Cutting behavior and related cracks in wear and fracture of ceramic tool materials

摘要

Wear and fracture resistance of several kinds of alumina series ceramic tool materials in continuous and intermittent machining of carbon steels are investigated. Morphologies of various wear and fracture cracks formed on the surface of tool insets after cutting operation are analyzed in detail. Mechanisms of cracks formation and their effects on wear and fracture resistance of ceramic tool materials are analyzed with SEM and TEM observation. The formed cracks in continuous machining can result in the acceleration of tool wear. In intermittent machining, the formation and propagation of cracks is also responsible for early fracture of cutting tools. The mechanical fatigue cracks and thermal cracks resulted from the combined action of both mechanical and thermal stresses are the dominant reasons for the late fracture of ceramic cutting tools.