3642031765......Page 1
Dislocation Dynamics During Plastic Deformation
......Page 4
Part I General Properties of Dislocation Motion......Page 14
1 Introduction......Page 15
1.1 Theoretical Yield Strength......Page 16
1.2 Plastic Shear by the Motion of Dislocations......Page 17
2.1 Macroscopic Deformation Tests......Page 22
2.2 Stress Pulse Double Etching Technique......Page 27
2.3 Transmission Electron Microscopy......Page 29
2.4 In Situ Straining Experiments in the Transmission Electron Microscope......Page 31
2.5 Other Methods......Page 37
2.5.2 Surface Studies of Slip Lines......Page 38
2.5.3 Internal Friction......Page 40
2.5.4 Nuclear Magnetic Resonance......Page 44
3.1.1 Burgers Vector......Page 46
3.1.2 Glide and Climb Motion of a Dislocation......Page 48
3.1.3 Relation Between Dislocation Motion and Plastic Strain and Strain Rate......Page 50
3.2 Elastic Properties of Dislocations......Page 51
3.2.1 Stress Fields of Straight Dislocations......Page 52
3.2.2 Dislocation Energy......Page 54
3.2.3 Forces on Dislocations......Page 58
3.2.4 Interaction Between Parallel Dislocations......Page 61
3.2.5 Interaction Between Nonparallel Dislocations......Page 63
3.2.6 Elastic Interaction Between Dislocations and Elastic Inclusions......Page 65
3.2.7 Bowed-Out Dislocations......Page 68
3.3 Dislocations in Crystals......Page 76
3.3.2 Stacking Faults and Partial Dislocations......Page 77
3.3.3 Twins......Page 81
3.3.4 Antiphase Boundaries......Page 82
4 Dislocation Motion......Page 84
4.1 Thermally Activated Overcoming of Barriers......Page 85
4.2 Lattice Friction......Page 89
4.2.1 PeierlsโNabarro Model......Page 90
Elastic Properties of Kinks......Page 94
Kinks in Thermal Equilibrium......Page 96
Thermally Activated Motion of Kinks......Page 97
Double-Kink Nucleation at High Stresses......Page 99
Dislocation Velocity in the Range of Double-Kink Nucleation......Page 101
4.2.3 Characteristics and Experimental Evidence of the Double-Kink Model......Page 103
4.3 Slip and Cross Slip......Page 104
4.4 The LockingโUnlocking Mechanism......Page 110
4.5 Overcoming of Localized Obstacles......Page 112
4.5.1 Friedel Statistics......Page 114
4.5.2 Mott Statistics......Page 121
4.6 Transition from the Double-Kink Mechanism to the Overcoming of Localized Obstacles......Page 124
4.7 Overcoming of Extended Obstacles......Page 127
4.8 Dislocation Intersections......Page 137
4.9 Dislocation Motion at High Velocitiesand Low Temperatures......Page 140
4.10.1 Point Defect Equilibrium Concentrations......Page 143
Force Required for Athermal Climb......Page 145
Applied Climb Forces......Page 146
4.10.3 Emission- or Absorption-controlled Climb......Page 148
4.10.4 Diffusion-controlled Climb......Page 151
4.10.5 Jog Dragging......Page 152
4.11 Drag Forces due to Point Defect Atmospheres......Page 154
4.12 Dynamic Laws of Dislocation Mobility......Page 161
5.1 Dislocation Kinetics......Page 166
5.1.1 Models of Dislocation Generation......Page 167
5.1.2 Experimental Evidence of Dislocation Generation......Page 173
5.1.3 Dislocation Immobilization and Annihilation......Page 177
5.2 Work-Hardening and Recovery......Page 182
5.2.1 Work-Hardening Models......Page 183
5.2.2 Thermal and Athermal Componentsof the Flow Stress......Page 191
5.2.3 Experimental Determinationof the Stress Components......Page 198
5.2.4 Steady State Deformation......Page 203
5.3 Plastic Instabilities......Page 207
Part II Dislocation Motion in Particular Materials......Page 213
6.1 Crystal Structure and Slip Geometry......Page 216
6.2 Microscopic Observations......Page 218
6.3 Dislocation Dynamics......Page 222
6.4 Recombination-enhanced Dislocation Mobility......Page 226
6.5 Macroscopic Deformation Properties......Page 227
6.6 Summary......Page 229
7.1 Alkali Halides......Page 230
7.1.1 Crystal Structure and Slip Geometry......Page 231
7.1.3 Macroscopic Deformation Properties......Page 232
7.1.4 Summary......Page 238
7.2.1 Microscopic Observations......Page 240
7.2.2 Statistics of Overcoming Localized Obstacles......Page 243
7.2.3 Kinematics of Overcoming Localized Obstacles......Page 248
7.2.4 Dislocation Dynamics......Page 251
7.2.5 Macroscopic Deformation Properties and Discussion......Page 252
