Effect of mold temperature on the solidification process and microstructure of Zr-based metallic glasses during casting

To explore the relationship between mold temperature and the formation of large-size metallic glasses, the influence of mold temperature on the solidification process and microstructure evolution of amorphous melts was investigated. It was found that increasing the mold temperature to 623 K contributes to improving the solidification time from similar to 1.79 s to similar to 2.32 s without affecting the solidification behavior of amorphous melt. However, the duration of the supercooled liquid state was prolonged by the excessively high mold temperature, resulting in a considerable increase in the glass transition time from similar to 12.78 s to similar to 145.7 s and a decline in the cooling rate from 27.6 K/s to 2.1 K/s, which ultimately leads to the crystallization of the sample. In addition, it has been observed that the 573 K mold temperature is not only the optimal mold temperature to ensure the amorphous nature of the sample but is also beneficial to improve the internal temperature gradient of the sample, thereby reducing the risk of deformation or cracking. Appropriate control of mold temperature can provide valuable guidance for large-size amorphous castings and associated process parameters.