Internal Material Flow Layers in AA6082-T6 Butt-Joints during Bobbin Friction Stir Welding (2019)

Type of Content
Journal ArticlePublisher
MDPI AGISSN
2075-4701Language
EnglishCollections
Abstract
Bobbin friction stir welding with a double-sided tool configuration produces a symmetrical solid-state joint. However, control of the process parameters to achieve defect-free welds is difficult. The internal flow features of the AA6082-T6 butt-joints in bobbin friction stir welding were evaluated using a set of developed reagents and optical microscopy. The key findings are that the dark curved patterns (conventionally called 'flow-arms'), are actually oxidation layers at the advancing side, and at the retreating side are elongated grains with a high-density of accumulation of sub-grain boundaries due to dynamic recrystallization. A model of discontinuous flow within the weld is proposed, based on the microscopic observations. It is inferred that the internal flow is characterized by packets of material ('flow patches') being transported around the pin. At the retreating side they experience high localized shearing at their mutual boundaries, as evidenced in high density of sub-grain boundaries. Flow patches at the advancing side are stacked on each other and exposed to oxidization.
Citation
Tamadon, Pons, Clucas, Sued Internal Material Flow Layers in AA6082-T6 Butt-Joints during Bobbin Friction Stir Welding. Metals. 9(10). 1059-1059.This citation is automatically generated and may be unreliable. Use as a guide only.
Keywords
bobbin friction stir welding; materials flow; metallography; AA6082-T6; weld defectANZSRC Fields of Research
40 - Engineering::4016 - Materials engineering::401607 - Metals and alloy materials40 - Engineering::4017 - Mechanical engineering::401707 - Solid mechanics
40 - Engineering::4014 - Manufacturing engineering::401408 - Manufacturing processes and technologies (excl. textiles)
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