抄録
Theoretical prediction of glass forming ability (GFA) of metallic alloys is one of the keys to explore metallic alloy compositions having excellent GFA and thus having potential to form a large-sized bulk metallic glass. Molecular dynamics (MD) simulation is a promising tool to archive the theoretical prediction. However, direct MD prediction is still challenging because of the time-scale limitation of MD. For the practical bulk metallic glass alloys, the time necessary for quenching at typical cooling rate is five or more orders of magnitude longer than the MD time-scale. In this study, therefore, I propose a method to depict Time-Temperature-Transformation (TTT) diagram of the alloys based on the classical nucleation theory, which is widely employed to understand nucleation phenomena, informed by MD simulations. The TTT directly provides the prediction of the critical cooling rate and GFA. Using the method, the TTT diagrams and critical cooling rates of two Cu-Zr alloy compositions (Cu50Zr50 and Cu20Zr80) were computed. I found that the proposed method reasonably predicts the critical cooling rate.
