take place due to intra- atomic DOS redistribution between valence d- and sp-states. It has been demonstrated that the composition variation leads to a substantial DOS redistribution in the valence band of Ti50Ni(50-х)Cuх alloys. The contribution of Ni d-states at the Fermi level is decreased, while Ni d-DOS exhibit shift toward higher binding energy, while Cu d-DOS shifts to lower binding energy upon increase of copper concentration in the Ti50Ni(50-х)Cuх alloys. The copper d-band occupation is decreased in Ti50Ni(50-х)Cuх compared with pure Cu and does not depend on the number of Ni atoms in the nearest environment. XPS and NEXAFS data show that the martensitic transformation in the Ti50Ni50 and Ti50Ni25Cu25 alloys does not lead to changes in the structure of the Ni, Ti and Cu d-DOS within the sensitivity limits of the methods used. 104 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 12 – P36, P38 ISOTHERMAL TRANSFORMATIONS IN Ni-Ti AND Ni-Ti-X (X=Fe, Cu) ALLOYS D. Salasa, S. Kustova, E. Cesaria, J. Van Humbeeckb aUniversitat de les Illes Balears, Palma de Mallorca, Spain b Katholieke Universiteit Leuven, Leuven, Belgium [email protected] The isothermal/athermal nature of the different transformation paths in the Ni-Ti shape memory alloy system has been investigated by means of AC impedance measurements. The possible martensite/austenite isothermal accumulation is detected when the continuous temperature cycle is interrupted and the system is hold isothermally. Binary Ni-Ti and ternary Ni-Ti-X (X=Fe, Cu) alloys have been studied to cover all possible transformation paths between the B2 austenite and R, B19 and B19´ martensites. The analysis of the experimental data obtained for different transformation sequences shows that all transitions to the B19‟ phase (both from austenite in one-step B2→B19´ martensitic transformation (MT) and from R and B19 martensite during intermartensitic R-B19´ and B19-B19´ transformations) are isothermal, as well as the reverse B19‟→R and B19‟→B19 transitions. These observations contradict the traditional idea that martensitic transformations in the Ni-Ti system are athermal. In contrast to the transitions to/from the B19´ martensite, the direct and reverse B2↔R and B2↔B19 MTs are athermal. The difference between the isothermal nature of the transition to/from the B19´ martensite and other transitions in the Ni-Ti system from the point of view of crystallography is explained by the fact that for the transformations to the B19´ phase (from B2, R or B19) the self accommodation is much more complex than in the B2↔B19 and B2↔R transformation paths. As far as the thermodynamics of MTs is concerned, we have found that isothermal MTs in the Ni-Ti system possess much wider transformation hysteresis than the athermal ones. This observation points to an important role of friction forces acting on interphase boundaries during the transition in determining its athermal/isothermal nature. We suggest that the observed isothermal effects in Ni-Ti should be attributed to the diffusionless but thermally activated motion of interfaces during the transformation. PROPERTIES OF Ti – 50.0 at. %Ni / Ti – 50.7 at. % Ni BIMETAL COMPOSITE PRODUCED BY EXPLOSION WELDING. Belyaev Sergey a, Resnina Natalia a, Rubanik Vasiliy b,c, Rubanik Vasiliy (jr) b,c, Rubanik Oksana b, Lomakin Ivan a a Saint-Petersburg State University, Saint-Petersburg, Russia b Vitebsk State Technological University, Vitebsk, Belarus c Institute of Technical Acoustics NAS of Belarus, Vitebsk, Belarus [email protected] A new bimetal composite Ti50.0Ni50.0 / Ti49.3Ni50.7 was produced by explosion welding. Martensitic transformations as well as distribution of micro-hardness across the joint in a bimetal samples after welding and subsequent annealing at 450oC for 2 hours or 600oC for 1 hour were studied. Differential scanning calorimetry (DSC) data have shown that after welding the bimetal composite demonstrates two calorimetric peaks on cooling and two peaks on heating. These peaks are due to the B2 B19‟ martensitic transformations occurring in two layers with different Ni concentration at different temperature ranges. It is found that annealing results in variation in temperatures and sequence of martensitic transformations. So, in the bimetal composite annealed at a temperature of 600 oC for 1 hour, both layers undergo B2 B19‟ martensitic transformation at two different temperature intervals. At the same time, in the bimetal composite annealed at a temperature of 450 oC for 2 hours, the nickel-rich layer undergoes B2 R B19‟ forward phase transformation on cooling and B19‟ B2 transition on heating. The equiatomic TiNi layer demonstrates B2 B19‟ martensitic transformation on cooling and heating. The temperatures of B2 B19‟ transformation in equiatomic TiNi layer in composite annealed at 450 oC is lower that the temperature of the same phase transition in the composite annealed at 600 oC. Probably it is due to the annealing of the composite at a temperature of 450 oC has not resulted in a full recovery of kinetics of martensitic transformation after explosion. Whereas, annealing at 600 oC has restored the parameters of martensitic transformation completely. The analysis of distribution of micro-hardness across the joint of the sample after explosion welding shows that maximum of hardness is on the joint interface. An increase in distance from the joint results in decrease in microhardness. Annealing results in a decrease in microhardness in the joint as well as in the layers situated far from joint. 105 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 12 – P40, P43 INFLUENCE OF STRESS REGIME ON WORK PERFORMANCE DURING THERMAL CYCLING TiNi ALLOY Belyaev Sergey, Resnina Natalia, Zhuravlev Roman Saint-Petersburg State University, Saint-Petersburg, Russia [email protected] Influence of value of the stresses applied on cooling and heating during symmetric scheme on work performance in the Ti – 51.5 at. % Ni shape memory alloy was studied. To produce a work output samples were subjected to thermal cycling through the temperature range of martensitic transformation under symmetric scheme. The symmetric scheme in the mode of torsion contained two asymmetric cycles where the stresses were applied in the opposite direction in each asymmetric cycle. In the odd half of cycle the sample was loaded up to stress of τc at a constant temperature of 400 K, then cooled under constant stress down to 220 K. At a temperature of 220 K the stress was increased up to τh, and then the sample was heated up to 400 K. After that the sample was unloaded down to a zero stress. Then, in the even half of symmetric cycle the sample was loaded up to (– τc) (in the opposite direction), then cooled under constant stress to a temperature of 220 K. At this temperature the stress was increased up to (– τh) and the sample was heated to a temperature of 400 K, and then unloaded. The value of τc was varied from 15 to 100 MPa and the value of τh was varied from 50 to 400 MPa. The data obtained had shown that an increase in |τh| at constant value of |τc| resulted in an increase in work performance of the TiNi alloy. It was found that thermal cycling under symmetric scheme did not influence a variation in work output if the |τc| was equal to 50 MPa. It was observed that variation in |τc| led to non-monotonic variation in work performance and the maximum value of work output was reached at the |τc| = 50 MPa. The data obtained had shown that thermal cycling under symmetric scheme resulted in non-monotonic variation in residual strain. It was found that an increase in |τh| at constant value of |τc| = 15 MPa resulted in an increase in the range of variation in residual strain. However, if |τc| = 50 MPa the range of variation in residual strain did not change. It was observed that an increase in |τc| at constant value of |τh| led to a decrease in the range of variation in residual strain. EFFECT OF TIME GRADIENT ANNEALING ON SHAPE MEMORY CHARACTERISTIC OF TI-50.4 AT.% NI ALLOYS Won Ki Ko, Su Ho Park, Jae Il Kim Materials Science and Engineering, University of Dong-A, Hadan-dong, Saha-gu, Busan, 604-714, Korea [email protected] Ti-Ni shape memory alloy actuators are more suitable than electrical motors in applications such as micro- robots, medical devices, and small mechanisms due to their light weight, compact size, and high power density. For progressive control in such applications, it is desirable for a shape memory component to have a reasonably wide controlling parameter, i.e., a wide transformation temperature range for thermally induced actuation. However, the thermoelastic martensitic transformation in Ti-Ni has small transformation temperature intervals that are typically <10 K. In this study, the shape memory behavior of Ti-50.4 at.% Ni alloys with time gradient annealing (TGA) was investigated via differential scanning calorimetry (DSC), thermal cycling tests under constant load and tensile tests. The ingot was prepared using a vacuum arc remelting method. The as-cast ingot was hot forged and extruded, followed by cold-drawing and intermediate annealing to produce wires of 0.5 mm in diameter, with a final cold- drawing of 34.5% reduction in cross-section. For the TGA treatment, a new type of radiant furnace was designed to maintain a constant temperature and create a time gradient along the length of the specimen. According to DSC measurements, a 34 K variation in the R-phase transformation interval (i.e., Rs − Rf) was obtained along the length of the specimen (80 mm) that was time-gradient annealed from 3 min to 20 min at 773 K. The results of thermal cycling tests under constant load revealed that the temperature dependence of transformation elongation (dε/dT) of the TGA specimen is smaller than that of the isochronously annealed specimen at every heat-treatment temperature (673 ~ 773 K). The lowest dε/dT of R-phase transformation (0.012%/K) was obtained for the specimen that was TGA-treated at 723 K. The difference in dε/dT of R-phase and the martensitic transformation of the TGA-treated and isochronously annealed specimen was largest at 773 K and increased with increasing stress. The critical stress for slip of TGA treated specimen was higer than that of isochronously annealed. The results of tensile tests revealed that unique Lüders-type deformation behavior with positive stress gradient occurred in TGA treated specimen. Such behavior provides superior controllability for actuation applications. 106 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 12 – P48, P50 THE INFLUENCE OF AGING CONDITIONS IN A SUPERELASTIC Ni-Ti SMA ALLOY Ribeiro, Shimenia, Rodrigues, Patríciaa, Marques Fontanezzi, Claudiaa, Gonçalves, Taffaela, Hauegen, Christiena, dos Santos Paula, Andersana, Bernardi, Heideb, Otubo, Jorgeb, Mahesh, Karimbic, Braz Fernandes, Francisco Manuelc aUniversidade Federal Fluminense, Volta Redonda, Brazil bInstituto Tecnológico da Aeronáutica, São José dos Campos, Brazil, c CENIMAT/I3N, Universidade Nova de Lisboa, Monte de Caparica, Portugal In this work, it was studied the influence of aging time on the mechanical properties and texture of a Ni- rich Ni-Ti alloy hot rolled at 850oC from 18 mm down to 1.6 mm thickness. Hot rolled samples were solution treated at 850oC for 1 h and subsequent aging treatment at 500oC in distinct times and then quenched in water. The aging condition and time were as follows: 30 minutes, 60 (two steps of 30 min) and 90 min (three steps of 30 min), 60 and 90 minutes (uninterrupted). The characterization of the transformation temperatures indicated a one step phase transformation on heating (B19'→B2) and two steps on cooling (B2→R→B19'). A shift to higher temperatures, in the martensitic transformation temperatures was observed for longer aging times. This modification could be associated to the presence of coherent/semicoherent precipitates in B2 matrix that promote R-phase formation before B19‟. The variation in hardness at room temperature can be associated to the presence of R-phase and decrease of grain size (determined by EBSD) observed in this material. The EBSD results showed a decline in confidence index for long aging times (60 and 90 min uninterrupted) that could be associated to the distortion of the crystal structure due to the presence of large amounts of coherent precipitates of the type Ni4Ti3. This distortion in precipitate-matrix interface promotes the R-phase formation in these alloys. The as-received sample exhibited a strong rolling texture of type {111} INFLUENCE OF PHASE COMPOSITION ON DEFORMABILITY AND SHAPE MEMORY PROPERTIES IN TiNi ROLLED WITH CURRENT Potapova А.А.a, Stolyarov V.V.a, Resnina N.N.b aMechanical Engineering Research Institute of RAS, Moscow, Russia, bSaint-Petersburg State University, Saint-Petersburg, Russia [email protected] It is known that structure refinement of metals to nanosize leads to an increase in strength and functional properties. Electropulse current applied to the TiNi alloy during intensive plastic rolling (EPR) provides sharp structure refinement and greater deformability than other traditional methods of metal working. In previous work it was shown that structural changes induced by the process of EPR influenced the temperatures of martensite transformations, so one may conclude that it may influence the functional properties of TiNi –based alloys. The goal of the present work is comparison of the deformability and functional properties depending on initial phase composition of alloy TiNi subjected to EPR. Hot-rolled bars of Ti49,3Ni50,7 and Ti50,0Ni50,0 alloys with a diаmeter of 6 mm and a length of 135 mm were used for the study. EPR of the samples was carried out at a room temperature in austenite B2 phase (for Ti49,3Ni50,7 alloy, average grain size of 30-60 m) and martensite B19‟ phase (for Ti50,0Ni50,0 alloy). The rolling was conducted on the rolling mill equipped with the generator of a pulse current. It was carried out at room temperature with a speed of 5 sm/s, a pulse current density of 90±5 А/mm2 and a pulse duration of 80х10-6 s. It is shown that deformability of Ti50.0Ni50,0 alloy at the rolling with current is considerably above, than in Ti49,3Ni50,7 alloy. EPR leads to formation in cross-section structure deformation bands. A thickness of bands decreases with increasing of true strain. Post-deformation annealing at a temperature of 450-500ºС for 1 hour leads to formation of nanostructure with the average grain size of 40-70 nm in the both studied alloys. It is found that EPR influences the martensite transformations temperatures. It is shown that the forward martensitic transformation is realized through the R phase in deformed alloy. At the same time both forward and reverse martensitic transformations occur through the R phase in annealed alloys. Hence, one may conclude that annealing of the deformed alloys results in change in sequence of reverse martensitic transformation. Strain recovery and stress generation were studied on heating the sample subjected to preliminary deformation by a three-point bending. It is shown that EPR (е=1.4) and subsequent annealing at a temperature of 450 °C leads to raising of recoverable strain in two times in comparison with an initial state. 107 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 12 – P53, P55 THE EFFECT OF AGING AND OXIDATION ON THE PHASE TRANSFORMATION BEHAVIOR OF POROUS NiTi SHAPE MEMORY ALLOY Hande Ozcan, Sule Cakmak, Benat Kockar Department of Mechanical Engineering, Hacettepe University, 06800, Ankara, Turkey [email protected] Porous NiTi alloys can be produced using different production methods and the microstructure and mechanical properties of these alloys may be adjusted to a specific need depending on the application. It has been proved that the open and interconnected porosity architecture promotes the bone growth. Therefore the production methods for creating the porous NiTi alloys are not all appropriate since many methods may cause the production of NiTi porous materials with closed cell structure. This work is giving details about producing 50.4at%Ni-Ti SMAs with 60% and 80% of porosity levels and the microstructure and phase transformation characteristics before and after aging. Prealloyed Ti-50.4%Ni powder has been used and mixed with pure Magnesium powder. After cold compaction, the samples are sintered under argon atmosphere using a vertical furnace. Pure magnesium powder evaporates during heating the samples in the furnace from room temperature to 1200°C by creating pores. After sintering, NiTi porous samples are aged at 400°C for 90 minutes. Differential scanning calorimetry and isobaric cooling/heating experiments under constant stress levels are conducted to determine the transformation behavior of the porous samples before and after aging such as transformation temperatures and strains. The microstructures of all samples are investigated using scanning electron and optical microscopes. It is observed that the small amount of irrecoverable strain levels determined in sintered samples becomes invisible after aging due to the increase in the strength of the material via precipitation hardening. It is also determined that very low oxidation which occurs during sintering causes a considerable decrease in the transformation temperatures of the porous NiTi alloys. However, sintering NiTi with Magnesium powder under argon atmosphere with giving certain attention is very suitable in producing the porous NiTi alloy with high level of porosity. WORK PERFORMANCE IN Ti-52 at. % Ni ALLOY IN TEMPERATURE RANGE OF B2R MARTENSITIC TRANSFORMATION Belyaev Sergey, Resnina Natalia, Anshukova Ksenia Saint-Petersburg State University, Saint-Petersburg, Russia [email protected] Usually to produce a work output shape memory elements subjected to thermal cycles under special stress conditions through the temperature range of B2 B19‟ transformation because this transition is accompanied by the largest reversible strain and as a results a larger work output may be produced. However, this transformation is characterised by large hysteresis that leads to low efficiency. Moreover, accumulation of large residual strain was observed during thermal cycles that led to degradation of functional properties of TiNi alloy and required a repeated adjustment of the heat engines. At the same time, another B2 R martensitic transformation with small hysteresis may be observed in TiNi –based alloy and the aim of this study is an investigation of work performance which may be produced on thermal cycling TiNi alloy at the temperature range of this martensitic transformation. To produce a work performance the Ti – 52 at. % Ni alloy was subjected to 30 thermal cycles when the sample was cooled under a stress of c through the temperature range of B2 R forward martensitic transformation and heated under a stress of h through the temperature range of R B2 reverse martensitic transition. Four series of experiments were carried out where the value of c was varied from 0 to 150 MPa. The value of h was 200 MPa in all experimental series. It was found that the maximum work output A 0.6 MJ/m3 was observed during thermal cycles where c was 0 or 50 MPa. An increase in value of c resulted in a decrease in work output. So, the work output was equal to 0.45 MJ/m3 in the experiments where the sample was cooled under a stress of 100 MPa and only 0.25 MJ/m3 was produced during thermal cycles where the cooling the sample was under 150 MPa. It was shown that the maximum efficiency was shown during thermal cycling the TiNi alloy through the temperature range of B2 R transition under a c = 100 MPa. This value was estimated as 1.2 % and it was lower than during thermal cycling through the temperature range of B2 B19‟ martensitic transformation. At the same time, the alloy demonstrated the stable functional properties and work performance and very small residual strain accumulation during thermal cycling the TiNi alloy through the temperature range of B2 R martensitic transformation. 108 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 12 – P58, Session 5 – P14 SYNTHESIS AND CHARACTERIZATION OF TITANIUM-NICKEL SHAPE MEMORY ALLOY VIA ELECTRODEPOSITION ROUTE De Guzman, Yvette Marie Melodi and Amorsolo, Alberto Villar Jr. University of the Philippines – Diliman, Department of Mining, Metallurgical and Materials Engineering, Quezon City, Philippines [email protected] TiNi shape memory alloys (SMAs) have been widely used in the fields of engineering and medicine due to their unique shape memory effect and super-elasticity, which are displayed during martensitic transformations. However, the fabrication process of TiNi SMA is very expensive. In this study, the feasibility of synthesizing a TiNi alloy which exhibits shape memory behavior using a much cheaper and less complicated method via electrodeposition of nickel on titanium foils followed by successive heat treatment in a tube furnace was investigated. Furnace annealing of the plated foils to achieve thermal alloying was performed for different time durations over the temperature range of 873K – 1273K under flowing nitrogen ambient. Annealed samples after quenching were subjected to shape memory tests using different heating rates. All samples exhibited shape memory effect (SME) and the sample annealed at 873K manifested very strong SME with a highest percent recovery of 92.23%. DSC analysis on the annealed samples showed austenite transformation temperatures close to 373K. XRD analysis showed TiNi-B2 and TiNi-B19‟ diffraction peaks on all annealed samples. SEM analysis in back scattered electron mode revealed the formation of a layered microstructure of Ti-Ni intermetallic compounds, with the number of layers increasing and becoming wider with increasing annealing temperature. The formation of the total intermetallic layer appears to obey very well the empirical Arrhenius type of kinetics equation reported in literature for intermetallic systems. The activation energy and diffusion coefficient of nickel and titanium interdiffusion in forming a homogenous TiNi intermetallic layer were estimated to be 138.47 kJ/mol and 1.938 x 10-7 m2/s respectively. This is within the range of activation energies for TiNi published in literature. STUDY OF TERMOMECHANICAL PROPERTIES OF NI49,8TI50,2 SHAPE MEMORY ALLOY AFTER INTENSIVE PLASTIC DEFORMATION Kalashnikov Vladimira, Mazaev Pavelb, Petrov Alexeyb, Gizatullin Ramilc, Koledov Victora aKotelnikovs’ IRE RAS, Moscow Russia bBamuman Moscow State Technical University, Moscow Russia cISC “Nano-dent” ltd, Moscow Russia e-mail: [email protected] One of the important problems of technology is the development of new materials. The solution of this problem is connected with the production of the material and with the perspectives of new applications in mechanical systems with desired characteristics [1-3] using improved Ni-Ti shape memory alloys due to their high termomechanical properties. Ni49,8Ti50,2 alloy with shape memory effect was chosen for studying. The samples represent four different thermomecanical treatments: quenching, equal channel angular pressing (ECAP), standard technology for bulk materials and forging technology. By using three-point bending method the primary hysteresis curves of the phase transformation under variable loads are obtained. Using energy capacity and functional inflexibility which are proposed as new general characteristics of the material, it became possible to defy the material that demonstrates the highest functional characteristics. As the studied alloy has a medical application, the most preferred material for the implant is the sample after ECAP, possessing high recoverable strain (about 6-7 %) while stresses of deformation resistance is about 1200 MPa. But ECAP is proposed to be not technological method because of non controllable process of recristalization during the processing and big size of blank. On the basis of the improved alloy Ni-Ti with shape memory effect “NANO- DENT” has developed new types of implants with surface covered with layer of diamond-like carbon in order to ensure high biocompatibility. [1]. V. Brailovski, S. Prokoshkin, P. Terriault, F. Trochu, Shape Memory Al-loys: Fundamentals Modeling and Applications, ETS Publ, Montreal, Canada, 2003, 851 [2]. V. Gunther, Nickelide titanium. Medical Supplies of the new generation, Moscow-MIC, Tomsk, Russia, 2006, 296 [3]. V. Gunther, G. Dambaev, P. Sysoletin, Medical materials and implants with shape memory, Tomsk State University, Tomsk, Russia 1998, 488 109 