Abstract
Effect of shot peening and self-crack-healing on rolling contact fatigue of Al_2O_3/SiC composite ceramics was investigated. The specimens were shot-peened using zirconium dioxide shots, and subsequently crack-healed at 950°C for 100 hours. The X-ray result clearly showed that the compressive residual stress was introduced at subsurface by shot-peening. Furthermore, the residual stress was not completely released by the heat-treatment. The compressive residual stress could attain the large increment of apparent fracture toughness K_<IC> of the composite. However, rolling contact fatigue strength could not be improved only by shot-peening, because numerical surface cracks were easily introduced by shot-peening. Meanwhile, rolling contact fatigue strength can be improved by shot-peening and subsequent crack-healing treatment. This implies that additional heat-treatment can attained the complete healing of shot-peening-induced cracks without complete release of residual stress, leading to improved rolling contact fatigue strength.
