Microstructure and Mechanical Properties of Thick Plate Friction Stir Welds for 6082-T6 Aluminum Alloy

Autor: Liang Zhimin, Wang Xue, Cai Congwei, Wang Dianlong
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: High Temperature Materials and Processes, Vol 38, Iss 2019, Pp 525-532 (2019)
Druh dokumentu: article
ISSN: 0334-6455
2191-0324
DOI: 10.1515/htmp-2018-0074
Popis: 6082-T6 aluminum alloy plate with thickness of 42mm was butt welded by friction stir welding (FSW) from two sides. The microstructures of the joints exhibited different grain sizes because of unequal frictional heating and plastic flow during FSW process. The transition from the heat affected zone (HAZ) to the nugget zone (NZ) in thermos-mechanical affected zone of advancing side (AS-TMAZ) was more sudden than thermos-mechanical affected zone of retreating side (RS-TMAZ). Kissing bond (KB) defect throughout the entire FSW joint was displayed both at the grain boundary and in the interior of the grain with semi-continuous bands. KB had no direct effect on tensile properties. Vickers hardness of the FSW joint was lower than the BM because its high heat input, dissolved and coarsened precipitates and little to the grain size after FSW. Hardness distribution of double-sided welding joint showed X-shaped area softening characteristics, that is to say the lowest hardness was the junction of two welding joint of NZ and the junction of TMAZ and HAZ. The tensile fracture position occurred in the lowest hardness region of the FSW joint, and it did not occur in the KB defect position.
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