Growth kinetics of reaction layers formed during diffusion bonding of SiC ceramic to TiAl alloy

Abstract

In order to comprehend and simulate the interfacial reactions between SiC ceramic and TiAl alloy, a mathematical model for describing the growth behaviour of reaction layers is established according to the synthetic effects of chemical reaction and physical diffusion, and the method and formulae for calculating the kinetic parameters from the experimental data are given. Two reaction layers, TiC and (Ti₅Si₃C_x+TiC), are formed during the diffusion bonding, and their kinetic parameters are determined. The calculation indicates that the two reaction layers have essentially the same critical growth time, but the chemical reaction constant and physical diffusion constant of the TiC layer are smaller than those of the (Ti₅Si₃C_x+TiC) layer. Therefore, the two reaction layers always grow in the same control regime, but the growth rate of the TiC layer is slower than that of the (Ti₅Si₃C_x+TiC) layer. In addition, the kinetic equations of the two reaction layers are presented, and the simulated results are quite consistent with the experimental data.