Three-dimensional numerical study of the behavior of thermoelectric and mechanical coupling during spark plasma sintering of a polycrystalline material

Spark plasma sintering (SPS) is a promising modern technology that sinters a powder, whether it is ceramic or metallic, transforming it into a solid. This technique applies both mechanical pressure and a pulsed direct electric current simultaneously. This study presents a three-dimensional (3D) numerical investigation of the thermoelectric (thermal and electric current density fields) and mechanical (strain-stress and displacement fields) couplings during the SPS process of two powders: alumina (ceramic) and copper (metallic). The ANSYS software was employed to solve the conservation equations for energy, electric potential, and mechanical equilibrium simultaneously. Initially, the numerical findings regarding the thermoelectric and mechanical coupling phenomena observed in the alumina and copper specimens were compared with existing numerical and experimental results from the literature. Subsequently, a comprehensive analysis was conducted to examine the influence of current intensity and applied pressure on the aforementioned coupling behavior within the SPS device. The aim was to verify and clarify specific experimental values associated with these parameters, as reported in the literature, and identify the optimal values of applied pressure (5 MPa for alumina and 8.72 MPa for copper) and electric current (1000 A for alumina and 500 A for copper) to achieve a more homogeneous material.