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 Zr61.7A18 Ni13CU17Sn0.3 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 Zr61.7Al8Ni13CU17 Sn0.3 alloy is estimated as 3.96 eV, which is about 2.8 times higher than that of the Z41.2Ti13.8 CU12.5Ni10Be22.5 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. © 2006 Materials Research Society.