Research Status of Numerical Simulation of Particle Deposition in Cold Spraying
In the cold spraying process,the original properties of the material are well preserved.Therefore,cold spraying technology has been widely used in recent years.Metal,ceramic,and composite coatings are the most common in this coating field.While the performance of the coating generally depends on the effective deposition of particles on the surface of the substrate,in the cold spraying process,the collision time between the particles and substrate is very short.Thus,the deformation of the particles after their collision can only be observed as a morphological feature.Therefore,numerical simulation is usually used to model and analyze the deposition mechanism of the particles and the factors affecting the deposition behavior,with the goal of understanding the principles and conditions influencing the coating deposition.In this paper,we summarize the studies on metal,ceramic,and composite particles based on numerical simulations,which have established two-and three-dimensional models;adopted and observed single-,two-and multi-particle deposition processes;and explored the deposition mechanism of particles in greater depth using the results from multiple perspectives.The results show that metal particles collide with the matrix,where they produce plastic deformation,are deposited on the surface of the matrix,and form a mechanical bond with it.However,there are also cases where the collision of the particles with the substrate leads to localized melting and the generation of jets,which results in the metallurgical bonding of the particles with the substrate.Ceramic particles are fragmented after collision with the substrate and are thus attached to its surface.However,it is difficult to deposit ceramic particles on the surface of the substrate because this collision fragmentation creates a very shallow pit in the substrate,which makes it difficult for the ceramic fragments to be attached to its surface.This process was analyzed using numerical simulation,and the retention of ceramics was studied in relation to the incidence angle of the particles and roughness of the substrate.The bonding effect of composite particles on the surface of the substrate is better than that of metal and ceramic particles.And in metal-ceramic composites,the fragmentation of the ceramic particles increases the deposition of metal particles and reduces the porosity to some extent.In addition,three influencing factors are discussed:the particle velocity,particle incidence angle,and particle size.The effect of temperature on the velocity was explored based on the injection of preheated particles into a preheated substrate.The deposition effect was explored in relation to different angles of incidence,and the effect of the particle size was explored based on particle sizes ranging from single particles of different sizes to mixtures of particles of different sizes.The final results showed that the particle velocity is directly related to whether the particles can be deposited on the substrate surface,whereas the particle size is velocity-dependent,with different critical velocities for the deposition of different sized particles.The angle of incidence is also inextricably linked to the velocity,with the magnitude of the angle of incidence related to the velocity component.Thus,it is shown that there is a relationship between the influencing factors,which affect each other.In addition,the analysis of the application of cold spraying to the aviation,naval,and medical fields showed that our country needs to strengthen the development of practical applications of cold spraying technology.
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