Evaluation of thermoplastic formability of Zr-based bulk metallic glasses and its correlation with characteristic temperature parameters

•Formability of BMGs is evaluated by the softness in entire super-cooled liquid region.•The reliability of the convenient evaluation is verified by mould forming experiments.•18 Be-free Zr-based BMGs are investigated.•Correlations between softness and several common used parameters are well explained.•A new parameter representing the best correlation with the softness is proposed.

Thermoplastic formability (TPFA) is a key factor in fabrication of bulk metallic glass (BMG) components by thermoplastic forming (TPF) technology. In this paper, the softness in the entire super-cooled liquid region (SCLR) is used to evaluate the TPFA of 18 Be-free Zr-based BMGs and the reliability is verified by mould forming experiments. The correlations between softness and thermo-dynamic characteristic temperature parameters are well explained under the assumption of linear SCLR in Angel plot. A parameter constructed by thermo-dynamic and thermal–mechanical characteristic temperatures is proposed, representing the best correlation with softness. These results help understand the TPFA of BMGs well.