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Author: Kaimiao Liu
Publisher:
ISBN:
Category :
Languages : en
Pages : 78
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Book Description
Structural material fatigue is a leading cause of failure and has motivated fatigue-resistant design to eliminate risks to human lives. Intrinsic microstructural features alter fatigue deformation mechanisms so profoundly that, essentially, fatigue properties of structural materials become deviant. With this in mind, we initiated this project to investigate the microstructural effect on fatigue behavior of potential structural high entropy alloys. With a better understanding of the effect of microstructure features on fatigue properties, the ultimate goal was to engineer the microstructure to enhance the fatigue life of structural materials. The effects of two major deformation mechanisms presented here are twinning-induced fatigue crack retardation, and transformation-induced fatigue crack retardation. The fundamental principle of both mechanisms is to delay the fatigue crack propagation rate by altering the work hardening ability locally within the crack plastic zone. In ultrafine grained triplex Al0.3CoCrFeNi, nano-sized deformation twins were observed during cyclic loading in FCC matrix due to low stacking fault energy (SFE). The work-hardening ability of the material near the crack was sustained with the formation of twins according to Considere's criteria. Further, due to the ultrafine-grained (UFG) nature of the material, fatigue runout stress was enhanced. In a coarse-grained, dual-phase high entropy alloy, persistent slip bands formed in FCC matrix during cyclic loading due mainly to the slight composition change that affects the SFE in the FCC matrix and eventually alters the deformation mechanism. Another way known to alter an alloy's work hardening (WH) ability is transformation-induced plasticity (TRIP). In some alloys, phase transformation happens due to strain localization, which alters the work-hardening ability. iii In a fine-grained, dual-phase metastable high entropy alloy, gamma (f.c.c.) to epsilon (h.c.p.) transformation occurred in the plastic zone that was induced from cracks. Thus, we designed a Cu-containing FeMnCoCrSi high entropy alloy that exhibited a normalized fatigue ratio of ̃ 0.62 UTS (ultimate tensile strength). Our design approach was based on (a) engineering the gamma phase stability to attain sustained work hardening through delayed gamma (f.c.c.) to epsilon (h.c.p.) transformation to hinder fatigue crack propagation, (b) incorporating an ultrafine-grained microstructure to delay crack initiation, and (c) forming deformation twins to reduce the crack propagation rate. We verified that a UFG gamma dominant microstructure could provide opportunities for exceptional fatigue resistance, as sustained WH activity strengthened the material locally in the crack plastic zone, thereby validating our expectation that the combination of UFG and TRIP is a path to design the next generation of fatigue-resistant alloys.
Author: Kaimiao Liu
Publisher:
ISBN:
Category :
Languages : en
Pages : 78
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Book Description
Structural material fatigue is a leading cause of failure and has motivated fatigue-resistant design to eliminate risks to human lives. Intrinsic microstructural features alter fatigue deformation mechanisms so profoundly that, essentially, fatigue properties of structural materials become deviant. With this in mind, we initiated this project to investigate the microstructural effect on fatigue behavior of potential structural high entropy alloys. With a better understanding of the effect of microstructure features on fatigue properties, the ultimate goal was to engineer the microstructure to enhance the fatigue life of structural materials. The effects of two major deformation mechanisms presented here are twinning-induced fatigue crack retardation, and transformation-induced fatigue crack retardation. The fundamental principle of both mechanisms is to delay the fatigue crack propagation rate by altering the work hardening ability locally within the crack plastic zone. In ultrafine grained triplex Al0.3CoCrFeNi, nano-sized deformation twins were observed during cyclic loading in FCC matrix due to low stacking fault energy (SFE). The work-hardening ability of the material near the crack was sustained with the formation of twins according to Considere's