Vanadium microalloying to regulate CrV phase interface characteristics and dislocation configuration in FeNiCoCr-based high-entropy alloys

• Precipitate size-interface-deformation pathway coupled strengthening mechanism. • V2 HEA: 22.9% UTS increase with 57.2% higher elongation. • V6 HEA enhances ductility to 67.87 % while keeping high strength (533.38 MPa). This study utilizes vanadium microalloying to investigate the influence of CrV phase on the evolution of dislocation configurations in Fe 30 Ni 20 Co 20 Cr 20 Si 10-x V x high-entropy alloys. Vanadium addition transforms Cr-rich phase into nanoscale CrV phase at low concentrations, promoting a perpendicular dislocation arrangement at phase boundaries. This microstructural evolution results in significant mechanical property improvements: the ultimate tensile strength (UTS) increases by 22.9 % (from 459.08 MPa to 564.29 MPa), while the elongation exhibits a remarkable 57.2 % enhancement (from 30.82 % to 48.44 %). With increasing vanadium content, the CrV phases undergo coarsening and facilitate intragranular slip, resulting in dislocation realignment parallel to the phase boundaries. Which further boosts ductility to 67.87 % while maintaining superior strength (533.38 MPa). These results illustrate that precise control of vanadium content enables a transition in CrV phase behavior, from dislocation pinning to slip channel formation. This study reveals critical microstructure-property relationships, enabling strength-ductility optimisation in high-entropy alloys.