Microstructure, hardness and wear resistance of AlCoCrFeNiTax (x = 0, 0.1, 0.3) high-entropy alloys enhanced by laser remelting and Ta addition.

Laser remelting (LR) treatment was used to regulate the microstructure of AlCoCrFeNiTa x high-entropy alloys prepared by vacuum arc melting, and the microstructure and properties of the alloys before and after LR treatment were analyzed. The original AlCoCrFeNiTa x alloys have typical dendritic morphology and the addition of Ta element promoted the formation of a Laves phase, gradually changing the alloys from two phase (BCC + B2) to three phase (BCC + B2 + Laves phase). After LR treatment, the grains were significantly refined, elemental segregation was alleviated, and a dense remelting layer with a thickness of 1200–1600 µm was formed on the surface of the alloy. In addition, the hardness and wear resistance of the alloys were improved with increasing Ta content and LR treatment, mainly caused by the combined effects of solution strengthening, second phase strengthening and fine grain strengthening. At the same time, the corrosion resistance of the alloys before and after LR treatment in 3.5 wt% NaCl solution is significantly improved by a stable Ta 2 O 5 and TaO 2 passivation films and the formation of a dense uniform remelting layer. • Refractory element was added and LR treatment was conducted on the surface of AlCoCrFeNiTax high entropy alloy. • After LR treatment, elemental segregation on the alloy surface is alleviated and the alloy grains are refined. • A remelted layer of about 1200–1600 µm thickness was formed on the alloy surface after LR treatment. • The hardness and wear resistance of the alloys were improved with increasing Ta content and LR treatment. • The corrosion resistance of the alloys in 3.5 wt% NaCl solution is improved by passivation film and remelted layer. [ABSTRACT FROM AUTHOR]