Deformation behavior of friction-stir welded Al-Mg-Mn alloy with ultrafine-grained structure

Low-temperature friction-stir welding (FSW) was successfully applied for the joining of Al-Mg-Mn alloy with an ultrafine-grained microstructure. The low-temperature conditions preserved fine-grained microstructure and nano-scale second-phase particles in the stir zone and thus provided nearly-100% joint efficiency of the produced welds. The deformation behavior of the welded joints was studied via the digital image correlation technique. The strengthening mechanisms of the base material and the stir zone material were examined. •Low-heat-input FSW is effective for retention of properties of fine-grained alloys.•The nearly-100% joint efficiency was achieved.•Fine-grained structure and nano-scale dispersoids were retained in the stir zone.