Microstructural characteristics and mechanical properties of bobbin-tool friction stir welded 2024–T3 aluminum alloy  

作　　者：Ji-hong Dong Chong Gao Yao Lu Jian Han Xiang-dong Jiao Zhi-xiong Zhu 

机构地区：[1]Mechanical and Electrical Engineering Institute,Beijing University of Chemical Technology,Beijing 100089,China [2]China Friction Stir Welding Center,Beijing Aeronautical Manufacturing Technology Research Institute,Beijing 100024,China [3]Chinalco Research Institute of Science and Technology,Beijing 100082,China [4]School of Mechanical,Materials and Mechatronic Engineering,University of Wollongong,New South Wales 2522,Australia [5]Research Centre of Joining Technology in Ocean Engineering,Beijing Institute of Petrochemical Technology,Beijing 102617,China

出　　处：《International Journal of Minerals,Metallurgy and Materials》2017年第2期171-178,共8页矿物冶金与材料学报（英文版）

摘　　要：Cold-rolled 2024-T3 sheet alloy was subjected to bobbin-tool friction stir welding （BTFSW）. The microstructural characteristics and mechanical properties of the nugget zone in the as-welded state were investigated. The results show that the equiaxed grain size of BTFSW 2024-T3 alloy decreases from 7.6 to 2.8 μm as the welding speed is increased from 80 to 120 mm/min; in addition, fine grains are generated in the nugget zone and the size distribution is non-uniform. All A12CuMg （S＇） precipitates dissolve into the A1 matrix, whereas Mn-rich phases confirmed as T phases （Al20CuEMn3, A16Mn, or AlaMn） remain unchanged. The optimized parameters for BTFSW are veri- fied as the rotation speed of 350 r/min and the travel speed of 100 mm/min. The variations in precipitation and dislocation play more impor- tant roles than grain size in the nugget zone with respect to influencing the mechanical properties during the BTFSW process. After the BTFSW process, the fracture mode of base material 2024-T3 alloy transforms from ductile rupture to ductile-brittle mixed fi＇acture.Cold-rolled 2024-T3 sheet alloy was subjected to bobbin-tool friction stir welding （BTFSW）. The microstructural characteristics and mechanical properties of the nugget zone in the as-welded state were investigated. The results show that the equiaxed grain size of BTFSW 2024-T3 alloy decreases from 7.6 to 2.8 μm as the welding speed is increased from 80 to 120 mm/min; in addition, fine grains are generated in the nugget zone and the size distribution is non-uniform. All A12CuMg （S＇） precipitates dissolve into the A1 matrix, whereas Mn-rich phases confirmed as T phases （Al20CuEMn3, A16Mn, or AlaMn） remain unchanged. The optimized parameters for BTFSW are veri- fied as the rotation speed of 350 r/min and the travel speed of 100 mm/min. The variations in precipitation and dislocation play more impor- tant roles than grain size in the nugget zone with respect to influencing the mechanical properties during the BTFSW process. After the BTFSW process, the fracture mode of base material 2024-T3 alloy transforms from ductile rupture to ductile-brittle mixed fi＇acture.

关 键 词：aluminum alloys friction stir welding mechanical properties microstructure 

分 类 号：TG453.9[金属学及工艺—焊接] TG146.21[一般工业技术—材料科学与工程]