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 8 – P1, P2 EFFECT OF NITROGEN ADDITION ON MARTENSITIC TRANSFORMATION AND ε-MARTENSITE FORMATION IN Fe-Mn-Al-С ALLOYS Bronz Alexander, Kaputkina Liudmila, Kindop Vladimir, Kremyansky Dmitry, Prokoshkina Vera, Svyazhin Anatoly National University of Science and Technology “MISIS”, Moscow, Russia [email protected] The particularities of structure and mechanical properties of cast Fe-Mn-Al-C-N alloys have been studied by methods of hot pressing test, hardness measurements, optical microscopy, X-ray diffraction analysis, calorimetric and magnetometric analyses, analysis of phase state diagrams,. Theirs strength and hot working behavior were estimated. The alloys of Fe – xMn – yAl – zC (where x = 13,8 – 25,6%, у = 0 – 14,3%, z = 0,01 – 2,11%) system, including the same steels microalloyed by nitrogen, were obtained by casting in argon or nitrogen atmosphere and were teemed into water-cooled copper pipes of 5 – 10 mm in diameter. Phase equilibrium diagrams of Fe-Mn-Al-C- N system were built and regions of phase equilibrium existence of studied alloys were defined. Binary Fe-Mn alloys with high Mn content are disposed to exfoliation in the liquid phase during cooling down to formation β-Mn and regions with low manganese content. The γ→ε transformation with formation of paramagnetic close packed hexagonal ε-martensite occurs during cooling. As a result, cast alloy with high manganese content may have three-phase γ + ε + β-Mn structure. Alloying by Al decreases the exfoliation, widens the α-phase region and inhibits γ→ε transformation. As result, in the same ternary alloys the structure consists of α- phase only or α-phase with low content of austenite or ε-martensite. Besides, nitrogen microalloying results in decreasing of the cast exfoliation, austenite stabilization and decreasing of martensite transformation temperature and ε-martensite content after cooling. The crystallization of highly alloyed Fe-Mn-Al-C-N alloys results in dendritic structure formation, conservation of non-equilibrium high-temperature phases after cooling and carbide precipitation even at cooling rates as high as 103-104 К/s. Precipitated carbides are stable during heating up to 1070 – 1090 ºС. High carbon highly alloyed Fe-Mn-Al-С cast alloys become hot deformed well, up to 40 – 50 % reduction without hot crack formation. Hot deformation resistance increases with increasing in aluminium, carbon and nitrogen contents. Control of alloy composition and thermomechanical treatment conditions allows formation of triplex-structures (γ – α – k-carbide; γ – ε – k-carbide; γ – ε – α) with various the ratio, sizes and phase distribution, which will ensure given complex of mechanical and physical properties. EFFECT OF NITROGEN ADDITION ON TEMPERING AND STRAIN AGING PROCESSES OF THERMOMECHANICALLY STRENGTHENED STRUCTURAL STEELS Kaputkina Liudmila, Prokoshkina Vera, Khadeev Grigory National University of Science and Technology “MISIS”, Moscow, Russia [email protected] Mechanical behavior of structural nitrogen-containing steels with various structures and compositions, including same steels with different summary C+N content and C/N ratio were studied using pressing testing in wide temperature range, tensile tests, impact bending tests, hardness measurements and resistance of shock-wave loading. The tempering and aging under load processes after quenching or thermomechanical treatment with various regimes have been investigated using optical and electron microscopies, X-ray diffraction analysis, calorimetric and dilatometric analyses. Hot strain resistance of the austenite is determined essentially by the steel composition, while the final structure and mechanical properties of hot-deformed austenite are determine mainly by hot deformation conditions. The higher the nitrogen content and C/N ratio, the higher hot strain resistance was and earlier the softening processes start, especially recrystallization process. For the same base composition of steels, the warm deformation resistance of steels is determined by the structure created during warm deformation and inherited during quenching by martensite, and by the steel composition itself. The higher the nitrogen content, the higher hot small and large plastic deformation resistance was. The nitrogen content rise enhances the strain aging effects during hot and warm deformation of austenite and martensite, as well as the strengthening during warm deformation of quenched and tempered steels. This effect is grows with increasing the summary C+N content and lowering C/N ratio. The nitrogen microalloying of low- alloyed structural steels of C0.4CrNiMoNV type changes kinetics of the martensite tempering. The two phase decomposition and ε-carbide existence temperature range extends to higher temperatures. Application of the high temperature thermomechanical treatment or combined thermomechanical strengthening with following tempering under loading allows raising the structural strength of these steels and their using in a high-strength state after low-temperature tempering. The high resistance to shock-wave loading is also reached. 110 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 8 – P6, P8 SUPERFICIAL MODIFYING BY MATERIALS WITH SME IN ENGINEERING APPENDICES Z.M. Blednova, P.O. Rusinov Kuban state university of technology, Krasnodar, Russia [email protected] Now wide introduction of alloys with SME in mechanical engineering is limited because of their high cost. Maintenance of economic feasibility of use of these alloys in mechanical engineering can be reached as at the expense of expansion of the nomenclature of materials and use of multicomponent alloys with SME, and at the expense of superficial modifying by alloys with SME. Technologies of formation of blankets (argon-arc and laser building-up, a plasma dusting, a method of thermal carrying over of weights in the environment of fusible metals in the conditions of a gradient of temperatures) from an alloy with SME on the basis of TiNi on a steel 45 and, 40Х, 30ХGSА, 08Х18N19Т with drawing of an intermediate layer of pure nickel both allowed to receive a strong and reliable covering of a demanded thickness are developed. The optimum sizes of a thickness of a covering from an alloy with SME, providing functional properties are defined. The developed technologies can be used for creation of a wide class of demountable connections of the details having a cylindrical surface of interface, type "shaft-plug". The design of a compound cranked shaft on the basis of connection of its details by means of alloys with SME which allows raising its durability is developed, to lower work of forces of a friction of the piston car at the expense of replacement of a sliding friction on radical and conrod shaft necks on a friction. Functional properties are superficial-modified alloys SME are realised in thermomechanical an operated ring bimetallic element shut-off valve. On the basis of the analysis of the is intense-deformed condition of the blade of the rowing screw of a vessel taking into account influence nanosize TiNi coverings it is shown, that the covering from a material with SME on the basis of TiNi leads to decrease in pressure in the most dangerous zone on a surface in 2-2,5 times and provides delay of process of accumulation of damages at a stage of the non-local damageability. In work experience of last years on working out of technologies of superficial modifying of steels by materials with SME, on research of structure and properties of the is superficial-modified layers is generalised, and also on working out of new is constructive-technological decisions of their use and some unresolved problems are noted. STUDY OF THE EFFECT, THE RATE OF BURNISHING OF CLUTCHES MADE OF SHAPE MEMORY ALLOY, BELONGING TO TI-NI-NB SYSTEM, POSES ON LABOR PRODUCTIVITY AS APPLIED TO THE TECHNOLOGY OF THERMO-MECHANICAL JOINING OF CONDUITS Popov N.N., Presnyakov D.V., Lar’kin V.F., Kostyleva A.A. The Russian Federal Nuclear Center (FSUE RFNC-VNIIEF), Sarov, Russia. [email protected] Shape memory alloys are used to produce numerous technical elements, such as clutches implemented for thermo-mechanical joining of conduits and structural elements in our case. The classic technology of thermo- mechanical joining is based on memory shape alloys belonging to Ti-Ni-Fe system. However, the clutches made of these alloys, are to be burnished (deformed) and stored at cryogenic temperatures prior to putting them into the assembly process [1]. To add more competitive strength to the technology of thermo-mechanical joining the alloys with wider martensite hysteresis can be used, for instance the alloys belonging to Ti-Ni-Nb system [2]. The present paper presents the characteristics of memory shaped alloy belonging to Ti-Ni-Nb system in its casted and extruded states. With a specially designed experimental-methodological source involved [1] the elementary composition of the alloy and its mechanical properties were studied as well as the temperature of martensite-austenite transformations, which were identified by X-ray-phase analysis and deformation methods. The profile analyzer was used to study the effect, the rate of burnishing (5, 20 and 90 mm/min) poses on geometrical parameters of state of the interior and exterior surfaces of the clutch under study. High pressure laboratory was used to identify hermetic sealing and the carrying capacity of thermo-mechanical joints of 12 mm conduits with couplings made of Ti-Ni-Nb alloy. It was determined that the burnishing rate (5, 20 and 90 mm/min) does not pose any statistically significant effect on geometrical parameters of thermo-mechanical clutches made of Ti-Ni-Nb alloy, as well as hermetic sealing and carrying capacity of dummy conduits with such clutches. The effect, which the rate of clutch burnishing poses on better labor productivity as applied to the method of thermo-mechanical joining of conduits was studied. It was identified, that with the burnishing rate increased from 5 mm/min to 90 mm/min the labor productivity grows up to 7 times. With time of mounting and cooling of clutches down to -60 C in liquid nitrogen vapors and time of clutch burnishing taken into consideration the labor productivity grows up to 2,5 times. Labor intensity drops down correspondingly. Thus, labor productivity as applied to the technology of thermo-mechanical joining of conduits using clutches made of Ti-Ni-Nb alloy in casted and/or extruded state can be substantially increased due to the increased rate of clutch burnishing up to 90 mm/min. [1] Popov N.N. Monograph. Sarov, FSUE "RFNC-VNIIEF". 2008. 315 p.(in Russian). [2] N. N. Popov, S. D. Prokoshkin, M. Yu. Sidorkin, et al. Russian Metallurgy (Metally). Vol. 2007, No. 1.p. 59. 111 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 8 – P9, P10 ANALYSIS OF THE FIRST PEAK OF SPONTANEOUS MAGNETIC EMISSION (SME) CORRESPONDING TO THE MARTENSITIC START TRANSFORMATION IN A FE-NI-C ALLOY Edgar Apaza Huallpaa, Hélio Goldensteina, Julio Capo Sanchezb, Linilson R. Padovesea aUniversity of São Paulo, São Paulo, Brazil bUniversidad de Oriente, Santiago de Cuba, Cuba [email protected] The Spontaneous Magnetic Emission (SME), a recently described phenomenon that has been proved to be a useful tool to monitor the martensitic transformation, is used in this study to characterize the first avalanches (“burst”) in a Fe-Ni-C alloy, corresponding to the beginning of the transformation (temperature Ms). The origin of these emission peaks is described semi-quantitatively from the application of Faraday‟s first Law, obtaining an estimate of the propagation speed of the avalanche and the order of magnitude of the number of Fe atoms involved in an avalanche. STRUCTURALLY-MECHANICAL CONTROL REACTIONARY ABILITY SAFE DEVICES ACCUMULATOR LITHIUM-IONIC (LIA) OF SPACE APPOINTMENT WITH USE OF ALLOYS WITH EFFECT OF MEMORY OF THE FORM Z.M. Blednova, N.A. Procenko Kuban state university of technology, Krasnodar, Russia [email protected] As secondary energy sources of space vehicles lithium-ionic storage batteries (LIA) now are used. For maintenance of high level of reliability LIA of space appointment it is necessary to provide safe devices (SD), parrying refusal in case of technological failures. The executed modeling of thermal processes in SB with the account degradation processes has allowed estimating admissible temperature (100 wasps) and time of operation SD (2-3). In work the choice of a material with SME on the basis of TiNi for a power element of a thermo drive taking into account the requirements formulated as a result of modeling shown to SD is proved. The technology of management by a complex of characteristics of working capacity (an interval of phase transformations, reversible deformation, jet pressure) an elastic element with use of modern methods and means of experimental techniques (metallographic the analysis, X-ray picture, differential scanning calorimetry) is developed. The modes of thermal processing providing a necessary interval of temperatures of phase transformations are optimized and degree of conformity of the received results to the technical requirements shown to these details is estimated. New is constructive-technological decisions with use of materials with SME are offered: thermomechanical power plant (patent № 2392494) and safe the switch (patent № 2415489) which distinctive features is possibility of reservation and check of operation of the device at manufacturing and carrying out of acceptance tests. Offered design SD provides 30 % weight decrease at maintenance of duplication of switching contacts. The offered technical decisions are noted by the diploma and the Gold medal of the International salon of the industrial property «Archimedes 2009», the diploma and a gold medal of an exhibition of scientific and technical creativity «NТТM- 2009». As a result of realization of the carried out research it is created thermomechanical SD, providing reliability LIA with lower in large quantities-dimensional, higher operational characteristics and the guaranteed level of reliability in comparison with domestic and foreign analogues. Working out is executed with reference to space vehicles "Glonass-K" and introduced on Open Society "Saturn" (Krasnodar). 112 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 8 – P12, P3 FORMATION OF DEFORMATION MARTENSITE AND CHANGE OF MAGNETIC PROPERTIES OF HIGH-NITROGEN AUSTENITIС STEELS ZavalishinV.A.a, Sagaradze V.V.a, Kataeva N.V.a, Mushnikova S.U.b, Kalinin G.U.b aInstitute of Metal Physics UD RAS, Ekaterinburg bCRISM «Prometey», Saint Petersburg [email protected] Austenite nitrogen Сr-Mn steels are known as the high-strength nonferromagnetic materials with high resistance to the stress corrosion cracking (SCC) and low magnetic permeability (μ < 1,01). The high level of strength and impact toughness of SCC-resisting metals is usually obtained due to the solid-solution nitrogen hardening, the formation of nanodimensional carbonitrides and the formation of dislocation subgrain structure with a help of high-temperature thermomechanical treatment (HTMT), warm or cold deformation. Depending on the composition and pretreatment the ferromagnetic α-martensite can arise in the nitrogen austenite steels during the cold deformation and this leads to the increase of magnetic permeability of steel to the level higher than acceptable. The results of investigations show that the cold deformation of the preliminary quenched nitrogen steel 0,04С-20Cr-6Ni-11Mn-0,45N-2Mo-Nb-V to 58% at -750С and to 97% at 200С does not lead to the formation of ferromagnetic martensite and does not change the paramagnetic properties of steel. Deformation to 8†25.8 % at cryogenic temperatures (-1960С) leads to the formation of thin plates of ε-martensite within which a very small amount (~0.20%) of ferromagnetic α-martensite is formed (fig.1). The registered appearance of deformation α- martensite does not decrease the magnetic permeability of steel to the level lower than acceptable. a b c (022) γ (002) (111)γγ 0,4 (011) мкм (010)ε Fig. 1. Structure of steel 0,04С-20Cr-6Ni-11Mn-0,45N-2Mo-Nb-V after quenching from 11000С and rolling to 28.5% at -1960С: а – bright- field image; b – dark-field image in compound reflection (002)α+(102)γ с – microdiffraction; USE MARTENSITE TRANSITION IN A MATERIAL WITH SHAPE MEMORY EFFECT FOR MICROMANIPULATOR CREATION Irzhak Aa., Koledov Vb., Shavrov Vb., Afonina Vb., Zakharov Db., Kalashnikov Vb., Mashirov Ab., Bekhtina Mb., Kuchin Db. aNational University of Science and Technology "MISIS" (MISIS) Kotel’nikov Institute of Radio Engineering and Electronics of RAS [email protected] The ability of shape memory alloys (SMAs) to exhibit giant deformations is widely used in micro- and nanoelectromechanical systems (MEMS and NEMS) and medicine [1]. For example nitinol. Our purpose was to develop the microtool based of nitinol for a manipulation micro- and nanoobjects. The proposed composite material consists of a SMA in the form of a ribbon, film or plate and an elastic layer of usual metal, which are tightly connected with each other. Before connecting to the elastic layer, SMA layer is subjected to pseudoplastic tensile deformation. The process of connecting layers is carried out at a temperature below that of the austenite- martensite phase transition. As a result, the composite acquires the ability to giant reversible bending deformation. This ability is based on the fact that the bending deformation of a composite plate is a contraction on the inner side and extension on the outer side. On heating, the SMA passes to the austenite state and exhibits contraction, thus producing tensile deformation of the elastic layer and bending of the composite. On cooling, the SMA returns to the martensite state, whereby the elastic layer contracts and compresses the SMA layer, thus restoring the initial rectified shape. Recently the micro tweezers [2] on the basis of an alloy with shape memory effect (SME) have been created. It has record-breaking small size. The principle of its work is based on effect of great reversible flexural deformation in composit structures Ti2NiCu/Pt. Today probably to create tools on the basis of materials with SME, which can do mechanical manipulations over micro- and nana objects of different nature in the vacuum chamber of an ionic scanning microscope [2]. [1] Fu Y. Q., Luo J. K., Flewitt A. J. et al. Smart Materials and Structures, 2007, V.16, P.2651. [2] Afonina V., Zakharov D., Lebedev G., Koledov V., Lega P., Kuchin, D., Irzhak A., Shavrov V. Physics Procedia 10, pp. 58-64 (2010). 113 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 3 – P1, P2 THE MICROSTRUCTURAL DESIGN AND CONTROL OF ULTRAHIGH STRENGTH-DUCTILITY MARTENSITIC STEELS BASED ON A NOVEL QUENCHING-PARTITIONING-TEMPERING PROCESS Yonghua Rong, Ke Zhang, Jiawei Dai, Hailiang Yu School of Materials Science and Engineering, Shanghai Jiao Tong University Shanghai 200240, China [email protected] Based on the microstructural design and quenching-partitioning-tempering (Q-P-T) process of ultrahigh strength-ductility martensitic steels proposed by Hsu, the first medium carbon Q-P-T steel exhibits ultra-high strength of over 2000MPa and the elongation of over 10%, and it consists of nano-lath martensite, nano-film-like retained austennite and nano-carbide particles precipitated from martensite matrix. After that, two low-carbon Q-P-T steels exhibit that their tensile strengths are over 1000MPa, being higher than those of advanced high strength steels (AHSSs) with carbon content of 0.05-0.2wt%. In order to obtain higher product of strength and elongation (PSE) than the upper limit value (25000 MPa%) of AHSSs, the composition and Q-P-T process of a new steel were designed. The result indicates that the Q-P-T steel has the tensile strength of 1558 MPa, elongation of 20.3%, and PSE is as high as 31627 MPa%. Microstructural characterization reveals the origin of ultrahigh strength-ductility and mechanism of retained austenite on the ductility enhancement. INFLUENCE OF MECHANICAL ALLOYING ON THE BEHAVIOUR OF Fe-Mn-Si-Cr-Ni SHAPE MEMORY ALLOYS MADE BY POWDER METALLURGY Bogdan Pricopa, Umut Söylerb, Burak Özkalb, Nicoleta Monica Lohana, Adrian Liviu Paraschiva, Marius Gabriel Surua, Leandru-Gheorghe Bujoreanua aFaculty of Materials Science and Engineering, The "Gheorghe Asachi" Technical University from Iaşi, Bd. D. Mangeron 61A, 700050 Iaşi, Romania bParticulate Materials Laboratory, Metallurgical and Materials Engineering Department, Istanbul Technical University, 34469 Maslak, Istanbul, Turkey [email protected] Fe-14 Mn-6 Si-9 Cr-5 Ni (mass. %) shape memory alloys (SMAs) were produced from raw powders employed both in initial commercial state and in a mixture state of equal fractions of commercial and mechanically alloyed (MA‟d) particles. The procedure was applied with the primary purpose to accurately control both chemical composition and grain size of SMAs. After blending, pressing and sintering, powder compacts were hot rolled (HR) and heat treated (HT) before being machined into plane-parallel lamellas. Specimens with special geometry were cut by spark erosion and pre-strained on a tensile testing machine. By means of X-ray diffraction (XRD) and scanning electron microscopy (SEM) the presence of ε hexagonal close packed and α‟ body center cubic stress induced martensites was revealed and their thermally induced reversion to γ face center cubic austenite was evaluated by differential scanning calorimetry (DSC). The results enabled the study of the influence of MA on shape memory effect (SME), associated with ε reversion to γ, on heating, while considering the effects of HR and HT temperatures as well as the effects of pre-straining magnitude. Finally, the lamellas were pre-heated and hot formed into rings, by means of a shape setting device comprising outer and inner calibrated tubes. The rings were trained in bending, by ring diameter enlargement at room temperature and diameter reduction during heating, by free recovery SME. After training, diameter reduction of enlarged rings was monitored as a function of temperature, by cinematographic analysis during heating. 