Effect of substituting elements on glass-forming ability of the new Zr ₄₈Cu₃₆Al₈Ag₈ bulk metallic glass-forming alloy

The effect of substituting elements on the glass-forming ability (GFA) of the quaternary Zr₄₈Cu₃₆Al₈Ag₈ alloy was investigated by thermal analysis and copper mold casting. Early transition metal Zr is replaced by Ti, Nb and Hf; and late transition metal Cu is substituted with Fe, Au, Pd and Ni. Addition of Ni and Pd was found to improve the GFA of the Zr₄₈Cu₃₆Ag₈Al₈ alloy. Addition of Au to replace Cu or Hf to replace Zr decreases the GFA slightly, while addition of Ti, Nb and Fe significantly degrade GFA. A good consistency between the GFA and the T_l or γ exists among all the alloys. The possible mechanisms for the improvement or damage to the GFA of the Zr ₄₈Cu₃₆Al₈Ag₈ alloy by addition of the substituting elements are interpreted in view of Inoue's three empirical rules and atomic structure of glassy alloys.