Deformation behavior of Zr-Al-Cu-Ni-Sn metallic glasses

A highly deformable Zr-Al-Cu-Ni-Sn alloy system without any catastrophic failure has been developed and the underling mechanism for exceptional plasticity has been investigated in terms of structural characteristics and atomic movement kinetics. The as-cast Zr_61.7A1₈ Ni₁₃CU₁₇Sn_0.3 bulk metallic glass has many local nanoscale ordering features. They can play a critical role in nucleating abundant shear bands that sufficiently accommodate global plasticity. During deformation at room temperature, the ordered regions do not grow, providing a structural stability, possibly from the sluggish atomic movement kinetics. Thermal activation energy for crystallization of the Zr_61.7Al₈Ni₁₃CU₁₇ Sn_0.3 alloy is estimated as 3.96 eV, which is about 2.8 times higher than that of the Z_41.2Ti_13.8 CU_12.5Ni₁₀Be_22.5 alloy [Vitreloy 1 (Vit1)] and the dynamic mass flow rate is around 10 times slower than that of Vit1. A thermomechanical estimation of compressive strain rates under constant stress shows a sluggish atomic movement upon the addition of Sn.