Plastic Deformation of Al-Pd-Mn Icosahedral Quasicrystal

Compression experiments have been performed for coarse-grained Al72Pd20Mn8 icosahedral quasicrystals at high temperatures. Above 950 K, specimens became deformed due to localized slip, exhibiting pronounced yield drop. Analysis of the stress-relaxation curve at the lower yield point has shown that the internal stress accounts for about half of the lower yield stress. From the strain-rate sensitivity and the temperature dependence of the effective stress, the activation volume and the activation enthalpy of plastic deformation have been analyzed. The obtained results have been interpreted in terms of dislocation glide in quasicrystals.