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ACKNOWLEDGEMENTS Figures have been reproduced with permission from the following sources: The following figures are copied from Acta Materialia with the permission of Elsevier Science,P.O.Box 800,Oxford OX5 IDX:Figure 13.10 from Nes,E.and Marthinsen K.(2002),Mats.Sci.and Eng.A322,176.'Origin of cube texture during hot rolling of commercial Al-Mn-Mg alloys',(figure 6).Figure 2.10 from Liu,Q.,Juul Jensen,D.and Hansen,N.(1998),Acta mater.46,5819.'Effect of grain orientation on deformation structure in cold rolled aluminium',(figure 2).Figure 16.6 from Upmanyu,M., Srolovitz,D.J.,Shvindlerman,L.S.and Gottstein,G.(1999).Acta Mater.47,3901. "Misorientation/dependence of intrinsic boundary mobility',(figure 2).Figure 4.19 from Goukon,N.,Yamada,T and Kajihara,M.(2000),Acta Mater.48,2837.'Boundary energies of E11 [110]asymmetric tilt boundaries',(figure 2).Figure 5.2 from Winning. M.Gottstein,G and Shvindlerman,L.S.(2001),Acta Mater.49,211.'Stress induced grain boundary motion',(figures 12 and 13).Figure 5.33 from Protasova,S.G., Gottstein,G.Sursaeva,V.G.and Shvindlerman,L.S.(2001),Acta mater.49,2519. 'Triple junction motion in aluminium tricrystals',(figure 5).Figure 2.33 from Duckham, A.,Knutsen,R.D.and Engler,O.(2001),Acta Mater.49,2739.'Influence of deformation variables on the formation of shear bands in Al-1Mg',(figure 3).The following figures are copied from Scripta Materialia with the permission of Elsevier Science,P.O.Box 800.Oxford OX5 IDX:Figure 5.12 from Molodov,D.A.,Czubayko. U.,Gottstein,G.and Shvindlerman,L.S.(1995),Scripta Metall.Mater.32,529. 'Mobility of <111>tilt grain boundaries...',(figures 4 and 5).Figure 4.3 from Hutchinson,W.B.,Ryde,L.,Bate,P.S.and Bacroix,B.(1996),Scripta Mater.35,579 "On the description of misorientations...',(figure 4).Figure 12.7 from Engler,O. (2001b),Scripta Mater.44,299.'An EBSD local texture study on the nucleation of recrystallization...',(figure 1).Figure 4.7 from Yang,C.-C.,Rollett,A.D.,and Mullins, W.W.(2001).Scripta Materialia,44,2735.'Measuring relative grain boundary energies...',(figure 4). The following figures are copied from Materials Science and Engineering,with the permission of Elsevier Science,P.O.Box 800,Oxford OX5 IDX:Figure 2.5 from Hughes,D.A.(2001),Mats.Sci.Eng.A319,46.'Microstructure evolution,slip patterns...',(figure 4).Figure 2.3b from Nes,E.and Marthinsen,K.(2002),Mats.Sci. and Eng.A322,176.'Modelling the evolution in microstructure and properties...', (figure 6).Figure 6.27 from Haslam,A.J.,Phillpot,S.R.,Wolf,D.,Moldovan,D.and Gleiter,H.(2001),Mats.Sci.Eng.A318,293.'Mechanisms of grain growth in nanocrystalline fcc metals...',(figure 4).Figure 15.3 from Engler,O.and Hirsch,J. xxix
ACKNOWLEDGEMENTS Figures have been reproduced with permission from the following sources: The following figures are copied from Acta Materialia with the permission of Elsevier Science, P.O. Box 800, Oxford OX5 1DX: Figure 13.10 from Nes, E. and Marthinsen, K. (2002), Mats. Sci. and Eng. A322, 176. ‘Origin of cube texture during hot rolling of commercial Al–Mn–Mg alloys’, (figure 6). Figure 2.10 from Liu, Q., Juul Jensen, D. and Hansen, N. (1998), Acta mater. 46, 5819. ‘Effect of grain orientation on deformation structure in cold rolled aluminium’, (figure 2). Figure 16.6 from Upmanyu, M., Srolovitz, D.J., Shvindlerman, L.S. and Gottstein, G. (1999), Acta Mater. 47, 3901. ‘Misorientation/dependence of intrinsic boundary mobility’, (figure 2). Figure 4.19 from Goukon, N., Yamada, T and Kajihara, M. (2000), Acta Mater. 48, 2837. ‘Boundary energies of 11 [110] asymmetric tilt boundaries’, (figure 2). Figure 5.2 from Winning, M. Gottstein, G and Shvindlerman, L.S. (2001), Acta Mater. 49, 211. ‘Stress induced grain boundary motion’, (figures 12 and 13). Figure 5.33 from Protasova, S.G., Gottstein, G. Sursaeva, V.G. and Shvindlerman, L.S. (2001), Acta mater. 49, 2519. ‘Triple junction motion in aluminium tricrystals’, (figure 5). Figure 2.33 from Duckham, A., Knutsen, R.D. and Engler, O. (2001), Acta Mater. 