DoE Optimization of Applied Pressure and Mold Size in Manufacturing Homogeneous Alumina Samples by SPS Process under 1000A Current

Spark plasma sintering (SPS) presents advantages over conventional sintering methods, notably high heating rates and reduced residence times. However, SPS suffers from uneven temperature and stress distributions due to suboptimal sintering parameters, such as uniaxial pressure and mold dimensions. These inconsistencies can result in microstructural inhomogeneities, adversely affecting the mechanical properties of the final products. To mitigate these issues, optimizing the sintering parameters is important for achieving a homogeneous polycrystalline material with desired mechanical characteristics. This study focuses on the numerical modeling of the thermoelectric and mechanical coupling behavior of alumina during SPS. Simulations were conducted using ANSYS software, and the model was integrated into a Box-Behnken Design of Experiment (BBD) to optimize three key factors: Factor 1 - uniaxial pressure (5 MPa to 20 MPa), Factor 2 - mold diameter (19 mm to 50 mm), and Factor 3 - mold height (4 mm to 8 mm). The results from the BBD optimization were analyzed using surface diagrams and ANOVA. The optimal SPS parameters identified for producing homogeneous alumina with desired mechanical properties are: uniaxial pressure of 20 MPa, mold height of 8 mm, and mold diameter of 34.5 mm, calculated for a current of 1000 A. This optimization approach effectively enhances the quality of SPS-sintered materials.