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一引言解理断裂应力σ_f~*是在断裂物理研究过程中所提出的一个与断裂有关的新的材料特征参量。它表征材料微观结构中裂纹成核和传播过程中最困难的一个阶段所需的临界拉应力。大量实验证明:在材料内部任何区域当应力达到σ_f~*时,立即发生解理断裂。因此它实际上就是裂纹体、切口体及光滑体解理断裂的基础判据——最大主应力判据。解理断裂应力σ_f~*这个参量一方面与材料的显微组织有关,可以想象为包含在缺口或裂纹尖部前方材料中一个微“拉伸试样”的解理断裂强度。其值可由断裂物理模型的分析经计算求得,另一方面它又可作为一个力学参量,根据试样的几何形状,用弹塑性力学的分析方法来定量计算。这样解理断裂应力σ_f~*就在微观的断裂机理和宏观的断裂力学之间架起一座桥
I. INTRODUCTION The cleavage fracture stress σ_f ~ * is a fracture-related new material characteristic parameter proposed in the fracture physics research. It characterizes the critical tensile stress required for the most difficult phase of crack nucleation and propagation in the material’s microstructure. A large number of experiments show that: in any region within the material when the stress reaches σ_f ~ *, cleavage fracture occurs immediately. Therefore, it is actually the basic criterion for the cleavage, incision and smooth body cleavage fracture - the criterion of the maximum principal stress. Cleavage fracture stress σ_f ~ * This parameter is related, on the one hand, to the microstructure of the material and can be imagined as the cleavage fracture strength of a micro “tensile specimen” contained in the material ahead of the notch or crack tip. Its value can be calculated by the analysis of the fracture physical model, on the other hand, it can be used as a mechanical parameter, which can be quantitatively calculated by the analysis method of elastic-plastic mechanics according to the geometry of the sample. This cleavage of the fracture stress σ_f ~ * raises a bridge between the microscopic fracture mechanics and the macroscopic fracture mechanics