Numerical study on single-particle deposition behavior of Al₂O₃ in detonation spraying

To elucidate the particle deposition mechanism and optimize coating quality in detonation spraying, this study established a single-particle deposition numerical model for Al₂O₃ particles impacting a stainless steel substrate. The model employed the Coupled Eulerian-Lagrangian (CEL) method integrated with the Johnson-Cook (J-C) constitutive model. It systematically investigates the effects of impact angle, initial particle temperature and velocity on the deposition process. The results indicate that the particle deposition process can be divided into three stages with temporal overlap: crater formation, spreading and flattening, and splashing and solidification. The final coating morphology exhibits a thicker center and a thinner periphery. Notably, the distribution of equivalent plastic strain (PEEQ) corresponds closely to the temperature field. Optimal coating quality is achieved at a normal impact angle of 90°, which yields the highest degree of flattening, the most uniform stress distribution, and the strongest coating-substrate bonding. In comparison, increasing the initial particle temperature promotes flattening and reduces internal stresses via thermal softening but also intensifies splashing, leading to material waste. Increasing the initial particle velocity significantly enhances both coating flattening and substrate crater depth, thereby strengthening the mechanical interlocking. Moreover, the influence of initial particle velocity on substrate deformation is approximately 4.5 times as great as that of initial particle temperature. Based on the multi-factor coupling analysis, a multi-level optimization strategy for the initial parameters of detonation spraying is proposed.