Anomalous temperature dependence of crystalline-to-amorphous transformation induced by high-pressure torsion in Zr50(Cu,Al)50

Abstract

Martensite phases of Zr50Cu50 and Zr 50Cu44Al6 were deformed by high-pressure torsion (HPT) at different temperatures ranging from 253 to 473 K. Microstructural observations revealed that the crystalline-to-amorphous transformation induced by HPT showed remarkable temperature dependence: an increase in deformation temperature up to 473K significantly increased the fraction of the amorphous structure. This result suggests that the lattice instability near martensitic transformation temperature promotes crystalline-to-amorphous transformation, which is coherent to the generalized Lindemann criterion of defect-induced amorphization. © 2013 The Japan Institute of Metals and Materials.