New criteria for predicting compositions with high glass-forming ability in Zr–Co–Al alloys

We show that the widespread parameters P _HS, P _HSS and δ related with mixing enthalpy, mismatch entropy, configurational entropy and atom size difference do not provide proper prediction of the bulk metal glasses (BMGs) compositions with high glass-forming ability in Zr-Co-Al system. A new computational approach has been developed for the accurate determination of BMGs compositions having a maximum critical diameter ( D _max). Using new parameters Θ _Co-Zr( x _Co), Θ _Al-Zr( x _Al), the range of Co-Zr-Al compositions with the best GFA was determined and Zr ₅₅Co ₂₉Al ₁₆ composition with maximum D _max was identified. The thermodynamic mixing functions (∆ G _mix, ∆ H _mix) for the glass-forming Zr-Co-Al system were calculated for the first time. The results obtained reveal a relationship between thermodynamic and geometric factors and open up prospects for the development of reliable theoretical methods for new metallic glasses discovery.