DOCSLIB.ORG

Recent Progress in the Field of Permanent Magnets K

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Recent Progress in the Field of Permanent Magnets K Recent progress in the field of permanent magnets K. Hoselitz To cite this version: K. Hoselitz. Recent progress in the field of permanent magnets. J. Phys. Radium, 1951, 12(3), pp.448-458. 10.1051/jphysrad:01951001203044800. jpa-00234404 HAL Id: jpa-00234404 https://hal.archives-ouvertes.fr/jpa-00234404 Submitted on 1 Jan 1951 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. LE JOURNAL DE PHYSIQUE ET LE RADIUM. TOME 12, MARS 1951~ PAGE 448. RECENT PROGRESS IN THE FIELD OF PERMANENT MAGNETS By K. HOSELITZ. Sommaire. - Après un bref rappel des conditions techniques exigées pour la construction des aimants permanents, le rapport classe les alliages magnétiques en quatre types principaux : les aciers à aimants, les alliages durcissant par précipitation, les alliages durcissant par diffusion et les aimants en poudres comprimées. Les aciers ne sont pas étudiés et quelques alliages à durcissement par précipitation seulement sont mentionnés : le « vicalloy » et les alliages fer-nickel-cuivre. On étudie, de façon plus détaillée, les alliages durcissant par diffusion et, après un bref historique de leur développement, on décrit les plus récents et les plus utiles d’entre eux, comme l’alcomax et l’alnico V. On tente d’expli- quer le champ coercitif élevé et l’anisotropie de ces matériaux. Leur champ coercitif élevé est attribué à l’hétérogénéité magnétique des alliages et les résultats expérimentaux sont en accord quantitatif raisonnable avec la théorie. L’origine de l’anisotropie réside probablement dans la forme des aggrégats hétérogènes, due à l’action du champ magnétique pendant le refroidissement. On indique les derniers progrès réalisés avec la construction des éléments à cristaux orientés parallèlement, qui ont des propriétés magnétiques supérieures à celles des aimants à cristaux orientés au hasard. Technical Requirements. - In the majority assumption that the major hysteresis loop in the of applications of permanent magnet materials second quadrant obeys an algebraical equation, the salient requirement is that a high magnetic usually of the second order and whilst such design field should be maintained in an air gap of the principles are possibly of considerable practical magnet system. The system must often be stable importance they are our not thought to be of funda- against external influences of changing temperature, mental scientific interest. Useful ,contributions to mechanical vibration or shock or electromagnetic the subject have been made by Hornfeck and fields and this should be achieved preferably with Edgar [I940], Desmond [1945, 1949] and San- a minimum of magnet alloy. For this purpose ford it is necessary that the magnet system is correctly Even greater complications arise in the case of designed. The basic principles governing the design external magnetising forces, arising for instance, of permanent magnets working under static condi- from armature reaction in a generator or magneto. i.e. in where there are no considerable some . tions, These also to been dealt . systems have, extent, external demagnetising fields, have been adequa- with by the above authors. In the present account tely described by Evershed [1920]. From these design considerations are not included because considerations it is clear that the most important a superficial description would be inadequate and a characteristic of a permanent magnet material detailed treatment would make this report into- is its product and the flux density and lerably long. demagnetising field strenght corresponding to the > In principle it is considered that the most impor- The of the point. significance tant characteristics are those of the major hyste- has been described and point extensively variously resis loop, probably with the addition of the rever- in the literature and I do not to existing propose sible permeability or recoil permeability. Consi- enter any further into this question. derable ambiguity is found in the values quoted If the magnet is applied in an instrument or for recoil permeability of permanent magnet mate- which involves either a external apparatus varying rials by various authors and hence no figures are reluctance or a varying external magnetising force, given in the present report. the of the economic utilisation of the question In an efficient permanent magnet material in material suffers some modification and the slight general one desires a high coercive force, a high minor have to be considered, as hysteresis loops remanence and a high energy product. Further- has been out Evershed. For the already pointed by more the manufacturing process will govern the case of external reluctance the varying only, working external shape of the magnet and in some cases point of the permanent magnet should preferably the mechanical properties will influence the appli- be chosen on that minor hysteresis loop on which cation. the useful recoil is a maximum. A number energy There exists four main of of workers have to find types permanent attempted algebraical materials : solutions to the problem of determining the optimum magnet magnet dimensions for a given application from the Firstly magnet steels, which are essentially carbon demagnetisation curve of the permanent magnet steels with additional elements. These are by now material. Such solutions usually rely on the standardised and cannot