Dual heterogeneous structure facilitating an excellent strength-ductility combination in an additively manufactured multi-principal-element alloy

Abstract

The (FeCoNi)86Ti7Al7 multi-principal-element alloy with a dual heterogeneous microstructure was successfully fabricated by selective laser melting, exhibiting an excellent combination of strength (ultimate tensile strength, 1085.2 ± 23.2 MPa) and ductility (30.5 ± 2.6%). It is evidenced that the joint effects of the hetero-deformation induced hardening from grains with heterogeneous geometrically necessary dislocations densities, in-situ formed B2 phase, and the coherent precipitation hardening from in-situ formed nano L12 phase were responsible for the strength. This work sheds light on the feasibility of simplifying the production of multi-mechanism strengthened alloys within one step and paves a new avenue to produce high-performance complex-shaped components.

Keywords

• Additive manufacturing
• multi–principal-element alloy
• dual heterogeneous microstructure
• mechanical properties
• hetero-deformation induced hardening