Effect of Substrate Material Properties on Microstructure and Mechanical Properties of Ni60 Coatings Prepared by Extreme High‐Speed Laser Cladding

Abstract

Using extreme high‐speed laser cladding technology, Ni60 coatings are laser cladded onto stainless‐steel, 20# steel, and 45# steel substrates. The effect of substrate material properties on the cracking behavior, microstructure, and tribological properties of the Ni60 coating is systematically studied. The results show that as the difference of the coefficient of thermal expansion between the substrate and cladding material decreases, the tendency for crack generation in the cladding layer is reduced. In addition, the difference of the thermal physical properties of the substrate has an important effect on the temperature gradient during the cooling process of the coating, and then affects the growth rate of the grain in the coating and the overall mechanical properties of the coating. Finer grain size, fewer macroscopic coating cracks, and the evenly distributed hard phase in the Ni60 coating on the 20# steel substrate lead to better wear resistance.