7.2.6 Dislocations in the Plastic Zone of a Crack......Page 258
7.2.7 Summary......Page 261
7.3.1 Crystal Structure and Slip Geometry of ZrO2โY2O3 alloys......Page 262
7.3.2 Microscopic Observations in Cubic ZrO2......Page 263
7.3.3 Dislocation Dynamics in Cubic ZrO2......Page 269
7.3.4 Macroscopic Deformation Properties of Cubic ZrO2......Page 270
The Athermal Stress Component......Page 272
Elastic Interactions Between Dislocations and Point Defects......Page 274
Precipitation Hardening......Page 275
The Peierls Mechanism......Page 276
Formation of Solute Atmospheres Around Dislocations......Page 277
Recovery Controlled Deformation at High Temperatures......Page 279
7.3.7 Tetragonal ZrO2......Page 282
Ferroelastic Deformation......Page 283
Plastic Deformation......Page 285
Partially Stabilized Zirconia......Page 287
Summary of Tetragonal Zirconia......Page 289
8.1 Precipitation Hardened Aluminium Alloys......Page 290
8.1.1 AlโZnโMg......Page 291
8.1.2 AlโAg......Page 294
8.1.3 AlโLi......Page 296
8.2 Dislocation Generation in Metals......Page 302
8.3 Oxide Dispersion Strengthened Materials......Page 306
8.3.1 Microscopic Observations in Oxide Dispersion Strengthened Alloys......Page 307
8.3.2 Macroscopic Deformation Properties......Page 312
Long-Range Dislocation Interactions......Page 313
Orowan Stress......Page 314
The Thermally Activated Detachment Model......Page 315
Solution Hardening......Page 316
8.3.4 Summary......Page 317
8.4 Plastic Deformation During Fracture of Al2O3/Nb Sandwich Specimens......Page 318
9.1 Introduction......Page 322
9.2.1 Microscopic Observations and Dislocation Dynamics......Page 325
9.2.2 Models of the Flow Stress Anomaly......Page 328
9.3 -TiAl......Page 331
9.3.1 Crystal Structure and Slip Geometry......Page 332
Room Temperature......Page 333
High Temperatures......Page 338
9.3.3 Macroscopic Deformation Parameters......Page 340
9.3.4 Deformation Mechanisms......Page 342
Room Temperature up to About 430C......Page 343
Flow Stress Anomaly......Page 346
9.4.1 Crystal Structure and Slip Geometry......Page 349
9.4.2 Microscopic Observations......Page 350
9.4.3 Macroscopic Deformation Parameters......Page 355
Room Temperature......Page 357
High Temperatures......Page 358
9.5.1 Microscopic Observations......Page 364
9.5.2 Macroscopic Deformation Parameters......Page 369
Room Temperature......Page 371
Flow Stress Anomaly......Page 372
High-Temperature Range......Page 376
9.5.4 Summary......Page 377
9.6.1 Crystal Structure and Slip Geometry......Page 378
Deformation Along "426830A 201 "526930B......Page 379
Deformation Along "426830A 110 "526930B......Page 383
Stacking Faults......Page 387
9.6.3 Macroscopic Deformation Parameters......Page 389
9.6.4 Deformation Mechanisms......Page 392
Low Temperatures......Page 393
Flow Stress Anomaly......Page 395
9.6.5 Summary......Page 398
9.7 Conclusions on Intermetallics......Page 399
10 Quasicrystals......Page 402
10.1 Structure of Quasicrystals......Page 403
10.1.1 Quasicrystals with Icosahedral Symmetry......Page 405
10.1.2 Quasicrystals with Decagonal Symmetry......Page 407
10.2.2 Phason Defects......Page 409
10.2.3 Dislocations......Page 412
Transmission Electron Microscopy of Deformed Specimens......Page 417
In situ Straining Experiments in an High-Voltage Electron Microscope......Page 424
10.3.2 d-AlโNiโCo......Page 431
10.4 Macroscopic Deformation Parameters......Page 440
10.4.1 i-AlโPdโMn......Page 441
10.4.2 d-AlโNiโCo......Page 447
10.5 Mechanisms of Dislocation Motion and Plastic Deformation......Page 449
10.5.1 Glide or Climb Motion of Dislocations......Page 450
10.5.3 Formation of Phason Faults......Page 452
10.5.4 Long-Range Dislocation Interactions......Page 454
10.5.5 Activation Parameters of Plastic Deformation......Page 455
10.5.6 Friction Mechanisms of Dislocation Motion......Page 457
10.5.7 Dislocation Kinetics in the High-Temperature Range......Page 462
10.5.8 The Climb-Exchange Model......Page 464
10.6 Conclusions on Quasicrystals......Page 468
11 Conclusion......Page 471
Comments on the Video Sequences Available in the Internet......Page 214
List of Abbreviations and Symbols......Page 473
List of Video Clips......Page 478
References......Page 482
Index......Page 505
