THERMOMECHANICAL COUPLED MODEL OF COATING SYNTHESIS ON A SUBSTRATE

Abstract

Among modern combined laser and electron-beam technologies, special attention is paid to those in which composition formation takes place directly in the process of product creation or coating synthesis. In the present work, a coupled model of coating synthesis on a substrate is constructed. When building the model, a sequential transition was carried out from a three-dimensional model of the coating synthesis process on the substrate to a one-dimensional model, which is useful for qualitative analysis. The one-dimensional model takes into account the main physical features of the physical and chemical processes during the synthesis, as well as the coupled nature of the heat transfer and deformation at the same time taking into account the differences in thermophysical and mechanical properties of different materials. When constructing the intermediate analytical solution, it is assumed that the system "substrate-coating" is in a plane stress state. As a result, explicit expressions for the components of stress and strain tensors connected with changes in temperature and composition are obtained. With the help of the obtained analytical solution, the thermokinetic part of the problem is modified and reduced to a more convenient form. Further, the experience accumulated in the field of macrokinetics is used, which allows us to model the processes of creating new materials (e.g., intermetallic or metal matrix composites) in modern technologies from the point of view of controlling the processes of phase formation in the reaction zone by a moving external source. The transition to dimensionless variables revealed complexes and parameters representing relations of characteristic scales of different processes. The parametric study of the model allowed us to establish interesting qualitative effects. It is demonstrated that the quasi-stationary regime is accompanied by physical and chemical processes in the region, which the laser beam had left, due to the heat accumulated in the materials. It is shown that the coupled nature of different processes significantly affects the dynamics of synthesis and the parameters of the quasi-stationary regime.