Modeling of grain-boundary diffusion under nonstationary heating conditions

Grain boundary diffusion appreciably affects the physicomechanical and chemical properties of constructional materials. Experimental studies show that transfer processes run more intensively in materials with a larger area of internal boundaries. For these materials, the temperature required for diffusion activation is reduced. Much attention is paid to grain-boundary diffusion in such areas as materials science, physics and chemistry of metals, and metal science. However, there are practically no published works where the diffusion along the grain boundaries and phases under non-isothermal conditions has been studied. This work presents a two-dimensional model of alloying element redistribution from the amorphous coating into the substrate. The substrate is represented by alternating grains with a clear selection of the triple junction. The areas adjacent to the grain boundaries are clearly selected in the model and have a finite thickness. Different ratios between the grain sizes and the boundaries widths relate to diffusion in micro- and nanocrystalline materials...