Vertical short cracks on surfaces resume propagating till 70-80 percent of the total RCF failure lives and then are accelerated to propagate, almost synchronously, the two types of short cracks resume growing with a turned mode in subsurface. 在疲劳失效寿命的70%-80%时,垂直短裂纹恢复扩展,并随即加速长大.几乎同时,两种短裂纹在亚表层以转折的方式重新扩展。