Correlation study of random deposition for WC-12Co multiparticles on the TC18 substrates

The TC18 titanium alloy as an aviation landing gear material is famous for its high strength and hardenability. However, under the influence of the harsh service environment, its corrosion resistance is relatively poor. WC-12Co ceramic material is one of the most widely used surface strengthening materials, and the coatings are often produced by high velocity oxygen fuel (HVOF) thermal spraying. In the spraying, the deposition state of particles directly affects the quality and strengthening ability of coating. This study combined the correlation of flow field calculation and impact process of particles, and the particle flight characteristics were analyzed in the three-dimensional HVOF spraying. The change law for temperature and velocity of particles was explored by changing the spraying distance, oxygen/fuel (O/F) ratio, and particle size. Based on the calculation results of flow field, a three-dimensional random deposition model of WC-12Co multiparticle was established by the coupled Euler-Lagrange method, and the crystal inhomogeneity was introduced by the Voronoi method. Compared the flattening rate and spreading degree of particles deposition, the evolution law of temperature and stress-strain fields for coating and substrate during the deposition was revealed.