Analysis of thermodynamic behaviour of bulk metallic glass forming melts and glass forming ability

Abstract

The thermodynamic behaviour of bulk metallic glass (BMG) forming melts have been studied by analyzing the temperature dependence of the Gibbs free energy difference (ΔG), entropy difference (ΔS) and enthalpy difference (ΔH)between the undercooled melt and the corresponding equilibrium solid phases. The study is made by calculatingΔG, ΔS and ΔH in the entire temperature range T m (melting temperature) to T g (glass transition temperature) using the expressions obtained on the basis of Taylor's series expansion. The entire analysis is made for La-based five samples of BMGs; La55Al25Ni20, La55Al 25Ni15Cu5, La55Al 25Ni10Cu10, La55Al 25Ni5Cu15, and La55Al 25Ni5Cu10Co5 and a comparative study is also performed between present results and results obtained in the framework of expressions proposed by earlier workers. An attempt has also been made to study the glass forming ability for BMGs. © 2009 Akadémiai Kiadó, Budapest, Hungary.