Restoration of fatigue damage in stainless steel by high-density electric current

• Healing of fatigue damage was realized by the application of electric current.
• Fatigue crack initiation was delayed due to the healing of fatigue damage.
• The recovery of residual plastic strain was evaluated quantitatively.
• Mircohardness within the plastic zone was studied.
• Dislocation structure illustrates the reason of the healing effect.

To investigate the effect of high-density electric current on healing of the fatigue damage, the recovery of residual plastic strain was quantitatively evaluated with the digital image correlation method. The microhardness was measured within the plastic zone at the root of notch. Furthermore, the dislocation structures before and after the application of electric current were investigated by transmission electron microscopy to further understand the mechanics of the healing effect. It was concluded that the fatigue damage was healed by a decrease in dislocation density. As a result, fatigue crack initiation was delayed by the healing of fatigue damage.