49, 2739. ‘Influence of deformation variables on the formation of shear bands in Al–1Mg’, (figure 3). The following figures are copied from Scripta Materialia with the permission of Elsevier Science, P.O. Box 800, Oxford OX5 IDX: Figure 5.12 from Molodov, D.A., Czubayko, U., Gottstein, G. and Shvindlerman, L.S. (1995), Scripta Metall. Mater. 32, 529. ‘Mobility of <111> tilt grain boundaries...’, (figures 4 and 5). Figure 4.3 from Hutchinson, W.B., Ryde, L., Bate, P.S. and Bacroix, B. (1996), Scripta Mater. 35, 579. ‘‘On the description of misorientations...’, (figure 4). Figure 12.7 from Engler, O. (2001b), Scripta Mater. 44, 299. ‘An EBSD local texture study on the nucleation of recrystallization...’, (figure 1). Figure 4.7 from Yang, C.-C., Rollett, A.D., and Mullins, W.W. (2001). Scripta Materialia, 44, 2735. ‘Measuring relative grain boundary energies...’, (figure 4). The following figures are copied from Materials Science and Engineering, with the permission of Elsevier Science, P.O. Box 800, Oxford OX5 IDX: Figure 2.5 from Hughes, D.A. (2001), Mats. Sci. Eng. A319, 46. ‘Microstructure evolution, slip patterns...’, (figure 4). Figure 2.3b from Nes, E. and Marthinsen, K. (2002), Mats. Sci. and Eng. A322, 176. ‘Modelling the evolution in microstructure and properties...’, (figure 6). Figure 6.27 from Haslam, A.J., Phillpot, S.R., Wolf, D., Moldovan, D. and Gleiter, H. (2001), Mats. Sci. Eng. A318, 293. ‘Mechanisms of grain growth in nanocrystalline fcc metals...’, (figure 4). Figure 15.3 from Engler, O. and Hirsch, J. xxix
XXX Acknowledgements (2002),Mats.Sci.Eng.A336,249."Texture control by thermomechanical processing...', (figure 10). The following figure is copied from Intermetallics,with the permission of Elsevier Science,P.O.Box 800,Oxford OX5 IDX:Figure 8.7 from Huang,Y.D.and Froyen L.(2002),Intermetallics,10,473.'Recovery,recrystallization and grain growth...',(figure 5). The following figures are copied from Materials Science and Technology with the permission of Maney Publishing,I Carlton House Terrace,London SWIY 5DB:Figure 3.3 from Hirsch.J.(1990b).Mats.Sci.and Tech.6,1048.'Correlation of deformation texture and microstructure',(figure 3).Figure 15.15 from Hayes,J.S.,Keyte,R.and Prangnell,P.B.(2000),Mats.Sci.and Tech.16,1259."Effect of grain size on tensile behaviour of a submicron-grained Al-3wt%Mg alloy',(figure 6). The following figure is copied from Materials Science Forum,with the permission of Trans Tech Publications Ltd.Brandrain 6,CH-8707,Ueticon-Zuerich.Switzerland: Figure 3.15 from Benum,S.,Engler,O.and Nes,E.(1994),Mats.Sci.Forum,157-162, 913. In the first edition of this book we acknowledged a great debt to those with whom we had discussed and argued over the subjects covered by this book over a period of very many years.During the writing of the book we had particularly useful discussions and correspondence with Brian Duggan,Bevis Hutchinson and Erik Nes.A large number of others helped by providing advice,material and in many other ways.They include Sreeramamurthy Ankem,Mahmoud Ardakani,Christine Carmichael,Michael Ferry, Brian Gleeson,Gunther Gottstein,Brigitte Hammer,Alan Humphreys,Peter Krauklis, Lasar Shvindlerman,Tony Malin,Paul Munroe,Nigel Owen,Phil Prangnell,Fred Scott,Karen Vernon-Parry and David Willis. A significant amount of the new research which has contributed to the second edition of the book has been carried out in Manchester,and the strong support of the Engineering and Physical Sciences Research Council and Alcan International is gratefully acknowledged.The help,advice and support of Pete Bate has been particularly valuable,and the Manchester Light Alloy Processing Group,including Philip Prangnell, Norman Ridley,Hedieh Jazaeri,Peter Hurley,Yan Huang,Andrew Clarke,Martin Ashton,Ian Brough,and Matthew Jones,and their provision of data and figures has made a major contribution to this edition.During the preparation of the second edition, critical comments and suggestions from Michael Ferry and Robert Moon of the University of New South Wales have been extremely valuable. Finally,and as in the first edition,we must acknowledge the patience and understanding shown by our wives Anna and Lorna during the writing of the book. XXX