be claimed in any way Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphysrad:01951001203044800 449 to be classed as recent developments. They are, for the tabulation of their main properties in therefore, not dealt with in this account, except Table I. ° TABLE I. Composition, magnetic, physical, mechanical properties anelheat treatlnent of magnet steels. Nominal composition percent (1) Unless otherwise specified; steels are available in Great Britain. (2) Equivalent to British steel, available under the name stiown in country inrlicated by letter G. : Germany : U. S. A. : United States of America. TABLE II. Jfagnetic properties of precipitation Hardening klagnetic aLloJ"s. Secondly there are various types of precipitation Thirdly there are the diffusion hardening magnet hardening permanent magnet alloys which can be alloys (Table III) based on the iron-nickel-alu- worked by hot or cold working methods. Here minium system with additions of one or more of we have the conventional alloys such as iron-cobalt- the elements cobalt, copper, titanium and niobium. molybdenum, iron-nickel-copper, and iron-cobalt- By far the greatest number of modern permanent vanadium. Many of the precipitation hardening magnets are made from one of the many good alloys alloys can be cold worked and after severe cold of this group. Some of these alloys exhibit a pro- reduction a pronounced anisotropy in the rolling nounced magnetic anisotropy when heat treated in a or wire drawing direction is observed. The manu- magnetic field and these anisotropic alloys are the most facture of these materials is usually expensive and efficient modern permanent magnet alloys. The they are used only to a small extent. Their charac- iron-nickel-aluminium alloys are all brittle and hard teristics are quoted in Table II. and at present there is no way of making them workable. 450 MARLE III. Magnetic properties of diilusion hardening Magnet alloys. TABLE IV. Magnetic properties of permanent magnet materials made from Consequently these alloys have to be cast approxi- of powder particles each of which are smaller than mately to shape and final accurate dimensions have a given critical size exhibit large coercive forces to be achieved by grinding. and this fact is used in manufacturing permanent Finally there is a large number of various per- magnets out of chemically produced colloidal powders manent magnet materials made by processes of of pure iron or iron-cobalt. powder metallurgy, but it does not appear at present as though their practical importance would justify Precipitation Hardening Permanent Magnet a very extensive discussion. Some of these materials Alloys. ---- It was suggested by Seljesater and are included in Table IV. Rogers [1931] and K6ster [I932 a, b] that preci- The most notable discoveries along newer lines, pitation of a second phase from a supersaturated are based on the magnetic properties of ferro- solution could be utilised in producing materials of magnetic materials in a fine state of sub-division high magnetic hardness for permanent magnets. (N6el, Weil and Aubry; 1942). Magnets composed The alloys investigated where those which form 451 extended solid solutions with iron at high temperatures for 3 hours at 65oo C. The material is now magne- with decreasing solubility at low temperatures, i.e. tically hard and is further cold rolled to the final iron-molybdenum, iron-tungsten, iron-beryllium. and dimensions where the reduction in area should iron-titanium. In order to obtain a supersaturated be about 80 to go per cent. The magnetic properties solid solution these alloys have to be quenched are somewhat spoilt during cold rolling, but further
Load more

Recommended publications
  • Investigation of Mg and Zr Addition on the Mechanical Properties of Commercially Pure Al Samiul Kaiser, M
    World Academy of Science, Engineering and Technology International Journal of Mechanical and Materials Engineering Vol:13, No:9, 2019 Investigation of Mg and Zr Addition on the Mechanical Properties of Commercially Pure Al Samiul Kaiser, M. S. Kaiser stable against particle coarsening. It causes additional Abstract—The influence of Mg and Zr addition on mechanical distribution of dislocations which pin grain boundaries and properties such as hardness, tensile strength and impact energy of inhibit recrystallization. The Al3Zr particles form from the commercially pure Al are investigated. The microstructure and melt as a primary phase during rapid solidification, act as fracture behavior are also studied by using Optical and Scanning nuclei for the solidification of Al, and Zr can thus operate as Electron Microscopy. It is observed that magnesium addition improves the mechanical properties of commercially pure Al at the grain refiner of Al [13]-[15]. Based on the above point of view, Mg is added to expense of ductility due to formation of β″ (Al3Mg) and β′ (Al3Mg2) phase into the alloy. Zr addition also plays a positive role through commercially pure Al used in this study to form the binary grain refinement effect and the formation of metastable alloy. The other element Zr is subsequently added with Mg to L12 Al3Zr precipitates. In addition, it is observed that the fractured study their mutual effect on the mechanical properties of cast surface of Mg added alloy is brittle and higher numbers of dimples Al at room temperatures. are observed in case of Zr added alloy. II. EXPERIMENTAL PROCEDURE Keywords—Al-alloys, hardness, tensile strength, impact energy, microstructure.
