Damage induced in sic by a particle impact

Abstract

Impact damage induced in silicon carbide ceramics was studied by using a SiC particle or a steel particle. Ring cracks, radial cracks and lateral cracks were observed on the specimen surface, and cone cracks were observed on the fracture surface. The outermost diameter of ring cracks increased with impact velocity; however, the innermost diameter was almost constant. The effect of temperature on these ring crack sizes could not be seen clearly. In order to evaluate the effect of the damage on the strength of a specimen, the residual strength was measured by four-point bending tests. The degradation in residual strength caused by an SiC particle impact was larger than the degradation in the case of steel particle impact, although larger ring cracks were observed on the surface in the case of steel particle impact compared with the case of SiC particle impact. For oblique impact, the degradation in residual strength of the specimen was large when it was impacted transversely with regard to specimen axis compared with longitudinal impact.