Concurrent solid-state amorphization and structural rejuvenation in Zr-Cu-Al alloy by high-pressure torsion

The aim of this study is to compare the difference between the amorphous phases produced by difference fabrication methods: melt quenching (MQ) and solid-state amorphization (SSA). SSA by high-pressure torsion (HPT) was achieved in a crystalline Zr-40at%Cu-10at%Al alloy. The sample deformed by 100 turns of HPT consisted of mostly amorphous phase with tau(5) nanocrystals embedded in the amorphous matrix. Compared to the MQ metallic glass, the SSA sample showed lower Vickers microhardness and homogenous plastic flow without shear bands under nanoindentation. Furthermore, the SSA sample exhibited a lower onset temperature of structural relaxation and larger relaxation enthalpy as measured by differential scanning calorimetry. These differences in mechanical and thermal properties can be attributed to the structural rejuvenation occurred concurrently with solid-state amorphization. (C) 2017 Elsevier B.V. All rights reserved.