Internal friction of an Al–Cu–Fe icosahedral quasicrystal and its crystal approximant

Abstract

The internal friction was measured for an Al–Cu–Fe icosahedral phase (i-phase) and an Al–Cu–Fe–Si 1/1 approximant phase (1/1-phase) by using a dynamical mechanical analyzer (DMA) in the frequency range 0.05–10 Hz and the temperature range 300–873 K. For the i-phase, four absorption peaks were observed at around 420, 580, 620 and 800 K, respectively. These were of the thermally activated relaxation type, and their activation parameters were evaluated. The parameters evaluated for the peak at 800 K indicate a relaxation process involving a collective atomic motion, which can be attributed to correlated phason jumps. This peak was absent for the 1/1-phase. These results are similar to the results of the internal friction measurements previously reported for an Al–Pd–Mn i-phase and its 1/1 approximant phase. Based on the phonon–phason dynamics model, the magnitudes of phason elastic constants were estimated for the Al–Cu–Fe i-phase.

Keywords:

• internal friction
• phason dynamics
• icosahedral quasicrystal
• crystal approximant

Acknowledgements

The authors would like to thank Professor S. Takeuchi of Tokyo University of Science (TUS) for the valuable comments and discussion, Professor Y. Kogo of TUS for his help in the internal friction measurements, and Professor T. Iida of TUS for his help in the PAS experiments. This work was financially supported by a Grant-in-Aid for the Japan Society for the Promotion of Science (JSPS) Fellows and by a Grant-in-Aid for Scientific Research on Priority Areas “Nano Materials Science for Atomic Scale Modification 474”, from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan.