The critical cooling rate and microstructure evolution of Zr41.2Ti13.8Cu12.5Ni10Be22.5 composites by Bridgman solidification

摘要

The critical cooling rate and microstructure evolution were experimentally studied at cooling rates between 0.85 and 15.34 K/s by a Bridgman technique in Vit-1 (Zr41.2Ti13.8Cu12.5Ni10Be22.5). Our results show that the sample solidified at the rate above 10.03 K/s was fully amorphous whereas the samples solidified between 1.70 and 10.03 K/s were partially amorphous with crystalline phases, and samples solidified below 1.70 K/s were essentially crystalline. As the cooling rate decreased from 15.34 K/s to 1.82 K/s, the values of Tg and Tx were around 628 K and 702 K, respectively, but the heat of crystallization (ΔHx) decreased with decreasing cooling rate.