陶瓷材料延性域去除临界条件新研究

Study on the Critical Conditions of Ductile Field Removal of Ceramics

本文是在对磨削过程的应力特征、微裂纹形成及扩展和材料去除机理研究的基础上 ,针对微裂纹扩展的稳定性条件进行研究。研究中 ,将宏观断裂力学及微观断裂物理相结合 ,根据位错产生微裂纹机制 ,对磨削过程的微裂纹的形成采用位错赛积模型来描述。并从能量平衡的角度 ,讨论位错裂纹的稳定性及临界裂纹尺寸。

Based on the behaviour of grinding stresses field of ceramics, indentation fracture mechanics, micro-fracture physics and finite element method, the formation mechanism of micro-crack and its effect factors in the process of grinding are 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.