DOCSLIB.ORG

Development of a Process to Obtain a Graded Distribution of Particles Along the Overlap of Adhesive Single Lap Joints

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Development of a Process to Obtain a Graded Distribution of Particles Along the Overlap of Adhesive Single Lap Joints ENGINEERING FACULTY OF UNIVERSITY OF PORTO DEPARTMENT OF MECHANICAL ENGINEERING Development of a process to obtain a graded distribution of particles along the overlap of adhesive single lap joints Supervisor: Lucas da Silva Author: Catarina Isabel Seixas da Silva Co-Supervisors: Ana Queirós José Marques A thesis submitted for the degree of MSc of Mechanical Engineering june, 2019 Development of a process to obtain a graded distribution of particles along the overlap of adhesive single lap joints ii Development of a process to obtain a graded distribution of particles along the overlap of adhesive single lap joints © Catarina Isabel Seixas da Silva Departamento de Engenharia Mecânica Faculdade de Engenharia da Universidade do Porto Rua Dr. Roberto Frias 4200-465 Porto Portugal Development of a process to obtain a graded distribution of particles along the overlap of adhesive single lap joints iv Development of a process to obtain a graded distribution of particles along the overlap of adhesive single lap joints Abstract The constant need for improvement and innovation at all industries leads to the development of new technologies. Adhesive bonding is a joining technique in constant growth as, replacing conventional methods of fastening such as bolts and rivets, as it offers potential weight and cost savings. The adhesive joint most studied and used in industrial applications is the single lap joint (SLJ), mainly due to its simplicity and efficiency. In typical SLJs, however, one of the problems associated with them is the nonuniform stress distribution (shear and peel), being concentrated at the ends of the overlap. This leads to early joint failure, especially if the adhesive is brittle. One of the main areas of investigation in the field of adhesive bonding is the development of methods for reducing such stress concentrations. In fact, functionally graded adhesive joints have been gaining attention as a technique to even those stress distributions along the joint, due to their potential high degree of customization, offering more solutions for application design. Essentially, this method consists of a modified adhesive with properties that vary gradually along the bondline, allowing an enhanced stress distribution along the overlap region. Therefore, the main goal of this work is to propose a new method to decrease stress concentrations by applying the concept of functionally graded adhesive joints using magnetised cork microparticles. Thereupon, a customized apparatus was designed. With the appropriate application of tailored magnetic fields, using a set of magnets arrays, the magnetised microparticles were strategically placed along the bondline, then creating a particle concentration gradient from the ends of the overlap (higher) to the middle (lower). Numerical models were developed to predict the particle distribution along the joint caused by the application of magnetic fields. Those models were based on the phenomenon of magnetophoresis of cork-magnetite microparticles. A characterisation of the magnetic behaviour of cork and magnetised cork microparticles was also performed. Early experimental tests using glass slides with the particles uniformly distributed within the adhesive selected were performed to validate the simulations. Mechanical tests were executed to determine the properties of the following composite arrangements: neat resin and resin with magnetised cork microparticles (uniform and graded distributions), considering various amounts. Bulk specimens were used to perform tensile tests and glass transition temperature measurements. SLJs were also done to evaluate the influence of the reinforcement inclusions (magnetised cork microparticles). Simultaneously to mechanical testing, SEM analysis was made in regard to the particles themselves and the bulk specimens fracture surfaces. i Development of a process to obtain a graded distribution of particles along the overlap of adhesive single lap joints Overall, it is concluded that the magnetised cork particles gradely distributed in the overlap region of the SLJ serve as reinforcement inclusions. This way, the newly developed method was validated, along with the apparatus conceived to produce such joints. Keywords: Epoxy adhesives, functionally graded adhesive joints, magnetised particles, cork microparticles, magnetophoresis, numerical analysis, stress distribution, mechanical properties. ii Development of a process to obtain a graded distribution of particles along the overlap of adhesive single lap joints Resumo A necessidade constante de melhoria e inovação em todas as indústrias conduz ao desenvolvimento de novas tecnologias. O uso de ligações adesivas está a ganhar destaque como método de ligação estrutural, substituindo métodos convencionais de fixação, tais como a utilização de