Development of fatigue crack healing in metals by controlling high-density electric current field and its evaluation

提出了一种通过控制高密度电流场来修复不锈钢疲劳裂纹的方法。从实验结果中，它被观察到的裂纹闭合和裂纹表面之间的桥接引起周围的裂纹尖端附近的高密度脉冲电流施加到试样后。结果表明，裂纹扩展暂时延迟愈合试样。此外，通过去除氧化膜和在裂纹表面涂覆防止再氧化的金属保护膜，促进了裂纹的闭合和桥接，并通过施加电流使分支小裂纹完全愈合。

A technique was developed to heal a fatigue crack in stainless steel by controlling a high-density electric current field. From the experimental results, it was observed that the crack closure and the bridging between the surfaces of a crack were caused around the vicinity of the crack tip after high density pulse current was applied to a specimen. It was shown that crack propagation was delayed temporarily in the healed specimen. Moreover, by removing oxide membrane and coating the metal protection film for preventing re-oxidation on the crack surfaces, the crack closure and the bridging were promoted, and the branched small crack was healed completely by application of current.