Microstructure and Anticorrosion Property of High-Entropy Alloy AlFeNiCrCoTi<sub>0.5</sub>V<sub><i>x</i></sub>

Abstract

The influence of vanadium element on the microstructure, microhardness, and electrochemical corrosion resistance properties of as-cast AlFeNiCrCoTi0.5Vx (x = 0, 0.5, 1, 1.5, 2) was studied. The microstructures of the alloys with V contents lower than 1.0 are mainly comprised of the simple body-centered cubic (BCC) and face-centered cubic (FCC) composite structures. With V mole ratio increased to 1.5, the FCC structure plays the leading role in the alloys, which enhances the plasticity and toughness of the alloys. The microhardness of the alloys increased with the increasing of V content in the alloys. Cr, Ni, Ti, and Al elements in the alloys facilitate passivation in 3.5 M NaCl solution. V element mainly enriched in interdendritic region of the alloys, which altering the distribution of Cr and Ti. Cr and Ti is benefit to the passivation, which enlarges the corrosion potential of the alloys and lowers the passive current. Consequently, the alloys present a protective effect in 3.5 M NaCl solution.