Effects of C content on the microstructure and properties of CoCrFeNiTi0.5Mo0.5Cx high-entropy alloy coatings by laser cladding
Tianxiang Lin, Meiyan Feng, Guofu Lian, Hua Lü, Changrong Chen, Xu Huang
Abstract
In order to deeply investigate the influence mechanism of different contents of non-metallic element C on the microstructure, microhardness, wear resistance and corrosion resistance of high-entropy alloy coatings. CoCrFeNiTi0.5Mo0.5Cx high-entropy alloy coating was prepared on the surface of AISI 1045 steel by laser cladding technology. The results show that the microstructure of CoCrFeNiTi0.5Mo0.5 without C addition consists of FCC phase, BCC phase, intermetallic compound phase and σ-phase structure, and the carbide phases (M 7 C 3 and TiC) start to appear after the addition of C element. The microhardness of the coating increases and then decreases with the increase of C content, and the average hardness is the highest when x = 0.03, 495.3HV0.5, which is 27.6% higher than that of C0. The abrasion resistance of the CoCrFeNiTi0.5Mo0.5Cx high-entropy alloy coatings is gradually increased and then decreased with the increase of C content, and the wear amount decreases from 0.0813 mm 3 to 0.0514 mm 3 , and the main frictional wear mechanisms are adhesive wear, abrasive wear and oxidative wear. With the increase of C content, the corrosion resistance of the coating is gradually improved and then reduced, when the C content is 0.03, the highest corrosion potential is −0.818V, the lowest corrosion current is 1.382E-4 A/cm 2 , at this time, the passivation film on the surface of the coating is the most stable and dense, with the best corrosion resistance. The results of this paper provide a theoretical reference for the effect of adding non-metallic elements on the microstructure and properties of high-entropy alloy coatings.