114 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 3 – P3, P4 EFFECT OF FLUX CONSTITUENTS AND BASICITY INDEX ON MECHANICAL PROPERTIES AND MICROSTRUCTURAL EVOLUTION OF SUBMERGED ARC WELDED HIGH STRENGTH LOW ALLOY STEEL Jindal Sandeepa , Chhibber Rahulb and Mehta N.P.c aMM Engineering College/Mech. Engg. Dept., Mullana, Ambala, India bIIT, Jodhpur (Rajasthan)/Mech. Engg. Dept., Jodhpur, India cM.M. Engineering College, Mullana, Ambala, India [email protected], The application of high strength low alloy (HSLA) steels has been limited by unavailability of suitable joining and filler metals in submerged arc welding (SAW) processes. The present work aims at the design and development of flux for Submerged Arc Welding of HSLA steel. In the work L8 array of Taguchi Design is used to formulate eight types of fluxes to vary basicity index (BI) from 1.26 to 2.81 and to study the effect of flux constituents and basicity index on tensile strength, microhardness and microstructure of the weld metal. Empirical models for ultimate tensile strength and microhardness at the centre of weld versus flux constituents and basicity index have been developed. From the experiments it is found that ultimate tensile strength increase with increase of basicity index with minimum at 1.26 increases upto 2.33 and then further decreases whereas opposite in case of microhardness which is highest at 1.26 and minimum at 1.9. Increase of CaO in the flux increases ultimate tensile strength but microhardness remains unaffected whereas increase of SiO2 decreases ultimate tensile strength but microhardness remains constant. Microhardness decreases critically with increase of CaF2. SHAPE MEMORY EFFECT IN MELT SPUN Fe-15Mn-5Si-9Cr-5Ni ALLOYS Druker A.a, La Roca P.b, Vermaut P.c, Ochin P.d, Malarría J.b aFacultad de Cs. Ex., Ingeniería y Agrimensura (UNR), Av Pellegrini 250, Rosario, Argentina bInstituto de Física Rosario (CONICET-UNR), Bv. 27 de Febrero 210 bis, Rosario, Argentina cGroupe de Métallurgie Structurale, UMR CNRS 70 45, ENSCP, 75231 Paris, France. dInstitut de Chimie et des Matériaux Paris-Est, UMR CNRS 7182, 94320 Thiais, France. [email protected] At room temperature, Fe-15Mn-5Si-9Cr-5Ni alloys are normally austenitic and the application of a stress induces a reversible martensitic transformation causing a shape memory effect (SME). However, when the material is obtained by a melt spinning technique, the rapid solidification stabilizes a high temperature ferritic phase. The goals of this work were to find the appropriate heat treatment in order to recover the equilibrium austenitic phase, characterize the ribbon form of this material and evaluate its shape memory behavior. We found that annealing at 1020ºC for 30 min, under an argon protective atmosphere, followed by a water quenching stabilizes the austenite to room temperature. The yield stress, measured by tensile tests, is 200MPa, well below that of conventionally rolled sheet of the same alloy. This difference results from the ribbon material´s microstructure and texture. Shape memory tests (Fig. 1) show that a strain recovery of 55% can be obtained, a value enough for certain applications. Fig. 1: Shape memory test showing a degree of shape recovery of 55% 115 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 3 – P5, P7 INTERNAL FRICTION IN HIGH TEMPERATURE Ru-Nb SHAPE MEMORY ALLOYS L. Diranda, M.L. Nóa , A. Denquinb, J. San Juanc a Dpt. de Física Aplicada II, Facultad de Ciencia y Tecnología, Universidad del País Vasco, Bilbao, Spain b Dpt of Metallic Materials and Structure, ONERA, Châtillon Cedex, France c Dpt. de Física Materia Condensada, Facultad de Ciencia y Tecnología, Universidad del País Vasco, Bilbao, Spain [email protected] At present there is a growing interest into developing new families of shape memory alloys for high temperature applications, this means from 300ºC to 1000ºC. Among the few systems that could be considered as candidates to fulfill this requirements, the Ru-Nb system is an important one because it exhibits two different martensitic transformations, depending on concentration [1, 2], one from cubic B2 phase to a body centered tetragonal martensite and the other one to a monoclinic martensite. On other hand, the measurement of the internal friction and dynamic modulus by mechanical spectroscopy is a powerful tool to study the relaxation processes of micro-structural defects, as well as a very sensitive technique to study phase transitions. In the present work we used two mechanical spectrometers working in temperature ranges from 200ºC to 1500ºC and -150ºC to 500ºC, to study the high temperature shape memory alloys based on the Ru-Nb system. We have studied the internal friction peaks linked to the martensitic transformations in the range from 300ºC to 1200ºC. In addition, we have discovered a low temperature internal friction peak around RT, which exhibits the behavior of a thermally activated relaxation peak. We have measured the activation enthalpy of this peak and discussed their microscopic origin. Finally we perform a complete analysis of the whole internal friction spectrum, taking into account the possible relationship between the relaxation peak and the martensitic transformation behavior. [1] K. Chastaing, A. Denquin, R. Portier, P. Vermaut, Mat Sci Eng A, 481-482 (2008) 702. [2] A. Manzoni, K. Chastaing, A. Denquin, P. Vermaut, R. Portier, Proc. ESOMAT-2009. SHAPE RECOVERY IN STAINLESS FE-MN-SI-CR-NI(-CO) SMA PROCESSED BY ECAE Bernardi, H.H.a; Käfer, K.A.a; Naito, L.K.F.a; Otubo, J.a aInstituto Tecnologico de Aeronautica, Sao Jose dos Campos, SP, Brazil [email protected] Stainless steel shape memory effect alloy presents lower shape recovery when compared to traditional NiTi SMA. However, recent results have shown that when the austenite grain sizes in these materials are decreased the shape recovery is improved. The shape memory effect in stainless steel is associated to non-thermoelastic (fcc) to (hc) martensitic transformation. The present work describes the influence of the austenite grain on the shape recovery in stainless shape memory alloy (SMA) deformed by equal channel angular extrusion (ECAE) using a die intersection angle of 120°. Two alloys, Fe-Mn-Si-(Cr-Ni) and Fe-Mn-Si-(Cr-Ni-Co), were deformed by one ECAE pass processing and then compared in the deformed state; deformed and annealed in different temperatures, from 450oC to 950oC for 1 h, with different grain sizes. Chemical compositions are presented in the Table 1. Microstructural characterization will be performed by SEM (Scanning Electron Microscopy), martensitic transformations temperatures will be analyzed by DSC (Differential Scanning Calorimetry) and DMA (Dynamic Mechanical Analyzer). The characterization of SME will be carried out by compression test. Table 1: Chemical composition (wt%). Alloy Fe C Mn Si Cr Ni Co Fe-Mn-Si-Cr-Ni Balance 0.008 14.20 5.3 8.8 4.65 ---- Fe-Mn-Si-Cr-Ni-Co Balance 0.009 8.26 5.3 12.8 5.81 11.84 116 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 3 – P9, P10 EXAMINATION OF TRIP/TWIP EFFECTS IN FEMN(CR) AUSTENITIC STEELS Márton Benke, Valéria Mertinger, Ferenc Tranta Institute of Material Sciences, Miskolc, Hungary [email protected] A group of austenitic steels exhibit extremely high deformability due to TRansformation Induced Plasticity (TRIP) or TWinning Induced Plasticity (TWIP). The TRIP and TWIP effects have been examined in details in many FeMnX alloy systems (X: Ni, Al, Si). However, less attention was given to the FeMn(Cr) alloys. The effect of Cr content on the TRIP/TWIP effects and the γ→ε, γ→α‟ and ε→α‟ transformations in austenitic FeMn(Cr) alloys have been examined by means of tensile tests, optical microscopy, SEM, DSC, XRD techniques and dilatometric measurements. VARIANT SELECTION DURING DISORDER-ORDER TRANSFORMATION UNDER A MAGNETIC FIELD IN Fe-Pd ALLOY Farjami Sahara, Tanaka Yuria, Mitsuhara Masatoshia, Itakura Masarua, Nishida Minorua, Fukuda Takashib, Kakeshita Tomoyukib a Department of Engineering Science for Electronics and Materials, Faculty of Engineering Science, Kyushu University, Fukuoka 816-8580, Japan b Department of Materials Science and Engineering, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan [email protected] Fe-Pd alloy exhibits a disorder-order transformation from an A1-type disordered structure to an L10-type ordered structure in the vicinity of the equiatomic composition and the ordered phase is composed of three variants. The ferromagnetic ordered phase is characterized by a high uniaxial magnetocrystalline anisotropy with an “easy” c- axis. Recently we reported formation of a single variant in Fe-55 at%Pd by a two-step ordering heat-treatment. The first step is made at 673 K for 1 h under a magnetic field of 4 T and higher applied in the [001] direction. It is followed by the second step at 773 K for 24 h without the magnetic field1. In this study, microstructure evolution during the ordering process under the magnetic field has been investigated by transmission electron microscopy (TEM). A high angle annular dark field scanning transmission electron microscopy (HAADF-STEM) image after the first step of ordering under 10 T field shows random distribution of three variants in disordered fcc matrix and the size of each ordered domain is about 5 nm. To know fraction of the variants at this stage, we compared intensity of superlattice reflection using an energy filtered TEM. The results indicate that the superlattice reflection of the preferred variant (Z-variant) is higher than that of the other two variants. A fine antiphase domain structure has been observed in the single variant state, which implies that the ordering proceeds by a homogeneous nucleation and growth process. We will also discuss the effect of magnetic field on preferentional formation of the Z-varaint at the early stage of ordering. [1] S. Farjami, T. Fukuda and T. Kakeshita, Mater. Trans. 49 (2008) 1970-1974. 117 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 3 – P19, Session 9 – P1 DEFORMATION TWINNING OF ε –MARTENSITE AND SHAPE MEMORY EFFECT IN Mn-V-C AUSTENITIC STEELS S.V. Afanasev, N.V.Kataeva, V.V.Sagaradze, Institute of Metal Physics, Ural Branch, Russian Academy of Science [email protected] The shape memory effect (SME) (to 2,5-3%) is realized in the austenite metastable Mn-V-C steels with carbide ageing as a result of preliminary γ→ε transformation at cold deformation and the subsequent reversible ε→γ transformation at heating. The use of non-ageing low-strength metastable austenitic alloys of Fe-20Mn-2Si type with 0,01-0,4 %С as the SME-materials turns out to be unpractical, since here the cold deformation of low degrees (4-5%) occurs mainly due to the glide of dislocations without the formation of proper amount of ε-martensite. The large amount of necessary ε-martensite is formed only at strong deformations (more than 40%) when the reversibility of direct and reverse γ-ε and ε-γ transformations weakens greatly. In the ageing steels of 40Г20С2Ф2 type with equally distributed nanocarbides VC a small deformation (to 5%) is realized mainly due to the movement of partial dislocations, formation and ordering of stacking faults with the creation of ε-phase to 70-90%. Evidently, the VC particles contribute to the splitting of perfect dislocations into the partial ones with the formation of stacking faults. The stored oriented elastic stresses, which occur around the VC particles at deformation during the transformation of austenite to ε-phase, also have to contribute to the development of reversible ε-γ transformation at heating. The investigations show that the SME close in value (to 2-2,5%) can be obtained in Mn-V-C steels in ε- martensite state. At that, the development of preliminary γ→ε transformation at cold deformation is not necessary but the shearing retwinning of ε-martensite during cold deformation is necessary. And it is possible to bend and unbend the samples many times, what leads to the “memorizing” of the last bending without any intermediate quenching from austenite area. The restoration of the sample shape, which was before the last bending, occurs at heating to 4000С as a result of transformation of retwinned ε-martensite to the austenite phase. With the growth of number of “bend-unbend” cycles the value of ESM slightly decreases. The initial ε-martensite of deformation can be obtained on the plane sample by means of preliminary rolling, tension or cooling (below Мн). SME is realized in these samples, in particular, at cold bending with the subsequent reversible deformation at heating. The proposed SME-steels can be utilized in gas, oil and nuclear power engineering for the joint of steel pipelines, creation of thermal sensors and hermetic sealing of different types of flaws. PRECURSOR NANOSCALE TEXTURES IN FERROICS Castán Teresaa, Lloveras Pola, Planes Antoniaand Saxena Avadhb aDepartament d’Estructura i Constituents de la Matèria, Facultat de Física, Universitat de Barcelona, Diagonal 647, 08028 Barcelona, Catalonia, Spain. bTheoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA. [email protected] First-order phase transitions are expected to occur abruptly at given values of external control parameters such as temperature, pressure or applied field (stress, magnetic or electric). However, in numerous homogeneous crystalline solids the transition is preceded by anomalies, typically detected in the response to certain types of excitations, which may arise from local symmetry breaking perturbations. Spatially inhomogeneous states often occur as precursors of the incoming phase in many ferroic materials including ferroelastic, ferroelectric, magnetic and superconducting systems. These states consist of coexisting regions with properties varying over nanometer length scale. Understanding these complex textures is a challenging nonlinear problem usually involving interplay of disorder and long range interactions. Strain, and thus elasticity, is known to be important in determining the actual symmetry properties of nanoscale patterns. From this point of view martensites offer a unique scenario where purely structural textures can be studied. Here, after providing an overview of general aspects of the problem we will discuss the combined role of elastic anisotropy (controlling long range effects) and disorder in the context of such textures. We will show that cross-hatched modulations (tweed patterns) occur for temperatures above the martensitic phase in the limit of high anisotropy or low disorder while a nano-cluster phase separated state occurs at low anisotropies or high disorder. In the latter case, nanoscale inhomogeneities give rise to glassy behaviour while the structural transition is inhibited. Interestingly, in this case the ferroelastic system also displays a large thermo-mechanical response so that the low symmetry structure can be easily formed by the application of relatively small stresses within a broad temperature range. 118 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 11 – P1, P4 TIME DEPENDENCES OF MAGNETIZATION DURING ISOTHERMAL TRANSFORMATION OF A Ni-Mn-In-Co ALLOY Pérez-Landazábal J.I.a, Recarte V.a, Sánchez-Alarcos V.a, Kustov S.b, Salas D.b, Cesari E.b aDepartamento de Física, Universidad Pública de Navarra, Campus de Arrosadía 31006 Pamplona, Spain bDepartament de Física, Universitat de les Illes Balears, Ctra. de Valldemossa, km 7.5, E-07122 Palma de Mallorca, Spain. [email protected] The Martensitic Transformation (MT) in Ni-Mn-In-Co metamagnetic shape memory alloys shows isothermal behaviour during the Austenite-Martensite phase change. The time evolution of the magnetization, M(t), under different applied fields and at different temperatures, upon stopping the cooling/heating ramps during the direct/reverse MT has been measured in order to analyze its isothermal characteristics. In agreement with previous DC resistance and AC electric impedance measurements, it has been found that M(t) follows a logarithmic dependence upon isothermal dwellings, both on cooling and heating. However, samples with different degree of long range order, which shifts significantly the transformation range, present distinct isothermal features. The logarithmic time dependences can be attributed to the behavior of a system that relaxes through a broad distribution of activation energies. A well known example of such relaxation is given by the thermal fluctuation magnetic after effect in ferromagnetic materials. The remarkable coincidence of the isothermal transformation rates as a function of the martensite fraction, for different applied fields and temperatures, points to the relevant role of the number of austenite-martensite interfaces in controlling the isothermal kinetics in these alloys. EFFECT OF PARTIAL THERMAL CYCLES ON NON-CHEMICAL FREE ENERGY CONTRIBUTIONS IN POLYCRISTALLINE CU-AL-BE SHAPE MEMORY ALLOY Daróczi Lajos, El Rasasi Tarek, Beke Dezső Department of Solid State Physics, University of Debrecen, Debrecen, Hungary [email protected] Thermoelasic martensitic transformations are controlled by the local equilibrium of chemical and non-chemical free energy (D and E being the dissipative and elastic energies, respectively) contributions. The derivatives of non- D E chemical free energies ( d, e ) as a function of the transformed martensite fraction (ξ) can be expressed from the experimental data obtained from the temperature-elongation, temperature-resistance, etc hysteresis loops. [1,2,3]. This method was used for the investigation of non complete, partial thermoelastic transformation cycles. In the first set of experiments the 160 35 140 120 subsequent cycles were started 30 100 min 80 below the Mf temperature and the 0.83 60 25 0.58 40 maximum temperature was 20 0.35 20 0 0.32 b increased gradually up to the Af -20 0.17 15 )+const (a.u.) -40 D(a.u.) 0.11 -60 a value. From the minor hysteresis e( 0.05 10 -80 -100 0 loops the d(ξ) and e(ξ) functions -120 5 -140 were evaluated as the function of -160 0 -0,1 0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0 1,1 ξ. Similar measurements were 0,0 0,2 0,4 0,6 0,8 1,0 performed starting from above the Af temperature. The derivative Fig.1 dependence of elastic energy derivative Fig.2 Dissipative energy of subcycles as of the elastic energy, e(ξ) shows a in partial loops characterised by the minimum function of minimum martensite content(a), ξ martensite content ξmin dependence of the partial dissipative energy of monotonic increase versus the the full cycle (b). transformed fraction and the ξ dependence of it is nearly identical in all subcycles (Fig.1). The integral value of the dissipative energy D was calculated from both the full cycle and the partial loops as well. The integral dissipative energy of the partial loops (Fig. 2a) is lower than the partial dissipative energy of the full cycle (Fig. 2b) at the same transformed fraction. (Except evidently the ξ=1 and 0 values.) [1] Beke, D.L., Daróczi L., Palánki Z., Lexcellent C.; SMST-2007; Tsukuba; 2007 [2] El Rasasi, T.Y., Daróczi, L., Beke, D.L; Intermetallics Volume 18, Issue 6, June 2010, Pages 1137-1142 [3] El Rasasi, T.Y., Daróczi, L., Beke, D.L; Journal of Alloys and Compounds in press 119 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 11 – P7, P9 THEORETICAL STUDY TWIN'S BOUNDARY MOTION IN HEUSLER ALLOYS BY MONTE CARLO SIMULATION Kostromitin K.I., Buchelnikiv V.D., Sokolovsky V.V. Chelyabinsk State University, Chelyabinsk, Russia [email protected] In this paper we study a simplified model of the kinetics of twin boundary motion in a real crystal lattice of Heusler alloys Ni-Mn-Ga by the classical Monte Carlo method [1]. We consider the lattice size 17x17x17 sites with periodic boundary conditions in two dimensions, taking into account the ab initio magnetic exchange interactions in the first two coordination spheres. It is assumed that the magnetic atoms are only Mn and Ni, so we take into account only the exchange interaction between these atoms. To describe the exchange interactions, we use the Heisenberg Hamiltonian in which the projections of the spins have continuous values in the range [-1,1] and with the external magnetic field ℋ J S S g HS . i, j i j B iz ij, We also consider two the low-temperature martensitic phases at constant temperature, in the z direction the boundary conditions are assumed to be open. In the first twin (the xy plane from 1 to 7 sites along the axis z) the initial distribution of spin projections of Mn atoms and Ni was assumed as follows: Sz = 1, Sx = 0, Sy = 0. In the second twin (the xy plane from 9 to 17 along the axis z) the initial distribution of spins set equal to Sz = 0, Sx = 1, Sy = 0. In the twin boundary (xy plane at z = 8), the initial spin distribution was specified as follows: Sz = 0.5, Sx = 0.866, Sy = 0. In the simulation of a twin motion boundary we use a standard Metropolis algorithm. Change the value of the spins of the atoms was carried out at random only in the transition region. The spins in the depth of the twins were unchanged. In the case when the spins in the twin boundary are oriented along the axis z, the boundary is shifted in the direction of the twin which is favorable. The following plane becomes the new plane of twin boundary. As a result of action of external magnetic the effect of motion of the twin boundary is caused in time and the lattice transmits to a single-domain state. [1] David P. Landau, Kurt Binder, A guide to Monte Carlo simulations in statistical physics, Cambridge, Cambridge University Press, (2000). ON THE INFLUENCE OF THE NI-CONCENTRATION ON THE MARTENSITIC TRANSFORMATION IN NITI SHAPE MEMORY ALLOYS Jan Frenzela, Easo Georgeb, Christoph Somsena, Martin Wagnerc, Antonin Dlouhyd, Gunther Eggelera a Institute for Materials, Ruhr University Bochum, 44801 Bochum, Germany, b Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, USA, c Institute for Materials Science and Materials Technology, Chemnitz University of Technology, Germany, d Institute of Physics of Materials, AS CR, Zizkova 22, CZ-616 62, Brno, Czech Republic, [email protected] In the present work, we provide a new set of data on phase transformation temperatures, hysteresis widths and transformation heats in NiTi. It is well known that the phase transformation temperatures in binary near equiatomic NiTi shape memory alloys decrease with increasing Ni-content. However, a large experimental scatter was observed in previous studies and even today, a high precision reference data set on the relation between alloy composition and transformation temperatures is not available. NiTi ingots with different Ni-levels were produced using an optimized melting procedure and analyzed by differential scanning calorimetry. We show why it is important to document details of the melting procedure and how precise Ni-concentrations of the NiTi matrix can be obtained. We provide clear experimental evidence showing that the predictions of Tang et al. (Acta Mat. 1999) on the increasing deviations from a linear relation between the thermodynamic equilibrium temperature and the Ni- content are correct. We also provide easy to handle numerical expressions for the effect of Ni on MS, MF, AS, AF and T0. We show that increasing Ni-contents not only affect phase transition temperatures but moreover result in decreasing widths of the thermal hysteresis and in decreasing heats of transformation and rationalize these findings on the basis of crystallographic data by Prokoshkin et al. (Acta Mat. 2004) in the light of the theory of Ball and James (Phil. Trans. Royal Soc. A 1992). 120 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 11 – P11, P5 CALORIMETRIC STUDY OF AVALANCHE CRITICALITY IN THE MARTENSITIC PHASE TRANSITION OF Cu67.64Zn16.71Al15.65 M.C. Gallardoa, F.J. Romeroa, J. Manchadoa, J.M. Martín-Olallaa, A. Planesb and E.K.H. Saljec aDepartamento de Física de la Materia Condensada, Universidad de Sevilla. Sevilla. Andalucia. Spain bDepartament d’Estructura i Constituents de la Matèria. Facultad de Física. Universitat de Barcelona. Barcelona. Catalonia, Spain cDepartment of Earth Sciences. University of Cambridge, , Cambridge, United Kingdom [email protected] The first-order diffusionless structural phase transition in Cu67.64Zn16.71Al15.65 is characterized by jerky propagation of phase fronts related to the appearance of avalanches. In this work a full analysis of this avalanche behaviour using calorimetric heat – flux measurements and acoustic emission measurements (AE) is described. Measurements of heat flux were performed using a high-resolution conduction calorimeter that work as a differential thermal analysis (DTA) device. It allow measurements of heat flux better than 0.1W and the temperature changes are some 10-3 K/h with temperature fluctuations of the calorimeter block smaller than 10-6K. DTA traces were obtained from heating and cooling runs at several constant rates of 0.29 K/h, 0.04K/h and 0.005K/h. In figure 1 the complete DTA trace is represented. Avalanches show criticality where each avalanche leads to a spike in the heat flux. Their statistical analysis leads to a power law [P(E)E-, where P(E)dE is the probability to observe an avalanche with energy E in the interval between E and E+dE] with an energy exponent of = 1.8 0.1 on heating experiment, as it is shown in figure 2. This value agrees with AE results. Figure 1 Figure 2 KINETICS OF PHASE TRANSITIONS AND FAST SHAPE MEMORY ACTUATION Kamancev Alexander a, Koledov Victor a, Morozov Evgeniy a, Antonov Roman a, Shavrov Vladimir a, Shelyakov Alexander b, Sitnikov Nikolayb and Zhikharev Alexey a aKotelnikov IRE RAS, 125009, Moscow, Russia bNational Reserach Nuclear University MEPhY,115409, Moscow Russia [email protected] Alloys with shape memory effect (SME) are used widely in technology and medicine as functional materials with unique combination of properties. Unfortunately their potential as working body of mechanical engines is not properly appreciated due to several drawbacks, particularly, small energy conversion efficiency and frequency of operation. Usually the time response of thermally controlled SME based device is restricted by heat transfer time th of an active element. Calculated values of th are in the range of microseconds for the small size designs based on thin films or melt spun ribbons with SME. But still there are no reports about more then 100 Hz frequency of operation of actuators with SME. The general thermodynamic theory describes the fundamental restrictions on the rate of 2d order phase transition in terms of Landau-Khalatnikov equation [1]. Up to date there is no experimental proof of this approach. It has not been published not only for martensitic transitions (MT) which are 1st order in fact, but also for some 2d order transitions like Curie point in ferromagnets yet. Here we report on experimental studies of the response time of Ti2NiCu melt spun ribbon (for actuator) with purpose to search for fundamental restrictions on the rate of MT and SME manifestation. The thickness of ribbon Ti2NiCu under investigation was 40 m. This ribbon is amorphous in as spun state and does not demonstrates SME. It demonstrates the MT and SME with temperature Mf = 52 C after annealing. In the present experiments the ribbon with bias spring element had been actuated by series of electric pulses and its response deformation was recorded by video camera and measured by optical displacement sensor. The heat transfer time th in the experimental unit was theoretically estimated and was found to be strongly dependant on the environment. The smallest th (1 ms) was found in conditions of flowing liquid heat exchange. The results of experimental measurements of ribbon actuator response in air and water environments are presented. Unexpectedly the as spun amorphous ribbons, which do not show SME also have demonstrated a remarkable actuation due to strong thermal expansion. [1] E.M.Lifshitz, L.P.Pitaevskii. Physical kinetics (course of theoretical physics vol. 10). Pergamon press. 