Simulation of the bulk synthesis of a composite from the mixture of Ni and Ti in a steel cylindrical reactor

Abstract

A new mathematical model of high-temperature synthesis of intermetallic composite in the mode of dynamic thermal explosion is proposed. It is assumed that the heating of a powder compact placed in a steel cylindrical reactor is carried out by high frequency currents from an inductor. This model takes into account the reactions of formation of the main phases represented on the Ni-Ti diagram equilibrium state diagrams of the binary system Ti-Ni and known from experimental data. Composition changes (the fraction of pure components and synthesis products) are described using theory of formal chemical kinetic. It is assumed that the reaction rates depend on the temperature according to the Arrhenius law, and on the concentrations according to the law of the mass action. The formulated problem is solved numerically. The presented model makes it possible to investigate the regularities of intermetallic composite synthesis, taking into account the melting process. The gradual appearance of the liquid phase is described by a separate equation in the melting temperature interval, which is formally similar to the two-phase zone theory. The results of numerical studies of the composition evolution are described. Numerical results are compared with the experiment. It is shown that the material of complex composition is formed during the volume synthesis in all parameter area under study.