Such dislocations slipping lead to permanent set which can lower breaking and fatigue strength in the area.The fact that this is the most danger position.

• 为了降低应变能，出现应力松驰，导致位错滑移产生永久变形，降低了局部区域的屈服强度及其疲劳极限，从而引起疲劳破坏。