Abstract: AlCoCrFeNi-2xMo-xTiC (x=0, 0.1, 0.25, 0.4) high entropy alloy clad layer was prepared on 40CrNiMo steel surface by laser cladding method. The effect of TiC and Mo content on the microstructure and wear resistance of the AlCoCrFeNi-2xMo-xTiC alloy clad layer was studied through XRD, SEM, EBSD, TEM, and wear resistance tests. The results show that after in-situ formation of TiC, the microstructure of the clad layer consists of BCC and TiC phases. As the atom fraction of TiC increases, the size of carbide precipitates gradually increases, and the grain size of the clad layer is significantly refined, decreasing from 109 μm to 15 μm. The AlCoCrFeNi-0.8Mo-0.4TiC clad layer has the highest hardness of 750 HV0.3, which is 300 HV0.3 higher than the AlCoCrFeNi alloy clad layer. The hardness and wear resistance of the clad layer increase with the increase of atom fraction of TiC. The wear surface of the AlCoCrFeNi alloy clad layer has more debris, and the wear mechanism is adhesive wear. The wear mechanism of the AlCoCrFeNi-0.2Mo-0.1TiC, AlCoCrFeNi-0.5Mo-0.25TiC, and AlCoCrFeNi-0.8Mo-0.4TiC alloy clad layers are abrasive wear.

Key words: high-entropy alloy, laser cladding, in-situ TiC reinforcement, microstructure, wear resistance