Prediction of parameters glass forming ability using thermodynamic

Abstract

Formation of a glassy phase in metallic systems is controlled to large extent by the composition of the alloy. Alloying behavior can be qualitatively predicted from the knowledge of enthalpy of mixing and atomic size mismatch among elements involved in bonding. A more quantitative description of Glass Forming Ability (GFA) can be obtained by using a parameter P_HS [= ΔH^C(ΔS_σ/k_B)], where ΔH^C is the chemical enthalpy of mixing and ΔS_σ/k_B is entropy due to atomic size mismatch normalized by Boltzmann constant. Using this criterion, alloys with high GFA were identified in several ternary systems. However, P_HS parameter was found to be insufficient to predict GFA in multicomponent systems. Present analysis indicates that the incorporation of configurational entropy into P_HS parameter resulted in more quantitative description to explain higher GFA in multicomponent systems. This new GFA parameter is called P_HSS (= P_HS × ΔS_C/R), where ΔS_C/R is the configurational entropy normalized by universal gas constant. Using P_HS and P_HSS parameters, GFA predictions are done for Fe–Zr–B, Fe–Cr–Zr–B, Fe–Cr–Ni–Zr–B, Cu–Zr–Ag–Ti, Cu–Zr–Al–Y and Cu–Zr–Al–Be systems and an attempt has been made establish the suitability of this new GFA parameter to various quaternary and quinary alloy systems.