We studied the complete set of elastic constants Cij and internal frictions tensor Qij-1 of anisotropic decagonal Al72Ni18Co8 single quasicrystal by electromagnetic acoustic resonance at low temperatures, to 5 K. Most C ij(T) showed usual stiffening upon cooling and their temperature behaviors are well characterized by an Einstein-lattice-vibration model. The average Grüneisen parameter estimated from the bulk modulus is 2.4, almost identical to crystalline Al. Ambient temperature Qij-1 show a linear relationship to the elastic-constants temperature derivatives |dCij/dT|/Cij with a slope of 1.28 K-1, suggesting that lattice anharmonicity plays a dominant role for Q ij-1. The longitudinal modulus for the decagonal axis C33 and corresponding internal friction Q33-1, however, showed significant deviation from such ideal behavior, suggesting additional low-frequency phonon-excitation modes along the decagonal axis.
ASJC Scopus subject areas
- Physics and Astronomy(all)