Effect of V on microstructure, wear and corrosion properties in AlCoCrMoVx high entropy alloy coatings by laser cladding

Abstract

To improve the service life and wear resistance of the agitator blade, AlCoCrMoVx (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0 at.%) high entropy alloy (HEA) coatings were prepared on the 904L-stainless-steel substrate by laser cladding, and the effect of V content on the microstructure, wear and corrosion behavior were investigated. The HEA coatings consist of body-centered cubic (BCC) phase, needle-like σ phase, and irregular black AlN phase. As the V content increases, the σ phase gradually disappears. The trend of microhardness decreases firstly and then increases. AlCoCrMoV1.0 HEA coating has the highest microhardness (942.6 HV0.1). The average friction coefficient of HEA coatings firstly increases and then decreases, but the specific wear rate is the lowest when x = 0.8 (about 0.630 × 10−5 mm3 N−1 m−1). The addition of V improves the corrosion resistance of the coatings, AlCoCrMoV0.8 coating has the lowest Icorr value of 2.74 × 10−5 A cm−2 and the largest impedance radius. In a word, the addition of V in AlCoCrMoVx HEA coatings greatly improves the performance of coatings.