Microstructure and properties of AlCoCrFeNiNbx (x = 0, 0.1 and 0.5) high-entropy alloys enhanced by laser remelting

In order to improve the properties of AlCoCrFeNiNbx (x = 0, 0.1, and 0.5) high-entropy alloys (HEAs), the microstructure of the AlCoCrFeNiNbx is regulated by laser remelting (LR). By testing the microstructure and properties of alloys before and after LR treatment，the results indicate that the original AlCoCrFeNiNbx alloys have typical dendritic morphology, and the addition of the Nb element promoted the formation of Laves phase. The grains were significantly refined after LR treatment, and the dense remelting layers with thicknesses ranging from 1200 μm to 1650 μm were formed on the surface of the alloys. In addition, the hardness and wear resistance of the alloys were improved with the increase of Nb content and LR treatment due to the combined effect of fine grain strengthening, solid solution strengthening, and the second phase strengthening. At the same time, the corrosion resistance of the alloys before and after LR treatment in 3.5 wt% NaCl solution was significantly improved by the stable Nb2O5 passivation film for Nb0 and Nb1 alloys.