(2002), Mats. Sci. Eng. A336, 249. ‘Texture control by thermomechanical processing...’, (figure 10). The following figure is copied from Intermetallics, with the permission of Elsevier Science, P.O. Box 800, Oxford OX5 IDX: Figure 8.7 from Huang, Y.D. and Froyen L. (2002), Intermetallics, 10, 473. ‘Recovery, recrystallization and grain growth...’, (figure 5). The following figures are copied from Materials Science and Technology with the permission of Maney Publishing, 1 Carlton House Terrace, London SW1Y 5DB: Figure 3.3 from Hirsch, J. (1990b), Mats. Sci. and Tech. 6, 1048. ‘Correlation of deformation texture and microstructure’, (figure 3). Figure 15.15 from Hayes, J.S., Keyte, R. and Prangnell, P.B. (2000), Mats. Sci. and Tech. 16, 1259. ‘Effect of grain size on tensile behaviour of a submicron-grained Al–3wt%Mg alloy’, (figure 6). The following figure is copied from Materials Science Forum, with the permission of Trans Tech Publications Ltd. Brandrain 6, CH-8707, Ueticon-Zuerich, Switzerland: Figure 3.15 from Benum, S., Engler, O. and Nes, E. (1994), Mats. Sci. Forum, 157–162, 913. In the first edition of this book we acknowledged a great debt to those with whom we had discussed and argued over the subjects covered by this book over a period of very many years. During the writing of the book we had particularly useful discussions and correspondence with Brian Duggan, Bevis Hutchinson and Erik Nes. A large number of others helped by providing advice, material and in many other ways. They include Sreeramamurthy Ankem, Mahmoud Ardakani, Christine Carmichael, Michael Ferry, Brian Gleeson, Gunther Gottstein, Brigitte Hammer, Alan Humphreys, Peter Krauklis, Lasar Shvindlerman, Tony Malin, Paul Munroe, Nigel Owen, Phil Prangnell, Fred Scott, Karen Vernon-Parry and David Willis. A significant amount of the new research which has contributed to the second edition of the book has been carried out in Manchester, and the strong support of the Engineering and Physical Sciences Research Council and Alcan International is gratefully acknowledged. The help, advice and support of Pete Bate has been particularly valuable, and the Manchester Light Alloy Processing Group, including Philip Prangnell, Norman Ridley, Hedieh Jazaeri, Peter Hurley, Yan Huang, Andrew Clarke, Martin Ashton, Ian Brough, and Matthew Jones, and their provision of data and figures has made a major contribution to this edition. During the preparation of the second edition, critical comments and suggestions from Michael Ferry and Robert Moon of the University of New South Wales have been extremely valuable. Finally, and as in the first edition, we must acknowledge the patience and understanding shown by our wives Anna and Lorna during the writing of the book. xxx xxx Acknowledgements
Chapter 1 INTRODUCTION 1.1 THE ANNEALING OF A DEFORMED MATERIAL 1.1.1 Outline and terminology The free energy of a crystalline material is raised during deformation by the presence of dislocations and interfaces,and a material containing these defects is thermodynam- ically unstable.Although thermodynamics would suggest that the defects should spontaneously disappear,in practice the necessary atomistic mechanisms are often very slow at low homologous temperatures,with the result that unstable defect structures are retained after deformation (fig.1.la). If the material is subsequently heated to a high temperature (annealed),thermally activated processes such as solid state diffusion provide mechanisms whereby the defects may be removed or alternatively arranged in configurations of lower energy The defects may be introduced in a variety of ways.However,in this book we will mainly be concerned with those defects,and in particular dislocations,which are introduced during plastic deformation.The point defects introduced during deforma- tion anneal out at low temperatures and generally have little effect on the mechanical properties of the material.In considering only materials which have undergone substantial plastic deformation,we necessarily limit the range of materials with which we will be concerned.Metals are the only major class of crystalline material to undergo substantial plastic deformation at low homologous temperatures,and much of this book will be concerned with the annealing of deformed metals.However, at high temperatures,many minerals and ceramics readily deform plastically,and the
