Effect of TiC addition on the microstructure and mechanical properties of FeCoCrNiMn high entropy alloy fabricated by selective laser melting

Abstract

FeCoCrNiMn high entropy alloy (HEA) has attracted significant interest due to its exceptional properties at both room and cryogenic temperatures; however, its relatively low yield strength limits its practical engineering applications. In this study, FeCoCrNiMn HEA composites with various TiC contents were manufactured using selective laser melting, and the effect of TiC content on their microstructures and mechanical properties was investigated. The results indicated that an energy density of 150 J/mm3 is adequate for achieving an optimal relative density of 99.0%. The TiC particles were uniformly distributed along the cellular boundaries of the FeCoCrNiMn matrix, contributing to grain refinement and significantly enhancing strength. Notably, HEA composites with 5 wt% TiC demonstrated an impressive combination of high yield strength of 725.8 MPa and excellent notch fracture toughness of 81.0 MPa·m1/2, presenting their substantial potential for engineering applications. Both experimental analysis and theoretical predictions suggested that the additional strength provided by TiC addition is mainly attributed to grain refinement, dislocation entanglement, and dispersion strengthening.