Grain Boundary Segregation in Metals (eBook)

The University of Bristol calls Lejcek 'an acknowledged expert in establishing and relating the crystallography and composition of grain boundaries to their mechanical, chemical and physical properties.

Preface 8
Contents 12
Chapter 1 Introduction 15
Chapter 2 Grain Boundaries: Description, Structure and Thermodynamics 19
2.1 Crystallographic Description of Grain Boundaries 19
2.2 Atomic Structure of Grain Boundaries 22
2.2.1 Low-Angle Grain Boundaries 23
2.2.2 High-Angle Grain Boundaries 24
2.3 Classification of High-Angle Grain Boundaries 27
2.3.1 Coincidence-Site Lattice Model 27
2.3.2 Interplanar Spacing 30
2.3.3 Hierarchy of Grain Boundary Planes 31
2.4 Basic Thermodynamics of Grain Boundaries 36
Chapter 3 Approaches to Study Grain Boundary Segregation 39
3.1 Basic Definitions and Terminology 39
3.2 Experimental Methods for Study of Grain Boundary Segregation 40
3.2.1 Surface Analysis Techniques 41
3.2.1.1 Auger Electron Spectroscopy 42
3.2.1.2 Secondary Ion Mass Spectroscopy 44
3.2.1.3 Other Spectroscopic Techniques 46
3.2.2 Microscopic Techniques 49
3.2.2.1 Analytical Electron Microscopy 49
3.2.2.2 Atom-Probe Field Ion Microscopy 51
3.3 Theoretical Approaches to Study Grain Boundary Segregation 52
3.3.1 Quantum Mechanical Methods 53
3.3.2 Interatomic Potentials 55
3.3.2.1 Pairwise Potentials 56
3.3.2.2 Embedded Atom Method 57
3.3.3 Simulation Techniques 57
3.3.3.1 Molecular Statics 58
3.3.3.2 Molecular Dynamics 58
3.3.3.3 Monte Carlo Simulations 59
3.3.3.4 Minimisation of the Helmholtz Energy 62
Chapter 4 Models of Equilibrium Grain Boundary Segregation 64
4.1 Thermodynamics of Grain Boundary Segregation 64
4.2 Gibbs Adsorption Isotherm 65
4.3 Langmuir–McLean Types of Segregation Isotherm 68
4.3.1 Physical Meaning of Thermodynamic State Functions Appearing in Segregation Isotherms 74
4.3.1.1 Gibbs Energy, Enthalpy and Entropy of Interfacial Segregation 74
4.3.1.2 Standard Thermodynamic Functions of Interfacial Segregation 76
4.3.1.3 Excess Thermodynamic Functions of Interfacial Segregation 79
4.3.1.4 Effective Thermodynamic Functions of Interfacial Segregation 80
4.3.2 Langmuir–McLean Model 87
4.3.3 Guttmann Model of Grain Boundary Segregation in Interacting Multi-component Systems 94
4.3.4 Fowler Model 99
4.3.5 Other Models for Grain Boundary Segregation 102
4.3.5.1 Modern Thermodynamic Calculation of Interfacial Properties 103
4.3.5.2 Model of Luthra and Briant 104
4.3.6 Models for Different Segregation Sites 105
4.3.6.1 BET Isotherm 105
4.3.6.2 Individual Site Models 106
4.4 Models for Thermodynamic Functions of Interfacial Segregation 107
4.4.1 Model of Wynblatt and Ku 108
4.4.2 Model of Seah 110
4.4.3 Model of Miedema 111
4.4.4 Model of Kumar 111
4.4.5 Model of Mukherjee and Morán-López 112
4.4.6 BFS Model 113
4.4.7 SMA–TBIM Approach 114
Chapter 5 Effect of Variables on Equilibrium Grain Boundary Segregation 116
5.1 Temperature and Bulk Composition 116
5.2 Pressure 120
5.3 Magnetic Effects 121
5.4 Grain Boundary Energy 124
5.5 Nature of Segregating Element 142
5.5.1 Truncated BET Isotherm 142
5.5.2 Grain Boundary Segregation Diagram 144
5.5.3 Enthalpy–Entropy Compensation Effect 148
5.6 Grain Size 154
5.7 Prediction of Grain Boundary Segregation 159
5.7.1 Model of Lejcek and Hofmann 159
5.7.2 Model of Wynblatt and Shi 163
Chapter 6 Principles of Non-equilibrium Segregation 166
6.1 Kinetics of Grain Boundary Segregation 166
6.1.1 Semi-infinite Solution of Fick Equation 166
6.1.2 Layer-by-Layer Model (Model of Hofmann and Erlewein) 169
6.1.3 Model of Limited Reaction Rates 171
6.2 Non-equilibrium Segregation 171
6.2.1 Thermally Induced Segregation 172
6.2.2 Radiation-Induced Segregation 175
6.2.3 Stress-Induced Segregation 178
6.2.4 Grain Boundary Segregation and Migration 180
Chapter 7 Grain Boundary Segregation and Related Phenomena 185
7.1 Grain Boundary Cohesion 185
7.1.1 Grain Boundary Cohesion and Temper Embrittlement 185
7.1.2 Hydrogen Embrittlement 193
7.1.3 Other Types of Non-reactive Environmental Decohesion 195
7.1.3.1 Liquid Metal Embrittlement 195
7.1.3.2 Dynamic Embrittlement 196
7.2 Grain Boundary Corrosion 197
7.2.1 Corrosion 198
7.2.2 Stress Corrosion Cracking 200
7.3 Grain Boundary Diffusion 202
7.3.1 Fundamentals of Grain Boundary Diffusion 202
7.3.2 Relationship Between Grain Boundary Diffusionand Segregation 207
7.4 Grain Boundary Engineering 208
Appendix A Parameters of Grain Boundary Segregation 214
A.1 Enthalpy, Entropy and Gibbs Energy of Segregation 214
A.2 Interaction Coefficients 221
Appendix B Predicted Values of Enthalpy and Entropy of Segregation 224
References 226
Index 245