Effect of laser remelting on microstructure and mechanical properties of CrMnFeCoNi high entropy alloy

Equiatomic CrMnFeCoNi high entropy alloy prepared by powder metallurgy was remelted by laser. The relative density and microstructure of fusion zone are evaluated. The nanoindentation tests are conducted to reveal the hardness difference of dendrite arms and interdendritic areas. Tensile tests are conducted to assess the mechanical properties of remelted HEA. After laser remelting, the number and morphology of voids changed significantly. Dendritic structure with face-centered cubic phase form in the fusion zone. Fe, Cr and Co are enriched in dendrite arm, while Mn and Ni are enriched in interdendritic area. Elements segregation led to a nanohardness difference between dendrite arm and interdendritic area. Local deformation occurs in interdendritic area during tensile tests and results in a fracture with directionality.