Nanoscale AFM and TEM Observations of Elementary Dislocation Mechanisms (eBook)

Supervisor’s Foreword 6
Abstract 8
Acknowledgments 9
Contents 10
Abbreviations 12
1 Introduction 14
References 15
2 Iron Rich Iron-Aluminides 16
2.1 Structure 16
2.1.1 Lattice Parameter 18
2.1.2 Long-Range Order and Sublattice Occupancies 18
2.1.3 Phase Transformations 19
2.1.4 Short-Range Order and K-State 20
2.2 Defects 20
2.2.1 Point Defects: Vacancies and Anti-site Atoms 20
2.2.2 Dislocations 23
2.2.3 Anti-phase Domains and Boundaries 24
2.3 Yield Stress Anomaly 24
References 25
3 Experimental Methods 31
3.1 Composition 31
3.2 Bridgman Method 31
3.3 Sample Cutting and Orientation 33
3.4 Laue Back-Reflection X-Ray Diffraction 35
3.5 Annealing 36
3.6 Atomic Force Microscopy 36
3.6.1 Contact and Tapping Mode 38
3.6.2 Feedback Loop Tuning 39
3.6.3 Sample Preparation 40
3.6.4 In-Situ Deformation 41
3.6.5 Step Fiting Method 43
3.6.6 Drift and Image Alignment 45
3.7 Transmission Electron Microscopy 46
3.7.1 Diffraction Contrast 46
3.7.2 Visibility of Dislocations 48
3.7.3 Kikuchi Line Fitting 48
3.7.4 Stereo Reconstruction 51
3.7.5 Sample Preparation 53
References 53
4 Observations of Dislocations and Other Results 57
4.1 Deformation 57
4.2 Order 59
4.2.1 Selected Area Electron Diffraction 59
4.2.2 Anti-phase Domains 61
4.3 Carbide Particles 61
4.4 Fe--Al20 64
4.4.1 TEM of Undeformed Material 64
4.4.2 Wavy Slip 64
4.4.3 Bowtie Structures 67
4.5 Fe--Al28 71
4.5.1 TEM of Undeformed Material 71
4.5.2 In-Situ AFM Observations 73
4.5.3 AFM Observations of Samples Deformed at Different Temperatures 73
4.5.4 TEM Observations of Samples Deformed at Diferent Temperatures 73
4.6 Fe--Al40 86
4.6.1 Square Dislocation Loops in Undeformed Material 86
4.6.2 In-Situ AFM Observations 87
4.6.3 TEM Observations of Deformed Sample 88
5 Discussion 93
5.1 Deformation 93
5.2 Order and Anti-phase Boundaries 94
5.3 Carbides 94
5.4 Fe--Al20 98
5.5 Fe--Al28 100
5.6 Fe--Al40 102
References 102
6 Summary 105
Reference 106
Appendix A Supplementary Material 107
A.1 Optical Images 107
A.2 In-situ Image Sequences 107
A.3 Interactive 3D Models 107
Curriculum Vitae 111