parafusos e rebites, uma vez que este método potencia reduções de peso estrutural, assim como de custo. A junta adesiva mais estudada e usada em aplicações industriais é a junta de sobreposição simples (JSS), devido principalmente à sua simplicidade e eficiência. Contudo, na maioria das JSSs, um dos problemas associados é a distribuição não uniforme de tensões (corte e arrancamento), estando estas concentradas nas extremidades da sobreposição. Por sua vez, tal desencadeia a rotura prematura das juntas, especialmente se o adesivo for frágil. Neste sentido, umas das áreas principais de investigação relativamente às juntas adesivas é o desenvolvimento de métodos para reduzir essas concentrações de tensões. Na realidade, as juntas adesivas funcionalmente graduadas têm vindo a ganhar mais relevância como uma técnica para igualar a distribuição de tensões, podendo ser facilmente modificadas para se melhor adaptarem ao carregamento e oferecendo uma vasta gama de soluções a nível de design. Essencialmente, este método consiste em ter- se um adesivo modificado com propriedades que variam gradualmente ao longo do comprimento de sobreposição, permitindo assim a existência de uma melhor distribuição uniforme de tensões nessa região. Deste modo, o objetivo principal deste trabalho é propor um novo método para diminuir as concentrações de tensões, através da aplicação do conceito de juntas adesivas funcionalmente graduadas, usando micropartículas de cortiça magnetizadas. Portanto, foi projetado um mecanismo para este efeito. Através da aplicação apropriada de campos magnéticos cuidadosamente desenhados, obtidos usando um conjunto de magnetes, as partículas magnetizadas foram estrategicamente colocadas ao longo da sobreposição de uma junta adesiva, criando assim um gradiente de concentração de partículas desde as extremidades (elevado) até ao centro (baixo). Modelos numéricos foram desenvolvidos de modo a prever a distribuição das partículas ao longo da junta, causada pela aplicação de campos magnéticos. Esses modelos basearam-se no fenómeno da magnetoforese de micropartículas de cortiça-magnetite. Por outro lado, foi também realizada a caraterização relativa ao comportamento magnético de partículas de cortiça pura e magnetizada. Testes experimentais preliminares usando lamelas de vidro com partículas uniformemente distribuídas no adesivo foram realizados de modo a validar as simulações feitas anteriormente. iii Development of a process to obtain a graded distribution of particles along the overlap of adhesive single lap joints Testes mecânicos foram executados para determinar as propriedades básicas dos seguintes arranjos compósitos: resina e resina com micropartículas de cortiça magnetizadas (distribuições uniforme e graduada), considerando quantidades variadas. Provetes bulk foram usados para executar testes de tração e medições da temperatura de transição vítrea. JSSs foram também feitas de modo a avaliar a influência de inclusões de reforço (micropartículas de cortiça magnetizada). Simultaneamente aos testes mecânicos, foi realizada uma análise pelo SEM relativamente às partículas e às superfícies de fratura dos provetes bulk. Globalmente, concluiu-se que as partículas magnetizadas de cortiça distribuídas gradualmente na zona de sobreposição de uma JSS funcionam como inclusões de reforço. Desta forma, o novo método desenvolvido foi validado, assim como o mecanismo concebido para produzir estas juntas. Palavras-chave: Adesivos epóxidos, juntas adesivas funcionalmente graduadas, partículas magnetizadas, micropartículas de cortiça, magnetoforese, análise numérica, distribuição de tensões, propriedades mecânicas. iv Development of a process to obtain a graded distribution of particles along the overlap of adhesive single lap joints Acknowledgements This thesis would not have been possible without the guidance from everybody listed next. So, for that, I am really thankful for all the help and support you all gave me. To my supervisor, Professor Lucas, I would like to thank, whose expertise was invaluable in the formulation of the research topic. I am especially thankful to Ana and Zé for their valuable guidance. You provided me with the tools that I needed to choose the right direction and successfully complete my dissertation. I am grateful to all of those whom I have had the pleasure to work with during this semester. Each of the members of ADFEUP has provided me extensive personal and professional guidance and taught me a great deal about scientific research and life in general. Also, I would like to thank Vítor Amaral, from CISM (Centre for Imaging and Structure of Materials), University of Aveiro, for providing me relevant content about the magnetic behaviour of the pure and magnetised
Load more

Recommended publications
  • The Influence of Age Hardening and Shot Peening on the Surface
