3D-printed strong and ductile high-entropy alloys with orientation arranged nanostructure complex

Abstract

The rapid development of 3D printing technologies demands new materials with novel properties, as many high-strength metallic materials (up to over 1000 MPa) suffer from a significant weakness in ductility despite their enhanced mechanical properties, particularly in tension strength. To address this issue, we fabricated precipitation-hardened high-entropy alloy (Fe28Co29.5Ni27.5Al8.5Ti6.5) and employed aging post-treatment to obtain a duplex multicomponent intermetallic nanoprecipitate arrangement while retaining the in-situ dislocation network features. This approach resulted in the formation of a novel orientation arranged nanostructure complex (NSC) in the alloy. The NSC structure is composed of duplex multicomponent intermetallic nanoprecipitates (L12 and L21 phases), disordered multicomponent FCC matrix, and in-situ dislocation network. This resulted in ultra-high tensile strengths of 1430 MPa and an excellent tensile elongation close to 16%, surpassing the performance of other advanced commercial steels and alloys. These findings offer an effective approach to facilitate the design of high-strength and high-ductility structural materials for industrial applications. This is achieved by tailoring the microstructure through a combination of in-situ generation of high-density dislocations structure and multicomponent intermetallic nanoprecipitates in additive manufacturing. As such, this study represents an important step forward in the development of advanced materials for 3D printing technologies.