Hightemperature Mechanical Properties of Sintered Alpha Silicon Carbide (13 October 1978 - 13 October 1979),

Failures on tensile-stressed, as-fired samples were caused primarily by processing defects and did not appear to be associated with compositional changes amount of sintering agent in the material. At high testing temperatures above 1340 C, the occurrence of processing defects appears to control strength, making it impossible to speculate on the effect of salt and oxidation during slow crack growth in these specimens. Over the variety of conditions tested such as salt, oxidation, and their combinations, strength did not vary greatly. Therefore, the defects from processing represents the reasonable lower limit of strength under the imposed testing conditions. The determined strength values probably represent reasonable design data for components with as-fired, as-formed surfaces of similarly processed SASC. Since these strength values represent a reasonable lower limit for as-fired, as-formed surfaces of SASC, the potential is good for improvement by processing improvements to eliminate defects. SASC continues to show promise as a viable engineering material. It will become more attractive for heat exchanger applications in aggressive environments as processing becomes more sophisticated.