Microstructure and Mechanical Behavior of CrFeNi2V0.5Wx(x=0,0.25) High-Entropy Alloys

CrFeNiVW(x=0,0.25) alloys based on these parameters of mixing enthalpy(△H,mixing entropy(△S,atomic radius difference(δ),valance electron concentration,and electronegativity difference(△χ) were designed and prepared.The microstructure and room-temperature mechanical behavior of both alloys were investigated.Compressive test results showed that the CrFeNiVWalloy had higher yield strength than that of the W-free CrFeNiValloy,although they all exhibited quite larger compressive plasticity(ε> 70%).Compression fracture surface of CrFeNiVWalloy revealed a ductile fracture in the face-centered cubic(FCC) phase and a brittle-like fracture in the σ phase.Moreover,tensile test results indicated that the CrFeNiVWalloy exhibited excellent mechanical property with an ultimate tensile strength of 640 MPa and a high tensile elongation of 15.7%.The tensile deformation mode of the FCC phase in the CrFeNiVWalloy is dominated by planar glide,relating to dislocation configurations,high-density dislocations,and dislocation wall.Therefore,dislocation slip plays a significant role in tensile deformation of CrFeNiVWhigh-entropy alloy.The higher strength of CrFeNiVWalloy is predominantly due to the solid solution strengthening of W element and σ phase precipitation strengthening.Combination of the higher tensile strength and plasticity suggests that the CrFeNiVWalloy can be a promising aerospace material.