超声对铝/镁异质合金搅拌摩擦焊接成形的影响

Effect of ultrasonic on friction stir welding formation of aluminum/magnesium dissimilar alloys

开展了厚度为4 mm的6061铝合金/AZ31B镁合金板的搅拌摩擦对接工艺实验,对比分析了常规搅拌摩擦焊(FSW)和超声振动强化搅拌摩擦焊(UVeFSW)的焊缝横截面与水平截面的材料流动情况、界面金属间化合物厚度、机械锁合程度以及接头拉伸性能等,探究了超声振动的作用机理。结果表明:超声振动能够促进接头不同部位的材料流动和热量传输,从而减小甚至消除焊接缺陷;施加超声振动后,铝/镁界面处的金属间化合物均有所减薄,同时界面机械锁合程度也均有所增强,因此UVeFSW接头的抗拉强度相比于同一工艺参数时FSW接头有所提高,施加超声振动后接头的最高抗拉强度达到了174.20 MPa。

The friction stir butt joint process experiment of 6061 aluminum alloy/AZ31B magnesium alloy plate with thickness of 4 mm was carried out.The material flow in transverse cross-section and horizontal-section,the thickness of the intermetallic compound layers,the mechanical interlocking,and the tensile properties of conventional friction stir welding(FSW)and ultrasonic vibration enhanced friction stir welding(UVeFSW)were compared and analyzed.The action mechanism of ultrasonic vibration was explored.The results show that ultrasonic vibration can promote material flow and heat transfer in different parts of the joint,thereby reduce or even eliminate weld defects.When ultrasonic vibration is applied,the intermetallic compound layer at the aluminum/magnesium interface is thinned,and the mechanical interlocking on the interface is enhanced,so the tensile strength of the UVeFSW joints is improved compared to the FSW joint under the same process parameters.The maximum tensile strength of the UVeFSW joints reaches 174.20 MPa.