Effect of ingredients proportions on mechanical properties in laser-coated WC-blend welds

Abstract

Abstract In this study, we investigated ceramic-matrix composite coatings created by laser cladding on 45 steel using tungsten carbide (WC) powder with varying weight percentages of Co or Ni additives. Our analysis focused on the influence of Co additives in WC powders on the key properties of the coatings, including the microstructural evolution, hardness, wear, and residual stress behaviors. High residual stresses led to significant cracking in coatings comprising 100% WC. The addition of Co at a concentration of 20% to WC reduces the cracking activity. The microhardness of the coating exceeded that of the substrate by a factor of more than five. The microstructural evolution revealed a typical intergranular fracture in the molten zone, with cracks propagating through the interior of the unmelted WC at 100% WC. In addition, by adding Ni alloys, the composite coatings were extended to three mixtures: WC-Co, WC-Ni, and WC-Co-Ni. The relationship between the three-component mixtures and wear volume of the laser cladding was established, and the ratios of the three-component mixtures were optimized. A reduced quadratic model for three-component mixtures, which provided a better mixture ratio pattern, showed an excellent fit. Based on the experimental results, the developed three-component mixture with better mixture ratios can enhance anti-wear behavior. A satisfactory agreement was obtained between the predicted and experimental values of the wear volume of the laser-coated welds. Overall, our study accomplishes the optimization of the mixture ratio of the three components, which ensured a reduction in the wear of the welds, thereby improving the performance of laser-coated welds.