Refinement of core-shell hybrid structure reinforced CuZr-based bulk metallic glass matrix composites via dealloying in metallic melt

Metallic glass matrix composites (BMGCs) with compositions of[(Zr_0.5Cu_0.5)_0.925Al_0.07Sn_0.005]_100-xTa_x (atomic fraction, %, x=3, 5, 7) were successfully prepared via dealloying in metallic melt. The reinforcing phase in these alloys has core-shell hybrid structure with Ta-rich particles as core and B2-CuZr as shell. In this method, the dealloyed Ta from Zr-Ta pre-alloys maintained in solid state and aggregated to form the fine Ta-rich phase in the final products. This effectively decreases the size of Ta-rich phase compared with that prepared via conventional arc-melting, where the Ta-rich phase was formed through dissolving and precipitation. Among the three compositions, [(Zr_0.5Cu_0.5)_0.925Al_0.07Sn_0.005]₉₅Ta₅ showed the highest plastic strain of 11.2%, much higher than that of the arc-melted counterparts (4.3%). Such improvement in mechanical properties was related with the refined core-shell hybrid reinforcing structure, which could hinder the rapid propagation of main shear band more efficiently and cause them to branch and proliferate at the interface.