In the practical cold-spraying process,a number of particles impact onto a substrate and then form a coating.To study the deformation behavior and multi-particle interactions,single-particle,two-particle,and three-particle impacts were simulated using the ANSYS/LS-DYNA version 970.A copper coating was prepared and scanning electron microscopy (SEM) was employed to analyze the microstructures of the powders and the coating.Numerical results reveal that the critical deposition velocity is 600 m/s for a copper particle/copper substrate.The particles deform more fully due to multi-particle interactions,such as tamping,interlocking,and extrusion effects.The compression ratio increases from 40% to 70% as a result of the tamping effect.This is beneficial for achieving the cold-sprayed coating.The multi-particle morphology and compression ratio in the experiment are consistent with those of simulation results.Based on these results,the coating of high performance can be prepared through selecting appropriate parameters and suitable pre-treatment processes.