criteria. Further, due to the ultrafine-grained (UFG) nature of the material, fatigue runout stress was enhanced. In a coarse-grained, dual-phase high entropy alloy, persistent slip bands formed in FCC matrix during cyclic loading due mainly to the slight composition change that affects the SFE in the FCC matrix and eventually alters the deformation mechanism. Another way known to alter an alloy's work hardening (WH) ability is transformation-induced plasticity (TRIP). In some alloys, phase transformation happens due to strain localization, which alters the work-hardening ability. iii In a fine-grained, dual-phase metastable high entropy alloy, gamma (f.c.c.) to epsilon (h.c.p.) transformation occurred in the plastic zone that was induced from cracks. Thus, we designed a Cu-containing FeMnCoCrSi high entropy alloy that exhibited a normalized fatigue ratio of ̃ 0.62 UTS (ultimate tensile strength). Our design approach was based on (a) engineering the gamma phase stability to attain sustained work hardening through delayed gamma (f.c.c.) to epsilon (h.c.p.) transformation to hinder fatigue crack propagation, (b) incorporating an ultrafine-grained microstructure to delay crack initiation, and (c) forming deformation twins to reduce the crack propagation rate. We verified that a UFG gamma dominant microstructure could provide opportunities for exceptional fatigue resistance, as sustained WH activity strengthened the material locally in the crack plastic zone, thereby validating our expectation that the combination of UFG and TRIP is a path to design the next generation of fatigue-resistant alloys.
Author: Claude Bathias
Publisher: John Wiley & Sons
ISBN: 1118617223
Category : Technology & Engineering
Languages : en
Pages : 279
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Book Description
The design of mechanical structures with predictable and improved durability cannot be achieved without a thorough understanding of the mechanisms of fatigue damage and more specifically the relationships between the microstructure of materials and their fatigue properties. Written by leading researchers in the field, this book, along with the complementary books Fatigue of Materials and Structures: Fundamentals and Application to Damage and Design (both also edited by Claude Bathias and André Pineau), provides an authoritative, comprehensive and unified treatment of the mechanics and micromechanisms of fatigue in metals, polymers and composites. Each chapter is devoted to one of the major classes of materials or to different types of fatigue damage, thereby providing overall coverage of the field. This book deals with multiaxial fatigue, thermomechanical fatigue, fretting-fatigue, influence of defects on fatigue life, cumulative damage and damage tolerance, and will be an important and much used reference for students, practicing engineers and researchers studying fracture and fatigue in numerous areas of materials science and engineering, mechanical, nuclear and aerospace engineering.
Author: Claude Bathias
Publisher: John Wiley & Sons
ISBN: 1118623371
Category : Technology & Engineering
Languages : en
Pages : 415
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Book Description
The design of mechanical structures with improved and predictable durability cannot be achieved without a thorough understanding of the mechanisms of fatigue damage and more specifically the relationships between the microstructure of materials and their fatigue properties. Written by leading experts in the field, this book (which is complementary to Fatigue of Materials and Structures: Application to Damage and Design, also edited by Claude Bathias and André Pineau), provides an authoritative, comprehensive and unified treatment of the mechanics and micromechanisms of fatigue in metals, polymers and composites. Each chapter is devoted to one of the major classes of materials or to different types of fatigue damage, thereby providing overall coverage of the field. The book deals with crack initiation, crack growth, low-cycle fatigue, gigacycle fatigue, shorts cracks, fatigue micromechanisms and the local approach to fatigue damage, corrosion fatigue, environmental effects and variable amplitude loadings, and will be an important and much used reference for students, practicing engineers and researchers studying fracture and fatigue in numerous areas of mechanical, structural, civil, design, nuclear, and aerospace engineering as well as materials science.
