Microstructure and mechanical properties of additively manufactured FeCoCrMnNi high-entropy alloy composite after aging

High-entropy alloy composites (HEACs) have attracted significant attention due to their exceptional mechanical properties and chemical stability. By adjusting the content of reinforcing particles in the high-entropy alloy and by employing advanced additive manufacturing techniques, high-performance HEACs can be fabricated. However, there is still considerable room for improvement in their performance. In this study, CoCrFeMnNi HEA powders were used as the matrix, and NiCoFeAlTi high-entropy intermetallic powders were used as the high-entropy reinforcement (HER). CoCrFeMnNi/NiCoFeAlTi HEACs were fabricated using selective laser melting technology. The study results indicate that after aging, the microstructure of HEACs with HER exhibits Al- and Ti-rich nano-oxide precipitates with an orthorhombic CMCM type structure system. After aging at 873 K for 2 h, HEACs with HER achieved excellent overall mechanical properties, with an ultimate tensile strength of 731 MPa. This is attributed to the combined and synergistic effects of precipitation strengthening, dislocation strengthening, and the high lattice distortion caused by high intragranular defects, which provide a multi-scale strengthening and hardening mechanism for the plastic deformation of HEACs with HER. This study demonstrates that aging plays a crucial role in controlling the precipitate phases in complex multi-element alloys. (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic). (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic). (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic) CoCrFeMnNi/NiCoFeAlTi (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic). (sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic) CMCM (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic) Al,Ti (sic)(sic)(sic)(sic)(sic)(sic). (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic) 873 K (sic)(sic)(sic)(sic) 2 h (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic) 731 MPa. (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic),(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic). (sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).