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

CrFeNi 2 V 0.5 W x ( x = 0, 0.25) alloys based on these parameters of mixing enthalpy (Δ H mix ), mixing entropy (Δ S mix ), atomic radius difference ( δ ), valance electron concentration, and electronegativity difference(Δ χ ) were designed and prepared. The microstructure and room-temperature mechanical behavior of both alloys were investigated. Compressive test results showed that the CrFeNi 2 V 0.5 W 0.25 alloy had higher yield strength than that of the W-free CrFeNi 2 V 0.5 alloy, although they all exhibited quite larger compressive plasticity ( ε > 70%). Compression fracture surface of CrFeNi 2 V 0.5 W 0.25 alloy 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 CrFeNi 2 V 0.5 W 0.25 alloy 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 CrFeNi 2 V 0.5 W 0.25 alloy 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 CrFeNi 2 V 0.5 W 0.25 high-entropy alloy. The higher strength of CrFeNi 2 V 0.5 W 0.25 alloy 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 CrFeNi 2 V 0.5 W 0.25 alloy can be a promising aerospace material.