放电等离子烧结制备NiCoV中熵合金微观结构与力学性能研究OA

The NiCoV face-centered cubic(FCC)single-phase medium-entropy alloy exhibits outstanding strength and ductility,making it a highly promising structural material.In this study,a NiCoV alloy was prepared using spark plasma sintering(SPS)technology,which is renowned for its rapid heating,low sintering temperature,and high product density,making it particularly suitable for the rapid fabrication of high-performance alloys with fine grains.By ball-milling the powder,porosity defects are eliminated in the alloy preparation process.During subsequent hot rolling,the hard phases distributed along the grain boundaries in the alloy are redistributed,forming a composite microstructure with abundant dislocation substructures,nanotwins,and uniformly distributed hard phases.This structure is distinct from the uniform FCC single-phase structure of NiCoV alloys produced by traditional casting methods.The composite microstructure generated by the SPS process combined with hot rolling,through the synergistic strengthening effect of dislocations,precipitates,nanotwins,and grain boundaries,results in achieving a yield strength of 1 360 MPa and a tensile strength of 1 593 MPa,while maintaining a uniform elongation rate of 18.7%,thus realizing excellent strength-ductility matching.This study not only optimizes the microstructure and mechanical properties of NiCoV alloys but also provides a new approach for the preparation of high-performance medium-entropy alloys.