    [Show full text]
  • Brazing Compilation of Literature References from 1973 to 1978
    OCTOBER 1979 BRAZING COMPILATION OF LITERATURE REFERENCES FROM 1973 TO 1978. BY J.C. RÖMER N et hf^rlfi rids E norqy R o soa re h \ oundation ECN does not assume any liability with respect to the use of, or for damages resulting from the use of any information, apparatus, method or process disclosed in this document. Netherlands Energy Research Foundation ECN P.O. Box 1 1755 ZG Petf.n(NH) The Netherlands Telephone (0)2246 - 62».. Telex 57211 ECN-7* OCTOBER 1979 BRAZING COMPILATION OF LITERATURE REFERENCES FROM 1973 T01978. BY J.C. ROMER -2- ABSTRACT This report is a compilation of published literature on high temperature brazing covering the period 1973-1978. The references are listed alphabetically with regard to the base material or combination of base materials to be brazed. Trade names are treated as base materials. The report contains approximately 1500 references, of which 300 are to patents. KEYWORDS BRAZING BRAZING ALLOYS FILLER METALS JOINING - 3 CONTENTS ABSTRACT 1. ALUMINIUM 2. ALUMINIUM (FLVXLESS) 3. ALUMINIUM - BERYLLIUM 4. ALUMINIUM/BORON COMPOSITES 5. ALUMINIUM - COPPER 5.1. Aluminium - graphite 5.2. Aluminium - nickel alloys 5.3. Aluminium - niobium 5.4. Aluminium ~ molyldenum 5.5. Aluminium - stainless steel 5.6. Aluminium - steels 5.7. Aluminium - tantalum 5.8. Aluminium - titanium 5.9. Aluminium - tungsten 6. BERYLLIUM 7. BORONNITRIDE• 8. BRASS 8.1. Brass - aluminium 8.2. Brass - steels 9. BRONZE 9.1. Bronze - stainless steels 10. CERAMICS 10.1. Ceramics - metal - 4 - CERMETS 61 11.1. Cermets - stainless steels 62 COBALT 63 COPPER ALLOYS 64 13.1. Copper alloys - brass 68 13.2.
    [Show full text]
  • X-Ray Diffraction Studies of 145 Mev Proton-Irradiated Albemet 162
    X-Ray Diffraction Studies of 145 MeV proton-irradiated AlBeMet 162 Mohamed Elbakhshwan1, Kirk T. McDonald2, Sanjit Ghose3, Zhong Zhong3, Nikolaos Simos1,3* 1Nuclear Science and Technology Department, Brookhaven National Laboratory, Upton, NY 11973 2Joseph Henry Laboratories, Princeton University, Princeton, NJ 08544 3National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY 11973 Abstract AlBeMet 162 (Materion Co., formerly Brush Wellman) has been irradiated with 145 MeV protons up to 1.2x1020 cm-2 fluence, with irradiation temperatures in the range of 100-220oC. Macroscopic post- irradiation evaluation on the evolution of mechanical and thermal properties was integrated with a comprehensive x-ray- diffraction study using high-energy monochromatic and polychromatic x-ray beams, which offered a microscopic view of the irradiation damage effects on AlBeMet. The study confirmed the stability of the metal-matrix composite, its resistance to proton damage, and the continuing separation of the two distinct phases, fcc aluminum and hcp beryllium, following irradiation. Furthermore, based on the absence of inter-planar distance change during proton irradiation, it was confirmed that the stacking faults and clusters on the Al (111) planes are stable, and thus can migrate from the cascade region and be absorbed at various sinks. XRD analysis of the unirradiated AlBeMet 162 showed clear change in the texture of the fcc phase with orientation especially in the Al (111) reflection which exhibits a “non-perfect” six-fold symmetry, implying lack of isotropy in the composite. * Corresponding author Tel.: +1 631 344 7229 E-mail address: [email protected] 1. Introduction AlBeMet, an aluminum-beryllium compound with high Be content, is better described as a metal-matrix composite rather than an alloy, since the two metals remain as separate phases.
