The fatigue damage recovery of 20 low carbon steel by pulse current as well as the mechanism were investigated. A pulse current was applied on the pre-fatigued specimens with 60% of the original fatigue life cycles to recover the fatigue damage

and the total fatigue life of the pulse current treated specimens is increased by 41% compared with the original ones. The effects of pulse current treatment on the microstructure and mechanical properties of the specimens were analyzed. The results reveal that absence of strengthing is observed in 20 low carbon steel under the action of pulse current

indicating that the prolongation of fatigue life is attributed to the recovery effect of pulse current. TEM observation reveals that after the pulse current treatment

the wall-like dislocation structure observed in ferrite of the fatigue specimens is partially disappeared

and the dislocation is more evenly distributed. Moreover

pulse current treatment may be an effective way to recover the micro-defects of fatigue-damaged materials

extending the service life of the materials.