    materials Article The Influence of Age Hardening and Shot Peening on the Surface Properties of 7075 Aluminium Alloy Sebastjan Žagar 1, Boštjan Markoli 2, Iztok Nagliˇc 2 and Roman Šturm 1,* 1 Faculty of Mechanical Engineering, Aškerˇceva6, 1000 Ljubljana, Slovenia; [email protected] 2 Faculty of Natural Sciences and Engineering, Aškerˇceva12, 1000 Ljubljana, Slovenia; [email protected] (B.M.); [email protected] (I.N.) * Correspondence: [email protected]; Tel.: +386-14-771-203 Abstract: The present study investigates the effect of shot peening (SP) on the mechanical properties and surface roughness of 7075 aluminum alloy during different stages and conditions of heat treatment. The mechanical properties were determined by measuring Vickers microhardness profiles and residual stress profiles, while the amount of alloying elements present in the solid solution of the samples under different heat treatment conditions was determined by measuring the electrical conductivity. The results show that the increase in microhardness near the SP surface and the maximum compressive residual stresses are mainly related to the content of alloying elements in the solid solution. Surface roughness increases with increasing SP Almen intensity, and samples with the highest microhardness and residual stresses have the lowest surface roughness. Keywords: aluminum alloy 7075; shot peening; microhardness; residual stresses; surface roughness Citation: Žagar, S.; Markoli, B.; Nagliˇc,I.; Šturm, R. The Influence of 1. Introduction Age Hardening and Shot Peening on Aluminum alloy 7075 is widely used in automotive and aerospace industries due to its the Surface Properties of 7075 high strength and light weight [1].
    [Show full text]
  • On Mechanical Properties of Aluminum Alloys
    Technical Journal, University of Engineering and Technology (UET) Taxila, Pakistan Vol. 25 No. 1-2020 ISSN:1813-1786 (Print) 2313-7770 (Online) The Effect of Filler Materials (Al 4047 and Al 5356) on Mechanical Properties of Aluminum Alloys (AA6061-O and Heat-Treated AA7075-T6) in Tungsten Inert Gas (TIG) Dissimilar Metal Welding A.Batool1, N.A.Anjum2, H.Jawaid3 1,2,3Department of Mechanical Engineering, University of Engineering & Technology, Taxila, Pakistan 2 [email protected] Abstract- The purpose of the current work is to any other Alloy. investigate the combined effect of thickness and the As compared to other alloys of aluminum, the 6061 mechanical properties of dissimilar aluminum alloys series Al-alloys have been examined broadly due to annealed AA6061-O and heat-treated AA7075-T6 on their attributes like medium strength, better weld- the tensile strength of the joint. The joint is made by ability, formability, good corrosion resistance and Tungsten Inert Gas (TIG) welding using suitable fillers reduced cost of Aluminum alloy 6061 is one of the most Al 4047 and Al 5356. Different samples i.e. Welded utilized of the 6000 series aluminum alloys [2]. It is a Over-Nugget Sample (WOS), Welded Ground Sample versatile heat treatable alloy with intermediate to (WGS) and Base Material (BM) were investigated advanced strength capabilities [3]. The 6061 under tensile loading. In order to avoid failure, the Aluminum alloys are extensively used in the thickness of weak strength AA6061-O must be greater fabrication of several Aircraft and aerospace as compared to the thickness of AA7075 comprising components, transport and bicycle frames, marine high strength in order to balance stresses on both sides.
    [Show full text]
  • Surface Deformation and Rebound for Normal Single-Particle Collisions in a Surrounding fluid
    J. Fluid Mech. (2019), vol. 871, pp. 1044–1066. c Cambridge University Press 2019 1044 doi:10.1017/jfm.2019.349 Surface deformation and rebound for normal single-particle collisions in a surrounding fluid https://doi.org/10.1017/jfm.2019.349 . Angel Ruiz-Angulo1, Shahrzad Roshankhah2 and Melany L. Hunt2,† 1Icelandic Meteorological Office, 108 Reykjavík, Iceland 2Division of Engineering and Applied Science, California Institute of Technology, 1200 E. California Blvd., MC 104-44, Pasadena, CA 91125, USA (Received 21 December 2018; revised 4 March 2019; accepted 23 April 2019; first published online 3 June 2019) This article presents experimental measurements involving immersed collisions https://www.cambridge.org/core/terms between a rigid impactor and a deformable target for a wide range of Reynolds and Stokes numbers. Three aluminium alloys are used as solid targets submerged in seven different fluids covering a wide range of viscosity and density. The collision and rebound velocities as well as the depth and diameter of the crater produced by the collisions are measured with high resolution. Most of the experiments in this study occur at velocities for which the deformation is within the elastic–plastic regime. Results of the experiments in air are analysed by elastic, plastic and elastic–plastic theories, and demonstrate the complexities of modelling elastic–plastic collisions. For collisions in a liquid, the measurements show that the size of the crater is independent of the fluid characteristics if the Stokes number is beyond a critical value. The normal coefficient of restitution can be estimated by including both viscous losses and plasticity effects and assuming that the collision time scale is significantly shorter than the hydrodynamic time scale.
