Effect of Al content on microstructure and wear properties of FeCrNiMnAlx high-entropy alloys

Abstract A series of FeCrNiMnAl x (x = 0, 0.3, 0.5, 0.8, 1.0 in molar ratio) high entropy alloys (HEAs) were prepared by the vacuum arc melting method. The effects of Al content on the microstructure, mechanical and wear properties were investigated. For FeCrNiMn alloy, the microstructure was main homogeneous structure with face-centered cubic (FCC) phase, whilst FeCrNiMnAl 0.3 produced a dendritic microstructure consisting of a mixture of FCC + BCC + B2 phases, and the mixture BCC + B2 dendritic interdendritic microstructure appeared when the molar ratio of Al is beyond 0.5. The hardness and yield stress of the HEAs are effectively improved with the increased Al amount but the ductility is lowered. In this case, FeCrNiMnAl alloy showed decreased yield stress due to the deteriorated ductility. Moreover, the friction coefficient decreases, and the wear resistance improved with the increased aluminum content. FeCrNiMnAl 0.8 HEAs have the best wear resistance due to the advantages of achieving a balance of strength and ductility.