1981. 121 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 6 – P2, P3 ROLE OF PHASE STRESS IN VARIATIONS OF CELL BEHAVIOR ON NiTi Danilov A.a, Muhonen V.b, Tuukkanen J.b and Jämsä T.c a Saint-Petersburg State University, Russian Federation b University of Helsinki, Finland c University of Oulu, Finland [email protected] The common functional task of the most of NiTi medical implants is to generate and sustain a certain level of mechanical stress. This is achieved by incomplete shape restoration which results in two-phase state of material, when along with austenite some volume fraction of martensite (residual or afresh stress-induced martensite, depending on nickel content) is present on its surface. Studies of cell behavior on such a surface demonstrated that two-phase state of NiTi alloys may have a pronounced negative effect on cell adhesion and viability. However cell behavior on one-phase martensitic and austenitic samples did not reveal such dramatic difference as on the surface of two-phase samples. Although different types of phase stress in austenite and martensite predicted by theory as a result of different crystal lattice volumes could be a reason for the variations in cell behavior, the direct experimental proves of this suggestion were not obtained. To clarify it, the stress in austenite and martensite during direct and reverse martensitic transformations in NiTi was studied by X-ray diffraction. The results obtained testified of opposite stress operated in austenite and martensite during B2B19 martensitic transformations. While austenite underwent tension, martensite underwent compression. The absolute stress values were shown to be functions of phase composition: they increased from the minimum level in the initial phase during the first half of transformations, achieved maximum at the equilibrium between the initial and new phases and decreased during the second half of transformations to the minimum level in the ultimate phase, so that the stress-volume fraction curves could be described by the Gaussian function. The variations in morphometric parameters of osteoblasts cultured on simulated two-phase samples welded of two NiTi plates with different transformation temperatures were studied. The effect of stress distribution in austenite and martensite on cell growth was demonstrated. The probable mechanism of cell apoptosis, caused by phase stresses operated at the astenite - martensite interface, is discussed. The recommendations concerning the choice of NiTi alloy composition and thermo- mechanical treatment to avoid two-phase state of material or to minimize the residual martensite after implant installation are given. EFFECT OF COLD-ROLLING RATE ON TEXTURE IN Ti-Mo-Al-Zr SHAPE MEMORY ALLOY Katsunori Hiramatsua, Masaki Taharab, Tomonari Inamurab, Hideki Hosodab, Shuichi Miyazakic aGraduate Student, Tokyo Institute of Technology, Midori-ku, Yokohama, Japan bPrecision and Intelligence Laboratory, Tokyo Institute of Technology, Midori-ku, Yokohama, Japan cInstitute of Materials Science, University of Tsukuba, Tsukuba, Japan [email protected] Effect of rolling rate on texure of Ti-Mo-Al-Zr shape memory alloy was investigated using X-ray pole figure measurement and electron backscattering pattern (EBSP) analysis to optimize the thermomechanical processing. Ti- Mo-Al-Zr alloy is a candidate Ni-free shape memory alloy in order to replace Ti-Ni alloy in medical applications. Shape memory effect and superelasticity in the -type Ti-based shape memory alloys are due to the (bcc)- '' (C- orthorhombic) martensitic transformation. The transformation strain of ''-martensite in β-Ti alloy is much smaller than that of Ti-Ni in general. Therefore, the orientation effect by a strong texture is necessary for the enhancement of apparent shape recovery strain. We have shown that the orientation effect is very effective on the improvement in superelasticity of Ti-Nb alloys. The alloy ingots were fabricated by Ar-arc melting and cold-rolled with various reduction rates between 30% and 99% and then solution-treated (1173K for 1.8ks and water quenching). Three typical compositions were selected for this study: (1) at room temperature (RT), (2) + ''(stress induced by rolling) and (3) single phase of '' at RT. Especially, the alloy (2) exhibited interesting results. The alloy (2) was single phase of before rolling and then ''-martensite was induced during the cold-rolling. Unlike the recrystallization texture in Ti-Nb alloy system, {110}<001> recrystallization texture of -phase was developed by the solution-treatment especially in the specimens with the reduction rate higher than 90%. This texture can exhibit both tensile and compressive transformation strain along both RD and TD direction, although it has never been observed in Ti-Nb systems. The guideline of thermomechanical process to control the mechanical properties is discussed on the basis of the observed textures and orientation dependence of the transformation strain in each texture. 122 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 6 – P4, P7 PHASE STABILITY AND MARTENSITIC TRANSFORMATIONS IN BINARY Ti-Nb ALLOYS Matthias Bönischa, Christine Mickela, Ajit Panigrahib, Michael Zehetbauerb, Thomas Waitzb, Annett Geberta, Mariana Calina, Werner Skrotzkic, Jürgen Eckerta,d aLeibniz Institute for Solid State and Materials Research Dresden (IFW Dresden), Germany bPhysics of Nanostructured Materials, Faculty of Physics, University of Vienna, Austria cInstitut für Strukturphysik, TU Dresden, Germany dInstitut für Werkstoffwissenschaft, TU Dresden, Germany [email protected] The Young‟s modulus of binary Titanium-Niobium (Ti-Nb) alloys shows a pronounced dependency on Nb content and is much lower for certain Nb contents than for other Ti-based biomedical alloys such as Ti-6Al-4V, Ti- 4Al-2.5Fe or pure Ti [1, 2]. The low stiffness of Ti-Nb based alloys renders them possible candidates as materials for load-bearing implants of which a Young‟s modulus close to that of bone is required in order to avoid stress- shielding. Moreover, Ti-Nb based alloys exhibit a martensitic transformation from the bcc β-phase to the orthorhombic α‟‟ phase, which may give rise to superelastic and shape memory behaviour [3]. This work reports on first results on a series of binary Ti-Nb alloys with Nb content ranging between 14 wt.% to 31.5 wt.%. From these alloys rods of 10 mm in diameter were prepared by cold crucible casting. The resulting microstructures and phase constitutions of the alloys in different states (as-cast, homogenized and water- quenched) were investigated by X-ray diffraction and Scanning Electron Microscopy. The preliminary results of the thermomechanical training of alloys through a constant stress thermal cycling (shape memory training) and constant temperature superelastic cycling (superelastic training) are presented. The thermal stability and critical phase transformation temperatures were determined by Differential Scanning Calorimetery and dilatometry. Transmission Electron Microscopy was used for complementing structural studies. Work supported within the EU 7th Framework Programme FP7/2007-13 under grant agreement No. 264635 (BioTiNet-ITN). [1] S. Hanada, T. Ozaki, et al., Mater. Sci. Forum, 426-432:3103–3108, 2003. [2] D. Kuroda, M. Niinomi, et al., Mater. Sci. Eng., 243A(1-2):244–249,1998. [3] H. Kim, Y. Ikehara, J. Kim, et al., Acta Mater., 54(9):2419 – 2429, 2006. INVESTGATION OF ELECTROCHEMICAL BEHAVIOR OF NOVEL SUPERELASTIC BIOMEDICAL ALLOYS IN SIMULATED PHYSIOLOGICAL MEDIA Zhukova Yulia, Konopatsky Anton, Yury Pustov National University of Science and Technology “MISiS”, Moscow, Russia [email protected] Nowadays biocompatible alloys exhibiting superelastic behavior are among the most perspective metallic materials for implantology. Nitinol Ti-Ni is the most extensively studied alloy of this type. However, development of Ni-free titanium-based alloys are carried out due to nickel carcinogenicity, for example, Ti-Nb-(Ta, Zr) solid solution based alloys. In these alloys superelastic behavior is caused by reversible martensitic transformation of β phase (disordered bcc) to orthorhombic martensite α''. The greater part of its vital cycle an implant interacts with quite aggressive bodily fluids, so it is necessary to investigate the corrosion and electrochemical behavior of the new alloys. Electrochemical behavior of superelastic Ti-Nb-Ta and Ti-Nb-Zr alloys was investigated in artificial saliva, neutral and acidified Hank‟s solutions at 37oC, as compared to titanium and Nitinol. In all solutions the alloys exhibited inclination for self-passivation. A mechanism of protective film formation on the alloys‟ surface during the immersion is proposed based on the analysis of open-circuit potential variation kinetic dependencies. The potential curve can be divided into two regions: the first one can be approximated by logarithmic equation, the second one – by reciprocal logarithmic one. This indicates the different mechanisms of oxide film growth during the immersion in solution. Ti-Nb-Ta alloy exhibited the highest rate of film growth during early stage of oxidation. Polarization curve measurements showed that in all media the new alloys exhibited quite large passivity region and low values of anodic dissolution current density comparable to those of pure titanium. Ti-Ni alloys was found to be susceptible to pitting corrosion. It is shown that Ti-Nb-Ta and Ti-Nb-Zr alloys corrosion and electrochemical characteristics are comparable to those of titanium and they are not susceptible to pitting corrosion as opposed to Ti-Ni alloy. 123 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 4 – P2, P3 MARTENSITIC TRANSFORMATION IN Ni-Mn-Sn ALLOYS R. Coll, J. Bonastre, J. Saurina, L. Escoda, J.J. Suñol Dept. Física, Campus Montilivi s/n, University of Girona, 17071 Girona, Spain [email protected] Ferromagnetic shape memory alloys exhibit ferromagnetic and shape memory effect simultaneously. Their potential functional properties include: magnetic superelasticity, large inverse magnetocaloric effect and large magneto-resistance change. These properties make them of noteworthy interest for developing new thermal or magnetically driven actuators, sensors and magnetic coolant for magnetic refrigeration. The observation of the martensitic transformation in ferromagnetic Heusler alloys of the system Ni50Mn50- 1 xSnx with 10 ≤x ≤16.5 was reported for the first time by Sutou et al. . Afterwards, Krenke et al studied the phase 2 transformation and magnetic properties of the system Ni50Mn50-xSnx, with 5 ≤x ≤25 . For the alloys with x=13 and 15, the martensitic phase is also ferromagnetic and the first order structural transition takes place at a certain temperature below the Curie points of both phases. In consequence, the system Ni-Mn-Sn shows possibilities and prospective importance as a ferromagnetic shape memory alloy. In all these studies the alloys were made in the shape of bulk polycrystals by melting with arc furnace, followed by homogeneization by thermal annealing during several hours at high temperature. In this work, we analyze several alloys of the Ni-Mn-Sn system. These alloys were produced as bulk polycrystalline ingots by arc melting as well as ribbons by melt spinning. The structural transformation was checked by calorimetry and X-ray diffraction. The transformation temperatures of shape memory alloys strongly depend on the composition and their values spread in a very wide range. Furthermore, thermodynamic parameters (enthalpy, entropy change) differ by comparing alloys with the same composition and different shape (bulk, annealed bulk, ribbon). Nevertheless, minor changes were detected in the transition temperatures and crystalline structure. [1] Y. Sutou, Y. Imano, N. Koeda, T. Omori, R. Kainuma, K. Ishida and K. Oikawa, Appl. Phys. Lett. 85 (2004) 4358. [2] T. Krenke, M. Acet, E.F. Wassermann, X. Moya, L. Mañosa and A. Planes, Phys. Rev. B 72 (2005) 014412. MODELING OF SMART MATERIAL PROPERTIES OF HEUSLER ALLOYS Teodor Breczkoa, Viatcheslav V. Barkalineb , Yana V. Douhayab aFaculty of Mathematics and Computer Science,University of Bialystok, Bialystok, Poland bBelarussian National Technical University, Minsk, Belarus [email protected] Over the last decade, great progress has been seen in the development of smart structure technology. This is partly due to the fact that intelligent materials usable as functional components of smart structures have been extensively studied. Particularly in actuator technology, active or smart materials have opened new horizons in terms of actuation simplicity, compactness and potential miniaturization. Heusler Ni2MnGa alloy is the class of materials known as ferromagnetic shape memory alloys able change their sizes by up to 10% under application of a magnetic field. Combination of ferromagnetism and structural phase transitions in Heusler alloys is perspective for the production of new devices based on the magnetic field control of the size and shape of the actuator active elements. The structural phase transition in these elements proceeds by the transformation of high-temperature austenite cubic phase into a tetragonal low-temperature martensite phase. Ni-Mn-Ga alloys with the composition about stoichiometric phase Ni2MnGa have at the room temperature the fcc lattice, Heusler's structure (L21, no. 225). Under cooling the compounds obtain the macroscopic strain due to the martesite's twin boundary moving. Detailed experimental studies of the regularities of formation and realignment of both martensitic and magnetic domain structures are necessary to define modeling and simulation strategy of magnetically induced phenomena in these alloys. These questions are studied intensively by the number of research groups. However, the available data are still fragmentary and need to be extended and generalized. In the present work we focus our attention on ab initio calculation of electronic properties of Ni2MnGa alloys. 124 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 4 – P4, P8 MICROSTRUCTURES OF FE-PD ALLOY RIBBONS SUBJECTED TO RAPIDLY SOLIDIFIED MELT-SPINNING Yoichi KISHIa, Takeshi KUBOTAb, Zenjiro YAJIMAa, Teiko OKAZAKIc and Yasubumi FURUYAc a AMS R and D Center, Kanazawa Institute of Technology, Hakusan, Japan b NJRISE, Hirosaki University, Aomori, Japan c Faculty of Science and Technology, Hirosaki University, Hirosaki, Japan [email protected] In our previous studies [1, 2], the FePd FSMA ribbons made by rapidly solidified melt-spinning showed a good ductility, giant magnetostriction as well as shape memory effect. In addition, we designed the FePd ribbon/PZT/FePd ribbon trilayer composites and investigated the composites for the application of microelectronic devices and magnetic field sensing [3]. The output magnetoelectric voltage VME of the composite was measured as a function of the frequency for the driving ac magnetic field. The values of VME on the frequency between 0.5 Hz and 100 Hz were almost constant. The maximum value of VME was exhibited at a resonance frequency of 61 kHz. These distinctive properties arise from the microstructures of the ribbon. In this paper, in order to further examine the microstructures of the Fe-29.6at%Pd ribbons are investigated. The crystal grains, whose diameter is about 20 m, were observed in the cross section of the ribbons. Relief effects corresponding to the formation of FCT martensite variants were observed on the surface of the crystal grains. TEM bright field images for the cross section of the ribbon showed high-density striation in the FCT martensites. Twin-related two sets of reflections were observed in the SAED patterns taken of the FCT martensites, accompanying streaks. The X-ray diffraction profiles at room temperature showed that the ribbon consists of FCT martensitic and FCC parent phases. Moreover, the ribbon exhibits a strongly 100-oriented texture analyzing with pole figure measurements. [1] Y. Furuya, N. W. Hagood, H. Kimura and T. Watanabe: Materials Transactions, JIM, Vol. 39, (1998) p. 1248, [2] Y. Kishi, Z. Yajima, T. Okazaki, Y. Furuya and M. Wuttig: Advances in Science and Technology, vol. 59, (2008) p. 24 [3] Y. Sado, C. Saito, Y. Furuya, Y. Kishi, Z. Yajima, T. Okazaki: Japanese Journal of Applied Physics, vol. 50, (2011) p. 113001 THERMOMECHANICAL BEHAVIOUR OF Ni-Mn-Ga AND Ni-Mn-Ga-Cu HIGH TEMPERATURE SHAPE MEMORY ALLOYS Picornell Catalinaa, Pons Jaumea, Sozinov Alexeib, Cesari Eduarda aDept. de Física, Univ. de les Illes Balears, Palma de Mallorca, Spain bAdaptamat Ltd., Helsinki, Finland [email protected] Some “classical” ferromagnetic shape memory alloys, like Ni-Mn-Ga, Ni-Fe-Ga, Co-Ni-Ga and Co-Ni-Al present martensitic transformations at high temperatures (and above the Curie point). In this study the superelastic behavior of Ni-Mn-Ga [001] oriented single crystals with transformation temperatures close to 200ºC and thermal hysteresis of 10 degrees has been analyzed by performing mechanical cycles under compressive loading at temperatures between 220ºC and 380ºC. Cooling/heating experiments under different external compressive stresses (between 40 MPa and 400 MPa) were also carried out. The results revealed that samples show a large superelastic temperature range, at least until 350ºC, and they demonstrate superelastic behavior up to very high applied critical stresses (about 700-800 MPa), with complete recoverable strains of 3%, being larger at lower critical stresses. The critical stress to induce the transformation depends linearly on the test temperature, with a slope value d/dT≈3MPa/K, which can be described through a Clausius-Clapeyron type equation. Young‟s modulus has been calculated from the curves and values between 20-40 GPa have been obtained in the interval of temperatures studied. Thermal cycles under applied constant compressive stress show that a strain close to 5% under 40 MPa and 3.5% under 350 MPa is developed upon cooling through the martensitic transformation, this strain being completely recovered upon heating back to the parent phase. From stresses higher than 350 MPa some residual strain remains. Similar series of experiments have been performed with a quaternary Ni-Mn-Ga-Cu alloy which shows slightly lower (near 15K) transformation temperatures. The obtained results do not reveal significant differences in the thermomechanical behavior of both alloys. 125 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 4 – P10, P13 MAGNETIC DOMAINS STRUCTURE IN 10M MARTENSITE Ni-Mn-Ga OBSERVED BY MAGNETIC FORCE MICROSCOPY Fekete Ladislav a, Kopeček Jaromír a, Straka Ladislav b, Kratochvílová Irenaa, Heczko Oleg a a Institute of Physics, ASCR, Na Slovance 2, 182 02 Prague, Czech Republic b Aalto University School of Science and Technology, PL 14200, FIN-00076 AALTO, Finland [email protected] Magnetic shape memory (MSM) alloys attract lot of attention due to their outstanding properties manily their ability to exhibit giant (up to 10% ) and simultaneously fast (around 1 kHz ) straining in a moderate magnetic field (< 1 T). The highly mobile twin boundary is necessary condition for the existence of magnetically induced reorientation (MIR) one of the family of MSM effects. The interaction of ferroelastic domains with ferromagnetic domains is important for understanding of the effect. The magnetic force microscopy, as a modification of a clasical AFM allows to visualise morfological and magnetic structure of the shape memory alloys and study the fine structure of the magnetic domains. The structure of 10M martensite with fine twins exhibiting MIR effect is shown in Fig. It shows surface relief of ferroelastic domains (variants) with two different orientation (perpendicular and in plane) of c-axis, which is also magnetic easy axis. The variant with c-axis perpendicular showed fine structure of the ferromagnetic domains with features smaller than 1µm and it apparently affects the structure in variant with c-axis in plane. Despite of the clear magnetic domain structure no magnetic domain structure could be observed using Kerr microscope (Fig. c). This negative result was confirmed in a detail study using all types of polarization, i.e. longitudial, transverse and polar. Unfortunately neither Kerr microscopy nor MFM cannot visualize the magnetic domains in cubic austenite, which could shed light on the interpretation of the magneto-elastic properties of Ni-Mn-Ga austenite.1 Additionally we will analyse the magnetic domain structure on single highly mobile twin boundary.2 Figure 1. Structure of the fine martenzitic twins with c surface relief (a) and ) corresponding structure of the magnetic domains (b) in Ni-Mn-Ga 10M martensite. ) In Kerr optical microscope picture (c) no domain ) structure is visible. [1] H. Seiner, O. Heczko, P. Sedlák, L. Bodnarová, J. Kopeček, J. Drahokoupil, M. Landa, Journal of Alloys and Compounds (2012) [2] L. Straka, O. Heczko, H. Seiner, N. Lanská, J. Drahokoupil, A. Soroka, S. Fahler, H. Hanninen, A. Sozinov, Acta Mater. 59 (2011) 7450. MAGNETOCALORIC EFFECT, MAGNETIC AND MECANICAL PROPERTIES OF COLD ROLLED Gd RIBBONS a, a a b c Taskaev Sergey , Buchelnikov Vasiliy , Bychkov Igor , Pelennen Anatoliy , Pastushenkov Uriy , Koshkidko c d d e f Uriy , Koledov Victor , Shavrov Vladimir , Skokov Konstantin , Khovailo Vladimir a Chelyabinsk State University, Chelyabinsk, Russia b South-Ural State University, Chelyabinsk, Russia c Tver State University, Tver, Russia d Institute of Radio Engineering and Electronics RAS, Moscow, Russia e IFW, Dresden, Germany f Moscow Institute of Steel and Alloys, Moscow, Russia [email protected] With the discovery of the “giant magnetocaloric effect“ (Pecharsky and Gschneidner, 1997) the development of magnetic refrigeration gained increased momentum [1]. One of the ways of engineering MCE materials is tightly connected with preparing very thin (a few microns) ribbons of high value MCE alloys with good mechanical properties. At present rapid solidification is the main technique for producing this kind of materials [2]. In our work we investigate magnetocaloric effect, magnetic and mechanical properties of Gd cold rolled samples of different thickness. Morphology of the surface was investigated by AFM methods. Magnetocaloric effect was measured by direct method on AMT&C setup. Mechanical properties was investigated on Netzsch DMA 242C. Magnetic properties was measured on SQUID magnetometer. X-ray analysis was performed on Brucker D8 Advance difractometer. It is shown, that cold rolling technique is the alternative way for producing thin ribbons of MCE materials with good mechanical properties. 1.Gschneidner K.A. Jr. et al. Int. J. Refrig, 31, 945 (2008). 2.P. M. Shan et al. Magnetic behavior of melt-spun gadolinium, Phys. Rev. B. 77, 184415 (2008). 126 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 4 – P11, P15 MICROSTRUCTURE STUDIES OF NiCoMnIn MAGNETIC SHAPE MEMORY RIBBONS Prusik Krystian, Bałdys Katarzyna, Stróż Danuta, Goryczka Tomasz, Lelątko Józef Institute of Materials Science, University of Silesia Katowice, Poland [email protected], Since Kainuma et al. [1] reported a magnetic field induced strain (MFIS) in Ni-Mn-Co-In alloys have received much attention as promising materials for magnetic actuators. Recently some researches were focused on ribbons [2] obtained by melt spinning techniques. In present paper two ribbons of the Ni44Co6Mn36In14 (at.