    [Show full text]
  • (11604843) Under the Guidance of Mr. Piyush Gulati Asst. Professor
    Evaluating the effects of reinforcement particles on mechanical and metallurgical properties of friction stir processed aluminum alloy composites Dissertation-II Submitted in partial fulfillment of the requirement for the award of degree Of MASTER OF TECHNOLOGY In MECHANICAL ENGINEERING By Kaushal Kumar (11604843) Under the guidance of Mr. Piyush Gulati Asst. Professor SCHOOL OF MECHANICAL ENGINEERING LOVELY PROFESSIONAL UNIVERSITY PUNJAB TOPIC APPROVAL PERFORMA School of Mechanical Engineering Program : P17H::M.Tech. (Design) [Full Time] COURSE CODE: MEC604 REGULAR/BACKLOG: Regular GROUP NUMBER : MERGD0013 Supervisor Name: Piyush Gulati UID:14775 Designation : Assistant Professor Qualification:________________________ Research Experience : ________________________ SR.NO. NAME OF STUDENT REGISTRATION NO BATCH SECTION CONTACT NUMBER 1 Kaushal Kumar 11604843 2016 M1671 8559999054 SPECIALIZATION AREA : Design Supervisor Signature:___________________ PROPOSED TOPIC : Evaluating the effects of reinforcement particles on mechanical and metallurgical properties of friction stir processed aluminum alloy composites Qualitative Assessment of Proposed Topic by PAC Sr.No. Parameter Rating (out of 10) 1 Project Novelty: Potential of the project to create new knowledge 7.50 2 Project Feasibility: Project can be timely carried out in-house with low-cost and available 7.00 resources in the University by the students. 3 Project Academic Inputs: Project topic is relevant and makes extensive use of academic 7.50 inputs in UG program and serves as a culminating effort for core study area of the degree program. 4 Project Supervision: Project supervisor’s is technically competent to guide students, 7.00 resolve any issues, and impart necessary skills. 5 Social Applicability: Project work intends to solve a practical problem. 6.50 6 Future Scope: Project has potential to become basis of future research work, publication 7.50 or patent.
    [Show full text]
  • Mechanical and Tribological Properties of Al7475-Sicp Composites by Stir Casting Method and Wear Rate Modeling Using RSM
    Sådhanå (2019) 44:129 Ó Indian Academy of Sciences https://doi.org/10.1007/s12046-019-1105-1Sadhana(0123456789().,-volV)FT3](0123456789().,-volV) Mechanical and tribological properties of Al7475-SiCp composites by stir casting method and wear rate modeling using RSM K SEKAR Department of Mechanical Engineering, National Institute of Technology Calicut, Calicut 673601, India e-mail: [email protected] MS received 21 July 2018; revised 26 December 2018; accepted 7 March 2019; published online 29 April 2019 Abstract. The microstructure, mechanical and wear properties of the Al 7475-SiCp composites and to investigate the effects of SiC micro-particles reinforcement with alloy have been studied. Al 7475-SiCp com- posites have been developed by a stir casting method. The SiCp size in the range of 15–40 lm with weight.% of 0, 5, 10 and 15 were injected in molten Aluminum 7475 alloy in argon gas environment and stirrer using a mechanical method at 450 rpm to ensure uniform distribution of SiC particles. The mechanical properties such as hardness and compressive strength of the composites were found to be gradually improved with the addition of 5–15% SiCp reinforcement. The ultimate tensile and impact strength increased with 10% of SiCp rein- forcement. For modeling the wear rate, the experiments were conducted in Pin-on Disc tribometer at room condition. A three-level central composite design with response surface methodology was used to reduce the experimental conditions and to predict the abrasive response of wear rate through the development of mathe- matical models. The model developed is efficiently predicted the rate of wear at 95% confidence level and the entire model validate with analysis of variance.
