Study on Microstructure and Mechanical Properties of CrCuFeNiV Multi Principal Element Alloy

Phase constitution, microstructure, and mechanical properties of the as-cast and homogenized CrCuFeNiV multi principal element alloys were investigated. Results show that the microstructures of CrCuFeNiV alloys either in the as-cast or homogenized state were constituted by the dispersed Cu-rich fcc regions and the matrix regions (intertwined bcc + σ phases). Thereinto, the σ phase, ranged from nanometers to microns, was a complex multicomponent intermediate phase with a high solubility for Fe, Cr, Ni, and V. This phase structure and hardness had an impressive thermal stability, which was evidenced by the current annealing treatment. High hardness (822 HV and 793 HV) was simultaneously achieved under an applied load of 200 g in the as-cast and homogenized CrCuFeNiV alloys, on account of the incorporation of the high-stiffness σ phase against the fcc and bcc phases. The ultimate compressive strength of ~ 1490 MPa was obtained in the as-cast alloy due to the high deformation resistance to the dislocation movement of bcc phase and precipitation strengthening of σ phase at the expense of plasticity. The deterioration in plasticity was attributed to the stress concentration easily triggered by the hard and brittle σ phase.