Estimating the Critical Glass Transition Rate of Pure Metals Using Molecular Dynamic Modeling

Аннотация

The critical cooling rates \({{{v}}_{{\text{c}}}}\) at which pure metals Mg, Al, Ti, Fe, Co, Ni, Cu, Zr, Mo, Pd, Ag, Ta, W, Pt, Au, and Pb transit to an amorphous state (vitrify), have been calculated for some alloys using the method of molecular dynamic modeling. These rates range from 7.9 × 10¹¹ for Al to 3.8 × 10¹³ for Zr. The atomic structures formed at different cooling rates are described. The temperature dependence of the specific volume is studied in the process of both glass transition and crystallization. The study of the thermal stability of metallic glasses has shown that the best stability is inherent in Fe, Mo, Ta, and W. Some estimates are given for the maximum radius of a melt drop, which can be cooled at the rate \({{{v}}_{{\text{c}}}}\). The comparison of the modeling results with the experimental data, which are currently known for Ta, Mo, and W, shows their good agreement.