Temperature evolution, microstructure, and properties of friction stir welded ultra-thick 6082 aluminum alloy joints

• Published in: International journal of advanced manufacturing technology Vol. 108; no. 1-2; pp. 331 - 343
• Main Authors: Zhu, Rui, Gong, Wen-biao, Cui, Heng
• Format: Journal Article
• Language: English
• Published: London Springer London 01.05.2020; Springer Nature B.V
• Subjects: Aluminum; Aluminum alloys; Aluminum base alloys; CAE) and Design; Computer simulation; Computer-Aided Engineering (CAD; Ductile fracture; Dynamic recrystallization; Engineering; Evolution; Friction stir welding; Grain size; Heat affected zone; Industrial and Production Engineering; Mathematical models; Mechanical Engineering; Mechanical properties; Media Management; Microhardness; Microstructure; Numerical models; Original Article; Temperature; Temperature gradients; Thick plates; Thickness; Welded joints; Numerical simulation; Ultra-thickness plate; 6082 aluminum alloy; Microstructure; Properties; Friction stir welding
• ISSN: 0268-3768; 1433-3015
• DOI: 10.1007/s00170-020-05422-7

In this study, the temperature evolution, microstructure, and mechanical properties of friction stir welded 80-mm super-thick plate 6082 aluminum alloy were investigated. Combined with numerical simulation and actual measurement, the thermal cycle curve during welding is obtained, and the accuracy of numerical calculation is verified. The numerical model calculating data shows that the peak temperature difference is up to 109 °C along the thickness direction of the weld in weld nugget zone (WNZ). Different degrees of dynamic recrystallization occur in WNZ, resulting in different grain sizes along the thickness direction of the weld. Each zone is subject to different heat cycle temperatures, so the type, number, and size of the precipitated phases are different. The microhardness curves of each layer of welded joints are all W-shaped, and the microhardness distribution between advancing side and retreating side has significant asymmetry. The fracture location of each layer of weld is located in the heat affected zone on the side of thermomechanical affected zone (HAZ TMAZ ). The surface of the joint has the highest mechanical properties. Fractures in all tensile specimens were ductile fracture.