Rejuvenation in a Zr-based bulk metallic glass via a modified cyclic elastic loading method

Abstract

The brittleness of bulk metallic glasses (BMGs) at room temperature poses a notable hindrance to their widespread application. Elastic loading is one of the most prevalent non-destructive rejuvenation methods for enhancing the plasticity of BMGs. However, achieving a satisfactory effect often necessitates either a relatively extended holding time or a considerable number of cycles. In this study, a modified cyclic elastic loading method with a higher efficiency was applied to rejuvenate a Zr₅₅Cu₃₀Al₁₀Ni₅ BMG by limiting the springback of the material during elastic loading cycling. Specifically, by applying just a few cycles of elastic loading, a substantial increase in plasticity in the Zr₅₅Cu₃₀Al₁₀Ni₅ BMG was observed. The plasticity increased from approximately 0.49 % in the as-cast sample to a maximum value of around 4.46 % after four cycles, albeit with a corresponding reduction in strength. This enhancement in plasticity, coupled with the diminished strength, was primarily attributed to the rapid increase in free volume. The increased free volume results in more "soft zones" in the BMG sample, which is conducive to the initiation of multiple shear bands. Meanwhile, the elastic modulus demonstrated relatively stable behavior, likely due to the interactive effects between the free volume and the icosahedral ordering within the BMG samples. This work introduces a straightforward yet effective method for enhancing the plasticity of BMGs, potentially broadening their range of applications.