%) were prepared under different conditions by melt- spinning technique. Microstructure of the ribbons was studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Depending on the liquid ejection overpressure two types of ribbons microstructure were observed. Ribbon T1 for which ejection overpressure was 0.2 bar showed typical melt-spinning ribbon‟s microstructure consisting of a top layer of small equi-axed grains and columnar grains below (Fig. 1a). For T2 ribbon (ejection overpressure 1.5 bar) only a small fraction of a columnar grains were observed (Fig. 1b). (a) (b) Fig. 1. SEM micrographs of the fracture of the as received Ni44Co6Mn36In14 ribbons (a) T1, (b) T2. Structure analysis of the ribbons performed by XRD and TEM showed that at room temperature both ribbons have L21/B2 parent phase superstructure. No phase precipitates were observed. In order to determine the orientation of the grains the EBSD technique was applied. [1] R. Kainuma, Y. Imano, W. Ito, Y. Sutou, H. Morito, S. Okamoto, O. Kitakami, K. Oikawa, A. Fujita, T. Kanomata, and K. Ishida: Nature, vol. 439, (2006), p. 957. [2] J. Liu, T.G. Woodcock, N. Scheerbaum, O. Gutfleisch: Acta Materialia, 57, (2009), p. 4911. EFFECT OF Ti ADDITION ON THE MARTENSITIC TRANSFORMATION AND MAGNETIC PROPERTIES OF Ni-Mn-In AND Ni-Mn-Sn METAMAGNETIC SHAPE MEMORY ALLOYS Recarte V, Sánchez-Alarcos V, Pérez-Landazábal JI, Pastor JM, Rubio E, Urdiaín A Departamento de Física – Universidad Pública de Navarra, Campus de Arrosadía 31006 Pamplona, Spain [email protected] The martensitic transformation, microstructure, magnetic and mechanical properties of Ti-doped Ni-Mn-In and Ni-Mn-Sn alloys have been investigated. In particular, a complete characterization of the effect partial substitution of In and Sn by Ti has been performed in a series of Ni50Mn37In13-xTix and Ni50Mn37Sn13-xTix (X = 0, 0.5, 1 and 2) polycrystalline alloys, respectively. The martensitic transformation temperature slightly increases with the increasing Ti concentration as a consequence of the increase of the electron per atom ratio in the Ni-Mn-In case and associated to volume effects in the isoelectronic substitution of Sn by Ti. On the other hand, the Curie temperature and the saturation magnetization monotonously decrease with the increasing Ti concentration in both systems. Interestingly, the grain size is extraordinarily reduced as a result of the Ti doping in both cases. A correlation between the mechanical response and microstructure, grain size and presence of Ti-rich second phases, has been determined by mechanical tests. 127 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 4 – P14, P16 MAGNETIC AND TRANPOSRT PROPERTIES OF Cu-Co MICROWIRES Zhukova Valentinaa, Ilyn Maxima, del Val Juan Josea, Ipatov Mihaila, Granovski Alexandera,b, Zhukov Arcadya,c aDpto. de Física de Materiales, Fac. Químicas, UPV/EHU, 20018, San Sebastián, Spain bMoscow State University, Moscow, 119991, Russian Federation cIKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain [email protected] Different families of granular materials exhibiting giant magnetoresistance (GMR) effect attracted considerable attention since their introduction in 1992 [1]. The relationship between microstructure of granular materials and their magnetotransport properties is still not fully understood. For obtaining of the granular structures, melt spinning technique is quite suitable. During last years considerable attention has been paid to the studies of glass-coated microwires produced by Taylor- Ulitovski technique allowing to achieve high quenching rate [2,3]. We present recent results on magnetic and transport properties of Cox-Cu100-x (5≤x40 at %) microwires with different ratios of the metallic nucleus diameter, d, to the total diameter, D, i.e. with different ratios d/D. This allowed us to control residual stresses, since the strength of internal stresses is mostly determined by the value In most of fabricated Co-Cu glass coated microwires with x=10-30% we observed considerable magnetoresistance (MR), R/R. Cooling resulted in increasing of R/R. In addition, MR is negative, tending to saturate in high magnetic fields, indicating that GMR is the major contribution to total MR of the studied microwires. Behaviour of the samples with low (x≤10%) and higher (x>20) are quite different. Co5Cu95 microwires exhibit a minimum in the temperature dependence of resistance at about 40K, which should be attributed to Kondo- type behaviour. Temperature dependence of the AC-susceptibility, χ, exhibit quite different behaviour too: for x >20 there is a maximum on χ (T). The temperature of such maximum depends on both Co content and ρ-ratio. Recently has been confirmed that the structure of Co-Cu ribbons and microwires is not exactly granular (as many works assume) but of a spinodal decomposed material [4]. The structure of studied samples consists of two phases: the main one, fcc Cu (lattice parameter 3.61 Ǻ), found in all samples and fcc α-Co (lattice parameter 3.54 Ǻ) which presents in microwires with higher Co content. In the case of low Co content the Co atoms are distributed within the Cu crystals. The quantity and the crystallite size of the formed phases strongly depend on the geometry of the microwire. Concluding, structure, magnetic and transport properties are affected by the glass coating inducing strong internal stresses, affecting the quenching rate. [1] A.E. Berkowitz et.al., Phys.Rev.Lett, 68 (1992) 3745 [2] V. Zhukova, M. Ipatov and A Zhukov, Sensors 9(2009) рр. 9216 [3] A. Zhukov, J. Gonzalez and V. Zhukova, J. Magn. and Magn., Mater. 294 (2005) 165 [4] M.N. Baibich , et.al. J. Magn. Magn. Mater. 320 (2008) e29 ADIABATIC TEMPERATURE CHANGE IN NI(CO)-MN-AL HEUSLER ALLOYS Khovaylo Vladimira, Skokov Konstantinb,c, Gutfleisch Oliverc, Xu Xiaod, Omori Toshihirod, Kainuma Ryosuked aNational University of Science and Technology "MISiS", Moscow 119049, Russia bFaculty of Physics, Tver State University, Tver 170000, Russia cLeibniz Institute for Solid State and Materials Research Dresden (IFW Dresden), Institute for Metallic Materials, P.O. Box 270016, D-01171 Dresden, Germany dDepartment of Materials Science, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan [email protected] Heusler-based Ni-Mn-X (X = Al, Ga, In, Sn, Sb) ferromagnetic shape memory alloys have attracted considerable interest over a decade. Observation of giant magnetic-field-induced strains and giant magnetocaloric effect in these materials has stimulated an active search for new systems undergoing thermoelastic martensitic transformation in magnetically ordered state. Recently, it has been demonstrated that in Ni-Mn-Al system a partial substitution of Ni by Co results in a marked modification of magnetic properties of the parent alloys [1]. Results of magnetic and structural characterization of several compositions of Ni(Co)-Mn-Al [1] have shown that the parent austenitic phase is strongly magnetic which is in a sharp contrast to the Ni-Mn-Al alloys. On cooling, Ni(Co)-Mn-Al undergoes a structural transformation to a product martensitic phase with zero net magnetization. It is interesting to note that kinetic arrest of the martensitic transformation can be realized in some these alloys [2]. This behavior is similar to Ni-Mn-In alloys which exhibit attractive magnetocaloric properties. In order to compare these alloys, we have studied magnetocaloric properties of selected Ni(Co)-Mn-Al alloys by a direct method and compared these properties with those observed in other representative of ferromagnetic shape memory alloys. [1] R. Kainuma, W. Ito, R. Y. Umetsu, K. Oikawa, and K. Ishida, Appl. Phys. Lett. 93, 091906 (2008) [2] X. Xu, et al., Mater. Trans. 51, 1357 (2010) 128 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 4 – P22, P23 SHAPE MEMORY EFFECT IN MICROSIZED SAMPLES OF FERROMAGNETIC HEUSLER ALLOYS K. Akatyevaa, V.Afoninaa, A.Irzhakb,V. Khovailob, V. Koledov a, V.Shavroa , S. von Gratowski a, F. Albertinic, S. Fabbricic a Kotelnikov Institute of Radioengineering and Electronics of RAS, Moscow, 125009 Russia b Moscow Institute of Steel and Alloys, Moscow, 119049, Russia c Istituto dei Materiali per l'Electronica ed il Magnetismo IMEM-CNR, Parma, 43010, Italy [email protected] Since the discovery of giant magnetic-field-induced strains in Ni-Mn-Ga ferromagnetic alloy with the shape memory effect (SME) much of works have been done with purpose to apply this phenomenon to micromechanics. Unfortunately, the SME is intrinsically irreversible. Usually, external force biasing or special procedure of „training‟ of the alloy for „two-way‟ SME should be applied. This is not convenient for microsized samples of the alloy. Recently, the new two-layer composite scheme is proposed, which allow obtaining of the reversible deformation using only one-way SME [1]. In the present work we describe the preparation and study of microsized composites with SME on the base of 50 m thick Ni-Mn-Ga Heusler alloy melt spun ribbons. a b Figure 1. Pure SME in melt spun ribbon of Ni-Mn-Ga alloy. Sample is in martensite (a) and in austenite (b). The microsized samples preparation and experiments on thermally actuated SME are achieved in vacuum chamber of FEI Strata 201 FIB device. The sample size is approximately 10x3x1 m3. The thicknesses of the layer with SME of the composite are down to 0.5 m and less. The experiments on thermal actuation and prospects of magnetic field control of the new type of actuators are discussed. [1]. A. V. Irzhak, V. S. Kalashnikov, V. V. Koledov, et al. Technical Physics Letters. V. 36, p. 329–332 (2010). MAGNETIC PROPERTIES AND MAGNETOCALORIC EFFECT IN Ni2.27-xFeXMn0.73Ga (X=0.03, 0.06, 0.09) HEUSLER ALLOY Fayzullin Rafael, Buchelnikov Vasiliy, Taskaev Sergey, Drobosyuk Mikhail Chelyabinsk State University, Chelyabinsk, 454001, Russia [email protected] The magnetocaloric effect (MCE) is the ability of magnetic materials to heat up or cool down when placed in or removed from an external magnetic field. It has great importance in the technology of magnetic refrigeration. The magnetic materials with large values of MCE can be applied in the magnetic refrigeration technique [1]. Recent experimental studies have shown that Ni-Mn-Ga Heusler alloys are also attractive for the application in magnetic refrigeration [2]. In this work we study experimentally MCE in Ni2.27-xFexMn0.73Ga (x=0.03, 0.06, 0.09) Heusler alloys. Polycrystalline ingots with nominal compositions were prepared by an arc-melting method. Since the weight loss during the arc-melting was small (0.2%) it was assumed that the real compositions correspond to the nominal ones. The ingots were annealed at 1100 K for 9 days quenched in ice water. Samples for MCE measurements were cut from the middle part of the ingots. The MCE measurements were performed by the setup produced by AMT&C (Russia). In this setup, the adiabatic temperature change Tad was measured by a direct method with help of a thermocouple. Magnetic field up to 2 T was created by Halbach permanent magnet. The magnetic field strength was measured by Hall probe. Signals from the thermocouple and Hall probe were recorded simultaneously what allowed us to measure Tad as a function of magnetic field H. The phase transition temperatures were determined from temperature dependencies of low field magnetization measured by original setup using Hall effect. The temperature dependencies of Tad for Ni2.27-xFexMn0.73Ga (x=0.03, 0.06, 0.09) Heusler alloys for the magnetic field change H = 2 T were measured. It is shown that maximal MCE takes place near the structural and magnetic phase transition and its value changes from 0.5 to 2 K. So, we can conclude that investigated alloys are perspective for magnetic refrigeration. [1] K. Gschneidner, Jr. and V.K. Pecharsky, Int. J. Refrig., 31 (2008) 945. [2] A. Planes, L. Manosa, and M. Acet, J. Phys.: Condens. Matter. 21 (2009) 233201. 129 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 4 – P31, Session 5 - P6 ORIENTATION DEPENDENCE OF STRESS-INDUCED MARTENSITIC TRANSFIRMATION IN NiFeGa FERROMAGNETIC SINGLE CRYSTALS Timofeeva Ekaterinaa, Panchenko Elenaa, Chumlyakov Yuria, Maier Hansb, Vetoshkina Nataliaa a Tomsk State University, Tomsk, Russia bUniversity of Paderborn, Paderborn, Germany [email protected] In the present study the orientation dependence of stress-induced martensitic transformations (MT), shape memory effect (SME) and superelasticity (SE) in N54Fe19Ga27 (at.%) single crystals oriented along [001], [011], [012] directions in compression has been investigated. These single crystals undergo stress-induced MT from the high-temperature L21 phase to the tetragonal L10-martensite via 14М layered modulated structure. It is shown, that in NiFeGa single crystals the sequence of the stress-induced MT, yield stress of martensite, temperature interval of SE and stress hysteresis are determined by crystal axis orientation. In [011]-oriented crystals two stages on the stress-strain response associated with stress-induced MT are found out. That is why in this crystals SME and SE are established in one temperature interval 200 К AB INITIO STUDY OF MAGNETIC PROPERTIES AND PHASE DIAGRAM OF NI-MN-GA HEUSLER ALLOYS M. Zagrebin, V. Sokolovskiy, V. Buchelnikov Chelyabinsk State University, Chelyabinsk, Russia [email protected]. Heusler Ni-Mn-Ga alloys are interesting for practical applications because of the numerous unusual effects such as a shape memory effect in ferromagnetic state, a giant magnetocaloric effect and etc. The strong magnetoelastic interaction between the magnetic and structural subsystems is one of the reason of these effects [1]. Experimental data shows that magnetic properties (such as exchange coupling parameters, magnetic moment, Curie temperature etc.) of these alloys depend on stoichiometry [2,3]. In our study we investigate magnetic properties with the help of ab initio calculations. Calculations are carried out using the spin-polarized relativistic Korringa-Kohn- Rostoker (SPR-KKR) code [4]. The calculation of exchange integrals in Ni-Mn-Ga alloys has shown that for disordered systems an interaction between the Mn atoms has large antiferromagnetic behaviour then for ordered one. Ab initio exchange integrals are used for calculation of Curie temperatures with the help of mean-field approximation [5]. Calculated Curie temperatures by mean field approximation in non-stoichimetric Ni-Mn-Ga alloys are in a good agreement with experimental data [2] and with existed theoretical results [6, 7]. Numerical results of the magnetic moment for Ni-Mn-Ga alloys show that in disorder case magnetic moment of Mn atoms, which plased on Ni sites is negative than magnetic momet of Mn atoms in regular sites. Theoretical composition dependencу of the total magnetic moment is a good agreement with observed experimental data [2,3]. [1] P. Entel, M.E. Gruner, A. Dannenberg et al, Materials Science Forum 635, 3 (2010). [2] V.V. Khovaylo, V.D. Buchelnikov, R. Kaimuma el al, Phys. Rev. B 72, 224408 (2005). [3] P. Lázpita, J.M. Barandiarán, J. Gutiérrez1et al, New J. of Phys., 13, 033039 (2011). [4] H. Ebert, D. Ködderitzsch and J. Minár, Reports on Progress in Physics, 74, 096501 (2011). [5] E. Sasıoglu, L.M. Sandratskii, and P. Bruno, Phys. Rev. B 70, 024427 (2004). [6] V.D. Buchelnikov, V.V. Sokolovskiy, H.C. Herper et al., Phys. Rev. B 81, 094411 (2010). [7] Chun-Mei Li, Hu-Bin Luo, Qing-Miao Hu et al., Phys. Rev. B 82, 024201 (2010). 130 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 4 – P32, S8-P4 P4 THE MARTENSITIC TRANSFORMATION AND ANTIFERROMAGNETIC TRANSITION IN MN86.4FE9.1CU4.5 ALLOY Y.G. Cui, J.F. Wan, Y.H. Rong, J.H. Zhang School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China [email protected] There is martensitic transformation and antiferromagnetic transition in MnCu, MnNi and MnFe alloys, the first order martensitic transformation and the second order antiferromagnetic transition show the coupling phenomena each other, which results in some special functions, for example, high damping, non-hysteresis two way shape memory effect and magnetic shape memory etc. Generally, martensitic transformation and antiferromagnetic transition have similar crystal lattice distortion of fcc-fct structure, the distortion degree of martensitic transformation is the order of 10-2, but that of antiferromagnetic trtansition is only is 10-5. With the change of alloy composition, martensitic transformation of some Mn-rich alloys shows the characteristics of second order transition, the relation between the kind of martensites transformation and their antiferromagnetic transition may be investigated. With the help of X-Ray low-frequency internal friction and TEM observation, the martensitic transformation and the antiferromagnetic transition in Mn86.4Fe9.1Cu4.5 alloy are investigated. The results show that o the Ms~TN=180 Cantiferromagnetic transition near TN temperature leads to a tweed morphology, with the decrease of temperature martensitic transformation forms (110) twin structure, though there is similar fct lattice distortion in antiferromagnetic transition, but martensitic transformation seem self-governed nucleation on base of antiferromagnetic tweed. The results in-Situ TEM observation with the increase and decease of temperature between room temperature and 277oC are shown in following: With the decrease of temperature from TN to room temperature ~227 oC (a) ~177 oC (b) ~120 oC (c) ~77K oC (d) ~13 oC (e) With the increase of temperature from room temperature to TN ~13 oC (a) ~77K oC (b) ~120 oC (c) ~177 oC (d) ~227 oC (e) APPLICATION OF COIL ORIENTATION CHANGE FOR SMA K. K. Jeea and W. Y. Jangb aDivision of Materials Science and Engineering, Korea Institute of Science and Technology, Seoul136-791, Korea bDivision of Metallurgical and Materials Engineering, Chosun University, Gwangju 501-759, Korea e-mail: [email protected] The present authors have invented a new method of changing coil orientation of a coil spring. The major merit of coil orientation change are saving of space and control of two way shape memory effect. For instance, when a coil is heated above Af temperature with a load, the coil contracts. There is unrecovered strain which is attributed to elastic deformation by the load. The elastic strain can be eliminated by changing coil orientation. If a coil spring works with a load between a displacement of 15mm at a low temperature and 5mm at a high temperature, space to accommodate the displacement of 15mm is needed. By removing elastic strain, the spring can be made to work with the same load between a displacement of 10mm at a low temperature and 0mm at a high temperature, reducing the necessary space. Besides generation and control of two way shape memory effect is presented using the reverse of coil orientation. 131 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 9 – P2, P5 FINITE ELEMENT CALCULATION OF B2 TO R TRANSFORMATION OF SHAPE MEMORY ALLOY aSung-Young Young and bTae-Hyun Nam aKorea University of Technology and Education, Chonan, Korea bGyongsang National University, Jinju, Korea [email protected] This paper presents a three-dimensional calculation model for martensitic transformation and the numerical results were compared with experimental load-biased thermal cycling data of B2 to R phase transformation of shape memory alloy. Our new model accounts for the self-accommodation part of the variants separately in addition to the conventional individual variants. Thermodynamic driving force of the martensitic transformation was provided for each variant, and kinetics parameters were applied differentially to the self-accommodation and the isolated variants. By this approach, interplay between thermodynamics and kinetics of self-accommodation could be successfully captured, and the model predicted experimental results more accurately. 0.1 = 400 MPa = 300 MPa 0.08 = 200 MPa n = 100 MPa i 0.06 = 50 MPa a r = 10 MPa t 0.04 S 0.02 0 100 200 300 400 Temperature (K) INFLUENCE OF STRUCTURAL DISORDER ON THE CURIE TEMPERATURE IN NI2MN1+XSN1-X Sokolovskiy V., Buchelnikov V., Zagrebin M. Chelyabinsk State University, Chelyabinsk, Russia [email protected] The huge interest in the Heusler alloys Ni-Mn-Z (Z = Ga, In, Sn, Sb), certainly due to the presence of the unique physical and technical properties such as shape memory effect, the giant magnetocaloric effect, large magnetoresistance, and exchange bias [1]. In this work, carried out theoretical studies of the influence of the degree of structural disorder in the austenitic phase of Ni2Mn1+xSn1-x (x = 0 - 0.4) on the magnetic properties, particularly at the Curie temperature. Studies were carried out with the help of ab initio calculations and Monte Carlo method. We have considered two types of structural disorder: a) a certain percentage of the excess Mn atoms placed in positions of the Ni atoms, whereas the Ni atoms which displaced are occupied in positions of the Mn atoms; b) a certain percentage of the excess Mn atoms placed in positions of the Sn atoms, while the Sn atoms which displaced are occupied in positions of the Mn atoms. To calculate the electronic structure and exchange interactions in alloys Ni2Mn1+xSn1-x, we have used the spin polarized relativistic code-Korringa-Kohn-Rostoker (SPR-KKR) [2]. Heisenberg exchange constants were calculated using the theory of Liechtenstein et al [3]. Simulation of the temperature dependence of magnetization curves and Curie temperature determination was performed using the Monte Carlo method and Heisenberg model on a realistic crystal lattice of Heusler alloys. Calculations showed that the inclusion of the second type of disorder can obtain the values of the Curie temperature, are close to the experimental values [4]. [1] Planes A., Manosa L., Acet M., J. Phys.: Condens. Matter, 21, 233201 (2009). [2] Ebert H., Ködderitzsch D., Minár J., Reports on Progress in Physics, 74, 096501 (2011). [3] Liechtenstein I., Katsnelson M.I., Antropov V.P., Gubanov V.A., J. Magn. Magn. Mater., 67, 65 (1987). [4] Kanomata T. et al., Mater. Science Forum, 583, 119 (2008). 132 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 9 – P6, P7 A MATERIAL MODEL FOR TRIP-STEELS UNDER THERMOMECHANICAL LOADING Prüger Stefan, Kuna Meinhard TU Bergakademie Freiberg,Institute of Mechanics and Fluid Dynamics,Freiberg, Germany [email protected] A macroscopic, phenomenological material model for initially fully austenitic TRIP-steels is presented. It accounts for the differences in yielding and rate dependent behaviour of the two phases, austenite (γ) and martensite (α‟), where the latter develops during inelastic deformation. The macroscopic viscoplastic properties of the TRIP- steel are determined by an homogenisation approach employing the constitutive behaviour of the single phases and the current phase compositon, given in terms of phase volume fractions. The strain-induced phase transformation (γ → α‟) is described as a function of the temperature, the equivalent inelastic strain of the parent phase (austenite) and the stress state. The latter is incorporated in order to account for the tension-compression asymmetry of the phase transformation. Experimental results show that the kinetics of the strain-induced phase transformation in TRIP-steels is rather sensitive to temperatures changes. Such changes must be taken into account, when the steel is subjected to moderate or high strain rate loading conditions. Therefore, the material model is reformulated in a thermomechanical framework. The temperature evolution during viscoplastic deformation and phase transformation is incorporated in the model through a thermomechanical coupling. The model is capable to describe both the thermal softening of the phases and the reduced martensite evolution associated with the temperature increase, observed in moderate and high strain rate applications. Model predictions are compared to experimental results. FEM SIMULATION OF TRANSIENT HEAT TRANSFER IN SMA PLATES EXHIBITING SINGLE-STEP AND TWO-STEP MARTENSITIC TRANSFORMATIONS. S. Jaegera, O. Kastnerb, G. Eggelera aRuhr-University Bochum, Bochum, Germany bGeoForschungsZentrum, Potsdam, Germany [email protected] Phase transformations in shape memory alloys (SMA) are accompanied by ab- and desorption processes of latent heat. Therefore, both load- and temperature induced transformations are inevitably accompanied by transient heat transfer problems. Due to the thermo-mechanical coupling presented in these materials, the resulting temperature fields affect the mechanical properties of a sample. But yet in mechanically unloaded samples heat transfer problems in the transformation regime bears interesting complexity. In our contribution we present a detailed experimental and theoretical investigation of this: We study transient temperature field evolutions in rectangular NiTi plates (dimensions 70 x 70 x 0.5 mm) which are thermally stimulated by a central laser spot. These experiments are used as benchmarks for transient FEM modeling on the basis of the Müller-Achenbach-Seelecke (MAS) model which provides a free energy-based description of the underlaying phase transformations [1, 2]. Rate equations are employed to model temperature induced transformations between austenite and generic variants of martensite. This model has been implemented into the finite-element environment ABAQUS™ in order to simulate phase transformation processes in complexer geometries [3, 4]. The model parameters are adjusted according to DSC characterisations prior to the thermographic tests. We show that our simulation results are capable to reproduce the experimental data with good accuracy. However, drawback of the present formulation of the MAS model is its limitation to single-step austenite-martensite transformations, hence neglecting multistep transformations. To overcome this limitaion we present an extension of the MAS model to incorporate austenite - R-phase – martensite transformations. The test material used for model evaluation is NiTiFe, which shows a particularly clear multi-step transformation. In the MAS model the R phase is characterised by additional free energy branches representing two generic R phases as a function of the order parameter strain and the temperature. Such free energy function is paramterized based on experimental data. We present first FEM simulations of temperature-induced two-step phase transformations showing the model properties of the thus extended MAS model in comparison with the single-step model. [1] M. Achenbach: Int. J. Plasticity 5 (1989), 371–395. [2] I. Müller and S. Seelecke: Math. Comput. Model. 