The effect of processing parameters on the temperature distribution and interface shape in Czochralski growth of Al₂O₃/YAG eutectic ceramic composite: Modeling and experiment

The temperature distribution and solid-liquid interface shape during crystal growth are critical for manufacturing high-quality bulk crystalline materials. However, as a kind of outstanding high-temperature structural material, the two phases of Al₂O₃/YAG eutectic ceramic composite still face the thermoelastic mismatch issue, and the process window is narrower compared to that of single crystal materials. In this study, numerical simulations and experiments were used to determine the effects of pulling rate, crystal rotation speed, crystal diameter, and insulation system configuration on the temperature and flow fields during Czochralski directional solidification of the Al₂O₃/YAG eutectic ceramic composites. The computational simulations show good agreement with the experimental results for as-grown Al₂O₃/YAG eutectic ceramic composite. By synergistically controlling the growth parameters, such as keeping the pulling rate ≤1.5 mm/h, the rotation speed ≤10 r/min, the diameter ≤30 mm, and using a ZrO₂ insulation barrel with a 25 mm thickness combined with 7 mm thick insulation cotton, a stable interface morphology with an equilibrious melt convection and a slightly convex solid-liquid interface could be achieved. Ultimately, all above research results guide the efficient production of large, crack-free, highly oriented Al₂O₃/YAG eutectic ceramic composites (Φ30 mm × 100 mm).