Small-Scale Mechanical Behavior of Ion-Irradiated Bulk Metallic Glass

The effect of ion irradiation on the hardness and yield strength of Zr57Nb5Cu15.4Ni12.6Al10 bulk metallic glass has been studied using nanoindentation and micropillar compression tests. The results for the amorphous alloy were compared with those for 304 stainless steel. After Ni2+ ion irradiation, the metallic glass was found on an average to have 16% lower hardness and 13% lower yield strength. In contrast, 304 stainless steel showed significant hardening (~ 50% hardness and strength increase) after irradiation under identical conditions. The irradiation-induced hardening of the steel was attributed to hindrance of dislocation movement from the defects generated, while the softening behavior of the metallic glass was attributed to structural change in the irradiated region while retaining a fully amorphous state. The present work paves the way for better understanding of the irradiation response of metallic glasses to develop degradation-resistant alloys for next-generation nuclear applications.