Effects of welding speed on microstructures and mechanical properties of AA2219-T6 welded by the reverse dual-rotation friction stir welding

被引:25
|
作者
Li, J. Q. [1 ]
Liu, H. J. [1 ]
机构
[1] Harbin Inst Technol, State Key Lab Adv Welding & Joining, Harbin 150001, Peoples R China
基金
中国国家自然科学基金;
关键词
Friction stir welding; Reverse dual-rotation friction stir welding (RDR-FSW); 2219-T6 aluminum alloy; Microstructures; Mechanical properties; 2219-T6; ALUMINUM-ALLOY; STRENGTH; JOINTS; RECRYSTALLIZATION; PRECIPITATION; PARAMETERS; STATE;
D O I
10.1007/s00170-013-4812-5
中图分类号
TP [自动化技术、计算机技术];
学科分类号
0812 ;
摘要
Reverse dual-rotation friction stir welding (RDR-FSW) is a novel FSW technology in which the tool pin and the assisted shoulder rotates reversely, thus it has the capability to obtain appropriate welding conditions through adjusting the rotating tool pin and surrounding assisted shoulder independently. In the present study, a RDR-FSW tool system was designed and successfully applied to weld high strength aluminum alloy 2219-T6, and the effects of welding speed on microstructures and mechanical properties were investigated in detail. At a constant rotation speed of 800 rpm for both the rotating tool pin and the reversely rotating assisted shoulder, defect-free joints were obtained at welding speeds ranging from 50 to 150 mm/min, while a cavity defect appeared at the three-phase confluction on the advancing side when the welding speed increased to 200 mm/min. With increasing of the welding speed, the width of the softened region decreased, but the minimum microhardness value increased gradually. When compared with the joints welded by the conventional FSW, there is only a minor variation of the Vickers hardness across the stirring zone in the joint welded by the RDR-FSW. The maximum tensile strength 328 MPa (73.7 % of the base material) was obtained at the welding speed of 150 mm/min, while the elongation reached its maximum 7.0 % (60.9 % of the base material) at the welding speed of 100 mm/min. All defect-free joints were fractured at the weakest region with the minimum Vickers hardness, while for the joint with cavity defects the fracture occurred at the defect location. The tensile fracture was in the ductile fracture mode.
引用
收藏
页码:2071 / 2083
页数:13
相关论文
共 50 条