Quasicrystals : types, systems, and techniques

QUASICRYSTALS: TYPES, SYSTEMS, AND TECHNIQUES......Page 3
QUASICRYSTALS: TYPES, SYSTEMS, AND TECHNIQUES......Page 5
Contents......Page 7
Preface......Page 9
Abstract......Page 15
1. Introduction......Page 16
1.1. Phase Diagram......Page 17
1.2. Magnetic Properties......Page 18
1.3. Electrical Conductivity......Page 19
3.1.1. Structural Characterization......Page 20
3.1.2. Magnetic Characterization......Page 22
3.1.3. Conductivity Vs. Temperature......Page 23
3.1.4. Magneto-Resistance......Page 32
4.1.1. Structural Characterization......Page 35
4.1.2. Magnetic Characterization......Page 36
4.1.3. Conductivity Vs. Temperature......Page 39
4.1.4. Magneto-Resistance......Page 44
5. Part III......Page 45
5.1.1. Structural Characterization......Page 46
5.1.2. Magnetic Characterization......Page 47
5.1.3. Conductivity Vs. Temperature......Page 49
5.1.4. Magneto-Resistance Measurement......Page 52
Annexure I......Page 53
References......Page 56
1. Introduction......Page 61
2. Model......Page 63
3.1.6.......Page 67
3.2.2. The Compromise Spacing Effect......Page 68
3.2.4. Enthalpy, the Driving Force......Page 69
3.2.7. Electronic States......Page 70
4. Evidence......Page 74
4.2. Ranking of Beam Intensities and Calculated ‘Structure Factors’......Page 75
4.2.2. Double Diffraction in CBED......Page 78
4.4. HREM Images of Clusters and Superclusters......Page 80
4.4.2. The 3-Fold Cluster Center in the 5-Fold Pattern......Page 82
5.2. Defects......Page 83
5.2.3. The ‘Hole’ in Superclusters of Higher Order......Page 84
5.3. Limitation to Binary Systems......Page 85
Conclusion......Page 86
Appendix 1. Quasi Bragg Diffraction......Page 87
Reference......Page 89
1. Introduction......Page 91
2.1. Positons in Materials......Page 92
2.3. Coincident Doppler Broadening Spectroscopy......Page 93
2.4. Positron Diffusion Experiment......Page 94
3.1. Al-Based QC......Page 95
3.2. CdYb Binary QC......Page 97
3.3. MgZnSc QC......Page 98
4.1. Al-Based QC......Page 100
4.2. CdYb Binary QC......Page 102
4.3. MgZnSc QC......Page 103
4. Detection Of High-Temperature Thermal Vacancy......Page 105
5. Detection of Electron-Irradiation Induced Vacancy......Page 109
6. Application of Positron to Structural Phase Transition......Page 111
References......Page 116
Abstract......Page 121
1. Introduction......Page 122
2.1. Strong Reflections Determine the Atomic Positions......Page 124
2.2. Similarity......Page 127
3.1. Re-Indexing and Phasing......Page 130
3.2. Identifying Atomic Positions......Page 135
4. Extending to Ideal Quasicrystals......Page 137
References......Page 139
1. Introduction......Page 141
2. Hydrogen in Quasicrystals......Page 142
3.1. Ti-Zr-Ni System......Page 143
3.2. Ti-Hf-Ni System......Page 146
4.1. Ti-Zr-Ni System......Page 147
5.1. Ti-Zr-Ni System......Page 152
5.2. Ti-Hf-Ni System......Page 157
6. Conclusion......Page 158
References......Page 159
1. Introduction......Page 161
2. Formation of Quasicrystalline Phase in the BMGs During Heat-Treatments......Page 163
3. Morphology, Structure and Chemical Composition of Quasicrystals Formed During Annealing BMGs......Page 165
4. Effect of Formation of Quasicrystalline Particles on the High-Temperature Creep of Metallic Glasses......Page 167
5. Influence of Quasicrystalline Phase Formation on the Room Temperature Mechanical Behavior of BMGs......Page 172
6. Conclusion......Page 173
References......Page 174
Abstract......Page 177
1. Introduction......Page 178
2. Experimental......Page 179
3.A. Step Structure of the 2-Fold Al-Ni-Co Decagonal Quasicrystal Surface......Page 180
3.B. Atomic Scale Disordering on the 2 Fold Al-Ni-Co Surface......Page 183
3.C. Atomic Structure of Second Phase Structures......Page 184
Acknowledgments......Page 185
References......Page 186
1. Introduction......Page 189
2. Plane Stress State of 2D Qcs......Page 190
3. Necessary Conditions for A Decaying State......Page 192
4. The Auxiliary Regular States......Page 195
5.3. Case B......Page 197
5.3. Case C......Page 198
5.6. Case G......Page 199
6. The Appropriate Boundary Conditions for  the Interior State......Page 200
References......Page 201
Abstract......Page 203
3. Results and Discussion......Page 204
Conclusion......Page 206
References......Page 207
Abstract......Page 209
Introduction......Page 210
Methods for Determining the Shapes of Quasicrystals......Page 211
Experimental Work......Page 214
Icosahedral Quasicrystalline Phase in Al-Mn-Be-X Alloys......Page 215
Morphology of the I-Phase in Melt-Spun Ribbons......Page 218
Shape of the Primary IQC in Alloys Cast Into a Copper Mould......Page 220
Eutectic IQC-Phase......Page 225
Presence of Other Phases......Page 227
Conclusions......Page 229
References......Page 230
Index......Page 233