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 AlCoCrFeNiTax 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 AlCoCrFeNiTax 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 mu m 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 Ta2O5 and TaO2 passivation films and the formation of a dense uniform remelting layer.(c) 2023 Elsevier B.V. All rights reserved.

Automated summary

Laser remelting (LR) treatment was used to regulate the microstructure of AlCoCrFeNiTax high-entropy alloys. The addition of Ta element promoted the formation of a Laves phase. After LR treatment, the grains were refined and a dense remelting layer was formed on the surface of the alloy. Additionally, the hardness, wear resistance, and corrosion resistance of the alloys were improved by the combined effects of different strengthening mechanisms.