Microstructure and wear resistance of atmospheric-plasma-sprayed AlCoCrFeNiTi high-entropy alloy coating

摘要

An equiatomic AlCoCrFeNiTi high entropy alloy coating with a thickness of about 236 urn, a porosity of about 1.6%, and an adhesive strength of higher than 50.3 MPa was deposited by atmospheric plasma spraying. Besides BCC1 and BCC2 phases, minor FCC was detected by X-ray diffraction in the as-sprayed coating. The microhardness of the as-sprayed AlCoCrFeNiTi high entropy alloy coating was 664 Hv, which was 4 times of that of the 316 stainless steel. The volume wear rate of the as-sprayed coating at room temperature was 0.77*10~(-4) mm3~3/(N-m), which was about a quarter of that of the substrate material (2.55x10~(-4)mm~3/(N-m)). The volume wear rate decreased as the wear temperature increased from 25°C to 700°C and increased when the temperature increased from 700°C to 900°C. At the temperature of 700°C, the volume wear rate was 0.23x10~(-4) mm~3/(N-m), which was about one-ninth of that of the substrate material. The wear mechanism changed from delamination wear to oxidation wear and adhesion wear.