弯曲疲劳裂纹萌生过程的细观实验与分析

基于细观实验，对夹杂物附近疲劳裂纹萌生的形式，方向和过程等进行了分析，结果表明：夹杂物与基体弹塑性，热性上的差异导致不同萌生形式；表面层应变状态与表面法向间的取向决定萌生方向和扩展平面，萌生过程以小裂纹汇合方式进行。

Analysis and Observation of Bending Fatigue Crack Initiation with Microscope Experiment

On the basis of the observation of microscopic experiment, the process, orientation and form of the fatigue crack initiation near the inclusion are studied and analyzed. The result shows that the different initiation forms are caused by different heat expansion coefficients and elasto plasticities that the orientation of initiation and growth of fatigue crack depend on the orienting strain state and surface, and that the crack length is expanded by crack convergence.