Thermodynamics of formation of aluminum–iron–germanium amorphous alloys

Abstract

Thermodynamic properties of ternary liquid Al–Fe–Ge alloys were studied by electromotive force method at 1050–1250 K and by high-temperature isobasic calorimetry at 1740 ± 5 K. The heat capacity change at ternary alloy formation (Δ mix C p) was estimated using the temperature dependence of integral enthalpy of mixing. Thermodynamics of the formation of Al–Fe–Ge amorphous alloys was evaluated by extrapolation of thermodynamic functions of mixing to the temperature of amorphization. The process of glass forming is preferable by both enthalpy and entropy for compositions of (0.1< x Fe<0.6, x Ge<0.5). The area with most negative integral Gibbs free energy and enthalpy of amorphous alloy formation corresponds well to the area of amorphization estimated by a glass-forming tendency (GFT) criterion.