An Investigation of the Microstructure and Wear Resistance of Laser Clad 316 Stainless Steel/TiC Coatings Containing Different LaB6 Contents

In this paper, 316 stainless steel/TiC coatings with different LaB6 contents (0%, 2%, 4%, 6%) were prepared on the surface of 45 steel by laser cladding technology. The effects of the LaB6 content on the phase composition, microstructure, microhardness, and wear resistance of the coatings were studied. The results show that without the LaB6 addition, the coating is composed of Austenite and TiC phases, with defects such as pores and cracks, and the microstructure is mainly equiaxed grains. With the addition of LaB6, Fe-Cr phases are formed in the coating, and the microstructure transforms into columnar grains and dendritic grains. The grains are first refined and then coarsened, among which the coating with 4% LaB6 (C4) has the smallest grain size. The experimental results indicate that the microhardness of the coatings first increases and then decreases with the increase in the LaB6 content, and the C4 coating has the highest microhardness (594HV0.2). The wear rate shows the same variation trend. The C4 coating has the lowest wear rate and the best wear resistance. This is attributed to the synergistic effect of the fine grain strengthening and TiC particle dispersion strengthening.