MxCy-Type Nanocarbide Crystallization in CrMnFeCoNi, CrMnFeCoNiV0.5, and CrMnFeCoNiMo0.5 HEAs Manufactured Through Powder Metallurgy

The study presents a comprehensive report on the kinetic and thermodynamic parameters of carbide crystallization in CrMnFeCoNi, CrMnFeCoNiV0.5, and CrMnFeCoNiMo0.5 HEAs. This study considers only carbon resulting from the decomposition of the process control agent, which diffuses and becomes trapped within the HEA structure (0.79–0.91 wt.% C). The crystallization and growth of the carbides were monitored through thermal analysis and thermo-XRD at different temperatures. The activation energy was calculated using the Kissinger and Flynn/Wall/Ozawa methods, and the crystallization kinetics were evaluated using the Avrami–Erofeev model. The results of the XRD analyses and DTA curves of the CrMnFeCoNi, CrMnFeCoNiV0.5, and CrMnFeCoNiMo0.5 HEAs showed the following nanocarbide crystallization sequences: M7C3→MC→M3C2, M23C6, and MC→M6C, respectively. The transitions observed in the DTA curves were associated with M7C3, M23C6, and MC phases with activation energies (Ea) of 238–251, 188–203, and 326–341 kJ/mol, respectively. Furthermore, kinetic analyses indicate that the crystallization of MxCy-type carbides occurs via nucleation.