Strain rate dependence of mechanical behavior in a CuZr-based bulk metallic glass composite containing B2-CuZr phase

Strain rate effect on the mechanical behavior of a Cu₄₈Zr₄₈Al₄ bulk metallic glass composite (BMGC) containing a B2-CuZr phase was investigated under quasi-static and dynamic compression. It was found that the CuZr-based BMGC exhibits remarkable strain-rate-softening, although the deformation-induced martensitic transformation of the B2-CuZr phase similarly occurred under both quasi-static and dynamic loading. The significant transformation-induced plasticity (TRIP) and pronounced work-hardening characteristic of the BMGC upon quasi-static loading were found to be considerably deteriorated under dynamic loading. Furthermore, the BMGC alloy was aboratively heat-treated into austenite and martensite states mainly containing the B2-CuZr phase and the B19'-CuZr phase respectively. By comparing the strain-rate responses of the mechanical behaviors in the austenite and martensite states, it was shown that the B2-CuZr phase itself presents dynamic softening due to the deformation-induced martensitic transformation with heat release effect. The dynamic softening characteristic of the B2-CuZr phase limits its contribution to the potential mechanical behavior of the CuZr-based BMGC containing the B2-CuZr phase under dynamic loading.