Abstract:
The mechanism of aluminum (Al) coating formation on a titanium (Ti) substrate during cold gas dynamic spraying was investigated. Structural studies of the coatings obtained by this method showed that they contain a rough transition layer in which Al and Ti atoms are intermixed. It is assumed that the transition layer forms during particle impact with the rough substrate due to a convective mechanism. Numerical modeling of mixing using the smoothed-particle method was performed for the problem of Al microparticle impact on a Ti substrate containing a conical cavity. It was shown that in this case, a cumulative jet of Al is formed, penetrating into the Ti substrate, cooling, crystallizing, and remaining in it as an aluminum inclusion. As a result of numerous microparticle impacts, a transition layer is formed on the substrate with reduced activation energy for bond formation between Al microparticle atoms and Ti atoms of the substrate. The impact of Al microparticles on the transition layer can lead to their adhesion to the surface and the formation of an aluminum coating.
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