The influence of vacancy generation on the impurity distribution in the target under the conditions of surface treatment by a particle beam

The paper presents a nonlinear coupled isothermal model of the process of surface treatment by a particle beam. The model takes into account the interaction of impurity diffusion and mechanical disturbances, as well as the transfer of the introduced impurity by the vacancy mechanism and under the action of stresses. The problem is solved numerically using an implicit symmetric difference scheme of the second order approximation in time and spatial coordinates. The finite time of mass flux relaxation and the dependence of diffusion coefficient on the composition and on the concentration of vacancies lead to peculiarities in the propagation of both the concentration wave and the wave of mechanical disturbances. Vacancies lead to acceleration of impurity propagation and the increase in strain/stresses.