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

Abstract

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 (ΔH_chem) and the mismatch entropy (ΔS_σ/k_B) has been used to correlate with glass forming ability in some Zr based BMGs. The new thermodynamic parameter, P_HS = ΔH_chem × ΔS_σ/k_B, is found to have strong correlation with glass forming ability in the configurational entropy (ΔS_config/R) range of 0.9-1.0. P_HS 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 (Z_c) of glass formation) is the one that corresponds to the highest negative P_HS value. Present approach using P_HS could be road map to design new BMG forming compositions.