34 (2001), 1307–1355. [3] F. Richter, O. Kastner and G. Eggeler: J. Mater. Eng. Perf. 18 (2009), 626–630. [4] F. Richter, O. Kastner and G. Eggeler:, in ESOMAT (2009). 133 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 9 – P8, Session 10 – P3 IMPLEMENTATION OF THE GENERAL 3D FORMULATION OF LIKHATCHEV’S MODEL INTO A FINITE ELEMENT PROGRAM Patrick Terriault and Vladimir Brailovski École de technologie supérieure, Montréal, Canada [email protected] Design of new devices benefiting from the remarkable properties of shape memory alloys is quite complex due to their strongly nonlinear, temperature-dependent and hysteretic behavior. Fortunately, several constitutive relations have been developed and experimentally validated in the past and one of them is the Likhatchev model also called structural-analytical model. This model is chosen in this work because it has many advantages, namely its easiness of characterization, its numerical efficiency and its generality in the sense that it can simulate all the shape memory related features using the same formulation (superelasticity, shape memory effect, stress generation, etc.). Also, it is built of a tensorial formulation, meaning that the model could be used to predict the response of the material subjected to 1D, 2D and even 3D loadings. Unfortunately, the model has a drawback because it is a stress-controlled formulation, meaning that the controlled parameters are temperature and stress tensor. Since the finite elements method applied to solid mechanics uses a displacement-based algorithm (the degrees of freedom of the problem are the model‟s displacements, from which strains and stresses are calculated), it becomes mandatory to have instead a formulation with strain tensor and temperature as the control parameters. This article presents a strain-controlled formulation of the Likhachev model which can be applied to 3D problems. Afterwards, a finite element implementation with ANSYS, a commercially available finite element software, is discussed. Finally, a case study concerning the finite element simulation of the compression of a porous shape memory material is presented. ABOUT THE MECHANISM OF DEFORMATION AT MARTENSITIC TRANSFORMATION IN THE Fe-31%Ni ALLOY Gundyrev Vyacheslav and Zel'dovich Vitaly Institute of Metal Physics of Ural Division of RAS , Ekaterinburg, Russia [email protected] According to the theory of Wechsler-Lieberman-Read (WLR) the shape deformation Р1 at the martensitic transformation receives from product of three matrixes: Bain deformation В, lattice invariant deformation Р and rotation R [1]: Р1 = RРВ. Bain deformation is required to obtain a new crystal lattice. Deformation Р and rotation R of martensite plate are necessary to create habit plane. In Fe-31wt%Ni alloy, lattice invariant deformation is fulfilled by the twinning of martensite. In this case the angle of rotation R is 9.75 degrees. However it is difficult to present the rotation of a martensite plate in a rigid matrix on such big angle. Therefore, this description of deformation at the martensitic transformation seems to us far from reality. To get the crystal lattice of martensite we use shear Г in austenite on (111) plane in [11-2] direction on 0.3536, proposed by Kurdyumov [2]. Then we make the lattice deformation В1 by elongation along [1-10] axis on 13.2% and compression along [11-2] and [111] axes on 7.6% and 2% accordingly. To create the habit plane we make deformation Р and rotation R1, as in theory WLR. In this case the angle of rotation is 1.75 degrees. Such small rotation can be at process of deformation В1. We write down the shape deformation Р1 as: Р1 = R1РВ1Г. Our calculation performed by the phenomenological theory of martensitic transformations gives the same crystallographic parameters of the martensitic transformation, as the method of WLR (orientation relationships – the intermediate between relationships of Nishiyama and Kurdyumov-Sachs; habit plane – {3 10 13}, twins fraction – 38%). The calculation results are in good agreement with experimental data [1]. Our description of the deformation mechanism at the formation of twinned martensite in Fe-31wt%Ni alloy is quite realistic. Thus, the main component of lattice deformation at the martensitic transformation is <11-2> shear on {111} plane. [1]Wayman C.M. Introduction to the Crystallography of Martensitic Transformations. New York – London. 1964. 193 p. [2] Kurdyumov G., Sachs G. Z. Phys. 1930. No.64. P.325 134 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 10 – P6, P8 EVOLUTION OF THE RESIDUAL STRESS FIELD AT THE REALIZATION OF THE SHAPE MEMORY EFFECT Vyunenko Yuriy N. Saint-Petersburg State University, Saint-Petersburg, Russia [email protected] The evolution of the residual stress field during shape recovery in heating across the temperature interval of the reverse martensitic transformation is studied on the example of a bent plate. The numerical simulation illustrates the use of the residual stress mechanism of the shape memory effect [1]. The material constants are adjusted to the physical characteristics of the equiatomic TiNi alloy. The physical properties of the material are assumed to be the same in the regions of tension and compression. It is supposed that the preliminary unelastic deformation in the low- temperature state occurs under the ideal plastic flow law in the conditions of pure bending. The strain recovery is realized by heating from the surface with a constant rate of the surface temperature. The calculated stress distribution allows to explain the two-way shape memory effect. [1] Vyunenko Y.N. Materialovedenie, N 12 (2003), P.2-6. (in Russian) CRYSTALLOGRAPHIC ANALYSIS OF MARTENSITIC TRANSFORMATION BY EBSD IN Fe-31.9Ni-0.02C ALLOY Calciolari Renata, Ribeiro Shimeni, dos Santos Paula Andersan, da Costa Viana Carlos Sérgio, Rangel Rios Paulo Universidade Federal Fluminense, Volta Redonda, Brazil [email protected] The martensitic transformations are diffusionless transformation with characteristic that not is time-dependent to start or continue it. However, issues such as transformation temperature, crystallography and the resulting product morphology of the martensitic transformation are influenced by external factors such as temperature and stress state before and during processing for a particular chemical composition. During the austenite to martensite phase transformation varying numbers of product martensite grains with different crystallographic orientations can be obtained from one single austenite parent grain. This present work investigates the Fe-Ni alloys with high Ni content and low carbon (Fe-31, 9% Ni-0, 02% C) with different martensite fractions transformed in order to map and identify orientation relations between austenite and martensite phases measured by Electron Backscattering Diffraction (EBSD) technique and compare with theoretically crystallographic orientation relations proposed by Kurdjumov-Sachs (K-S) and Nishiyama- Wasserman (N-W). An EBSD detector installed in a Scanning Electron Microscope (SEM) with LaB6 filament was used to identify the crystallographic orientations in austenite (face center cubic – fcc) and martensite (body center cubic) previously characterized by X-ray diffration on Fe-Ni alloy in study, associated with the morphological and mechanical microstructural characterization by SEM images and microhardness maps. The EBSD files (type “.ang”) register for each diffraction point a position (coordinates x and y) with related with Euler angles, IQ (index quality), IC (index confidence) and the respective crystallographic phase. A FORTRAN program was specially developed to calculate the rotation axial-angle pair from austenite and martensite (close to phase boundaries and twin boundaries in martensite identified by EBSD), and three product variants within the confined space of Euler, suggesting a selection rule of variants. 135 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 2 – P2, P5 EFFECT OF MARTENSITIC TRANSFORMATION ON THE OPTICAL SPECTRA OF Cu-Mn-Al ALLOY Kudryavtsev Y.V.b, Kokorin V.V.a, Kozlova L.E.a, Iermolenko V.N.,b and Konoplyuk S.M.a aInstitute of Magnetism NAS of Ukraine, Vernadsky str, 36-b, 03142 Kiev, Ukraine, bInstitute of Metal Physics, Vernadsky str 36,03142, Kiev, Ukraine [email protected] The effect of martensitic transformation on the transport and optical properties of Cu-4.9Mn-23.4Al (at.%) alloy is reported. The resistivity measurements revealed the transformation temperatures Ms =284K and Af=303K. The optical properties of Cu-4.9Mn-23.4Al (at.%) alloy have been investigated at several temperatures near the region of austenite-martensite transformation. It was shown that intraband absorption is dominates in alloy for ħω 2.5 eV energy range. Plasma p and relaxation frequencies of free charge carriers for Cu-4.9Mn-23.4Al (at.%) alloy were evaluated at several temperatures on the basis of Drude analysis of the alloy optical properties in the intraband absorption region. The growth of electrical resistance induced by martensitic transformation upon alloy cooling obtained directly from the resistivity measurements correlates nicely with the results derived from the optical measurements and can be explained by the reduction of the plasma frequency p as well as increase in relaxation frequency of free charge carriers. OBTENTION AND CHARACTERIZATION OF CU-AL-NI THIN FILMS Gómez-Cortés J. F.a, San Juan J.a, López G.A.b, Nó M. L.b a Dpt. Física de la Materia Condensada, Facultad de Ciencia y Tecnología, Universidad del País Vasco, Apdo. 644, 48080-Bilbao, Spain. b Dpt. Física Aplicada II, Facultad de Ciencia y Tecnología, Universidad del País Vasco, Apdo. 644, 48080-Bilbao, Spain. [email protected] In the last two decades, there has been a growing interest in developing shape memory alloy (SMA) thin films for micro electromechanical systems (MEMS), mainly based in Ni-Ti alloys [1]. However, in recent years it was demonstrated that Cu-Al-Ni SMA exhibit outstanding properties at micro and nano-scale [2,3], opening new promising possibilities for applications in MEMS and attracting the interest on this system. Nevertheless, the thermo-mechanical properties of Cu-Al-Ni SMA show a strong dependence on concentration, making difficult the production of thin-films by the usually employed techniques, in particular by sputtering. In this work we have produced Cu-Al-Ni thin-films by e-beam evaporation, onto <100> silicon wafers, of alternating layers of Ni, Cu and Al with a set of thickness in order to obtain the weight alloy composition after a solid diffusion treatment at 900ºC under inert atmosphere. Cu-Al-Ni multilayer thin films were characterized by Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDX), as well as by electrical resistivity measurements. Images obtained by back-scatter electrons detection in a Jeol JSM 7000F SEM were used to characterize the metallic multilayer obtained under different experimental conditions, as well as to evaluate the effect of the solid diffusion treatment. At the end of the process samples showed the typical microstructure of a martensite phase. Then, the treated thin-film was studied by EDX to analyze the obtained alloy composition of 73.6 Cu-23.1 Al-3.4 Ni at%, which match quite well the target composition for the alloy. Finally the standard four-point electrical resistivity measurement was also used to characterize the martensitic transformation temperatures of the thin-films. [1] S. Miyazaki, Y. Q. Fu and W. M. Huang (Eds.), Thin Film Shape Memory Alloys (Fundamentals and Device Applications), Cambridge University Press (2009). [2] J. San Juan, M. L. Nó and C. A. Schuh, Advance Materials, 20 (2008) 272-278. [3] J. San Juan, M. L. Nó and C. A. Schuh, Nature Nanotechnology, 4 (2009) 415-419. 136 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 2 – P7, P8 SHAPE MEMORY ALLOY CuZnAl SYNTHESIS AND CARACTERIZATION Y. Amioura K. Zemmoura, M. Gueriounea and D. Vrelb. aLaboratoire LEREC, département de physique, Université de Annaba, Algérie blaboratoire LIMHP. Villetaneuse,; Paris 13, France Shape memory alloys (SMAs) are knows to exhibit a range of novel thermomechanical properties due to thermo elastic martensitic transformation. This pseudo elastic effect constitutes one of the interesting effects associated with martensitic transformation in Cu-based alloys. Several experimental works have been performed aiming at elaboration the CuZnAl samples utilising the beneficial properties such as thermomechanical behavior of SMAs. Self-propagating High temperature Synthesis (SHS) is based on the ability of highly exothermic reactions. This process involves the propagating of the reaction interface in the form of a combustion wave which is sustained by the large enthalpy release in the reaction front. The purpose of this work is to investigate the milling and the stoechmetry effects on the phase formation and intrinsic properties of SMAs by S.H.S and Thermal Explosion (TE). Methods. This paper focus on the results of investigating on the mechanisms of SHS and TE reactions in the synthesis of CuZnAl alloy. The nominal composition of the CuZnAl alloy used in this study is Cu(1-x) Zn(1-y) Al(1-z) with x;y;z ranging from 0.29 CHARACTERIZATION OF Cu-Al-Ni SMA WITH A HIGH Ni CONTENT N. Egido-Péreza, J. San Juanb, G. A. Lópeza, M.L. Nóa aDepartamento de Física Aplicada II, Facultad de Ciencia y Tecnología, Universidad del País Vasco, Apdo. 644, 48080 Bilbao, Vizcaya, España. bDepartamento de Física de la Materia Condensada, Facultad de Ciencia y Tecnología, Universidad del País Vasco, Apdo. 644, 48080 Bilbao, Vizcaya, España. [email protected] The most remarkable consequence of the martensitic transformation in Shape Memory Alloys (SMA) is their interesting thermo-mechanical properties, such as superelasticity, pseudoelasticity and the one- or two-way shape memory effects. Among Cu-based SMA Cu-Al-Ni alloys are offering very good thermo-mechanical properties at temperatures between 100K-500K in the range of compositions 13-15% wt. of Al and 3-6% wt. of Ni. On the other hand recent advances and developments for applying this family of shape memory alloys (SMA) in micro devices have stimulated the characterization of the martensitic transformation at nano scale. These SMA remarkable thermo-mechanical properties, depending on the martensitic transformation, are strongly related to the alloy composition [1]. However the high temperature phase must be quenched in a metastable state, avoiding the decomposition into the equilibrium phases, to further obtain the martensitic transformation. This way the high temperature thermal treatment and further quenching become of paramount importance for the control of the precipitates appearance and consequently for the control of the martensitic transformation. Then the aim of this work is to study how the thermal treatment affects the precipitation in Cu-Al-Ni alloys, analyzing the influence of the microstructure on the martensitic transformation. In order to achieve this objective, Cu-Al-Ni samples with a high Ni content have been deeply analyzed as a function of different thermal treatments by post-mortem and in-situ optical microscopy, Scanning Electron Microscopy, and Transmission Electron Microscopy. The in-situ stress-induced experiments are correlated to the macroscopic pseudoelastic tests. [1] Recarte V., Pérez-Saez R.B., Bocanegra E.H., Nó M.L., San Juan J., Metallurgical and Materials Transactions A, 33 (2002) 2581-2591. 137 9th European Symposium on Martensitic Transformations ESOMAT 2012 Poster presentations, Session 2 – P9, P10 ITERNAl FRICTION DURING REVERSE MARTENSITIC TRANSFORMATION IN Mn-Cu ALLOY WITH 45 % Mn Markova G., Klueva E. Tula State University, Tula, Russia [email protected] Mn-Cu alloys have a complex of specific properties: reversible shape memory effect, high damping capacity and others. These properties appear in Mn-Cu alloys (~40...90 % Mn) after solid solution decomposition of fcc (γ)- phase in miscibility gap and the phase transition fcc-fct starting in Mn-rich regions. This transition attributes to the thermoelastic martensite transformations. The mechanical spectroscopy is an informative experimental method of investigating of mechanisms and parameters of phase transformations. This method enables to study the martensitic transformation in situ. The temperature of minimum frequency of resonance oscillations (f2 ~ G and E) on the f2(T) curve and the maximum internal friction (IF) correspond to the phase transformation temperature. The temperature dependences of low- frequency internal friction and frequency of resonance oscillations were studied for Mn45Cu55 alloys in the range of (-130…300 °) C. -1 -4 2 2 Q ·10 f , Hz -1 -4 2 2 Q ·10 f , Hz 175 2,4 2 175 2,4 f Q-1 150 2,2 2,2 -1 -4 2 2 150 Q ·10 f , Hz 25 2,4 125 2,0 125 2,0 20 2,3 100 2,2 1,8 100 1,8 15 P 1 P 2 2,1 1,6 75 10 1,6 75 2,0 -1 5 1,9 Q 50 1,4 50 -150 -100 -50 0 50 100 150 1,4 t, С P P 1,2 25 2 1,2 25 1 2 f 0 1,0 0 1,0 -150 -100 -50 0 50 100 150 200 250 300 -150 -100 -50 0 50 100 150 200 250 300 t, С t, С Fig. 1. Q-1 and f2 vs temperature of Mn45Cu55 Fig. 2. Q-1 and f2 vs temperature of Mn45Cu55 alloy in the initial state. Forced bending alloy, aged at 400 °С for 12 h vibrations γ = 10-5 to 10-4, f ~ 1 Hz Two low-temperature IF peaks (Fig. 1) have been discovered. Their physical mechanisms were supposed. The anomalous behavior of the oscillation frequency accompanies the phase transformation IF peak (P1) at around (- 50 °) C. The temperature of this peak is independent of frequency and relative shear deformation. The peak P2 on the temperature dependence IF is supposed to be the relaxation effect with the activation energy H = 0,14 eV. Fig. 2 shows the frequency and IF spectrum as the function of temperature for the aged at 400 °C specimen. The transformation peak shifts to higher temperatures up to 70 °С. It enables us to come to the conclusion that the aging contributes to thermoelastic martensite transformation in Mn45Cu55 alloy. The work was supported by the Government of Tula region – grant Ds/184 CHARACTERIZATION OF Cu-Zn-Al SHAPE MEMORY ALLOY FABRICATED VIA ELECTRODEPOSITION-ANNEALING ROUTE Almadrones, Emma L.a, Espiritu, Richard DV.b and Amorsolo, Alberto V.b aMaterials Science and Engineering Program and bDepartment of Mining, Metallurgical and Materials Engineering, University of the Philippines Diliman, Quezon City, Philippines [email protected] Cu-Zn-Al Shape Memory Alloy (SMA) fabricated via electrodeposition of brass on aluminum substrate with average bulk composition in at.% of Cu –18.35Zn – 39.58Al was annealed over an increasing temperature range from 300, 350, 400, 420, 450 and 500C with dwell time of 5 hours under flowing nitrogen ambient. Microstructures of the fabricated Cu-Zn-Al SMA set in both intermittent and continuous annealing conditions were investigated under electron microscopy. Microstructure analyses show images that indicate alloying has taken place forming distinct layers but the two annealing routes notably produced images having dissimilar features of its intermetallic layers. Alloying also produced brittle phases due to the presence of microcracks which may indicate that phase transformation likely occured during the quenching step. The XRD patterns yielded peaks consistent with the presence of binary phase of Cu5Zn8 and ternary SMA phases of CuZnAl including martensite variant of M18R. More martensite peaks were observed as annealing temperature is increased. These martensitic phases are attributed to the shape memory behavior observed in the alloyed and quenched strips. 138 9th European Symposium on Martensitic Transformations ESOMAT 2012 Sponsor Information MODERN SOLUTIONS FOR ANALYSIS OF MATERIALS AND THEIR TRANSFORMATIONS Analit Ltd., Saint-Petersburg, Russian Federation www.analit-spb.ru Analit Company was established more than 20 years ago and in 1996 became the general distributor of SHIMADZU – one of the world`s leading manufacturers of analytical and testing equipment. Analit also cooperates with a large number of other manufacturers of a diverse range of equipment and materials, e.g. Carl Zeiss (wide range of microscopy equipment),Retsch (equipment for sample preparation), Leco (equipment for elemental analysis), Labtech (cooling solutions for different kind of equipment), etc. Analit Ltd. has its own accredited analytical laboratory in which we perform a wide range of research works and commercial analyses, develop analytical methods and hold specialty trainings. Our laboratory is equipped with a broad range of equipment: UV/VIS and FTIR-spectrophotometers, AA and ICP-spectrometers, Energy Dispersive and Wavelength Dispersive X-Ray Fluorescence Spectrometers, HPLC, Gas Chromatographs and mass spectrometers, Universal testing machines and Microhardness tester. 