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

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 Tg/Tx − 2Tg/(Tg + Tl) (Tg, Tx and Tl 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 (Dmax) as well as the critical cooling rate (Rc) for glass formation among other criteria proposed in recent years, such as Trg(=Tg/Tl), ΔTx(=Tx − Tg), γ(=Tx/(Tg + Tl)), γm(=(2Tx − Tg)/Tl), ΔTrg(=(Tx − Tg)/(Tl − Tg)), δ(=Tx/(Tl − Tg), φ(=Trg(ΔTx/Tg)0.143, α(=Tx/Tl), β(=(Tx/Tg + Tg/Tl) and β(=Tx × Tg/(Tl − Tx)2). Therefore, it can be anticipated that this new criterion will be used as a useful and efficient guideline for exploring new BMG formers.