6005A-T6铝合金搅拌摩擦焊接头组织与力学性能特征

采用光学显微镜、扫描电子显微镜、透射电子显微镜、拉伸实验机和显微硬度计对6005A铝合金搅拌摩擦焊接头的微观组织及力学性能进行了研究.结果表明:焊核区为细小的等轴晶,几乎所有粒子溶于基体;热机械影响区呈现为被拉长的畸变晶粒,且存在大量的位错;热影响区的组织明显粗化,处于过时效状态.与母材相比,搅拌摩擦焊接头的强度及伸长率均有下降趋势,且接头出现软化,最小硬度值出现在前进侧的热影响区内.搅拌头旋转速率为1200r/min、焊接速率为200mm/min时可获得优质接头,抗拉强度达到母材强度的72％,伸长率达到母材的69％.

Microstructural and Mechanical Characteristics of Friction Stir Welded 6005A-T6 Aluminium Alloy

Microstructural and mechanical characteristics of friction stir welded 6005A aluminum alloy were investigated by means of optical microscope,scanning electron microscopy(SEM),transmission electron microscope(TEM),tensile test machine and Vickers hardness tester.The results show that the nugget zone(NZ),thermo-mechanically affected zone(TMAZ) and heat affected zone(HAZ) are characterized by a fine equiaxed,elongated and coarse grain structures,respectively.All the precipitates dissolved in the NZ,and the TMAZ contains high density dislocation,and the HAZ shows over-aged state.Compared with the base metal,the FSW joint has a reduction in strength and elongation,and there is a distinctly soften region where the minimum hardness value located in HAZ of advancing side.At the optimum welding parameters(rotation speed of 1200r/min and welding speed of 200mm/min),the tensile strength and elongation of the FSW joint are equivalent to 72% and 69% of those of the base metal,respectively.