２Ｃｒ１３马氏体不锈钢应变疲劳过程中发生了循环软化．微观结构分析表明，疲劳亚结构为位错胞状结构，但胞的特征受板条形貌、碳化物分布和循环应变幅的影响．应变幅恒定时，随循环周次的增加，微观亚结构的演变过程为：首先是可动螺型位错进行交叉滑移，将基体中的自由位错束集；然后与碳化物或板条界相连，形成壁较厚的位错胞状结构． 2Cr13 martensitic stainless steel strain fatigue occurred during the cycle of softening. The microstructure analysis showed that the sub-structure of fatigue was a dislocation cellular structure, but the characteristics of the cells were affected by the morphology of the lath, the distribution of carbides and the amplitude of cyclic strain. When the strain amplitude is constant, with the increase of the number of cycles, the evolution of the microstructure is as follows: first, the movable screw dislocations cross-slip and the free dislocations in the matrix are bundled; then, the carbides or slats Boundary to form a wall thicker dislocation cell structure.