Deformation behavior of Zr-based metallic glasses

Abstract

Multi-component bulk Zr-based glassy alloys exhibit a wide supercooled liquid region, which provides excellent stability against crystallization. Microstructures consisting of a metallic glass matrix with crystallite precipitates of different shapes and sizes are synthesized. The compressive deformation behavior of metallic glassy matrices with and without second-phase precipitates is reviewed. At room temperature, fully amorphous alloys exhibit microplasticity without significant work hardening. In contrast, alloys with a large volume fraction of crystallites introduced either in dendritic form during casting or as nano-scaled precipitates during post-annealing of fully amorphous structures are brittle. At high temperatures, amorphous and partially crystalline alloys exhibit Newtonian viscous flow at low strain rates. At both temperatures the deformation behavior is described within the framework of the free volume model.