The formation of glasses in Zr–Cu(Co, Ni)–Al systems: Development of a combined thermodynamics and geometrical model

Abstract

The prediction of bulk metal glasses (BMGs) with high glass-forming ability (GFA) is important for understanding the origin of glass formation, and critical for the design and development of new BMGs. We propose a new criterion for predicting BMG regions based on two parameters ΘX−Y(X),ΘX−Y(Y), which consider both thermodynamic and geometric factors. The main idea is to search for a local minimum of the parameter PHSS (product of mixing enthalpy, configurational entropy and mismatch entropy) with simultaneous consideration of the individual geometric factors. To verify the method, we accurately predict high-GFA compositions in Zr–Cu(Co,Ni)–Al systems. We suggest that large differences in GFA for Zr–Co(Ni)–Al alloys are mainly due to the ratio of atomic size mismatches between Co(Ni)–Zr and Al–Zr species. Similarly, for Zr–Cu–Al system, the ratio of atomic size mismatches between Cu–Al and Zr–Al plays an important role. Our findings open up prospects for the development of reliable theoretical methods for predicting new metallic glasses.