    [Show full text]
  • A Survey of Al7075 Aluminium Metal Matrix Composites
    International Journal of Science and Research (IJSR) ISSN (Online): 2319-7064 Index Copernicus Value (2013): 6.14 | Impact Factor (2013): 4.438 A Survey of Al7075 Aluminium Metal Matrix Composites Rajendra .S .K1, Ramesha .C .M2 1Research Scholar, Jain University, Bengaluru, Department of Industrial Engineering and Management, Dr. Ambedkar Institute of Technology, Bengaluru 2Department of Mechanical Engineering, M S Ramaiah Institute of Technology, Bengaluru Abstract:A composite material is a combination of two or more chemically distinct and insoluble phases; its properties and structural performance are superior to those of the constituents acting independently. Metals and ceramics, as well, can be embedded with particles or fibers, to improve their properties; these combinations are known as Metal-Matrix composites. Aluminum 7075 alloy constitutes a very important engineering material widely employed in the aircraft and aerospace industry for the manufacturing of different parts and components. It is due to its high strength to density ratio that it a sought after metal matrix composite. In this paper we present a survey of Al 7075 Metal Matrix Composites. Keywords: Metal Matrix Composites (MMC’s), Aluminium Metal Matrix, Beryl, Al7075, Aluminium alloy 1. Introduction Aluminium alloy 7075 is an aluminium alloy, with zinc as the primary alloying element. It is strong, with a strength The effects of research in Aluminium based Metal Matrix comparable to many steels, and has good fatigue strength and Composites (MMC’s) are far reaching these days. These average machinability, but has less resistance to corrosion composites find various applications in the automobile than many other Al alloys. Its relatively high cost limits its industry, the aerospace industry and in defence and marine use to applications where cheaper alloys are not suitable.
    [Show full text]
  • Turbulent Heat Transfer and Pressure Drop
    DESIGN OPTIMIZATION OFMAGNETIC ALLOYS AND NICKEL-BASED SUPERALLOYS FOR HIGH TEMPERATURE APPLICATIONS Rajesh Jha George S. Dulikravich Department of Mechanical and Materials Engineering, MAIDROC Lab. Florida International University 10555 West Flagler Street, Miami, Florida 33174, U.S.A. [email protected], [email protected] Marcelo J. Colaço Department of Mechanical Engineering –POLI/COPPE Federal University of Rio de Janeiro - UFRJ Cidade Universitaria, Cx. Postal: 68503, Rio de Janeiro, RJ, 21941-972, Brazil [email protected] Abstract. Developing a new material or even improving properties of an existing material is a complex and time- consuming task. In recent years, materials scientists around the globe proposed a number of ways to speed up the alloy development process by using various computational tools. In this work, we made an attempt to demonstrate the efficacy of using computational tools in design optimization of materials, especially for high-temperature applications. We addressed two different material systems: Alnico alloys (magnetic) and Nickel-based superalloys. Alnico type alloys are hard magnetic alloys and well known for high-temperature applications. In this work, we defined the variable range of various elements and generated an initial set of alloys by a quasi-random sequence generation algorithm. These alloys were synthesized and tested for determining various material properties. We used a response surface methodology approach to develop surrogate models (meta-models) that approximately linked alloy chemistry with desired properties for these multi-component systems while being computationally affordable. These models were further used for multi-objective optimization of desired (conflicting) properties by using a number of algorithms based on evolutionary approaches, as well as our hybrid optimizer.
