Enhanced plasticity of Fe-Nb-B-(Ni, Cu) bulk metallic glasses by controlling the heterogeneity and elastic constants

Influence of the micro-alloying of Cu and the partial substitution of Fe by Ni on mechanical properties was investigated in Fe-Nb-B-(Ni, Cu) bulk metallic glasses (BMGs). When the addition of Cu content was properly adjusted with 0.5 at.%, the (Fe _0.71Nb _0.06B _0.23) _99.5Cu _0.5 alloy exhibits enhanced plasticity of 4.5% due to the precipitation of nano-scale particles. Meanwhile, the partial replacement of Ni for Fe also effectively improves the plastic strain caused by tuning the elastic constants. The (Fe _0.5Ni _0.5) ₇₁Nb ₆B ₂₃ alloy with 1:1 Ni-to-Fe concentration ratio shows a large Poisson's ratio (0.356) and a pronounced plastic strain of 4.2%. These results indicate the improved room temperature plasticity of Fe-Nb-B-(Ni, Cu) BMGs can be achieved by the appropriate control of the heterogeneity and intrinsic elastic properties.