Author: Claude Bathias
Publisher: Wiley-ISTE
ISBN: 9781848212671
Category : Technology & Engineering
Languages : en
Pages : 0
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Book Description
The design of mechanical structures with improved and predictable durability cannot be achieved without a thorough understanding of the mechanisms of fatigue damage and more specifically the relationships between the microstructure of materials and their fatigue properties. Written by leading experts in the field, this book (which is complementary to Fatigue of Materials and Structures: Application to Damage and Design, also edited by Claude Bathias and André Pineau), provides an authoritative, comprehensive and unified treatment of the mechanics and micromechanisms of fatigue in metals, polymers and composites. Each chapter is devoted to one of the major classes of materials or to different types of fatigue damage, thereby providing overall coverage of the field. The book deals with crack initiation, crack growth, low-cycle fatigue, gigacycle fatigue, shorts cracks, fatigue micromechanisms and the local approach to fatigue damage, corrosion fatigue, environmental effects and variable amplitude loadings, and will be an important and much used reference for students, practicing engineers and researchers studying fracture and fatigue in numerous areas of mechanical, structural, civil, design, nuclear, and aerospace engineering as well as materials science.
Author: Abby Cisko
Publisher:
ISBN:
Category :
Languages : en
Pages : 226
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Book Description
Technological and design advances in military aircraft have dramatically changed the face of war. The need to rapidly deploy troops, military equipment and technology into conflict areas all over the globe, have placed aircrafts in a pivotal role in strategic battlefield operations. While enhanced aircraft designs now allow significantly heavier loads, greater fuel efficiency and higher speeds, there has been little change in the underlying infrastructure and materials that are used to construct the runways that allow these more sophisticated aircraft to successfully land on a variety of terrains in remote areas of the world. For these reasons, there is a need to improve the strength and weight of temporary aircraft matting used to build temporary runways, landing pads, and other readily usable surfaces for transportation applications. Despite the increasing use of aluminum lithium alloys in aerospace applications because of strength and density, the inability to join higher strength Al alloys with conventional welding techniques made it difficult to use in applications that required welding such as the matting for military runways. Aluminum lithium alloys are currently replacing conventional alloys in the aerospace industry. In comparison to other aluminum alloys, enhanced fatigue crack growth resistance, greater specific strength, high fracture toughness, density reduction, stiffness increase, and superior corrosion resistance can be achieved in Al-Li alloys. The ability to provide lower density with comparable strength gives these alloys an advantage over traditional aluminum alloys. However, conventionally welding these Al-Li alloys is difficult and can materially weaken the resulting product. This disadvantage limits a more widespread implementation of Al-Li alloys. Friction stir welding (FSW) offers the capability to join these high strength aluminum lithium alloys, with environmental, metallurgical, and adaptability advantages over other joining techniques. While FSW has been effectively authenticated and studied for traditional aluminum alloys, there is a necessity for understanding the application of FSW to join AL-Li alloys. The purpose of this research is to examine the microstructural and mechanical performance of AA2099 under static and cyclic loading, as well as the effects of the welding process parameters on the microstructure and mechanical performance of friction stir welded AA2099. This study will aid in the implementation of AA2099 in military applications, specifically for producing high strength, light-weight airfield mats for rapid expansions of airfields.
Author: The Minerals, Metals & Materials Series
Publisher: Springer
ISBN: 9783030058609
Category : Technology & Engineering
Languages : en
Pages : 1731
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Book Description
This collection features papers presented at the 147th Annual Meeting & Exhibition of The Minerals, Metals & Materials Society.
Author: Mahadzir Ishak
Publisher: BoD – Books on Demand
ISBN: 9535125966
Category : Technology & Engineering
Languages : en
Pages : 286
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Book Description
Joining and welding are two of the most important processes in manufacturing. These technologies have vastly improved and are now extensively used in numerous industries. This book covers a wide range of topics, from arc welding (GMAW and GTAW), FSW, laser and hybrid welding, and magnetic pulse welding on metal joining to the application of joining technologies for textile products. The analysis of temperature and phase transformation is also incorporated. This book also discusses the issue of dissimilar joint between metal and ceramic, as well as the technology of diffusion bonding.
