Electrocatalytic Mapping\nof Metal Fatigue with Persistent\nSlip Bands

Metal\nfatigue, characterized by the accumulation of dislocation\ndefects, is a prevalent failure mode in structural materials. Nondestructive\nearly-stage detection of metal fatigue is extremely important to prevent\ndisastrous events and protect human life. However, the lack of a precise\nquantitative method to visualize fatigue with spatiotemporal resolution\nposes a significant obstacle to timely detection. Here, we demonstrate\na nondestructive electrocatalytic method to visualize metal fatigue,\nwhich is promising for future fatigue early detections. The persistent\nslip band (PSB) is considered one of the most consequential defect\nstructures for metal fatigue failure. The selective electrochemistry\nis highly dependent on the metal crystallography and the collective\ndislocations in the PSB structure, enabling the amplification of the\nelectrochemical response and differentiation of the fatigue stages\nat a submillimeter resolution. In addition, this nondestructive electrocatalytic\nmethod is applicable to several common metals, including copper, silver,\niron, and aluminum, holding great significance where metal fatigue\nis a critical concern.