    [Show full text]
  • Isinox Metaltec Private Limited
    +91-8042974287 Isinox Metaltec Private Limited https://www.indiamart.com/isinoxalloys/ Isinox Metaltec Private Limited is one of the renowned names occupied in manufacturing and exporting an inclusive collection of products comprising Aluminium Alloy Wire and Copper Cladding Wire. About Us Incepted in the year 2013, Isinox Metaltec Private Limited is one of the excellent business organization effortlessly engrossed in manufacturing and exporting a range of products which include Aluminium Alloy Wire and Copper Cladding Wire. Made in adherence with the prevailing market set standards, we guarantee that only optimal-class material and different modern tools and machines are used in their improvement procedure. In compliance with the trends and advancements taking place in the market, these are especially applauded. Underneath the path of our mentor Mr. Ravi Bansal, we have finished massive popularity and credibility of our customers. For more information, please visit https://www.indiamart.com/isinoxalloys/profile.html ALUMINIUM ALLOY WIRES P r o d u c t s 5052 Aluminium Alloy Wire Aluminum Alloy Wire Aluminum Alloy TIG Welding 5056 Aluminium Alloy Wire Wire ALUMINUM WELDING WIRE P r o d u c t s Aluminium Alloy Wire for 5052 Aluminum Alloy Wire Water-Bottle Carrier 1050 Aluminum Wire 2011 Aluminium Alloy Wire ALUMINIUM ALLOY WIRE P r o d u c t s 1060 1080 1085 High Quality Aluminium Alloy Wire For Aluminum Wire Used In Refrigerator Grilles Aluminium Alloy Wire For 1120 Aluminium Alloy Wire Clothes Pegs ALUMINUM WIRE P r o d u c t s 5154
    [Show full text]
  • Evolution of Microstructure During Recrystallization in As-Cast Aluminium - Magnesium Alloys with Ternary Titanium/ Zirconium Addition
    ISSN(Online) : 2319 -8753 ISSN (Print) : 2347 -6710 International Journal of Innovative Research in Science, Engineering and Technology (An ISO 3297: 2007 Certified Organization) Vol. 4, Issue 10, October 2015 Evolution of Microstructure during Recrystallization in As-cast Aluminium - Magnesium Alloys with Ternary Titanium/ Zirconium Addition Abdullah Al Shafea, Sanjidah Akter Urmib, A. H. M. Azadur Rahmanb, Fahmida Gulshanc, ASW Kurnyd Research Engineer, Foundry Section, Department of Metallurgy, Walton Hi-Tech Industries Ltd, Chandra, Kaliakoir, Gazipur- 1750, Bangladesha Student, Department of Materials and Metallurgical Engineering, Bangladesh University of Engineering and Technology, Dhaka-1000, Bangladeshb Assistant Professor, Department of Materials and Metallurgical Engienering, Bangladesh University of Engineering and Technology, Dhaka-1000, Bangladeshc Professor, Department of Materials and Metallurgical Engineering, Bangladesh University of Engineering and Technology, Dhaka-1000, Bangladeshd ABSTRACT: The purpose of this research was to investigate the influence of Zirconium and Titanium on Al-5Mg alloy. Zirconium and Titanium in the range of 1.5-2wt% individually and combined have been added to Al-5Mg alloy by melt processing technique. The cast alloys were then subjected to investigation for their microstructure and mechanical properties.The evolution of microstructures during as cast condition was studied extensively using optical microscope (OM) which identifies the refining action of both Zr and Ti. Use of different kinds of etching reagent in the microstructural analysis showed different perspective results. The morphology of the intermetallic formed- Al3Zr and Al3Ti, the presence of dendrite structures and the relation of tensile strength on secondary dendritic arm spacing were studied. Use of Zr as third party material provides greater mechanical properties compared to Ti addition but Zr does not influence hardness as does the Ti alone.
