Evaluation of glass-forming ability for bulk metallic glasses based on characteristic temperatures

Abstract

A new criterion ω 2, defined as T g/(2 T x− T g)− T g/ T l (wherein T g is the glass transition temperature, T x the onset crystallization temperature, and T l the liquidus temperature), has been proposed to assess the glass-forming ability (GFA) of bulk metallic glasses (BMGs) based on the classical crystallization theory and the crystallization resistance. The analysis indicates that the factors T g/(2 T x− T g) and T g/ T l could reflect the crystallization resistance and liquid phase stability of metallic glasses, respectively. From the available experimental data in literatures, the new criterion ω 2 has a better correlation with the GFA of metallic glasses than all other existing criteria such as T rg(= T g/ T l), Δ T x(= T x− T g), γ(= T x/( T g+ T l)), Δ T rg(=( T x − T g)/( T l − T g)), α(= T x/ T l), β(= T x/ T g + T g/ T l), δ( =T x /( T l − T g)), φ( =T rg(Δ T x /T g) 0.143), γ m(=(2 T x − T g)/ T l), β(= T x × T g/( T l − T x) 2) and ξ(=Δ T x/ T x+ T g/ T l). It has also been demonstrated that this ω 2 parameter is a simple and efficient guideline for exploring new BMG formers.