Effect of continuous and random multi-particle impaction on the aluminum coating and copper substrate in cold spraying

In this study, the process of multi-particle cold spraying has been numerically simulated and compared with the actual cold spraying results. The results show that in the continuous multi-particle models, the maximum depths of compressive residual stress reached 4.90 μm, 3.99 μm, 4.78 μm, and 5.19 μm for each increment in particle number. The penetration depth of residual stress increases then decreases, due to two opposite factors effects on the penetration depth of residual stress. the maximum compressive residual stresses on the substrate are 438.14 MPa, 293.57 MPa, 286.19 MPa, and 279.30 MPa respectively, declining as the number of impacting particles grows. With the subsequent deposition of particles, the further deformation of the substrate causes the stress on the side to gradually homogenize, and the peak value decreases. Surface stress of the workpiece alleviates after multiple Al particles impact Cu substrate. In all random multi-particle models of different gas pressure, the residual stress begins to disappear at about 100 μm from the surface, and basically disappear at about 300 μm. As the collision speed of particles increases, the substrate deformation increases, but the growth rate of deformation decreases. The influence of coating thickness on the substrate deformation gradually decreases with the increase of coating thickness.