Chapter 1 INTRODUCTION 1.1 THE ANNEALING OF A DEFORMED MATERIAL 1.1.1 Outline and terminology The free energy of a crystalline material is raised during deformation by the presence of dislocations and interfaces, and a material containing these defects is thermodynamically unstable. Although thermodynamics would suggest that the defects should spontaneously disappear, in practice the necessary atomistic mechanisms are often very slow at low homologous temperatures, with the result that unstable defect structures are retained after deformation (fig. 1.1a). If the material is subsequently heated to a high temperature (annealed), thermally activated processes such as solid state diffusion provide mechanisms whereby the defects may be removed or alternatively arranged in configurations of lower energy. The defects may be introduced in a variety of ways. However, in this book we will mainly be concerned with those defects, and in particular dislocations, which are introduced during plastic deformation. The point defects introduced during deformation anneal out at low temperatures and generally have little effect on the mechanical properties of the material. In considering only materials which have undergone substantial plastic deformation, we necessarily limit the range of materials with which we will be concerned. Metals are the only major class of crystalline material to undergo substantial plastic deformation at low homologous temperatures, and much of this book will be concerned with the annealing of deformed metals. However, at high temperatures, many minerals and ceramics readily deform plastically, and the 1
2 Recrystallization (a) (b) (c) (d) (e) (f) Fig.1.1.Schematic diagram of the main annealing processes;(a)Deformed state, (b)Recovered,(c)Partially recrystallized,(d)Fully recrystallized,(e)Grain growth and (f)Abnormal grain growth. annealing of these is of great interest.In addition,some annealing processes such as grain growth are relevant to cast or vapour deposited materials as well as to deformed materials. On annealing a cold worked metal at an elevated temperature,the microstructure and also the properties may be partially restored to their original values by recovery in which annihilation and rearrangement of the dislocations occurs.The microstructural changes during recovery are relatively homogeneous and do not usually affect the boundaries between the deformed grains;these changes in microstructure are shown schematically in figure 1.1b.Similar recovery processes may also occur during deformation
annealing of these is of great interest. In addition, some annealing processes such as grain growth are relevant to cast or vapour deposited materials as well as to deformed materials. On annealing a cold worked metal at an elevated temperature, the microstructure and also the properties may be partially restored to their original values by recovery in which annihilation and rearrangement of the dislocations occurs. The microstructural changes during recovery are relatively homogeneous and do not usually affect the boundaries between the deformed grains; these changes in microstructure are shown schematically in figure 1.1b. Similar recovery processes may also occur during deformation, Fig. 1.1. Schematic diagram of the main annealing processes; (a) Deformed state, (b) Recovered, (c) Partially recrystallized, (d) Fully recrystallized, (e) Grain growth and (f ) Abnormal grain growth. 2 Recrystallization