A new criterion for predicting the glass-forming ability of bulk metallic glasses

Abstract

Based on the consideration of both the resistance of amorphous phase against crystallization and the stability of under-cooled liquid against competing crystalline phase formation, a criterion ω, defined as T g/ T x − 2 T g/( T g + T l) ( T g, T x and T l denote the glass transition temperature, the onset crystallization temperature and the liquidus temperature, respectively), has been proposed for evaluating the glass-forming ability (GFA) of bulk metallic glasses (BMGs). A survey of the readily available experimental data associated with the thermal analysis of various glass-forming alloys shows that the new criterion ω exhibits the best correlation with the maximum section thickness ( D max) as well as the critical cooling rate ( R c) for glass formation among other criteria proposed in recent years, such as T rg(= T g/ T l), Δ T x(= T x − T g), γ(= T x/( T g + T l)), γ m(=(2 T x − T g)/ T l), Δ T rg(=( T x − T g)/( T l − T g)), δ( =T x /( T l − T g), φ( =T rg(Δ T x /T g) 0.143, α(= T x/ T l), β(=( T x/ T g + T g/ T l) and β(= T x × T g/( T l − T x) 2). Therefore, it can be anticipated that this new criterion will be used as a useful and efficient guideline for exploring new BMG formers.