TWO-LEVEL MODEL OF COMPOSITE SYNTHESIS ON A SUBSTRATE FROM A POWDER MIXTURE OF TIO2 AND AL. 1. MODEL DESCRIPTION AND SIMPLE EXAMPLES

Abstract

Modern 3D-technologies are of considerable interest due to the possibility of direct creation of products from composite materials, which are formed directly by laser action. This article presents a thermo-kinetic model of laser treatment of a powder layer on a substrate, taking into account the evolution of the composition. The model variant on a macrolevel is convenient for a detailed investigation of accompanying phenomena when varying technological parameters. Two variants of composition evolution are considered. In the formal-kinetic approach, taking into account successive parallel stages, kinetic equations are described in which the reaction rate depends on the temperature according to the Arrhenius law, and on the concentrations according to the law of active masses. In the second version, the evolution of composition is described on the mesolevel basis. Thermal processes are calculated in the macro problem and diffusion-kinetic ones in mesosystems. Melting in a mixture of powders is described on the macro scale by introducing a melting temperature interval and a fraction of the liquid phase. If, in the first variant, the mathematical model remains one-dimensional. In the second variant, the model becomes two-dimensional. Examples of calculations illustrating features of different subtasks and their possibilities for TiO2-Al system are presented.