Stress and dislocations in diamond–SiC composites sintered at high pressure, high temperature conditions

Diamond–silicon carbide composites were sintered at 10 GPa and three different temperatures: 1600, 1800, and 2000 °C. Distributions of residual surface stresses in diamond crystals were obtained by the analysis of Raman band shifts and splitting. It was noted that stresses concentrate around points of contacts between diamond crystals. Average stress increase with increasing sintering temperature. Complementary information on average sizes of crystallites, concentration of stacking faults, and population of dislocations in both diamond and SiC were obtained from X-ray diffraction profile analysis. It was observed that for both diamond and silicon carbide phases the average crystallite sizes decrease. The population of dislocations in the diamond phase increases with increasing sintering temperature and the population fluctuates in the SiC phase. Concentration of stacking faults was significant only in SiC.