Numerical simulation of the infiltration behavior of molten metal in a ceramic porous preform

Investigating the infiltration mechanism of molten metal in ceramic particle porous preforms provides critical theoretical guidance for optimizing the casting infiltration process and improving the quality of castings. In this study, the microstructural model of the zirconia-toughened alumina ceramic porous preform was precisely reconstructed using high-resolution X-ray computed tomography. Based on the lattice Boltzmann method, the infiltration process of the high-chromium cast iron molten metal in the porous preform of ceramic particles was simulated at the pore scale. The effects of molten metal viscosity (0.00175–17.5 Pa·s), injection velocity (0.005–0.1 m/s), surface tension (0.072–5 N/m), contact angle (20–80°), and preform placement positions on the infiltration behavior of the molten metal in the preform were investigated. The results indicate that increased molten metal viscosity enhances flow front stability by mitigating pore heterogeneity effects, thereby achieving higher steady-state saturation. However, it also increases flow resistance, which reduces steady-state saturation when the driving pressure is insufficient. Increasing the injection velocity or reducing the surface tension significantly improves steady-state saturation. The steady-state saturation distribution diagram of capillary number (Ca) and viscosity ratio (M) yields the empirical relation defining the boundary between high and low saturation regions: LogCac − 0.93LogM = −6.79. Moreover, reducing the contact angle of the preform wall significantly enhances steady-state saturation. Furthermore, positioning the preform in the top or middle regions of the cavity improves steady-state saturation under low injection velocities.