Influence of melt temperature on the compressive plasticity of a Zr–Cu–Ni–Al–Nb bulk metallic glass

Zr_63.78Cu_14.72Ni₁₀Al₁₀Nb_1.5 BMGs (bulk metallic glasses) were cast at the melt temperatures ranging from 1,073 to 1,313 K with the same interval of 40 K. The structure, thermal, and mechanical properties of the BMGs were investigated by XRD, DSC, HRTEM, dilatometric measurements, micro-hardness tests, and uniaxial compression. The results indicate that the higher the casting temperature, the fewer the nano-crystallites, the more the free volumes, and the lower the micro-hardness in the BMGs, leading to the larger plastic strains. The plasticity of BMGs deteriorates with the increase of nano-crystallites as decreasing the casting temperature. The free volume, instead of the nano-crystallites, favors the plastic deformation in Zr_63.78Cu_14.72Ni₁₀Al₁₀Nb_1.5 BMGs. The microstructures and mechanical performance of BMGs are closely affected by the casting temperature. The preparing parameters are important to improve the plasticity of the BMGs.