Temperature effects on mechanical properties, deformation behavior and formability of Zr-Ti-Cu-Ni-Be-Nb bulk metallic glass composite

Abstract

The deformation behavior and macroscopic formability of a Zr-based bulk metallic glass composite (BMGC) has been investigated in this study by performing a series of compression and laboratory-scale extrusion tests under various deformation rates within the supercooled liquid temperature region. The morphology of Zr-Ti-Nb-rich dendrite precipitates after warm deformation was first examined by using optical microscopy (OM) and a field emission scanning electron microscope (FE-SEM). The extrusion of this BMGC alloy within the supercooled liquid temperature region was found more difficult than the extrusion of other Zr-based monolithic BMG alloys, possibly due to the existence of dendrite phases hindering the characteristic viscous flow generated in the amorphous phase. A FEM simulation has also been carried out by utilizing the stress-strain behaviors obtained from high temperature compression tests, and the results have been compared with the experimental extrusion test results. The FEM simulation results for the extrusion process as well as a processing map based on a dynamic materials model (DMM) were found to agree relatively well with the actual macroscopic extrusion formability.