Hierarchical multiphase microstructure in additively manufactured (CoCrNi)83Al17 multi-principal element alloy with high strength

Abstract

The design of hierarchical microstructure is considered as an effective approach to enhance the mechanical properties of alloys. This study has reported a novel hierarchical multiphase microstructure in an additively manufactured (CoCrNi)₈₃Al₁₇ multi-principal element alloy. The basic cellular unit of this novel structure is composed of a network face-centered cubic phase wrapped around an equiaxed ordered body-centered cubic (B2) phase. Three nano-phases with different compositions, sizes, and orientation relationships with the matrix are further precipitated in the equiaxed B2 phase. This novel hierarchical multiphase microstructure significantly enhances the strength of the alloy and effectively hinders the propagation of microcracks, resulting in a good combination of strength and ductility in the as-built (CoCrNi)₈₃Al₁₇ alloy.