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 (Fe0.71Nb0.06B0.23)99.5Cu0.5 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 (Fe0.5Ni0.5)71Nb6B23 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.

► We examine the effect of additional elements on the microstructure and mechanical properties of Fe–Nb–B–(Ni, Cu) glassy alloys. ► The micro-alloying of Cu effectively enhances the plasticity due to the precipitation of nanocrystalline phases into the glassy matrix. ► The partial substitution of Fe by Ni increases the plastic strain via tuning the intrinsic elastic constants.