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 delta 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 Theta(Co-Zr)(x(Co)), Theta(Al-Zr)(x(Al)), the range of Co-Zr-Al compositions with the best GFA was determined and Zr55Co29Al16 composition with maximum D(max)( )was identified. The thermodynamic mixing functions (Delta G(mix), Delta 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.