Application of Gel Electrode to Fatigue Testing of Aluminum Components

摘要

The gel electrode [1–4] is a simple probe for detecting and imaging fatigue damage in aluminum alloys, which is substantially more sensitive than conventional techniques. The procedure consists of: 1) precoating the component with a uniform anodized film, 2) fatigue testing for a predetermined number of cycles, 3) contacting the surface with a flexible gel containing potassium iodide and starch, and 4) applying a voltage pulse. If a fatigue crack is present the current flows preferentially to it and an image of the crack is formed in the surface of the gel. The basic principle of the technique was reviewed in same detail at the previous conference in this series [5], with emphasis on selecting the various parameters, such as the pulse duration and the concentration of ingredients, to yield clearly visible and repeatable images.