    [Show full text]
  • Mechanical Properties of 7075 Aluminium Matrix Composites Reinforced by Nanometric Silicon Carbide Particulates
    Mechanical Properties of 7075 Aluminium Matrix Composites Reinforced by Nanometric Silicon Carbide Particulates By Zheng Ren A thesis submitted for the Degree of Master of Engineering School of Materials Science and Engineering Faculty of Science University of New South Wales September 2007 PLEASE TYPE THE UNIVERSITY OF NEW SOUTH WALES Thesis/Dissertation Sheet Surname or Family name: Ren First name: Zheng Other name/s: Abbreviation for degree as given in the University calendar: ME School: Materials Science and Engineering Faculty: Faculty of Science Title: Mechanical Properties of 7075 Aluminium Matrix Composites Reinforced by Nanometric Silicon Carbide Particulates Abstract 350 words maximum: (PLEASE TYPE) Aluminium composites reinforced by particles have received considerable attention because of their superior mechanical properties over monolithic aluminum matrix. Over the last ten years, nanocomposites with nano-sized reinforcements have become a revolutionary progress for composites because they have different strengthening mechanisms as compared to that in composites with micro-sized reinforcements. Consequently novel properties can be expected from the nanometric particulate reinforced composites. The aim of this project was to fabricate SiC (50nm)/7075 aluminium composites via a modified powder metallurgy and extrusion route. Ageing treatment was used to increase the strength of the composites and mechanical tests, including tensile test and abrasive wear test, were performed. The effects of nanometric silicon carbide particulates to the ageing behaviours and mechanical properties of the composites have been studied by optical metallography, scanning electron microscopy and transmission electron microscopy. It was found that the dispersion of nanometric silicon carbide was not homogeneous, but tended to disperse along grain boundaries.
    [Show full text]
  • Mechanical Behavior of Multiple Forged Al 7075 Aluminium Alloy
    Acta Polytechnica Hungarica Vol. 11, No. 7, 2014 Mechanical Behavior of Multiple-forged Al 7075 Aluminum Alloy Tareg S. Ben Naser, György Krallics Dept. of Materials Science and Engineering, Budapest University of Technology and Economics, Bertalan Lajos út 7, H-1111 Budapest, Hungary taregnaser@ eik.bme.hu, [email protected] Abstract: The mechanical behavior of any material can be described using several tests, such as, compression tensile, hardness test, etc. In this work, cold and hot compression tests and hardness measurements were utilized. The subject material of this study was the Al 7075 alloy in the initial state (IS) and the multiple forged (MF) state. The cold compression test at room temperature was used to measure the deformation anisotropy on the MF specimen, while the hot compression test results were used as a source data in order to establish the constitutive equation in the wide ranges of working temperature (from 250 to 450°C) and strain rate (from 0.002 to 2 s-1). The homogeneity and structure of the material were evaluated using the Vickers hardness measurements and optical microscopy images. Keywords: 7075 aluminium alloy; multiple forging; constitutive equations; hot compression test, cold compression test 1 Introduction The Al 7075 alloy is a very interesting material because of its mechanical properties, namely, low density, high strength, moderate ductility and toughness. Due to these properties, the alloy is mainly used for highly stressed structural parts. This material has a wide range of applications such as aircraft fittings, gears and shafts, fuse parts, meter shafts and gears, missile parts, regulating valve parts, worm gears, keys and various other parts of commercial aircrafts and aerospace vehicles [1].
