Elastic and viscoelastic properties of glassy, quasicrystalline and crystalline phases in Zr 65Cu 5Ni 10Al 7.5Pd 12.5 alloys

Abstract

The elastic and viscoelastic properties of Zr 65Ni 10Cu 5Al 7.5Pd 12.5 bulk metallic glass have been studied over a wide temperature and frequency range. In the amorphous state the mechanical response of the alloy is simple, similar to that observed in other bulk metallic glasses. In contrast, the phase-transformation process which occurs during annealing at elevated temperature induces a complex evolution. This alloy transforms to a supercooled liquid and then primarily forms an icosahedral phase followed by the formation of a mixture of crystalline phases. The mechanical properties in the amorphous state are well described using a physical model based on the concept of defects in amorphous materials. Atomic mobility is then governed by two parameters: activation energy U el (0.92 eV) and correlation factor χ (0.39). The influence of the phase composition on the properties is discussed.