INFLUENCE OF TiC CONTENT ON MICROSTRUCTURE AND PROPERTIES OF AlCoCrFeNi HIGH-ENTROPY ALLOY COATINGS PREPARED BY LASER CLADDING

In this study, AlCoCrFeNi-TiCx (x values in molar ratio, x = 0, 0.1, 0.2, 0.3) high-entropy alloy coatings (HEAcs) were prepared on the surface of H13 steel by laser cladding (LC). The microhardness, corrosion resistance, and wear resistance of the HEAcs were analyzed using a microhardness tester, electrochemical workstation, and friction and wear tester, respectively. The results showed that with an increase in the TiC content of the coatings, the interior of the coatings mainly consisted of disordered body-centered cubic (BCC), ordered BCC (B2), and TiC phases, and lattice distortion occurred inside the coatings. TiC was distributed as white particles at the grain boundaries, and the internal microstructure was mainly composed of equiaxed crystals (EC) and petal-like dendrites. The EC were gradually refined owing to the pinning effect. The spinodal decomposition causes a large number of reticulated microstructures inside the grains, and nanoscale TiC precipitation appears in the reticulated microstructures. Owing to lattice distortion and solid solution strengthening, the microhardness of the TiC0.3 coating was up to 966 HV0.5, which was approximately 3.2 times that of the substrate. As the TiC content increases, the friction coefficient and mass loss of the coatings gradually decreased, the self-corrosion current (Icorr) gradually decreased and the self-corrosion potential (Ecorr) gradually increased. The coatings exhibited good wear and corrosion resistance.