摘要 |
Early fatigue damage in aluminum is assessed by detection of microcracks in an anodized surface film using a hand-held electrode having a contact tip formed of a gel containing an iodide salt and starch. The gel tip is pressed against the anodized film and an electrical pulse is applied to pass current through the microcracks to oxidize iodide in the gel to form black iodine-starch complex. Thus, dark spots in the gel indicate the sites of fatigue-induced microcracks in the oxide and thus the extent of fatigue damage in the metal. |