Effects Of Particle And Substrate Property On Impact And Adhesion Process In Cold Spray By Numerical Simulation

Because of its low temperature, particle maintaining solid state feature, cold spray can effectively avoid thermal effect in its spraying process. It also has many other advantages, so cold spray technology gets more and more attention from scholars both at home and abroad. It is the key problem of cold spray technology that the process of impacting and bonding between particle and substrate be understood. The success or failure of cold spray coating depends on the process of impacting and bonding. The strength of the combination is very important for judging coating quality. Since the time of particle impacting on substrate is very short in the actual cold spray experiment, the process is not easily observed and the combination mechanism of cold spray has not been unified understanding and needs to be further studied at home and abroad. The study of the impacting and combination process in cold spray has a vital significance in academic study as while as industrial application. And due to its convenience and certain visibility, numerical simulation method becomes the primary study method of the impacting and bonding process in cold spray.In this paper, the impacting and bonding process of aluminum alloy particles deposition on magnesium alloy substrate has been simulated using ABAQUS/explicit, which is nonlinear finite element analysis software. Effects of different particle and substrate preheating temperatures, different particle incident velocities, particle spherical and ellipsoid shapes, limited space of substrate surface and different particle incident angles on the impact process have been studied. And the process of multiple particles impacting on limited space surface character is also simulated.Simulation results show that deformation degree of particle and substrate are different at different particle or substrate preheating temperatures, which are indicated by the compression ratio of particle, substrate crater depth and maximum contact surface area between particle and substrate. It is advantageous to the impacting process when preheating the particle and substrate within a certain range. Ellipsoid shape and the incident angle of the particle have great influence on impacting process too. The material deformation degree is severe and particle rebound kinetic energy is smaller when particle impacting on substrate along its long axis direction of ellipsoid particle. When ellipsoid particle impacts on substrate along its short axis, although the biggest contact surface area increases, the maximum relative surface area decreases, and particle rebound kinetic energy increases. The material deformation also becomes weak. The deformation of material is also different when limited space(micro groove) exisit on the substrate surface, Particle impacting character is different on different substrate position and with different particle. When multiple particles impact on the substrate with limited space, the compaction effects of the subsequent particles on pre-deposited particles are obvious. At the same time, increasing of particle impacting speed and material preheating are beneficial to the combination process between particles and substrate.