Microstructure and Properties of FeCoNiCr_0.5Al_0.8 High Entropy Alloy Pulsed Laser Cladding Layer on Pure Titanium Surface

The FeCoNiCr_0.5Al_0.8 high entropy alloy cladding layer was prepared on the surface of TA2 industrial pure titanium by pulsed laser cladding technique, and the microstructure, phase composition, hardness and high temperature oxidation resistance of the cladding layer were studied. The results show that a good metallurgical bonding was formed between the cladding layer and the substrate, there were no defects such as cracks and pores in the cladding layer, and the fusion interface was relatively straight. There were fine equiaxed crystals at the molten pool boundary of the cladding layer and dendrites in the middle of the molten pool. The section structure of the cladding layer was layered distributed fine crystals. The cladding layere was mainly composed of simple face-centered cubic structure Ti₂Ni and AlCTi₂. The average hardness of the cladding layer was 761.23 HV, which was more than 4 times the hardness of the substrate. The cladding layer had excellent high temperature oxidation resistance, and the mass grain per unit area of the cladding layer oxidized at 800℃ for 120 h was about 17 mg·cm^-2, which was about only one third of the substrate.