    [Show full text]
  • Masterarbeit
    Montanuniversität Leoben – University of Leoben Department Metallurgie – Department of Metallurgy Nichteisenmetallurgie – Nonferrous Metallurgy MASTERARBEIT Thema: Einfluss von Wärmebehandlungen auf das Eigenschaftsprofil von Aluminium-Knetlegierungen der 7xxx-Serie Ersteller: Dominique Alf, Bsc. Betreuer: Dipl.-Ing. Gernot Kolb Ass.Prof. Dipl.-Ing. Dr.mont. Stefan Pogatscher Leoben, Oktober 2015 NICHTEISENMETALLURGIE MONTANUNIVERSITÄT Dominique Alf, Bsc. Oktober 2015 A-8700 LEOBEN Einfluss von Wärmebehandlungen auf das Eigenschaftsprofil von Aluminium-Knetlegierungen der 7xxx-Serie Die AMAG Austria Metall AG, ist der größte österreichische Aluminiumkonzern und Anbieter von Primäraluminium und Aluminiumhalbzeugen. Als Zulieferer für die Automobil- und Luftfahrindustrie wird von der AMAG neben einer sicheren Prozessführung auch eine ständige Weiterentwicklung der bestehenden Werkstoffe gefordert. Um diese Anforderungen erfüllen zu können, ist die AMAG stets bestrebt neue Verfahren und Werkstoffe zu entwickeln. Die Luftfahrlegierung 7075 (AlZnMgCu) gehört zu der Gruppe der aushärtbaren Werkstoffe. Abhängig von dem jeweiligen Auslagerungszustand ergeben sich hohe Festigkeiten, bei mittelmäßigen Dehnungs- und Korrosionswerten (T6) bis hin zu mittelhohen Festigkeiten mit guten Zähigkeits- und Korrosionseigenschaften (T73). Hervorragende Kombinationen der Kennwerte sind mit einer RRA (Retrogression and Reversion)-Behandlung erzielbar. Ziel dieser Arbeit ist es, ein neues thermomechanisches Verfahren – eine Kombination eines Umformschrittes
    [Show full text]
  • Influence of Milling Parameters on Mechanical Properties of AA7075
    materials Article Influence of Milling Parameters on Mechanical Properties of AA7075 Aluminum under Corrosion Conditions María Jesús Martín * , María José Cano, Germán Castillo , Manuel José Herrera and Francisco Martín Civil, Material and Manufacturing Engineering Department, EII, University of Málaga, 29071 Málaga, Spain; [email protected] (M.J.C.); [email protected] (G.C.); [email protected] (M.J.H.); [email protected] (F.M.) * Correspondence: [email protected] (M.J.M.); Tel.: +34-951-952-243 Received: 1 July 2018; Accepted: 14 September 2018; Published: 17 September 2018 Abstract: The paper describes an experimental study developed on the AA7075 T651, which is an aluminum alloy extensively used in the aeronautical industry. This work presents a double approach of investigation where there is no literature about previous research. This includes the analysis of the results obtained by the combination of mechanical and chemical actions on the mechanical properties of this material. On the one hand, the combinations of relevant milling parameters (feed rate, cutting speed) on flat samples (flat specimens have been selected by attempting to reproduce with the most accurate way the geometry and the type of machining process known as face milling is usually used in this manufacturing field). On the other hand, the stimulating effect of the corrosion by salt spray on selected batches of specimens was machined in the previous stage. Results from tensile tests performed on the whole of specimens allowed us to evaluate how the main mechanical properties (yield strength, tensile strength, and elongation at break) have been affected by the processes applied. Elongation at the break presents a reduction in an inverse order to feed a rate increase (up to 24.5%) and this reduction is extended (additional 19.17%) in specimens under corrosion conditions, which results in a greater fragility of the material.
    [Show full text]
  • Characteristics of Dissimilar FSW Welds of Aluminum Alloys 2017A and 7075 on the Basis of Multiple Layer Research Krzysztof Mroczka, Anna Wo´Jcicka, and Adam Pietras
    JMEPEG (2013) 22:2698–2705 ÓThe Author(s). This article is published with open access at Springerlink.com DOI: 10.1007/s11665-013-0570-7 1059-9495/$19.00 Characteristics of Dissimilar FSW Welds of Aluminum Alloys 2017A and 7075 on the Basis of Multiple Layer Research Krzysztof Mroczka, Anna Wo´jcicka, and Adam Pietras (Submitted December 29, 2012; in revised form April 18, 2013; published online May 8, 2013) This work is concerned with the structure of the FSW joint of 2017A/7075 aluminum alloys, which was analyzed on the basis of a number of longitudinal and cross-sectional sections. Various ways and degrees of alloy stirring were identified, depending on the distance from the face of the weld. Furthermore, consid- erable variation in the length of the weld microstructures was demonstrated, reflecting the variability of the welding process. Studies of mechanical properties are also presented—the distributions of hardness on individual layers. A significant effect of plastic deformation on the hardness of the alloy 7075, which strengthened in deformed areas and shows weakness in the heat-affected zone, was noticed. The influence of the weld structure on the fracture of the sample, which was broken in the static tensile test, was analyzed applying scanning electron microscopy. The presence of non-deformed areas was revealed within the ductile fracture of the sample. remembered, however, that the strengthening of the material Keywords advanced characterization, aluminum, joining, metal- lography, optical microscopy, welding depends not only on the condition and amount of hardening precipitates but also on the grain size (Ref 9) and the density of dislocations (Ref 6).