Author: Amit Bhaduri
Publisher: Springer
ISBN: 9811072094
Category : Technology & Engineering
Languages : en
Pages : 758
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Book Description
This book is intended to serve as core text or handy reference on two key areas of metallic materials: (i) mechanical behavior and properties evaluated by mechanical testing; and (ii) different types of metal working or forming operations to produce useful shapes. The book consists of 16 chapters which are divided into two parts. The first part contains nine chapters which describe tension (including elastic stress – strain relation, relevant theory of plasticity, and strengthening methods), compression, hardness, bending, torsion – pure shear, impact loading, creep and stress rupture, fatigue, and fracture. The second part is composed of seven chapters and covers fundamentals of mechanical working, forging, rolling, extrusion, drawing of flat strip, round bar, and tube, deep drawing, and high-energy rate forming. The book comprises an exhaustive description of mechanical properties evaluated by testing of metals and metal working in sufficient depth and with reasonably wide coverage. The book is written in an easy-to-understand manner and includes many solved problems. More than 150 numerical problems and many multiple choice questions as exercise along with their answers have also been provided. The mathematical analyses are well elaborated without skipping any intermediate steps. Slab method of analysis or free-body equilibrium approach is used for the analytical treatment of mechanical working processes. For hot working processes, different frictional conditions (sliding, sticking and mixed sticking–sliding) have been considered to estimate the deformation loads. In addition to the slab method of analysis, this book also contains slip-line field theory, its application to the static system, and the steady state motion, Further, this book includes upper-bound theorem, and upper-bound solutions for indentation, compression, extrusion and strip drawing. The book can be used to teach graduate and undergraduate courses offered to students of mechanical, aerospace, production, manufacturing and metallurgical engineering disciplines. The book can also be used for metallurgists and practicing engineers in industry and development courses in the metallurgy and metallic manufacturing industries.
Author: J. Schijve
Publisher: Springer Science & Business Media
ISBN: 1402068085
Category : Science
Languages : en
Pages : 627
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Book Description
Fatigue of structures and materials covers a wide scope of different topics. The purpose of the present book is to explain these topics, to indicate how they can be analyzed, and how this can contribute to the designing of fatigue resistant structures and to prevent structural fatigue problems in service. Chapter 1 gives a general survey of the topic with brief comments on the signi?cance of the aspects involved. This serves as a kind of a program for the following chapters. The central issues in this book are predictions of fatigue properties and designing against fatigue. These objectives cannot be realized without a physical and mechanical understanding of all relevant conditions. In Chapter 2 the book starts with basic concepts of what happens in the material of a structure under cyclic loads. It illustrates the large number of variables which can affect fatigue properties and it provides the essential background knowledge for subsequent chapters. Different subjects are presented in the following main parts: • Basic chapters on fatigue properties and predictions (Chapters 2–8) • Load spectra and fatigue under variable-amplitude loading (Chapters 9–11) • Fatigue tests and scatter (Chapters 12 and 13) • Special fatigue conditions (Chapters 14–17) • Fatigue of joints and structures (Chapters 18–20) • Fiber-metal laminates (Chapter 21) Each chapter presents a discussion of a speci?c subject.
Author: M. Bos
Publisher: Springer Science & Business Media
ISBN: 9048127467
Category : Technology & Engineering
Languages : en
Pages : 1340
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Book Description
The 31st Conference and the 25th Symposium of the International Committee on Aeronautical Fatigue will be hosted in Rotterdam, The Netherlands, by the National Aerospace Laboratory NLR, under the auspices of the Netherlands Association of Aeronautical Engineers NVvL, the Technical University of Delft and Stork Fokker AESP B.V. These Proceedings will consist of reviews of aeronautical fatigue activities presented by the national delegates of the 14 member nations of ICAF. It will also contain specialist papers presented by international authors with design, manufacturing, airworthiness regulations, operations and research backgrounds. The papers will be based on the theme “Bridging the gap between theory and operational practice”.
