Prediction of Glass Forming Ability Using Thermodynamic Parameters

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 PHS [= ΔHC(ΔSσ/kB)], where ΔHC is the chemical enthalpy of mixing and ΔSσ/kB 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, PHS parameter was found to be insufficient to predict GFA in multicomponent systems. Present analysis indicates that the incorporation of configurational entropy into PHS parameter resulted in more quantitative description to explain higher GFA in multicomponent systems. This new GFA parameter is called PHSS (= PHS × ΔSC/R), where ΔSC/R is the configurational entropy normalized by universal gas constant. Using PHS and PHSS 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.