A novel Widmanstätten-patterned multicomponent alloy : κ-strengthened VCoNi medium-entropy alloy

We strategically introduced a novel Widmanstätten-patterned κ phase into the VCoNi medium-entropy alloy, aiming to enhance the strain-hardening capability while maintaining the large ductility. Microstructural evolutions, mechanical properties, and associated plastic deformation micromechanisms were comprehensively explored. Such a newly designed κ-strengthened alloy exhibited a remarkable strength-ductility combination at room temperature, resulting in an ultimate tensile strength of ∼ 1350 MPa and a uniform elongation of ∼ 45 %. Extensive investigations by transmission electron microscope revealed that the strengthening effect can be mainly attributed to the impeded dislocation motion due to the hard yet deformable κ laths featuring a Widmanstätten pattern. Our results not only enhance the appeal of the VCoNi alloy for advanced structural applications but also open up a new, promising precipitation-strengthening approach. © 2024 Acta Materialia Inc.