Thermodynamic prediction of bulk metallic glass forming alloys in ternary Zr–Cu–X (X = Ag, Al, Ti, Ga) systems

Prediction of bulk metallic glass (BMG) forming compositions has always been a challenge due to thermodynamic and kinetic constraints. In the present investigation, a parameter based on the enthalpy of chemical mixing (∆Hchem) and the mismatch entropy (∆Sσ/kB) has been used to correlate with glass forming ability in some Zr based BMGs. The new thermodynamic parameter, PHS = ∆Hchem × ∆Sσ/kB, is found to have strong correlation with glass forming ability in the configurational entropy (∆Sconfig/R) range of 0.9–1.0. PHS has been calculated for compositions in Zr–Cu–Ag, Zr–Cu–Al, Zr–Cu–Ti and Zr–Cu–Ga ternary systems. It is observed that in all the systems studied, the best BMG composition (highest critical diameter (Zc) of glass formation) is the one that corresponds to the highest negative PHS value. Present approach using PHS could be road map to design new BMG forming compositions.