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The Gleeble System is produced in a number of different sizes and configurations. These machines typically have a high speed heating system, a servo hydraulic system and a computer control and data acquisition system. www.gleeble.com FCT Systeme GmbH - is the leading producer of hot presses, gas pressure sintering furnaces and vacuum sintering equipments for maximum temperatures. The high standards of FCT equipments, components and services are secured by constant research and development in our technology center and by close cooperation with universities and research institutes. http://fct-systeme.de/en/ Prüftechnik MT GmbH Saint-Petersburg Representative office: tel.: +7 (812) 313 80 38/39, fax: +7 (812) 313 80 44 [email protected], http://www.mt-gmbh.ru 141 9th European Symposium on Martensitic Transformations ESOMAT 2012 Sponsor Information MANUFACTURING OF EQUIPMENTS AND SUPPLIES FOR USE IN METALLOGRAPHY ATM GmbH Russian office, Moscow, Saint-Petersbrug,Russia [email protected] ATM GmbH - the leader in the manufacturing of equipments and supplies for use in metallography. Metallography (Materialography) is fascination in details. Therefore, your smallest wish concerning laboratory equipment is important for us, as manufacturer with direct trading. ATM products "made in Germany" are successfully represented worldwide by in so far 30 countries. Our program sets new standards. Besides our reliable single machines, we have developed a system that puts metallographic laboratories into a completely new dimension. With ATM you are always one step ahead, because we are constantly looking for new ways of improvement. This is why our machines are setting benchmarks with quality and innovating details. But we also score with user friendly and long-lasting high-tech, clear design and modular construction. Therefore, whether cutting, mounting, grinding, polishing or analyzing, ATM meets your demand with custom made machines. All elements are designed to enable environmentally-friendly return of materials. Offices in Russia: Moscow: tel.:+7 (495) 783-88-12/14, fax: +7 (495) 783 88 13 St.Petersburg: tel.: +7 (812) 313 80 38/39, fax: +7 (812) 313 80 44 Ekaterinburg: tel./fax:+7 (343) 379 30 20, +7 (912) 601 95 95 [email protected], http://www.atm-mt.ru 142 9th European Symposium on Martensitic Transformations ESOMAT 2012 Sponsor Information WORLD’S LEADING SUPPLIERS OF MATERIALS AND COMPONENT TESTING SYSTEMS Zwick Roell Group Russian offices, Moscow, Saint-Petersburg, Russia [email protected] The Zwick Roell Group - the world’s leading suppliers of materials and component testing systems Static, servohydraulic and high-frequency materials Testing Machines Hardness testing machines and instruments Pendulum impact testers Temperature chambers from 150°С to +350°С and high temperature furnaces up to +1600°С Test tools for all kinds of tests including special applications testXpert II® - new easy-to-use software which provides a uniform operating platform for all applications and educational purposes Fully qualified service Annual International Forum for Materials Testing testXpo Offices in Russia: Moscow: tel.:+7 (495) 783-88-12/14, fax: +7 (495) 783 88 13 St.Petersburg: tel.: +7 (812) 313 80 38/39, fax: +7 (812) 313 80 44 Ekaterinburg: tel./fax:+7 (343) 379 30 20, +7 (912) 601 95 95 [email protected], http://www.zwick.ru 143 9th European Symposium on Martensitic Transformations ESOMAT 2012 Author Index Surname Name Number of presentation (page) Aaltio Ilkka S1-P1 (96) Abramova M.M. S5-P18 (102) Abreu H.F.G. S10-O1 (79) Acar Emre S12-O25 (54) Adamchuk V.K. S12-P34 (104) Aeby-Gautier Elisabeth S1-P2 (42), S1-O10 (45) Afanasev S.V. S3-P19 (118) Afonina V. S8-P3 (113), S4-P24 (129) Akatyeva K. S4-P24 (129) Albertini F. S4-O10 (71), S4-P24 (129) Aliev A.M. S4-O8 (70), S4-O9 (71) Almadrones Emma L. S2-P10 (138) Amigó V. S2-O2 (82) Amiour Y. S2-P7 (137) Amorsolo Alberto Villar Jr. S12-P58 (109), S2-P10 (138) Ancharov Alexey S1-P6 (96) Andersan dos Santos Paula S1-O4 (42), S12-P48 (107), S10-P8 (135) Andreev Vladimir S12-P61 (95) Andronov I.N. S12-P6 (87) Aneziris C. S1-O2 (41) Anselmo G. C. S. S12-P27 (94) Anshukova Ksenia S12-P55 (108) Antonov Roman S11-P5 (121) Appolaire B. S1-O10 (45), S1-P2 (42) Arbab Chirani R. S6-O1 (57) Arbab Chirani Shabuam S12-O29 (55), S6-O1 (57), S11-O4 (64) Ari-Gur Pnina S1-P1 (96) Arneodo Larochette P. S9-O2 (76), S2-O5 (84) Auguet Carlota S12-O26 (53) Aushev A.A. S12-P21 (93) Bakulin A.V. S12-O3 (34) Bałdys Katarzyna S4-P11 (127) Barkaline Viatcheslav V. S4-P3 (124) Barrio M. S4-O10 (71) Baruj A. S2-O5 (84) Basaran Burak S12-O25 (54) Batdalov A. B. S4-O9 (71) Baturin Anatoly S5-O3 (48) Bechthold C. S12-O11 (37) Beke Dezső S11-P4 (119) Bekhtina M. S8-P3 (113) Belyaev Sergey S12-P19 (92), S5-P12 (100), S5-P16 (101), S12-P29 (103), S12-P38 (105), S12-P40 (106), S12-P55 (108) Benafan O. S12-O20 (51) 144 9th European Symposium on Martensitic Transformations ESOMAT 2012 Benke Márton S3-P9 (117) Berbenni S. S2-O4 (83) Berek H. S1-O2 (41) Bernardi Heide S3-P (49), S12-P48 (107), S3-P7 (116) Bertolino G. S2-O5 (84) Biermann H. S1-O2 (41) Biffi C.A. S2-O1 (82) Biswas Aniruddha S12-P56 (109) Blednova Z.M. S5-P10 (100), S8-P6 (111), S8-P10 (112) Bodnárová Lucie S4-P21 (56) Bonastre J. S4-P2 (124) Bondarev Andrey S12-P61 (95) Bönisch Matthias S6-P4 (123) Bourgeois N. S12-P23 (37), S12-O14 (39) Bragov Anatoly S12-P1 (85) Brailovski Vladimir L9 (31), S1-O8 (44), S5-P3 (99), S9-P8 (134) Braz Fernandes Francisco M. S12-P4 (86), S12-P5 (86), S12-P48 (107) Breczewski T. S1-O11 (46), S2-O3 (83), S12-P8 (88) Breczko Teodor S4-P3 (124), S12-P13 (89) Bronz Alexander S8-P1 (110) Buchelnikov V.D. S4-O11 (72), S11-P7 (120), S4-P13 (126), S4-P22 (129), S4-P23 (129), S4-P33 (130), S9-P5 (132) Bujoreanu Leandru-Gheorghe S3-P2 (114) Bychkov Igor S4-P13 (126) Caballero-Flores R. S4-O9 (71) Caër C. S2-O4 (83) Calciolari Renata S10-P8 (135) Calin Mariana S6-P4 (123) Calloch Sylvain S12-O29 (55), S6-O1 (57), S11-O4 (64) Cao Huibo S1-P1 (96) Capo Sanchez Julio S8-P9 (112) Carlota Auguet S12-P17 (90) Carreras Guillem S12-O26 (53) Castán Teresa S9-P1 (118) Castrodeza E.M. S2-O5 (84) Cellard Christophe S12-O19 (50) Certain Maryline S11-O3 (63) Cesari Eduard L2 (29), S12-O6 (35), S12-O24 (53), S4-O1 (67), S4-O13 (73) S12-P36 (105), S11-P1 (119), S4-P8 (125), Chashchina V.G. S10-O2 (79) Chemisky Y. S12-P23 (37), S12-O14 (37) Chen F. S12-O22 (52) Chen X. S4-P30 (56), S4-O12 (73) Chernyshov Eugeny S1-P6 (96) Chhibber Rahul S3-P3 (115) Chikosha Silethelwe S8-O2 (84) Chulist Robert S4-O2 (67), S4-O4 (69) 145 9th European Symposium on Martensitic Transformations ESOMAT 2012 Chumlyakov Y.I. S12-O25 (54), S3-O4 (56), S4-O7 (70), S4-O13 (73), S4-O15 (74), S4-P31 (130) Churakova A.A. S5-O5 (48) Cinca Nuria S12-O26 (53) Coke Ashley S1-P1 (96) Coll R. S4-P2 (124) Cortés J. S2-O2 (82) Costa Cardoso Marcelo S1-O4 (42) Craciunescu Corneliu M. S12-P4 (86) Cui Y.G. S9-O4 (77), S4-P32 (131) da Costa Viana Carlos Sérgio S10-P8 (135) Dadda J. S1-O5 (43) Danilov A. S12-P1 (85), S6-P2 (122) Daróczi Lajos S11-P4 (119) de Araújo C. J. S12-P27 (94) de Castro W. B. S12-P27 (94) De Guzman Yvette Marie Melodi S12-P58 (109) De la Flor Silvia S12-P28 (94) Dehmas M. S1-O10 (45) del Val Juan Jose S4-P14 (128) Delobelle Vincent S12-O19 (50) Dementyeva Tatyana S1-O7 (44), S1-O9 (45) Denquin A. S3-O7 (61), S3-P5 (116) Dirand L. S3-P5 (116) Dlouhy Antonin S12-O13 (38), S11-P9 (120) Dobatkin S.V. S5-P18 (102) Dorodeiko V. S12-P26 (92) dos Santos Freitas Maria Carolina S1-O4 (42) Douhaya Yana V. S4-P3 (124) Drobosyuk Mikhail S4-P22 (129), S4-P23 (129) Drozdova Maria S5-P16 (101) Druker A. S3-P4 (115) Dubinskiy Sergey L9 (31), S1-O8 (44) Dudkin I.V. S12-O3 (34) Dunne D.P. S3-O3 (59) Echchrorfi R. S12-P23 (37), S12-O14 (39) Eckert Jürgen S6-P4 (123) Eggeler Gunter S12-P39 (35), S12-P35 (36), S11-P9 (120), S9-P7 (133) Egido-Pérez N. S2-P8 (137) Egorov V.M. S11-P2 (63) Eifler Dietmar S3-P8 (60) El Rasasi Tarek S11-P4 (119) Emre B. S4-O10 (71) Enikeev N. S5-P18 (102) Entel P. S4-O11 (72), S4-P27 (74) Escoda Ll. S4-O9 (71), S4-P2 (124) 146 9th European Symposium on Martensitic Transformations ESOMAT 2012 Esina Elena V. S12-P2 (85) Espiritu Richard DV. S2-P10 (138) Evard Margarita E. S9-O5 (78) Ezer Y. S4-O17 (75) Fabbrici S. S4-O10 (71), S4-P24 (129) Fabregat-Sanjuan Albert S12-P28 (94) Fähler Sebastian S4-P27 (74) Fan Sun S6-O2 (66) Farias Vieira Thiago S1-O4 (42) Farjami Sahar S3-P10 (117) Favier Denis S12-O19 (50) Fayzullin Rafael S4-P22 (129), S4-P23 (129) Fedotkin Alexey S12-P32 (104) Fekete Ladislav S4-P21 (56), S4-P10 (126) Fernandez Javier S12-O26 (53) Ferrando Francesc S12-P28 (94) Fesenko Vladimir S1-O7 (44), S1-O9 (45) Figini A. S2-O1 (82) Filonov Mikhail L9 (31), S5-P3 (99) Firstov Georgiy S12-O12 (38), S1-O1 (41), S10-O3 (80), S1-P14 (81) Flores H. S2-O2 (82) Freitag Marlena S12-P7 (87) Frenzel Jan S12-P39 (35), S12-P35 (36), S1-P4 (43), S11-P9 (120) Frolova Natalia S5-P12 (100), S5-P15 (101) Frotscher Matthias S12-P39 (35) Fukuda Takashi L1 (29), S11-O2 (64), S3-P10 (117) Furuya Yasubumi S4-P4 (125) Fyodorov A.V. S12-P34 (104) Gaitzsch Uwe S4-P (57) Galieva Alesia S12-P1 (85) Gallardo M.C. S11-P11 (121) García F. N. S2-O2 (82) Garder Azdiar A. S3-O5 (60) Garlea V. Ovidiu S1-P1 (96) Ge Yanling S4-O3 (68), S4-P17 (68), S1-P1 (96) Geandier G. S1-O10 (45) Gebert Annett S6-P4 (123) George Easo S11-P9 (120) Girsova Natalia S12-O12 (38) Gizatullin Ramil S5-P14 (109) Glezer A.M. S5-O1 (47), S12-P60 (95) Goldenstein Hélio S8-P9 (112) Gómez-Cortés J. F. S2-P5 (136) Gonçalves Andrade Jessica S1-O4 (42) Gonçalves Taffael S12-P48 (107) González J. G. S2-O2 (82) 147 9th European Symposium on Martensitic Transformations ESOMAT 2012 González L. S4-O9 (71) Goryczka Tomasz S12-P7 (87), S12-P10 (88), S4-P11 (127) Granovski Alexander S4-P14 (128) Grigorieva Viktoria S12-P1 (85) Grishkov Victor S12-O12 (38), S5-O3 (48) Grolleau Vincent S12-O19 (50) Gruner Markus Ernst S4-P27 (74) Guerioune M. S2-P7 (137) Guillem Carreras S12-P17 (90) Gunderov D.V. S5-O5 (48) Gundyrev Vyacheslav S5-P15 (101), S10-P3 (134) Guo B. S12-O22 (52) Gusev D. S12-P52 (54) Gutfleisch Oliver S4-P16 (128) Gyu-bong Cho S12-O31 (55) Hahnenberger Frank S3-P8 (60) Hailiang Yu S3-P1 (114) Hannula Simo-Pekka S4-O3 (68), S4-P17 (68), S1-P1 (96) Hara T. S12-O1 (33) Hauegen Christien S12-P48 (107) Hayashi Taisuke S11-P (60), S3-O11 (62) He Y.J. S4-P30 (54), S4-O12 (73) Heczko Oleg S4-P21 (54), S4-P10 (126) Hernando B. S4-O9 (71) Hideki Hosoda S12-O2 (31), S6-P3 (122) Hu Q.M. S12-O3 (34) Huallpa Edgar Apaza S8-P9 (112) Hürrich Claudia S4-P (57) Hwang Kyu Hong S6-P1 (97), S7-P1 (98) Hyun Yong-Taek S12-P18 (91) Ibarra A. S1-O11 (46) Iermolenko V.N. S2-P2 (136) Ilyn Maxim S4-P14 (128) Inaektan Karine L9 (31), S1-O8 (44) Inamura T. S12-O1 (33), S12-O2 (33), S6-P3 (122) Indrani Sen S12-O27 (39) Ipatov Mihail S4-P14 (128) Irzhak A. S8-P3 (113), S4-P24 (129) Isaenkova Margarita S1-O7 (44), S1-O9 (45) Isalgue Antonio S12-O26 (53), S12-P17 (90) Ishida K. S3-O1 (58) Itakura Masaru S3-P10 (117) Ivanchenko Volodymyr S1-P14 (81) Ivo Szurman S12-O13 (38) Jae Il Kim S12-P43 (106) Jaeger S. S9-P7 (133) Jämsä T. S6-P2 (122) 148 9th European Symposium on Martensitic Transformations ESOMAT 2012 Javier Fernandez S12-P17 (90) Jiawei Dai S3-P1 (114) Jindal Sandeep S3-P3 (115) Jung-pil Noh S12-O31 (55) Jurek Karel S4-P21 (56) Kabanova I.G. S3-O2 (59) Käfer K.A. S3-P (49), S3-P7 (116) Kainuma Ryosuke S4-P16 (128) Kakeshita Tomoyuki L1 (29), S11-O2 (64), S3-P10 (117) Kalashnukov Vladimir S5-P14 (109), S8-P3 (113), Kalinin G.U. S8-P12 (113) Kamancev Alexander S11-P5 (121) Kanaf‟eva Anna S4-O15 (74) Kanaizumi T. S3-O11 (62) Kaputkin Dmitry E. S12-P2 (85) Kaputkina Liudmila S8-P1 (110), S8-P2 (110) Karaca H.E. S1-O5 (43), S12-O25 (54) Karaman Ibrahim S1-O5 (43), S4-O7 (70), S4-O13 (73) Karimbi Mahesh S12-P4 (86), S12-P5 (86), S12-P48 (107) Kashchenko M.P. S10-O2 (79) Kasimsev A.V. S12-P31 (103) Kastner O. S9-P7 (133) Kataeva N.V. S3-O2 (59), S8-P12 (113), S3-P19 (118) Katsunori Hiramatsu S6-P3 (122) Kauffmann Alexander S4-P27 (74) Kauffmann-Weiss Sandra S4-P (57), S4-P27 (74) Kawano H. S12-O1 (33), S12-O2 (33) Kaya Irfan S12-O25 (54) Ke Zhang S3-P1 (114) Keun Hong Jae S12-P18 (91) Khadeev Grigory S8-P2 (110) Khelifati G. S1-O10 (45) Khmelevskaya Irina L11 (32) Khovaylo Vladimir S4-P13 (126), S4-P16 (128), S4-P24 (129) Khusainov Mikhail S12-P61 (95) Kim G.C. S6-P1 (97) Kim H. S6-P1 (97) Kim Jeoung Han S12-P18 (91) Kim Seong Woong S12-P18 (91) Kim Tae Suk S6-P1 (97) Kindop Vladimir S8-P1 (110) Kireeva Irina S3-O4 (58), S4-O13 (73) Kirillov Vladimir S4-O13 (73) KISHI Yoichi S4-P4 (125) Klueva E. S2-P9 (138) Klyukina M.F. S3-O2 (59) 149 9th European Symposium on Martensitic Transformations ESOMAT 2012 Kockar Benat S12-O9 (36), S6-03 (66), S12-P53 (108) Kohl M. S12-O11 (37), S4-O17 (75) Kokorin V.V. S2-P2 (136) S4-O9 (71), S1-P1 (96), S5-P14 (109), S8-P3 (113), S11-P5 (121), S4-P13 (126), Koledov Victor S4-P24 (129) Kollerov M. Yu S12-P52 (54) Kolomytcev V.I. S5-P4 (99) Kompatscher Arno S5-O2 (47) Konopatsky Anton S6-P7 (123) Konoplyuk S.M. S2-P2 (136) Konstantinov Alexandr S12-P1 (85) Kopeček Jaromír S4-P21 (56), S4-P10 (126) Kopecký Vít S4-P21 (54) Kopylov Vladimir S5-O3 (46) Korneev Alexander S12-P14 (90) Korotitskiy Andrey L9 (31), S12-P15 (91) Korznikov Alexander S5-O6 (49) Koshkidko Uriy S4-P13 (126) Kostyleva A.A. S8-P8 (111) Koval Yuri S12-O12 (38), S1-O1 (41), S10-O3 (80), S1-P14 (81), S5-P4 (99) Kozlova L.E. S2-P2 (136) Kratochvílová Irena S4-P21 (56), S4-P10 (126) Kremyansky Dmitry S8-P1 (110) Kretinina Irina S4-O13 (73) Krevet B. S12-O11 (37) Krishnan Madangopal S12-P56 (109) Kubota K. S3-O11 (62) Kubota Takeshi S4-P4 (125) Kuc Olga S4-O13 (73) Kuchin D. S8-P3 (113) Kucza Nikki S5-O2 (47) Kudryavtsev Y.V. S2-P2 (136) Kulkova S.E. S12-O3 (34) Kuna Meinhard S9-P6 (133) Kuranova Natalia S5-P17 (102) Kursa Miroslav S12-O13 (38) Kus Krzysztof S12-P13 (89) Kustov S. L2 (29), S12-O6 (35), S12-O24 (53), S4-O1 (67), S12-P36 (105), S11-P1 (119) Kоsоrukоvа Tatiana S1-P14 (81) La Roca P. S3-P4 (115) Labenda Patrick S8-O1 (46) Lackmann J. S1-O5 (43) Laguna M F S9-O2 (76) Lakrit Mohamed S11-O4 (64) Landa Michal S4-P21 (56) Lanska Nataliya S4-O2 (67), S4-O4 (69) Lar‟kin V.F. S12-P21 (93), S8-P8 (111) 150 9th European Symposium on Martensitic Transformations ESOMAT 2012 Laydi R. S9-O3 (77) Lecomte J.-S. S2-O4 (83) Lee Jong Kook S6-P1 (97), S7-P1 (98) Lee Kee-Young S12-P18 (91) Lee Yong-hee L1 (29) Legrand Vicent S12-O29 (55), S6-O1 (57) Leindl Mario S11-O1 (78) Lekston Zdzislaw S12-P7 (87), S5-P2 (98) Lelatko Jozef S12-P7 (87), S12-P10 (88), S4-P11 (127) Lexcellent C. S9-O3 (77) Li L. S12-O22 (52) Likhachev Alexander S4-O14 (72) Lippmann Thomas S4-O2 (67) Litovchenko Igor S5-O6 (49) Liu Yinong S12-O19 (50) Lloveras Pol S9-P1 (118) Lohan Nicoleta Monica S3-P2 (114) Lomakin Ivan S12-P38 (105) Lomunov Andrey S12-P1 (85) López G.A. S2-P5 (136), S2-P8 (137) López-Echarri A. S1-O11 (46), S2-O3 (83), S12-P8 (88) López-Ferreño I. S2-O3 (83) Lotkov Alexander S12-O4 (34), S12-O12 (38), S5-O3 (48) Lucia I S4-O6(69) Ludwig Schultz S4-P (57) Lukina E. S12-P52 (54) Lukyanov A.V. S5-O5 (48) Lygin Konstantin S8-O1 (46) Maass Burkhard S12-P35 (36) Madiligama Amila SB S1-P1 (96) Maier H.J. S1-O5 (43), S4-O13 (73), S4-O15 (74), S4-P31 (130) Maji Bikas C. S12-P56 (109) Makarov Vladimir S5-P17 (102) Malarría J. S3-P4 (115) Malygin G.A. S11-P2 (63) Manchado J. S11-P11 (121) Mangler Clemens S5-O2 (47) Mañosa L. S4-O10 (71) Manzoni Anna S3-O7 (61) Mari D. S12-O6 (35) Markova G.V. S12-P31 (103), S2-P9 (138) Marques Fontanezzi Claudia S12-P48 (107) Martín-Olalla J.M. S11-P11 (121) Masaki Tahara S6-P3 (122) Mashirov A. S8-P3 (113) Mason P. S12-P52 (54) Mazaev Pavel S5-P14 (109) 151 9th European Symposium on Martensitic Transformations ESOMAT 2012 Mehta N.P. S3-P3 (115) Meisner Ludmila S12-O4 (34) Meisner Stanislav S12-O4 (34) Menushenkov Alexey S12-P14 (90) Meraghni F. S12-P23 (37), S12-O14 (39) Mertinger Valéria S3-P9 (117) Michalik S. S4-O8 (70) Michler J. S12-O27 (39) Mickel Christine S6-P4 (123) Miliukina S. S12-P26 (92) Minagi Y. S3-O11 (62) Miranda Rosa M. S12-P4 (86) Mironov Yurii S12-O4 (34) Mitsuhara Masatoshi S3-P10 (117) Miyazaki Shuichi S6-P3 (122) Monastyrsky G.E. S5-P4 (99) Monroe J. S1-O5 (43), S4-O7 (70) Monteiro Almeida Guilherme S1-O4 (42) Moreira Pessanha Luciano S1-O4 (42) Morito Shigekazu S11-P (62), S3-O11 (62) Morozov Evgeniy S11-P5 (121) Motorin Alexander S12-P1 (85) Moumni Z. S4-P30 (56), S4-O12 (73) Moyne S. S6-O1 (57) Muhonen V. S6-P2 (122) Müllner Peter S5-O2 (47), S4-P (57) Mushnikova S.U. S8-P12 (113) Naito L.K.F. S3-P (49), S3-P7 (116) Nam Tae-Hyun S12-O31 (55), S12-P12 (89), S9-P2 (132) Neves Filipe S12-P5 (86) Nicholson D.E. S12-O20 (51) Niendorf T. S1-O5 (43) Nikolaev V.I. S11-P2 (63) Nishida M. S12-O1 (33), S12-O2 (33) Nishida Minoru S3-P10 (117) Nishiura T. S12-O1 (33), S12-O2 (33) Nó M.L. L4 (30), S1-O11 (46), S2-O3 (83), S12-P8 (88), S3-P5 (116), S2-P5 (136), S2-P8 (137) Noebe R.D. S12-O20 (51), S12-O25 (54) Nunes C.S. S10-O1 (79) Nuria Cinca S12-P17 (90) Oberaigner Eduard Roman S11-O1 (78) Ocaña J.L. S12-P4 (86) Ochin P. S12-P10 (88), S5-P4 (99), S3-P4 (115) Odnosum V.V. S1-O1 (41), S5-P4 (99) Oertel Carl-Georg S4-02 (67), S4-O4 (69) Ohba Takuya S11-P (62), S3-O11 (62) 152 9th European Symposium on Martensitic Transformations ESOMAT 2012 Okazaki Teiko S4-P4 (125) Oliveira João Pedro S12-P4 (86) Omori Toshihiro S4-P16 (128) Ostropiko Eugeni S12-P1 (85) Otubo J. S3-P (49), S12-P48 (107), S3-P7 (116) Ozcan Hande S12-O9 (36), S12-P53 (108) Özkal Burak S3-P2 (114) Padovese Linilson R. S8-P9 (112) Padula S.A. II S12-O20 (51) Palka Jakub S5-P2 (98) Panchenko E. S1-O5 (43), S4-O15 (74), S4-P31 (130) Pang W. S3-O3 (59) Panigrahi Ajit S6-P4 (123) Pankova M.N. S5-P18 (102) Paraschiv Adrian Liviu S3-P2 (114) Park W.W. S6-P1 (97) Park Chan Hee S12-P18 (91) Pascal Laheurte S6-02 (66) Pasko A.Yu. S5-P4 (99) Pasttor J.M. S4-P15 (127) Pastushenkov Uriy S4-P13 (126) Patoor E. S12-P23 (37), S12-O14 (39), S2-O4 (83) Patselov Alexander S1-P6 (96), S5-P15 (101) Patte Renaud S11-O3 (63) Payton E.J. S3-O10 (61) Pazgalov A. S12-P61 (95) Peigney Michaël S10-O4 (80) Pelegrina J L S9-O2 (76) Pelennen Anatoliy S4-P13 (126) Pereloma Elena S3-O5 (60) Pérez-Landazábal J.I. S4-O6(69), S11-P1 (119), S4-P15 (127) Perlovich Yuriy S1-O7 (44), S1-O9 (45) Petrov Alexey S5-P14 (109) Petrova-Burkina O.A. S12-O16 (40) Petrzhik Michail L9 (31), S11-O5 (65), S5-P3 (99) Pham H.A. S11-P (62) Picornell Catalina S4-P8 (125) Pilyugin Vitaly S1-P6 (96), S5-P12 (100), S5-P15 (101), S5-P16 (101) Pinneker V. S12-O11 (37), S4-O17 (75) Pino Laurent S12-O29 (55), S6-O1 (57) Piotrowski B. S12-P23 (37), S12-O14 (39) Planes Antoni L5 (30), S4-O10 (71), S9-P1 (118), S11-P11 (121) Pons Jaume S4-P8 (125) Popov A. S12-O32 (50) Popov N.N. S12-P21 (93), S8-P8 (111) Popov S. S12-P61 (95) 153 9th European Symposium on Martensitic Transformations ESOMAT 2012 Portier Richard S3-O7 (61) Potapova А.А. S12-P50 (107) Pötschke Martin S4-P (57) Presnyakov D.V. S12-P21 (93), S8-P8 (111) Pricop Bogdan S3-P2 (114) Prida V. M. S4-O9 (71) Prima Frédéric S3-O7 (61), S6-O2 (66) Procenko N.A. S8-P10 (112) Prokofiev E.A. S5-O5 (48) Prokoshkin Sergey L9 (31), S1-O8 (44), S5-O5 (48), S5-P3 (99) Prokoshkina Vera S8-P1 (110), S8-P2 (110) Prüger Stefan S9-P6 (133) Prusik Krystian S4-P11 (127) Pulnev S.A. S11-P2 (63) Pushin A. S12-O32 (50) Pushin V.G. S5-O5 (48), S12-O32 (50), S5-P17 (102) Pustov Yury S6-P7 (123) Quandt E. S12-O11 (37) Raghavan R. S12-O27 (39) Rahim Mustafa S12-P39 (35) Rangel Rios Paulo S10-P8 (135) Razov Alexander S12-P1 (85) Recarte V S4-O6(69), S11-P1 (119), S4-P15 (127) Resnina Natalia S12-P19 (92), S5-P12 (100), 5-P16 (101), S12-P29 (103), S12-P38 (105), S12-P40 (106), S12-P50 (107), S12-P55 (108) Rhode M. S12-O11 (37) Ribeiro Shimeni S12-P48 (107), S10-P8 (135) Rio Gérard S12-O19 (50) Rodrigues Patrícia S12-P48 (107) Rodríguez-Velamazán JA S4-O6(69) Romberg Jan S4-P (57) Romero F.J. S11-P11 (121) Rong Y.H. S9-O4 (77), S4-P32 (131), S3-P1 (114) Rosa W.O. S4-O9 (71) Roth Stefan S4-P (57) Rubanik Oksana S12-P38 (105) Rubanik Vasiliy S12-O16 (40), S12-P26 (92), S12-P38 (105) Rubanik Vasiliy (jr) S12-O16 (40), S12-P26 (92), S12-P38 (105) Rudio E. S4-P15 (127) Ruiz-Larrea I. S1-O11 (46), S2-O3 (83), S12-P8 (88) Rusinov P.O. S5-P10 (100), S8-P6 (111) Ryba T. S4-O8 (70) Rybalchenko O.V. S5-P18 (102) Ryklina Elena S12-O21 (51) Rynko Ramona S1-P4 (43) S. Shariat Bashir S12-O19 (50) Saakyan Sergey S12-P14 (90) 154 9th European Symposium on Martensitic Transformations ESOMAT 2012 Sadek Tim S8-O1 (46) Sagaradze V.V. S3-O2 (59), S8-P12 (113), S3-P19 (118) Saghaian Sayed S12-O25 (54) Saint-Sulpice Luc S12-O29 (55), S11-O4 (64) Salas D. L2 (29), S12-O6 (35), S12-O24 (53), S12-P36 (105), S11-P1 (119) Salje E.K.H. S11-P11 (121) San Juan Jose L4 (30), S1-O11 (46), S2-O3 (83), S12-P8 (88), S3-P5 (116), S2-P5 (136), S2-P8 (137) Sánchez F. M. S2-O2 (82) Sánchez-Alarcos V S4-O6(69), S11-P1 (119), S4-P15 (127) Santamarta R. S12-O6 (35), S4-O1 (67) Sapozhnikov K. S12-O24 (53), S4-O1 (67) Saurina J. S4-P2 (124) Saxena Avadh S9-O1 (76), S9-P1 (118) Schell Norbert S12-P4 (86), S12-P5 (86) Schryvers Dominique L6 (31), S12-P44 (52), S1-P13 (97) Schultz Ludwig S4-P27 (74) Sedlák Petr S4-P21 (56) Seiner Hanuš S4-P21 (56) Senkovskiy B.V. S12-P34 (104) Settefrati Amico S1-P2 (42), S1-O10 (45) Shalimova Anna V. S12-P60 (95) Sharma Meenu S12-P56 (109) Shavkov Vladimir S11-P5 (121) Shavrov Vladimir S8-P3 (113), S4-P13 (126), S4-P24 (129) Shelyakov Alexander S12-P14 (90), S12-P34 (104), S11-P5 (121) Sheremetyev Vadim S5-P3 (99) Shi Hui S1-P13 (97) Shuytsev A.V. S12-P31 (103) Sibirev Alexey S12-P19 (92), S12-P29 (103) Sitnikov Nikolay S12-P14 (90), S11-P5 (121) Šittner Petr S4-P21 (56) Skokov Konstantin S4-P13 (126), S4-P16 (128) Skrotzki Werner S4-O2 (67), S4-O4 (69), S6-P4 (123) Slesarenko Viacheslav S5-P12 (100), S5-P16 (101) Smaga Marek S3-P8 (60) Sochugov Nikolai S12-O4 (34) Soejima Y. S12-O1 (33) Solov'ev Alexander S12-O4 (34) Somsen Christoph S11-P9 (120) Soroka Aleksandr S4-O2 (67), S4-O4 (69) Söyler Umut S3-P2 (114) Sozinov Alexei S4-O2 (67), S4-O4 (69), S4-O17 (75), S4-P8 (125) Stark Andreas S12-P5 (86) Steegmüller Rainer S12-P39 (35) Stern E. S4-O10 (71) Stolyarov Vladimir S12-O17 (40), S5-O5 (48), S12-P32 (104), S12-P50 (107) 155 9th European Symposium on Martensitic Transformations ESOMAT 2012 Straka Ladislav S4-O2 (67), S4-O4 (69), S4-P10 (126) Stroz Danuta S5-P2 (98), S4-P11 (127) Su Ho Park S12-P43 (106) Sule Cakmak S12-O9 (36), S12-P53 (108) Sundeev Roman V. S12-P60 (95) Suñol J.J. S4-O9 (71), S4-P2 (124) Suru Marius Gabriel S3-P2 (114) Svyazhin Anatoly S8-P1 (110) Sysoeva T.I. S12-P21 (93) Taillebot V. S9-O3 (77) Takaiwa T. S3-O11 (62) Tamarit J.L. S4-O10 (71) Tanaka Yuri S3-P10 (117) Taskaev Sergey S4-P13 (126), S4-P22 (129), S4-P23 (129) Terriault Patrick S9-P8 (134) Thierry Gloriant S6-O2 (66) Tian B. S12-O22 (52) Timkin Victor S12-O12 (38) Timofeeva Ekaterina S4-O15 (74), S4-P31 (130) Timokhina Iiana S3-O5 (60) Timoshevskii Andrei S10-O3 (80) Tolmachev Timofey S1-P6 (96) Tong Y.X. S12-O22 (53) Torrens-Serra J. S12-O24 (53) Tranta Ferenc S3-P9 (117) Troiani H.E. S2-O5 (84) Tuissi A. S2-O1 (82) Tuukkanen J. S6-P2 (122) Tverskov Anton S3-O4 (58) Tyumentsev Alexander S5-O6 (49) Uksusnikov Alexsey S5-P17 (102) Urbina Cristina S12-P28 (94) Urdiaín A. S4-P15 (127) Usachov D.Yu. S12-P34 (104) Vahid Attari S6-O3 (66) Vaidyanathan R. S12-O20 (51) Valiev R.Z. S5-O5 (48), S12-O22 (52), S5-P18 (102) Van Humbeeck J. S12-O6 (35), S12-P44 (52), S12-O24 (53), 4-O1 (67), S10-O3 (80), S1-P14 (81), S1-P13 (97), S12-P36 (105) Varga R. S4-O8 (70) Vargova Z. S4-O8 (70) Vélez J S4-O6(69) Verbakhovskaya R. A. S12-P6 (87) Verlinden Bert S12-P44 (52) Vermaut Philippe S3-O7 (61), S3-P4 (115) Vetoshkina Natalia S4-P31 (130) Viana, N.F. S10-O1 (79) 156 9th European Symposium on Martensitic Transformations ESOMAT 2012 Vicenç Torra S12-O26 (53), S12-P17 (90) Von Gratowski S. S4-P24 (129) Volkov Aleksandr E. S9-O5 (78) Vrel D. S2-P7 (137) Vyunenko Yuriy N. S10-P6 (135) Wafa El May S6-O2 (66) Wagner M.F.-X. S12-O27 (39), S11-P9 (120) Wagstaff P. S12-P52 (54) Waitz Thomas S5-O2 (47), S6-P4 (123) Wan J.F. S9-O4 (77), S4-P32 (131) Wang Xiebin S12-P44 (52) Weidner A. S1-O2 (41) Weiss B.A. S2-O5 (84) Wierzchoń Tadeusz S12-P7 (87) Wohlschlögel Markus S12-P39 (35) Won Ki Ko S12-P43 (106) Xiao Fei S11-O2 (64) Xu Xiao S4-P16 (128) Yablonovskii Sergey S10-O3 (80) YAJIMA Zenjiro S4-P4 (125) Yakushev P.N. S11-P2 (63) Yardley V.A. S3-O10 (61) Yaso M. S3-O11 (62) Yegin C. S4-O7 (70) Yeom Jong-Taek S12-P18 (91) Yeon-min Im S12-O31 (55) Yeon-wook Kim S12-P12 (89) Yin R. S4-O17 (75) Young Sung-Young S9-P2 (132) Yuce S. S4-O10 (71) Yulin Hao S6-O2 (66) Zagrebin M. S4-P33 (130), S9-P5 (132) Zapolsky Helena S11-O3 (63) Zárubová Niva S4-O3 (68), S4-P17 (68) ZavalishinV.A. S8-P12 (113) Zehetbauer Michael S6-P4 (123) Zeldovich Vitali S5-P12 (100), S5-P15 (101), S10-P3 (133) Zemmour K. S2-P7 (137) Zhang J.H. S9-O4 (77), S4-P32 (131) Zhang Jian S1-P4 (43) Zhapova Dorzhima S12-O12 (38) Zheng Y.F. S12-O22 (52) Zhikharev Alexey S11-P5 (121) Zhukov Arcady S4-O8 (70), S4-P14 (128) Zhukova Valentina S4-O8 (70), S4-P14 (128) Zhukova Yulia S6-P7 (123) Zhuravlev Roman S12-P40 (106) 157 9th European Symposium on Martensitic Transformations ESOMAT 2012 Social Events Conference Social Programme includes Saint-Petersburg Sightseeing tour One-day excursion to the most beautiful Saint-Petersburg suburb – Peterhof Accompanying person tour Get-together party Conference dinner Saint-Petersburg Sightseeing tour (duration about 3 hours, September 9) During this tour following historical places will be visited. The Peter and Paul Fortress is the historical core of St.