Modeling of Volumetric Synthesis of Composite with Regard the Subsequent Structurization

The paper proposes a two-dimensional thermokinetic model of the composite synthesis process in the mode of dynamic thermal explosion taking into account the structurization of the synthesis product. Structurization in the model is understood as a transition from amorphous to crystalline state. The model takes into account the heating of the reactor walls by thermal radiation from the device, the temperature of which can vary at different rates. Chemical reactions are described by a summary scheme that corresponds to the synthesis of Ni₃Al composite. The kinetic law takes into account a possible strong inhibition of the rate of the reaction with the accumulation of the synthesis product, which is typical for reactions controlled by diffusion at the particle level. The effective thermophysical properties of the components of mixture and reaction products in the reactor depend on the properties of the constituents of the initial mixture and the fraction of reaction product. The properties of the latter also depend on the degree of structurization. The structurization process is described by a special additional parameter whose evolution is modeled by a reversible reaction. It is assumed that the structurization process starts from the moment of product appearance and continues during the cooling of the system. It is shown that synthesis results in the formation of a composite containing the initial components and the reaction product with the matrix partly in the amorphous state and partly in the structured state. The dynamics of synthesis and structurization are influenced by heating conditions and reactor size.