    [Show full text]
  • Read Journal
    Online ISSN : 2249-4596 Print ISSN : 0975-5861 Land Observation Satellites An Algorithm for Integration Industrial Augmented Reality Properties of Recycled Materials VOLUME 14 ISSUE 7 VERSION 1.0 Global Journal of Researches in Engineering: J General Engineering Global Journal of Researches in Engineering: J General Engineering Volume 14 Issue 7 (Ver. 1.0) Open Association of Research Society © Global Journal of Global Journals Inc. Researches in Engineering. (A Delaware USA Incorporation with “Good Standing”; Reg. Number: 0423089) Sponsors: Open Association of Research Society 2014. Open Scientific Standards All rights reserved. Publisher’s Headquarters office This is a special issue published in version 1.0 of “Global Journal of Researches in Global Journals Headquarters Engineering.” By Global Journals Inc. All articles are open access articles distributed 301st Edgewater Place Suite, 100 Edgewater Dr.-Pl, under “Global Journal of Researches in Wakefield MASSACHUSETTS, Pin: 01880, Engineering” United States of America Reading License, which permits restricted use. Entire contents are copyright by of “Global USA Toll Free: +001-888-839-7392 Journal of Researches in Engineering” unless USA Toll Free Fax: +001-888-839-7392 otherwise noted on specific articles. No part of this publication may be reproduced Offset Typesetting or transmitted in any form or by any means, electronic or mechanical, including Global Journals Incorporated photocopy, recording, or any information storage and retrieval system, without written 2nd, Lansdowne, Lansdowne Rd., Croydon-Surrey, permission. Pin: CR9 2ER, United Kingdom The opinions and statements made in this book are those of the authors concerned. Packaging & Continental Dispatching Ultraculture has not verified and neither confirms nor denies any of the foregoing and Global Journals no warranty or fitness is implied.
    [Show full text]
  • A Review on Effect of Tool Geometry on Mechanical Properties of Friction Stir Welding of AA 6082-T6 Mr
    Vol-1 Issue-5 2015 IJARIIE-ISSN(O)-2395-4396 A Review On Effect of Tool Geometry on Mechanical Properties of Friction Stir Welding of AA 6082-T6 Mr. K.S Bhagwat1, Prof. Hredeya Mishra 2 1 PG Student, Mechanical Engineering Department, JCEI’SJaihind College of Engineering, Kuran- 410511 [MS], India. 2 Assistant Professor, Mechanical Engineering Department, JCEI’S Jaihind College of Engineering, Kuran- 410511 [MS], India. ABSTRACT Friction stir welding (FSW) is a novel solid state welding process for joining metallic alloys and has been employed in several industries such as aerospace and automotive for joining aluminum, magnesium and copper alloys. The various parameters such as rotational speed, welding speed, axial force and attack angle play vital role in FSW process in order to analyze the weld quality. The aim of this study is to investigate the effect of rotational speed, welding speed and tool pin profile on weld quality. Friction stir welds find use for structural and other fabrication industries. This report provides details of FSW equipment used and explains the effect of welding speed and rotational speed on the mechanical properties of butt joints in AA6082-T6 material of 5mm thickness for different tool profiles. Weld tensile strength was measured and influence of process parameters was assessed. The weld’s microstructure in various zones was analyzed using optical microscope. Microhardness measurements were performed on the weld’s cross-sections. As tool profile is vital, Special Design (SD) profiled pins were designed and manufactured for trials. The appearance of the weld was studied for surface defects and found to be small in weld nugget.
