Excellent cryogenic temperature strength-ductility synergy in laser-powder-bed-fused TiB2p/CrMnFeCoNi high-entropy composite

The combination of tensile strength and ductility of equiatomic CrMnFeCoNi high-entropy alloy (HEA) is a critical issue in achieving intended mechanical properties for cryogenic applications. Here laser powder bed fusion (LPBF) technology is used to prepare TiB2 particle reinforced CrMnFeCoNi high-entropy composite, which exhibits similar to 1350 MPa ultra-high tensile strength (UTS) and similar to 19 % fractured elongation at cryogenic temperature, almost twice that of room temperature. The underlying mechanisms were unraveled, in which the formation of stacking faults (SFs), deformation twins (DTs) in the matrix and hard sigma phase particles, TiB2 particles, and their generated dislocation networks were found to synergistically promote the substantial improvement of strength and elongation during cryogenic temperature deformation.