Optimization of glass-forming ability and synergistic enhancement of strength plasticity in Cu₅₀Zr₄₆Al₄ metallic glasses through Ag additions

Bulk metallic glasses (BMGs) are typically characterized by high strength and elasticity. However, they generally demonstrate a deficiency in plastic deformation capability at room temperatures. In this work, Cu_50−xZr₄₆Al₄Ag_x (x = 0, 1, 2, 3, 4) alloys were prepared by arc melting and copper mold casting to investigate their structure, glass-forming ability, and mechanical properties. The results show that the addition of Ag can increase the parameter of ΔT_x and γ in Cu₅₀Zr₄₆Al₄ alloy by 116% and 1.5% respectively, effectively enhancing its thermal stability and glass-forming ability. Compressive fracture tests reveal that the addition of Ag can significantly improve the yield strength, ultimate strength, and plasticity of the Cu₅₀Zr₄₆Al₄ alloy. Specifically, with the Ag addition of 1 at.%, the alloy’s ultimate strength and plasticity increased by 71.8% and 21 times, respectively. Furthermore, the introduction of Ag can effectively control the free volume content in the Cu₅₀Zr₄₆Al₄ alloy, thereby tuning the hardness of the material. This work provides valuable insights into improving the mechanical performance of BMGs through micro-alloying approaches.