    [Show full text]
  • AMIE Material Science.Pdf
    Material science Question Papers (AD-302) MATERIAL SCIENCE (AMIE) Q. No. Year Questions 1a S-2000 Calculate the volume of FCC unit cell in terms of ththee atomic radius R. Also calculate It's packing factor. Why are the most metals and alloys used in common applicaapplicationstions polycrystalline in nature ? Is it possible to form single 1b S-2000 crystals of metals and alloys ? Describe a common memetmethodthodhod for measuring grain size in metals and alloys ? What is Burger's Vector ? How does dislocation densitydensity influence mechanical properties ? Is dislocatiodislocationn dendensitysity in 2a S-2000 materials influenced by annealing ? 2b S-2000 Explain phenomenon of yielding in mild steel. Why iiss the yield point in copper not distinct ? 3a S-2000 Briefly explain the mechanism of fatigue crack initiinitiationation in metals ? 3b S-2000 How does creep differ from high temperature fatigue ? Explain different stages of creep ? 3c S-2000 What is Tharmal Fatigue, explain with an example ? 4a S-2000 What is diamagnetism and paramagnetism? Explain in brbrief.ief. Name one material of each type ? Calculate (i) The saturation magnetisation and (ii) thethe saturation flux density for Nickel, which has a density of 8.90 4b S-2000 g/cm3. Atomic weight of Nickel -58.71. Magnetic moment per Nickel atom =0.6 Bhor magneton μB = 9.27*10 and μ0 = 4 π* 10 -7 h/m 4c S-2000 Cite the similarities and differences between ferromagnetic and ferrimagnetic materials. What is the nature of bonding in semiconductivity materialmateriamaterialslss ? What is meant by semiconductor device and whawhatt areare 5a S-2000 typical components of a semiconductor device ? What areare dielectric materials and explain their applicaapplicatiotionsns ? Name a dielectric material.
    [Show full text]
  • Semi-Solid Processing of Alloys and Composites • Shahrooz Nafisi and Reza Ghomashchi Semi-Solid Processing of Alloys and Composites
    Semi-Solid Processing of Alloys and Composites • Shahrooz Nafisi and Reza Ghomashchi Semi-Solid Processing of Alloys and Composites Edited by Shahrooz Nafisi and Reza Ghomashchi Printed Edition of the Special Issue Published in Metals ww.mdpi.com/journal/metals Semi-Solid Processing of Alloys and Composites Semi-Solid Processing of Alloys and Composites Special Issue Editors Shahrooz Nafisi Reza Ghomashchi MDPI • Basel • Beijing • Wuhan • Barcelona • Belgrade • Manchester • Tokyo • Cluj • Tianjin Special Issue Editors Shahrooz Nafisi Reza Ghomashchi University of Alberta The University of Adelaide Canada Australia Editorial Office MDPI St. Alban-Anlage 66 4052 Basel, Switzerland This is a reprint of articles from the Special Issue published online in the open access journal Metals (ISSN 2075-4701) (available at: https://www.mdpi.com/journal/metals/special issues/semi solid processing). For citation purposes, cite each article independently as indicated on the article page online and as indicated below: LastName, A.A.; LastName, B.B.; LastName, C.C. Article Title. Journal Name Year, Article Number, Page Range. ISBN 978-3-03928-975-2 (Hbk) ISBN 978-3-03928-976-9 (PDF) Cover image courtesy of Shahrooz Nafisi. c 2020 by the authors. Articles in this book are Open Access and distributed under the Creative Commons Attribution (CC BY) license, which allows users to download, copy and build upon published articles, as long as the author and publisher are properly credited, which ensures maximum dissemination and a wider impact of our publications. The book as a whole is distributed by MDPI under the terms and conditions of the Creative Commons license CC BY-NC-ND.
    [Show full text]