Microstructure evolution and mechanical properties of friction stir spot welded dissimilar aluminum-copper joint
Microstructure evolution and mechanical properties of friction stir spot welded dissimilar aluminum-copper joint
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DOI：
10.1016/j.jallcom.2018.10.045
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发表时间：
2019-02
影响因子：
6.2
通讯作者：
L. Zhou;G.H. Li;R.X. Zhang;W.L. Zhou;W. He;Y.X. Huang;X.G. Song
中科院分区：
文献类型：
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作者：
L. Zhou;G.H. Li;R.X. Zhang;W.L. Zhou;W. He;Y.X. Huang;X.G. Song
采用搅拌摩擦点焊方法，在不同转速下对1060铝合金和T2紫铜进行了异种搭接接头的焊接试验。在焊接过程中测量的过程变量显示，增加旋转速度导致较高的峰值温度，但由于材料的软化程度较大，扭矩和插入力较低。在最高转速下，Al-Cu界面形成连续的CuAl 2-CuAl-Al 4Cu 9层合层，而在较低转速下，界面形成断续分布的CuAl 2层。根据热力学原理预测了CuAl 2、CuAl和Al 4Cu 9金属间化合物（IMC）的形成顺序，与透射电镜（TEM）观察到的界面组织演化相一致。除了通过Al-Cu界面处的IMC层的冶金结合之外，接头具有通过销工具从下部Cu片向上挤压到上部Al片中的Cu钩，这提供了片之间的附加机械互锁。接头的拉伸性能与界面IMC层厚度和弯钩的几何特征密切相关，界面IMC层连续、厚度合适、弯钩穿透深度大的接头拉伸性能较高。
Dissimilar lap joints of 1060 aluminum and T2 copper were obtained by friction stir spot welding (FSSW) at various rotational speeds. The measured process variables during welding revealed that an increasing rotational speed leads to a higher peak temperature but a lower torque and plunging force due to the greater softening degree of material. A continuous CuAl2-CuAl-Al4Cu9laminated layer developed at the Al-Cu interface under the highest rotational speed, while the interface was characterized by the interruptedly distributed CuAl2layer under lower rotational speeds. Intermetallic compound (IMC) formation sequence for CuAl2, CuAl and Al4Cu9was predicted according to thermodynamic principles, which is consistent with the interfacial microstructure evolution identified by the transmission electron microscope (TEM). Besides the metallurgical bonding through the IMC layer at the Al-Cu interface, joints have a Cu hook extruded upward by the pin tool from the lower Cu sheet into the upper Al sheet, which provided additional mechanical interlocking between the sheets. Tensile properties of the joints were closely related to the thickness of the IMC layer and geometric features of the hook, higher tensile properties were found in joints owning a continuous interfacial IMC layer with a proper thickness as well as a high penetration depth of the hook into the upper Al sheet.