Thermodynamic characteristics of metallic glass-forming liquids

Abstract

On the basis of analyzing the thermodynamic model of regular melt, the mixing enthalpy ΔHmix and the mixing entropy ΔSmix of typical metallic glass melts were calculated. The distribution of ΔHmix vs. ΔSmix for typical metallic glasses was generalized, and a strategy for pinpointing metallic glass formers has been proposed by combining the critical cooling rate Rc based on the atomic intrinsic characteristics of the alloys including atom size, composition, and mixing enthalpy of binary systems among the components. On the condition of ΔSmix greater than 0.6 J·K-1mol-1 and ΔH less than -15 kJ·mol-1, the alloy tends to form a bulk metallic glass(BMG). It shows that Rc is intimately related with ΔSmix, and can be expressed as Rc=42.24×104 exp(-13.91 ΔSmix)+19.66. Two new glass formers, Zr40Al10Ni15Cu35, located far from the glass forming area of the existing Zr-Al-Ni-Cu BMGs with a content of 55at%—65at% zirconium, and Fe53Co5Nd12B30 of quaternary Fe-B-based BMG, were successfully prepared with this approach.