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

开发了一种通过控制高密度电磁场来修复不锈钢疲劳裂纹的技术。从实验结果可以看出，高密度脉冲电流作用于试件后，在裂纹尖端附近产生了裂纹闭合和裂纹表面之间的桥联。结果表明，在愈合后的试件中，裂纹的扩展被暂时延迟。此外，通过去除氧化膜，在裂纹表面涂覆防止二次氧化的金属保护膜，促进了裂纹的闭合和桥联，使分叉的小裂纹在施加电流的情况下完全愈合。

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.