Spark plasma sintering: A high strain rate low temperature forming tool for ceramics

Spark plasma sintering (SPS) technique is being widely used to produce nanocrystalline materials by virtue of rapid sintering at relatively lower temperatures. In this investigation, fully dense Al2O3–ZrO2–MgAl2O4 composite was superplastically formed into a complex shape using SPS equipment with a strain rate of approximately 10−2 s−1 at temperatures as low as 1150 °C which is impossible to obtain by using conventional forming methods. Furthermore, a powder compact can be directly shaped into a complex shape, combining sintering and forming into one step. The product is fully dense and free of surface cracks. These results indicate that SPS can be a very competitive forming tool for ceramics as well other hard materials.