The critical cooling rate and microstructure evolution of Zr_41.2Ti_13.8Cu_12.5Ni₁₀Be_22.5 composites by Bridgman solidification

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 (Zr_41.2Ti_13.8Cu_12.5Ni₁₀Be_22.5). 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 T_g and T_x were around 628 K and 702 K, respectively, but the heat of crystallization (ΔH_x) decreased with decreasing cooling rate.