Effect of substituting elements on glass-forming ability of the new Zr48Cu36Al8Ag8 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 Tl or γ exists among all the alloys. The possible mechanisms for the improvement or damage to the GFA of the Zr48Cu36Al8Ag8 alloy by addition of the substituting elements are interpreted in view of Inoue's three empirical rules and atomic structure of glassy alloys.