High-strength lamellar high-entropy alloys in-situ synthesized by laser additive manufacturing

A high-strength lamellar high-entropy alloy (HEA) of Zr45Ti31.5Nb13.5Al10 with excellent ductility was fabricated by in-situ alloying of blended elemental powders via laser directed energy deposition (DED). Microstructure characterizations suggest that the molten pools with body-centred cubic (BCC) structure and heat affected zones with mixed structure of BCC + ordered BCC (B2) nanoprecipitates, are alternately distributed in the DED-processed HEA with a lamellar structure. During the deformation process, the molten pools are dominated by dislocation planar slipping, while in the heat affected zones, frequent cross-slip and dislocations pinning caused by dispersed B2 nanoprecipitates occurred, which endows a significant strain hardening capability and deformation uniformity in the DED-processed HEA. This research provides new options for the design and manufacturing of HEAs with outstanding mechanical properties for structural applications.