Microstructure and mechanical properties of dissimilar pinless friction stir spot welded 2A12 aluminum alloy and TC4 titanium alloy joints
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The microstructure and mechanical properties of dissimilar pinless friction stir spot welded joint of 2A12 aluminum alloy and TC4 titanium alloy were evaluated. The results show that the joint of Al/Ti dissimilar alloys can be successfully attained through pinless friction stir spot welding (FSSW). The joint can be divided into three zones (SZ, TMAZ and HAZ). The microstructure of joint in Al alloy side changes significantly but it basically has no change in Ti alloy side. At the same rotation speed, the maximum load of welded joints gradually rises with the increase in dwell time. At the same dwell time, the maximum load of the welded joint increases with the increase of the rotational speed. In addition, optimal parameters were obtained in this work, and they are rotation speed of 1500 r/min, plunge speed of 30 mm/min, plunge depth of 0.3 mm and dwell time of 15 s. The fracture mode of welded joints is interfacial shear fracture. The microhardness of the joint on the Al side distributes in a typical “W” type and is symmetry along the weld center, but the distribution of the microhardness on the Ti side has no obvious change.
Key wordsmicrostructure mechanical properties friction stir spot welded dissimilar joints
2A12 铝合金与TC4 钛合金无针搅拌摩擦点焊组织及性能
本文针对2A12 铝合金与TC4 钛合金,采用无针搅拌摩擦点焊工艺研究了不同工艺参数下的异 质接头的组织及性能。研究结果表明,通过无针搅拌摩擦焊可以成功获得Al/Ti 异质合金接头,并且 接头可分为三个典型的区域:搅拌区、热力影响区和热影响区。Al 侧接头的微观组织变化比较显著, 而Ti 侧组织没有明显的变化。拉剪试验的结果表明,在相同的搅拌头旋转速度下,接头的最大拉剪 载荷随停留时间的增大而增大。在同一停留时间下,转速越大接头的最大拉剪载荷也越大。此外,在 转速1500 r/min、停留时间15 s 时接头的强度最高,接头的断裂模式为界面剪切断裂。显微硬度测试 结果显示,接头Al 侧的硬度值呈典型的“W”分布并沿接头中心线对称,而Ti 侧的硬度值没有明显的 变化。
关键词显微组织 力学性能 搅拌摩擦点焊 异质接头
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- YANG Xia, FENG Wu, LI Wen, XU Ya, CHU Qiang, MA Tie, WANG Wei. Numerical modelling and experimental investigation of thermal and material flow in probeless friction stir spot welding process of Al 2198-T8 [J]. Science and Technology of Welding and Joining, 2018, DOI: 10.1080/13621718.2018.1469832.CrossRefGoogle Scholar