Investigation of the Mechanism of Brittle Fracture of Cutting Ceramic

Abstract

The fatigue strength of Russian-made oxide-carbide ceramic during intermittent turning in machining hardened steel specimens set in the faceplate body was studied. The turning was conducted up to fracture of the cutting edge of plates. The structure of the fractured surface layer was studied and the mechanism of fracture of the cutting edge of tool plates made from cutting ceramic was determined. It was found that during intermittent turning the low productivity of cutting plates made from oxide-carbide ceramic is mainly caused by chipping of the cutting edge as a result of the formation of microcracks on intergrain boundaries. A distinctive feature of the mechanism of brittle fracture of cutting ceramic is intergrain tear-out and chipping of large grains of Al₂O₃.