ABSTRACT: Based on the behaviour of grinding stresses field of ceramics, indentation fracture mechanics, micro-frac-ture physics and finite element method, the formation mechanism of micro-crack and its effect factors in tile process of grindingare studied. The distribution model of crack is built. According to the mechanism that micro cracks come into being from the dislocation, the dislocation piled-up model is used to describe the grinding crack. Following the principle of equilibrium of energy, the relations of the length of dislocation crack and critical grinding stresses are discussed, and the critical condition of realizing ductile/brittle transform is confirmed.

KEYWORDS: Engineering ceramics    Grinding micro-cracks     Critical condition       Dislocation