Comparative study on internal friction in an Al-Pd-Mn icosahedral quasicrystal and its crystal approximants

Article

关键词: RATIONAL APPROXIMANT;    DIFFUSE-SCATTERING;    ELASTIC-CONSTANTS;    CU-CO;    ALLOYS;    PHASE;    DISLOCATIONS;    STABILITY;    DYNAMICS;   

DOI  :  10.1103/PhysRevB.80.224204

来源: SCIE

【 摘 要 】

The internal friction was measured for an Al-Pd-Mn icosahedral phase (i-phase) and its 1/1 and 2/1 approximant phases in an Al-Pd-Mn-Si system in a forced flexural-oscillation mode in a frequency range of 0.05-20 Hz and a temperature range of 300-873 K. For the i-phase, large and small absorption peaks were observed with Q(-1)approximate to 1.3x10(-2) and 8x10(-4), respectively. These two peaks were absent for the 1/1-phase, which showed two other peaks instead. The 2/1-phase exhibited the features of both the i and 1/1-phases; it showed two peaks of the i-phase and one of the two peaks of the 1/1-phase. All the observed peaks were of the thermally activated relaxation type, and their activation enthalpies and frequency factors were evaluated. The larger peak of the i-phase, which was absent for the 1/1-phase and present with a much reduced intensity for the 2/1-phase, was shown to result from a relaxation process involving collective atomic motion. Collective and correlated phason jumps were discussed as a possible mechanism for it. It was speculated that the other peaks observed only for the approximant phases are due to Zener relaxations by the reorientation of atom pairs involving Si.

【 授权许可】

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