    [Show full text]
  • Thermomechanical Ageing (TMA) of 2014 Aluminium Alloy for Aerospace Applications
    Bull. Mater. Sci., Vol. 14, No. 1, February 1991, pp. 35-41. © Printed in India. Thermomechanical ageing (TMA) of 2014 aluminium alloy for aerospace applications S SINGH and D B GOEL Department of Metallurgical Engineering, University of Roorkee, Roorkee 247 667, India MS received 4 June 1990; revised 13 February 1991 Abstract. Various thermomechanical ageing (TMAJ treatments for 2014 Al-alloy have been developed which include partial peak ageing, warm rolling and further ageing to peak hardness at 160°C. Electron microscopic studies reveal that the TMA treatments affect substantially the ageing characteristics. The TMA-Ib treatment yields finest O' needles having longitudinal dimensions of ~400A,. TMA treatment leads to precipitate- dislocation network of different magnitudes. Among the TMA treatments, the TMA lib treatment results in thickest precipitate-dislocation tangles. In addition to 0', two types of dispersoids A14CuMgsSi,, and AI12(Fe, Mn)3Si have been observed. The density or concentration of these dispersoids is drastically reduced due to TMA treatments. Thus an optimum TMA treatment i.e. TMA-IIb has been developed which results in a significant improvement in the mechanical properties of 2014 Al-alloy. Keywords. Thermomechanical ageing; 2014 aluminium alloy. 1. Introduction The 2014 Al-alloy has a nominal composition: 4.40 Cu, 0-40 Mg, 0.80 Mn, 0.80 Si (Wt.%) and Fe as impurity element. Although this alloy has its own importance in the aircraft industry due to high hardness and high strength at room temperature, its effective application is significantly hampered because of the poor dynamic properties like fatigue strength and fracture toughness and tensile properties at elevated temperatures.
    [Show full text]
  • Application of a State Variable Description of Inelastic Deformation to Geological Materials
    APPLICATION OF A STATE VARIABLE DESCRIPTION OF INELASTIC DEFORMATION TO GEOLOGICAL MATERIALS A thesis submitted for the degree of Doctor of Philosophy (University of London) and for the Diploma of University College by Stephen John Covey-Crump Department of Geological Sciences, University College London, Gower Street, London, WC1E 6BT ProQuest Number: 10630768 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a com plete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. uest ProQuest 10630768 Published by ProQuest LLC(2017). Copyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States C ode Microform Edition © ProQuest LLC. ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106- 1346 2 ABSTRACT The work reported in this thesis is an investigation of the potential for employing non­ steady-state constitutive relations to describe the inelastic deformation properties of rock forming minerals. Attempts to determine generally applicable constitutive equations for inelastic deformation are complicated by the severe path dependence of the deformation response and by the wide range of mechanisms by which that deformation is accomplished. In the geological literature it has been normal practice to circumvent these problems by approximating the deformation as occurring at steady-state. This presents difficulties for the description of deformation by inherently transient mechanisms, for the description of small strain deformation, and for the reliability of extrapolating laboratory mechanical properties to geological deformation conditions.
    [Show full text]
  • Couplant Effect and Evaluation of FSW AA6061-T6 Butt Welded Joint
    COPYRIGHT AND CITATION CONSIDERATIONS FOR THIS THESIS/ DISSERTATION o Attribution — You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use. o NonCommercial — You may not use the material for commercial purposes. o ShareAlike — If you remix, transform, or build upon the material, you must distribute your contributions under the same license as the original. How to cite this thesis Surname, Initial(s). (2012) Title of the thesis or dissertation. PhD. (Chemistry)/ M.Sc. (Physics)/ M.A. (Philosophy)/M.Com. (Finance) etc. [Unpublished]: University of Johannesburg. Retrieved from: https://ujcontent.uj.ac.za/vital/access/manager/Index?site_name=Research%20Output (Accessed: Date). Couplant Effect and Evaluation of FSW AA6061-T6 Butt Welded Joint By Itai Mumvenge 217093863 Submitted in partial fulfilment of the requirements for the degree of Master of Engineering in Mechanical Engineering In the Department of Mechanical Engineering Science Of the Faculty of Engineering and the Built Environment At the University of Johannesburg, South Africa Supervisor: Dr Stephen A. Akinlabi Co-Supervisor: Dr Peter M. Mashinini November, 2017 i 1. DEDICATION This dissertation is dedicated to my late grandmother Esnath Mvenge ii 2. COPYRIGHT STATEMENT The copyright of this dissertation is owned by the University of Johannesburg, South Africa. No information derived from this publication may be published without the author’s prior consent, unless correctly referenced. ………………………………….. 25 November 2017 Author’s Signature Date: iii 3. AUTHOR DECLARATION I, Mumvenge Itai hereby declare that the research work documented in this dissertation is my own, and no portion of the work has been submitted in support of an application for another degree or qualification at this or any other university or institute of learning.
    [Show full text]