Thermal modeling of selective area laser deposition (SALD) and SALD vapor infiltration of silicon carbide

摘要

A 3D finite element model was developed that simulates selective area laser deposition vapor infiltration (SALDVI) of silicon carbide. The model predicts the laser input power history needed to maintain constant surface temperature and the distribution of vapor deposited SiC within the powder bed as well as on the surface of the powder bed. The model considers a moving Gaussian distribution laser beam, temperature- and pore-dependent thermal conductivity, specific heat and temperature-dependent deposition rate. Furthermore, the model also includes closed-loop control of the laser power to achieve a desired target processing temperature on the surface of the power bed. Effects of laser scanning rates have been investigated. For simple geometries, the simulated pyrometer temperature and incident laser power agree fairly well with the experimental data and the discrepancy is less than 10 percent. The simulated solid fraction and SALD distributions are also consistent in the trend with the experimental data.