Microstructure and Performance of MoNbTaTiV Refractory High Entropy Alloy Coating by Laser Cladding Technology

MoNbTaTiV refractory high-entropy alloy coating was prepared on the surface of Q235 steel by laser cladding.The phase structure, microstructure, cross-sectional hardness distribution and wear resistance of MoNbTaTiV refractory highentropy alloy coatings were studied by X-ray diffractometer, scanning electron microscope, microhardness tester and friction and wear testing machine. Then the corrosion behavior of refractory high entropy alloy coating in NaCl solution was studied by electrochemical workstation. The results show that the phase of laser cladding MoNbTaTiV refractory high entropy alloy coating is mainly composed of BCC solid solution and a small amount of intermetallic compounds; the microstructure of the top of the coating is fine equiaxed crystals, and the bottom and middle areas of the coating are mainly columnar dendrites; the average hardness of the coating can reach 756.7 HV0.2, which is 4 times of the matrix hardness（189 HV0.2）; the wear amount of matrix Q235 steel in 20 min is 3.6 mg, which is 2.77 times of that of refractory high-entropy alloy coating（1.3 mg）. MoNbTaTiV refractory high-entropy alloy coating has a larger arc radius, self-corrosion potential correction, and the self-corrosion current density in NaCl solution is an order of magnitude lower than that of the matrix, showing good corrosion resistance.