-Petersburg. It is a monument of military and engineering craft. It was laid by the order and to the plot-plan of Peter the Great on May 27 1703 on Zayachy Island. The Fortress forms an irregular hexagon stretched from West to East with 6 bastions at the corners. The fortress was constructed "in quite a haste" under supervision of Peter the Great and his closest associates. In 1706-1740 the walls of the fortress that face the Neva River were lined with granite blocks. Most worth seeing is the Cathedral of Sts. Peter & Paul, with its landmark needle-thin spire and the weather-vane on top in the form of an Angel with a Cross. The Palace Square is the most grandiose among the squares of the city. The focal point of its architectural ensemble is the Winter Palace, an architectural masterpiece of the flamboyant Russian Baroque and the royal residence of all the Russian Emperors but Paul. It was built by Bartholomeo Rastrelli at the close of the Empress Elizabeth reign, in 1754-1762. He decorated the edge of the roof with huge bronze figures and reduced the emerald wall space to the minimum disguising it by decorative columns and golden tracery, plastic Amours, vases and sculptures. The colossal Alexander Column with the bronze figure of an angel at the top was erected in the centre of the Square in 1834 to commemorate the triumphant victory of the Russians over Napoleon in the Patriotic War 1812. The cape of Basil Island (Vasilievsky Island) is called a Strelka (Tongue of the Land) because it sticks out into the Neva River and divides it into two estuaries. The spot ranks as one of the most prominent architectural sights in Saint-Petersburg. Rostral Columns rose in 1810 and designed by an architect Tomas de Tomon as a symbol of the naval supremacy of the Russian Empire and in honour of the Russian fleet victories. The St.Isaac Square got its name from the magnificent St.Isaac Cathedral, located in its centre, that is dominating building linking with the Decembrist Square. It is the biggest Orthodox Cathedral in St.Petersburg. In 1818 Alexander I approved a project submitted by Ogust Montferrand, a talented drawer who had just arrived from Paris; however, he had had but little experience in architecture. The building process lasted so long that people made fun of the architect saying that Montferrand dragged it on because a prophet had predicted him he would die the day the Cathedral was completed. "The Resurrection Church" marvelous Russian-style multicolored, onion-domed church was built on the spot where Emperor Alexander II was assassinated in March 1, 1881. The original name of the square is Senat's Square, because there are the yellow and white buildings of a former Senat and Sinod, built in 1834 by Karlo Rossy. The Senat was the highest legislative body under the tsar and the Sinod was the main governing body of the Church. Now it houses the Central Historical Archives. The most famous and impressive monument to the founder of St.Petersburg, Peter the Great, the Bronze Horseman, in the middle of the Square is the first monument in the city. The monument was built by order of the Empress Catherine the Great as a tribute to her famous predecessor on the Russian throne, Peter the Great. The Nevskiy prospect, Art Square, Russian Museum, Mikhail Castle, Kazan Cathedral, embankments of the Neva river, small rivers and channels and most popular bridges and many other historical places will be attended during excursion. 158 9th European Symposium on Martensitic Transformations ESOMAT 2012 One-day excursion to Peterhof (September 13) One of St.-Petersburg's most famous and popular visitor attractions, the palace and park at Peterhof (also known as Petrodvorets) are often referred to as "the Russian Versaille", although many visitors conclude that the comparison does a disservice to the grandeur and scope of this majestic estate. Versailles was, however, the inspiration for Peter the Great's desire to build an imperial palace in the suburbs of his new city and, after an aborted attempt at Strelna, Peterhof - which means "Peter's Court" in German - became the site for the Tsar's Monplaisir Palace, and then for the original Grand Palace. The estate was equally popular with Peter's daughter, Empress Elizabeth, who ordered the expansion of the Grand Palace and greatly extended the park and the famous system of fountains, including the truly spectacular Grand Cascade. The Grand Palace at Peterhof was designed to be the centerpiece of Peter the Great's "Russian Versaille". Around 1720, the Tsar gave up on attempts to establish his court at Strelna, mainly because the boggy ground proved entirely unsuitable for the canals and fountains that he envisioned. Moving his attentions further east to Peterhof, the Tsar began to draw up his own plans for the grounds and palace. Work had already begun on a modest palace, designed by Jean- Baptiste Le Blond, in 1714, and that building was completed in 1721. The spectacular parkland at Peterhof is remarkable for the sheer variety of styles encompassed in its layout and features. Representing nearly two centuries of European aristocratic fashion executed to the highest standards, Peterhof is like an encyclopedia of park design through the age of empire. Particularly impressive is the fact that the master landscapers and garden designers who worked on the estate at Peterhof managed to overcome the extremely inclement conditions of the northern climate to create a wonderland of greenery and flowers, sweeping vistas and ornate architectural decorations. The fountains of Peterhof are one of Russia's most famous tourist attractions, drawing millions of visitors every year. Fountains were intrinsic to Peter the Great original plans for Peterhof - it was the impossibility of engineering sufficiently powerful jets of water that prompted him to move his attentions from the Strelna site to Peterhof - and subsequent generations competed with their predecessors to add grander and ever more ingenious water features to the parkland surrounding the Grand Palace. The most famous ensemble of fountains, the Grand Cascade, which runs from the northern facade of the Grand Palace to the Marine Canal, comprises 64 different fountains, and over 200 bronze statues, bas-reliefs, and other decorations. At the centre stands Rastrelli's spectacular statue of Samson wrestling the jaws of a lion. The vista of the Grand Cascade with the Grand Palace behind it, the first sight to great visitors who arrive in Peterhof by sea, is truly breathtaking. The Grotto behind the Grand Cascade, which was once used for small parties, contains the enormous pipes, originally wooden, that feed the fountains. Elsewhere in the park, the range and diversity of fountains is astounding, from further monumental ensembles like the Chess Cascade and the Pyramid Fountain, to the ever-popular Joke Fountains, including one which sprays unwary passers-by who step on a particular paving stone. 159 9th European Symposium on Martensitic Transformations ESOMAT 2012 Get-together party Get-together party will be organized in Hotel “Holiday Inn Moskovskye Vorota” in foyer “Levinson”. Get-together party will be organized with elements of the Russian folk traditions. Conference dinner Conference dinner will be organized in Restaurant “Podvorye” Opened in 1993, the Podvorye (Coach House) restaurant has since become known as «Russian most authentic Russian restaurant». In addition to having its own regular clientele, it has established a reputation in Saint Petersburg and far beyond. Restaurants at travel destinations worldwide may as a rule be divided into those patronized by tourists and those favored by connoisseurs of fine cooking. Podvorye is remarkable for being equally esteemed by travelers as well as local residents. Intellectuals and aristocrats from various countries, actors, sports figures, politicians – and all those who appreciate the art of good eating and love genuine Russian cuisine– thoroughly enjoy their visits to Podvorye. (www.podvorye.ru) The photos of Restaurant “Podvorye” are taken through the www.podvorye.ru 160 9th European Symposium on Martensitic Transformations ESOMAT 2012 Accompanying person programme September, 10. Monday 9:30-12:30 – visit of Russian museum. The Russian Museum is the first state museum of Russian fine arts in the country. It was established in 1895 in St Petersburg by a decree of the Emperor Nicholas II. 12:30-14:00 – Lunch. 14:00-17:00 – visit of Alexander Nevsky Lavra. Nevsky Lavra, which was founded in 1710 on that very place where according to the legend Alexander Nevsky defeated Swedish troops. September, 11. Tuesday 9:30-12:30 – visit of Yusupov Palace A long yellow building, which was once the residence of the wealthy and respected Yusupov family and the place of the most dramatic episodes in the history of Russia – the murder of Gregory Rasputin. 13:00 – Lunch. 14:00 – visit of Hermitage Museum. The State Hermitage (Winter Palace) occupies six magnificent buildings situated along the embankment of the River Neva, right in the heart of St Petersburg. The leading role in this unique architectural ensemble is played by the Winter Palace, the residence of the Russian tsars that was built and designed by Francesco Bartolomeo Rastrelli in 1754-62. The basic display areas of the State Hermitage occupy 365 rooms in the Main Museum Complex located in the historic centre of St Petersburg. It consists of six buildings constructed in the 18th and 19th centuries, among which the most important is the Winter Palace, the former imperial residence. September, 12. Wednesday 9:30 – 12:00 visit of Peter and Paul Fortress + visit of «Aurora» cruiser Peter the Great founded the city of St. Petersburg in 1703 and the very first building to be constructed was the Peter and Paul Fortress. The historical ship Aurora has been turned into a museum and is docked just a few hundred yards upstream from the Cabin of Peter the Great, opposite the "St Petersburg" Hotel. The ship gave the signal (by firing a blank shot) to storm of the Winter Palace during the October revolution of 1917, 12:00-13:00 – Lunch 14:00-18:00 –Boat trip St. Petersburg was built on the delta of the River Neva and is spread out over numerous islands of varying sizes, frequently prompting the nickname the "City of 101 Islands". September, 14, Friday 9:30-13:00 – visit of Kazansky Cathedral +visit of metro + shopping. Kazan Cathedral, constructed between 1801 and 1811 by the architect Andrei Voronikhin, was built to an enormous scale and boasts an impressive stone colonnade, encircling a small garden and central fountain. The cathedral was inspired by the Basilica of St. Peter‟s in Rome and was intended to be the country‟s main Orthodox Church. After the war of 1812 (during which Napoleon was defeated) the church became a monument to Russian victory. Moreover, accompanying person programme includes all social activities of the conference ( Saint-Petersburg Sightseeing tour, One-day excursion to the most beautiful Saint-Petersburg suburb – Peterhof, Get-together party, Conference dinner) 161 9th European Symposium on Martensitic Transformations ESOMAT 2012 Optional programme Dear colleagues! Company “Favorit” is very glad to offer you the following excursions in the period of September 11 to September 15. Excursions Date Start of End of Price excursions excursions per person Hermitage museum 11.09.2012 14.00 19.00 1200 RUB Tuesday 32 EUR 42 USD St.Petersburg by night 11.09.2012 23.30 02.30 1000 RUB (open drawbridges) Tuesday 27 EUR 35 USD Pushkin (Tsarskoe 12.09.2012 14.00 18.00 1600 RUB Selo), Catherine’s Wednesday 43 EUR Palace with Amber room 55 USD Boat trip 12.09.2012 14.00 18.00 850 RUB Wednesday 22 EUR 30 USD Boat trip 12.09.2012 19.00 22.00 850 RUB Wednesday 22 EUR 30 USD Hermitage museum 14.09.2012 14.00 19.00 1200 RUB Friday 32 EUR 42 USD One day tour to Velikiy 15.09.2012 3 500 RUB Novgorod Saturday 8.00 20.00 95 EUR 120 USD Tour to Pushkin 15.09.2012 2 000 RUB (Tsarskoe Selo), Saturday 9.00 17.00 55 EUR Catherine’s Palace with Amber room 70 USD + Pavlovsk, Palace of Paul I Hermitage theatre September 9 to 20.00 From 3500 RUB (ballet) September 15 95 EUR 120 USD The price of excursions includes: comfortable bus, English speaking guide, entrance tickets. You may book the seats by e-mail ([email protected]) or during registration on September 9. 162 9th European Symposium on Martensitic Transformations ESOMAT 2012 Access guide from the Hotel “Rossiya” to Hotel “Holiday Inn – Moskovskye vorota” 1.Go along Chernyshevsky‟s square up to “Moskovskiy avenue”. 2.Turn to the right and go along “Moskovskiy avenue” up to underground passage. 3.Downstairs to the passage, cross “Moskovskiy avenue” and upstairs 4.Go to the building marked be letters and enter the subway station 1 2 4 3 5.Take a train to the direction “PARNAS” 6. Go to the station “MOSKOVSKIYE VOROTA” (The second station from the station “PARK POBEDY”) 163 9th European Symposium on Martensitic Transformations ESOMAT 2012 6 164 9th European Symposium on Martensitic Transformations ESOMAT 2012 7.Go out the subway station “MOSKOVSKIYE VOROTA” 8. Turn to the left and go along “MOSKOVSKIE VOROTA” square and along “Moskovskiy avenue” 9. Use the entrance 1 to enter the hotel and to enter a conference venue on September 11, 12 and 14 10.Use the entrance 2 to enter the conference venue on September 9 and September 10. 10 9 8 7 165 9th European Symposium on Martensitic Transformations ESOMAT 2012 Access guide from the Hotel “Holiday Inn – Moscovskye vorota” to the historical center of Saint-Petersburg If you are going to visit historical center of Saint-Petersburg, following information will be useful for you. To reach “Nevskiy prospect”, Russian Museum, Kazan Cathedral, The Resurrection Church, Mikhailovsky castle, Summer garden please take a subway. 1.Enter the subway station “MOSKOVSKIYE VOROTA”. 2.Take a train to the direction “PARNAS” 3. Go to the station “NEVSKIY PROSPEKT”. 4.The order of subway stations “MOSKOVSKIYE VOROTA” “FRUNZENSKAYA” “TEKHNOLOGICHESKIY INSTITUTE 2” “SENNAYA PLOSCHAD” “NEVSKIY PROSPEKT” 5.The station “Nevskiy prospekt” has two exits. Please go to the exit “Mikhailovskaya street”. To reach Palace square, Winter palace, the Neva river, St.Isaac Cathedral, the bronze horseman, the cape of Basil Island, please take a subway 1. Enter the subway station “ MOSKOVSKIYE VOROTA”. 2. Take a train to the direction “PARNAS” 3.Go to the station “SENNAYA PLOSCHAD”. This station connects to the station “SADOVAYA” 4.The order of subway stations “MOSKOVSKIYE VOROTA” “FRUNZENSKAYA” “TEKHNOLOGICHESKIY INSTITUTE 2” “SENNAYA PLOSCHAD” 5.Change the blue line of subway (station “SENNAYA PLOSCHAD”) to the purple line of subway (station “SADOVAYA”). 6. At the station “SADOVAYA” take a train to the direction “ KOMENDANTSKIY PROSPEKT” 7. Go to the station “ADMIRALTEYSKAYA”. This station has one exit. 8.The order of subway stations “SADOVAYA” “ADMIRALTEYSKAYA” To reach the Peter and Paul Fortress, please take a subway: 1.Enter the subway station “ MOSKOVSKIYE VOROTA”. 2.Take a train to the direction “PARNAS” 3. Go to the station “GORKOVSKAYA”. 4.The order of subway stations “MOSKOVSKIYE VOROTA” “FRUNZENSKAYA” “TEKHNOLOGICHESKIY INSTITUTE 2” “SENNAYA PLOSCHAD” “NEVSKIY PROSPEKT” “GORKOVSKAYA” 5. This station has one exit. 166 9th European Symposium on Martensitic Transformations ESOMAT 2012 Access guide from the Hotel “Rossiya” to the historical center of Saint-Petersburg If you are going to visit historical center of Saint-Petersburg, following information will be useful for you. To reach “Nevskiy prospect”, Russian Museum, Kazan Cathedral, The Resurrection Church, Mikhailovsky castle, Summer garden please take a subway. 1.Enter the subway station “PARK POBEDY”. 2.Take a train to the direction “PARNAS” 3. Go to the station “NEVSKIY PROSPEKT”. 4.The order of subway stations “PARK POBEDY” “ELEKTROSILA” “MOSKOVSKIYE VOROTA” “FRUNZENSKAYA” “TEKHNOLOGICHESKIY INSTITUTE 2” “SENNAYA PLOSCHAD” “NEVSKIY PROSPEKT” 5.The station “Nevskiy prospekt” has two exits. Please go to the exit “Mikhailovskaya street”. To reach Palace square, Winter palace, the Neva river, St.Isaac Cathedral, the bronze horseman, the cape of Basil Island, please take a subway 1.Enter the subway station “MOSKOVSKIYE VOROTA”. 2.Take a train to the direction “PARNAS” 3. Go to the station “SENNAYA PLOSCHAD”. This station connects to the station “SADOVAYA” 4. The order of subway stations “PARK POBEDY” “ELEKTROSILA” “MOSKOVSKIYE VOROTA” “FRUNZENSKAYA” “TEKHNOLOGICHESKIY INSTITUTE 2” “SENNAYA PLOSCHAD” 5. Change the blue line of subway (station “SENNAYA PLOSCHAD”) to the purple line of subway (station “SADOVAYA”). 6. At the station “SADOVAYA” take a train to the direction “ KOMENDANTSKIY PROSPEKT” 7. Go to the station “ADMIRALTEYSKAYA”. This station has one exit. 8. The order of subway stations “SADOVAYA” “ADMIRALTEYSKAYA” To reach the Peter and Paul Fortress, please take a subway: 1.Enter the subway station “ PARK POBEDY”. 2.Take a train to the direction “PARNAS” 3. Go to the station “GORKOVSKAYA”. 4.The order of subway stations “PARK POBEDY” “ELEKTROSILA” “MOSKOVSKIYE VOROTA” “FRUNZENSKAYA” “TEKHNOLOGICHESKIY INSTITUTE 2” “SENNAYA PLOSCHAD” “NEVSKIY PROSPEKT” “GORKOVSKAYA” 5.This station has one exit. 167 9th European Symposium on Martensitic Transformations ESOMAT 2012 Important information Weather Saint-Petersburg has a marine climate as in London. The weather may change every day from sunny to shower. The average temperature in begin of September is 14-16 oC. The maximum temperature was 19 oC, the lowest temperature was 10 oC. Saint-Petersburg has only 40 sunny days per year and a shower is more typical for our autumn weather. We would like to ask you to take warm clothes and umbrella. On September 13 we will have a one-day excursion to Petergof, please take comfortable shoes for walking. Transport The network of public transportation in St. Petersburg is extensive. There are 5 lines of subway, buses, trolleybuses, trams, marshrutka. Subway (In Russian – “Метро” [Metro]) The subway is more comfortable and useful transport in Saint-Petersburg. The subway (metro) has five lines which are numbered and assigned specific colors on a metro map (see page 164). Normally trains arrive every 1-2 minutes in the afternoon, and 3-5 minutes in the morning and at night. The stations open at about 5:45 am and close at midnight 00:00 am. To enter the subway station you should pay the token (in Russian – “Zheton”), which can be purchased at ticket office (in Russian “КАССА” [Kassa]) located at every station. The price of one token is 27 RUB. You may pay the token only by CASH. One token may be used only for one trip. One trip includes line‟s changes if it is needed and does not depend on time. In the streets all stations are marked by the blue sign In Saint-Petersburg subway the platform is located in the center and the trains go on the left and right sides. On the stations there are the guides with the directions of the final destination of the train. The name of the station (in Russian and English) is located in the wide colour line on the wall of the station. The colour of the line is correspondent to the line of the subway. All announcements in the trains are in Russian. When the train comes to the station, the announcement of name of current station and the name of next station becomes. The expression “Next station is” in Russian “Sleduyushaya stancia” [sledujuʃaia stansia]. The hotel “Holiday Inn – Moskovslye vorota” is located at the subway station “MOSKOVSKIYE VOROTA” (in Russian “МОСКОВСКИЕ ВОРОТА” [Moskovskie vorota]) and the hotel “Rossiya” is located in the subway station “PARK POBEDY” (in Russian “ПАРК ПОБЕДЫ” [Park pobedy]). Both stations are in the blue line of subway. If you go from the city center to the hotels, then your direction is “KUPCHINO” (in Russian “Купчино” [Kupchino]). If 168 9th European Symposium on Martensitic Transformations ESOMAT 2012 you go from the hotel to the city center then your direction is “PARNAS” (In Russian “Парнас” [Parnas]). Tram (in Russian – “Трамвай” [tramvai]) Tram stops are marked with signs above the tracks (with a letter "T" on them). All trams have conductors on board. You should pay in cash to a conductor. The cost of one ticket is 23 RUB. One ticket may be used only for one trip. Please keep the ticket before finish of your trip. You may be asked to show your ticket during your trip. Bus (in Russian – “Автобус” [avtobus]) Bus stops are marked by signs with the letter "A". Most of busses have conductors on board. You should pay in cash to a conductor. The cost of one ticket is 23 RUB. One ticket may be used only for one trip. If in the bus there is no a conductor, thus you should pay the ticket at the bus driver. Please keep the ticket before finish of your trip. You may be asked to show your ticket during your trip. Trolleybus (in Russian – “Тролейбус” [troleibus]) Trolleybus stops are marked with signs with blue letter "T". All trolleybuses have conductors on board. You should pay in cash to a conductor. The cost of one ticket is 23 RUB. One ticket may be used only for one trip. Please keep the ticket before finish of your trip. You may be asked to show your ticket during your trip. Marshrutka (in Russian – “Маршрутка” [marʃrutka]) Marshrutka or marshrutnoe taksi is a privately owned minivan or small bus that follows a fixed route, collecting and depositing passengers anywhere along the way. The network of marshrutki is too complicated to be worth using in the city center, because you should ask the driver to stop in the place where you need. All drives speak Russian and practically do not understand English. However, Marshrutka is the best way for getting to St. Petersburg's suburb. If you are going to visit some suburbs by yourself, please ask the Conference Secretariat and we will explain you who to use “marshrutka” to get it. Taxi (in Russian – “Такси” [taksi]) Saint-Petersburg has many taxis. We have no any special stops for taxi as in other European cities. To book the taxi it is necessary to call to taxi number. If you are going to book a taxi, please contact to conference secretariat and we will help you to do it. Please do not take a taxi in airport or in the street, it will be dangerous. Please use the taxi which will be booked for you by conference secretariat. 169 9th European Symposium on Martensitic Transformations ESOMAT 2012 Cash and credit cards Many stores, restaurants, cafes, museums accept credit cards – VISA and MASTER CARDS. There are many cash dispensers in the banks, stores, subway station where you may receive roubles in cash from your credit cards. Meanwhile, in small shops, subway ticket office, ticket office of river boat trips, busses, trams, trolleybuses, marshrutka and other places you may pay only by CASH. Pay attention to all payment must be in Rubles only. You may change dollars and euro to roubles in currency exchange offices (in Russian – “Обмен валюты” [obmen valuti]). The rate of dollars to rouble is approximately 1$ = 30 RUB, the rate of EURO to roubles is approximately 1EURO = 39.5 RUB. You may change other currency to roubles however, the rate will be very low. Please do not use the currency exchange office in airport, because the rate of currency including dollars and euro is very low. The currency exchange offices are in the banks (Bank is in Russian – “Банк”). Most banks work from 10:00 to 19:00 (from Monday to Friday), from 10:00 to 18:00 on Saturday. Banks are usually closed on Sunday. Some banks are open on Sunday too. Be sure to bring along your passport because without a passport you can not change money. Average charge is about 20-30 RUB for change money. Dining In Saint-Petersburg there are many restaurants and cafes. In the central part of the city most of restaurants and cafes have a menu in English. Usually, these places have a notice on the door “English menu”. The price of the menu depends on the places. The average price in large restaurants is 100 – 300 EURO for one person and in a small restaurant is 50 – 100 EURO. The average price in the cafés is 30 – 50 EURO. In the Saint-Petersburg there are many fast food places. All well-known fast food companies such as McDonalds, BurgerKing, Subway and other are located in the center of a city. Moreover, there are Russian fast food companies such as “Теремок” [teremok] or “Чайная ложка” [chainaya lozhka]. The average price for one person is 7-10 EURO. Emergency and security In the case of emergency situations please call to conference secretariat +7-911-9949636, call to police 112 and to your consulate. The address of consulate of your country in Saint- Petersburg and phone of your consulate are located on the back side of your badge. In the crowd places such as museums, squares, public transports and etc, please keep your bag behind you. Do not put your passport and money in the hip or side pockets. In the hotel, please use a safety box. 170