High-pressure and high-temperature sintering of pure cubic silicon carbide: A study on stress–strain and densification

Silicon carbide (SiC) is a high-performance structural ceramic material with excellent comprehensive properties, and is unmatched by metals and other structural materials. In this paper, raw SiC powder with an average grain size of 5 μm was sintered by an isothermal-compression process at 5.0 GPa and 1500 °C; the maximum hardness of the sintered samples was 31.3 GPa. Subsequently, scanning electron microscopy was used to observe the microscopic morphology of the recovered SiC samples treated in a temperature and extended pressure range of 0–1500 °C and 0–16.0 GPa, respectively. Defects and plastic deformation in the SiC grains were further analyzed by transmission electron microscopy. Further, high-pressure in situ synchrotron radiation x-ray diffraction was used to study the intergranular stress distribution and yield strength under non-hydrostatic compression. This study provides a new viewpoint for the sintering of pure phase micron-sized SiC particles.