Calculations of mixing enthalpy and mismatch entropy for ternary amorphous alloys

Chemical mixing enthalpy (ΔH^chem) and mismatch entropy normalized by Boltzmann constant (S_σ/k_B) corresponding to the three empirical rules for the achievement of high amorphous-forming ability (AFA) were calculated with thermodynamical functions for the gross number of 6450 alloys in 351 ternary amorphous systems. The ternary amorphous alloys have ΔH^chem of -86 to 25 kJ/mol and S_σ/k_B of 1.0 × 10^-3 to 5.7. The average values of ΔH^chem and S_σ/k_B are calculated to be -33kJ/mol and 0.33, respectively. The 30 alloys in 9 ternary amorphous systems including 10 alloys in Ag-Cu-Fe system have positive values of ΔH^chem. Most of the ternary amorphous alloys have the values of ΔH^chem and S_σ/k_B inside a trapezoid region in ΔH^chem - log(S_σ/k_B) chart except mainly for the H- and the C-containing alloys, Si-W-Zr system and the 32 alloys having positive values of ΔH^chem. The analysis of AFA was carried out for typical five ternary amorphous systems. The following four results are derived. 1) Al-La-Ni and B-Fe-Zr alloys have high AFA in accordance with the concept of the three empirical rules. 2) The further multiplication of alloy components causes an increase in the AFA of Al-B-Fe alloys. 3) Thermodynamical factors represented by melting temperature and viscosity at the melting temperature are required for evaluation of AFA for Mg- and Pd-based amorphous alloys. 4) A tendency for log(S_σ/k_B) to increase with decreasing ΔH^chem is recognized in each alloys system, implying the stabilization of an amorphous phase against solid solution and intermediate phase.