Effect of WC Mass Fraction on the Microstructure and Properties of 316L Coatings Prepared by Laser Cladding

In this study, 316L-x%WC (x=0, 3, 5, 8) alloy coatings were fabricated on gray cast iron brake discs using laser cladding technology. The objectivewas to investigate the influence of WC ceramic phase on the phase structure, microstructure, microhardness, wear resistance, and corrosion resistance of 316L-based coatings. The results indicate that the coating phases mainly consist of γ-Fe 3 -Ni, Fe 3 C, M 23 C 6 , and M 7 C 3 . With the addition of WCphase, the Cr 3 C 2 phase is introduced into the coating. A sound metallurgical bond is formed between the coating and the substrate. The main matrix of the coating is a carbon-rich γ-Fe-Ni solid solution, presenting as uniform equiaxed grains and columnar grains. Reticulated carbides composed of uniform petal-like and chain-like M 23 C 6 , M 7 C 3 , and Fe 3 C act as reinforcing phases distributed between grains and grain boundaries.As the WC content increases, elements Cr and Mo accumulate at the grain boundaries, leading to coarsening of the intergranular phases and refinement of the grains. Under the combined action of strengthening mechanisms such as second-phase strengthening and grain refinement strengthening, the coatings exhibit excellent wear resistance and corrosion resistance. The wear mechanism of the coating is predominantly abrasive wear, which improves coating hardness and wear resistance, reduces wear loss, and provides support for mitigating brake particle emissions.