AA1060铝合金和C1100工业纯铜搅拌摩擦点焊的演变性能

摘要

采用搅拌摩擦点焊技术连接纯铜(C11000)和纯铝(AA1060)板材，并表征了焊缝的演变性能。在不同转速和送入深度下，采用不同形状刀具制备点焊焊缝。在焊缝两边可观察到不同长度铜环，这表明铜向前挤压进入铝板，有助于得到高强焊缝。采用能量散射谱和X射线衍射研究手段可观察到在铝基体中存在铜粒子，且有各种不同的金属间化合物存在。除了在转速800 r/min 下采用锥形销和凹形肩得到的焊缝外，最大的拉伸断裂载荷随着送入深度的增加而增大。在剪切−拉伸载荷条件下，所有的搅拌摩擦点焊接头产生了点焊熔核滑脱失效模式。在样品锁眼附近得到了峰值硬度，这同焊接搅拌区存在金属间化合物有关。%Friction stir spot welding technique was employed to join pure copper (C11000) and pure aluminium (AA1060) sheets. The evolving properties of the welds produced were characterized. The spot welds were produced by varying the rotational speed, shoulder plunge depth using different tool geometries. The presence of a copper ring of different lengths was observed on both sides of the welds indicating that Cu extruded upward into the Al sheet which contributed to obtaining strong welds. The microstructure showed the presence of copper particles in the aluminium matrix which led to the presence of various intermetallics observed by the energy dispersive spectroscopy and X-ray diffraction. The maximum tensile failure load increases with an increase in the shoulder plunge depth, except for the weld produced at 800 r/min using a conical pin and a concave shoulder. A nugget pull-out failure mode occurred in all the friction stir spot welds under the lap-shear loading conditions. High peaks of Vickers microhardness values were obtained in the vicinity of the keyhole of most of the samples which correlated to the presence of intermetallics in the stir zone of the welds.