Effect of heat treatment on microstructure and mechanical properties of CrMnFeCoNi high-entropy alloy with SiC addition fabricated via additive manufacturing

The aim of the present work was to investigate the effect of heat treatment on the mechanical properties of CrMnFeCoNi high-entropy alloys with SiC addition (SiC-HEA) which were prepared using laser metal deposition (LMD). With the 2-h heat treatment at 900 °C, the yield strength, tensile strength and elongation of 5 at.% SiC added HEA samples were enhanced from 343 MPa, 631 MPa and 33.2% to 431 MPa, 717 MPa and 36.4%, respectively. For the 10 at.% SiC added HEA samples, comprehensive improvement in tensile strength and ductility was achieved to 706 MPa and 30.3% after 2-h heat treatment at 700 °C. The improvement in mechanical properties can be attributed to carbide particle morphology in the HEA with SiC addition transformed from coarseness to fine and uniform via heat treatment leading to the excellent combined effects of precipitation strengthening and stress dispersion. The present work introduces an innovative approach to utilizes heat treatment that adjust the morphology of strengthening phases in high-entropy alloys prepared by additive manufacturing, ultimately achieving outstanding mechanical properties.