Abstract: In order to enhance the wear resistance of 42CrMo steel surface and improve the porosity and crack defects frequently generated in the clad layers, as well as the performance of the clad layer, TiC-Fe₃Al-Ni clad layer was prepared on the surface of 42CrMo steel via laser cladding, and mechanical vibration carrying different modes was introduced. The phase composition, microstructure and properties of the clad layer under different vibration directions were analyzed by means of SEM, XRD, microhardness tester and friction and wear tester. The results show that the porosities and cracks in the clad layer are significantly restrained due to the mechanical vibration. Furthermore, part of crystal arms of dendrites is broken by the mechanical energy coming from the vibration during the process of grain growth, and the dendrite growth is reduced. Therefore, the condition of equiaxial crystal growth is developed, and the compactness of the clad layer is strengthened. The clad layer primarily contains the phases of TiC, Ti₈C₅, Fe₃Al, FeO, as well as AlNi. Mechanical vibration has a little effect on changing the phase constituent of the clad layer. Vertical vibration significantly improves the microstructure of the clad layer. The mean hardness of the clad layer at vertical vibration reaches up to 1891.78 HV0.2, which is obviously higher than that without mechanical vibration, the wear resistance of the clad layer is optimal, with wear loss of 1.57 mg, and the wear process has small fluctuation.

Key words: laser cladding, mechanical vibration, 42CrMo steel, microstructure, hardness