Elastic-plastic fracture toughness of metastable, dual-phase, Fe49.5Mn30Co10Cr10C0.5, high entropy alloy (HEA)

Elastic-plastic fracture toughness of a metastable, dual-phase carbon-containing, Fe49.5Mn30Co10Cr10C0.5 high entropy alloy (HEA), was evaluated using the crack tip opening displacement (CTOD) method. Processed on a large semi-industrial scale, the alloy exhibits a microstructure containing FCC matrix and HCP laminates. In addition to the stacking faults contained in the fcc matrix, Cr-rich carbide particles were also found distributed in the matrix. The elastic–plastic fracture toughness of the alloy was found to be 47% higher (301 MPa·m1/2) than that of Fe50Mn30Co10Cr10 alloy which did not contain carbon. Associated deformation mechanisms, explaining this improvement in the fracture toughness of the alloy containing carbon, have been discussed.