Effect of Temperature Dynamics on TiAl Oxidation Due to Grain-Boundary Diffusion of Oxygen

Grain boundary diffusion accelerates the penetration of oxygen and oxidation during heating of the material with a micro- and nanostructure. The article presents a two-dimensional model for investigation of this process. The TiAl structure is specified as symmetrically alternating grains with a clear separation of boundaries and triple junctions between them. The properties of the boundaries and grains are different. Dimensionless variables are used for visual presentation and convenience of analysis of the results. The problem has been solved numerically. The diffusion equation is solved using an implicit difference scheme. The equations of chemical kinetics are solved using an algorithm similar to the implicit Euler method and an iterative process. The results demonstrate the influence of different temperature regimes on the concentration distribution and the integral accumulation of reagents and oxides.