Microstructure and mechanical properties of friction stir welded thin sheets of 2024-T4 aluminum alloy

• Published in: Transactions of Nonferrous Metals Society of China Vol. 16; no. A03; pp. 1256 - 1260
• Main Author: 李炼 佟建华 万发荣 龙毅
• Format: Journal Article
• Language: English
• Published: Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083, China%Department of Materials Science, University of Science and Technology Beijing, Beijing 100083, China 01.12.2006
• Subjects: 微观结构; 有色金属; 机械性能; 铝合金; tensile properties; Vickers hardness; microstructure; friction stir welding; low angle boundary; EBSD; 2024-T4 aluminum alloy
• ISSN: 1003-6326

Friction stir welding （FSW） is a new and promising welding processing that can produce low-cost and high-quality joints of aluminum alloys. 1 mm thick sheets of 2024-T4 aluminum alloys which are always used as building and decorating materials were welded by FSW. The microstructure and mechanical properties of fiiction stir welded 1 mm thick sheets of 2024-T4 aluminum alloy were studied. It was found that the thinner the 2024 aluminum alloy, the larger the FSW technological parameters field. The grains size of weld nugget zone （WNZ） is approximately 10 times smaller than that of the parent material, but the second phase in the material is not refined apparently in the welding. The FS welded joints have about 40% higher yield strength than the parent material, but the elongation of FS welded joints is under about 50% of the parent material. The electron backscattered diffraction （EBSD） results show that there are much more low angle boundaries （LAB） in WNZ than that in parent material, which indicates that FSW causes a number of sub-grain structures in WNZ, and this is also the reason of the increase of yield strength and Vickers hardness of the welded joint.