摘要
Friction stir welding （FSW） of 6061 aluminium alloy butt joint was carried out at each rotation speed of 600, 800, 1000, 1200 r/min for two different travel speeds, 80 and 100 mm/min, at a constant probe depth of 1.85 mm. The calculated energy input based on the FSW parameters studied shows that the ultimate tensile strength （UTS） of the butt joint is obtained within a certain range of energy input of 297 kJ to 354 kJ out of total range of energy input studied from 196 kJ to 405 kJ. The fatigue behaviors of high-strength and low-strength joints performed at different stress ratios, i.e., 0.5, 0.3, 0.1, -0.3, -0.5, indicate that the fatigue behaviors of both the welds are sensitive to the microstructural features, such as stir zone （SZ）, thermo mechanically affected zone （TMAZ） and heat affected zone （HAZ）. The observed fatigue strengths were discussed in terms of the microstructure, crack path behavior and fracture surface.
对6061铝合金进行搅拌摩擦对接焊，其焊接工艺参数为：旋转速度600、800、1000、1200 r/min，前进速度80、100 mm/min，探针插入深度1.85 mm。基于搅拌摩擦焊参数计算得到的能量输入结果表明，在输入能量为196～405 kJ的情况下，接头在297～354 kJ的输入能量范围内有最大的抗拉强度。在不同的应力比（R=0.5,0.3,0.1,-0.3,-0.5）下，将高强度、低强度2种焊接头进行疲劳测试。结果表明，对于这2种焊接头，显微组织特征明显影响其疲劳性能，比如搅拌区、热力影响区（TMAZ）和热影响区。从接头的显微组织、裂纹扩展路径和断裂表面观察等方面对其疲劳强度进行讨论。
