Localised corrosion at the weld periphery of AZ31B friction stir spot welds has been associated with microstructural evolution during the welding process. Several attempts have been made to correlate these changes to the corrosion resistance of a joint; however, the influence of grain reorientation arising from the welding process has been overlooked. Here, the role of grain reorientation during FSSW was investigated using a combination of microcapillary polarisation and analytical microscopy. The influence of changes in grain orientation was shown to have a direct effect on the magnitude of the galvanic couple formed between the stir zone and the base metal.
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