Effects of three-dimensional vibration on laser cladding of SS316L alloy

Abstract

As a widely used approach for surface modification, laser cladding plays a significant role in surface hardening and repairing of metallic parts. However, the defects existing in laser cladding parts, such as cracks, tensile residual stress, and pores, significantly affect the performance and the application of the cladding parts. In this study, an SS316L layer was fabricated on a 45 steel substrate using a laser cladding process assisted by three-dimensional vibration. The microstructures and the properties of the coating and the bonding interface with various vibration parameters were analyzed and compared. The microstructures of the cladding layer and the matrix were analyzed by an optical microscope and a scanning electron microscope. The results show that the three-dimensional vibration is able to refine the columnar dendrites in the cladding layer. The oscillation accelerates both the liquid flow and the thermal transfer of the molten pool, which not only reduces the temperature gradient but also increases the solidification growth rate. Meanwhile, the porosity and the maximum pore size in the cladding layer were significantly reduced by the vibration. The average microhardness of the cladding layer significantly increased assisted by the three-dimensional vibration. Experimental results demonstrate that the effects of the three-dimensional vibration are more significant than the single vertical vibration. The proposed approach provides a potential way to improve laser additive manufacturing and remanufacturing.