片状切变型夹杂导致的脆性开裂

片状切变型夹杂可以表现一些重要物理过程的力学特征,例如在晶体材料中形成的滑移带、形变孪晶带以及片状马氏体等。这些过程与材料的断裂密切相关。本文采用位错连续分布方法,导出了位于片状夹杂端部的裂纹的应力强度因子的解析表达式。根据本文的结果,我们讨论了片状夹杂所导致的微裂纹扩展的特征。由夹杂理论可以得到多晶体孪晶脆断应力的Hall-Petch关系,理论计算与实验结果符合得好。 关键词：

CRACKING DUE TO A PLATE-FORM INCLUSION OF SHEAR TYPE

Plate-form inclusions of shear type represent the mechanical aspect of many important processes, such as the formation of slip bands, twin bands and martensitc plates in crystalline materials. All these processes connect closely with fracture of materials. Analytical expressions for stress intensity factors of the crack near the inclusion have been derived by using dislocation theoretical method. Using the results of this paper, some aspects of the cracking due to a plate-form inclusion are discussed. The Hall-Petch relation of twin-fracture stresses can be obtained from the inclusion model, and the theoretical results are in good agreement with experiments.