System simulation of multi-physical field coupling in electric current-assisted sintering

The densification mechanism of silicon carbide powders in electric current-assisted sintering was investigated by the phase field model based on the strongly thermo-mechano-electro-diffusional coupling theory. The influence of current density on the activation energy of sintering was introduced into the coupled equations by the diffusion coefficient, and the real-time effects of activation on the diffusion were characterized in simulation. The relationships of conductivity and temperature for the silicon carbide materials were considered. The boundary conditions of current and temperature in the morphological evolution were identified by the macroscopic finite element method during the silicon carbide sintering. The results show that, the densification curves in the microstructure evolution simulations are consistent with the experimental results under the different heating rates. The calculations indicate that, the activation can greatly promote the densification process in electric current-assisted sintering. What's more, increasing the heating rate can also increase the diffusion driving force, thereby increasing the densification rate.