摘  要：1060铝合金和T2紫铜以其良好的物理力学性能而被广泛应用于工业领域，铝-铜异种金属的连接也是国内外研究的热点之一。搅拌摩擦焊作为一种金属固相连接方法，常用于连接铝、镁、铜等有色金属。铝铜异种金属搅拌摩擦搭接焊工艺目前尚处于实验研究阶段，对铝铜异种金属搭接接头中金属迁移行为的研究报道还不多。研究并创新铝铜搅拌摩擦焊搭接工艺，对于1060铝合金和T2紫铜应用的推广具有基础意义，研究接头金属流动行为对提高接头性能具有指导意义。

本文采用搅拌摩擦焊工艺对厚度6mm的1060铝合金板材和2mm的T2紫铜板材进行搭接试验，通过改变焊接工艺参数，对比实验结果确定最优工艺参数。并在最优焊接工艺参数下对铝和铜进行搅拌摩擦焊搭接试验，研究铝铜搭接接头金属迁移行为以及搅拌针长度对接头金属迁移行为的影响规律。

对搭接接头试样的横截面、纵截面、轴肩摩擦平面和铝铜界面平面进行金属流动行为分析发现，在焊缝厚度方向塑性金属迁移分为三个区域：轴肩扰动区金属做水平圆周运动，紊流区金属发生垂直方向的对流运动，搅拌区金属发生椭圆形环流。在轴肩摩擦平面，塑性金属一方面在前进侧沿径向迁移，一方面受轴肩推动向焊接方向迁移。在铝铜界面平面，大量的铝铜相互迁移形成混合组织，混合组织发生短距离的径向迁移。二次焊接使焊缝截面紊流区混合组织减少，使铝铜界面平面金属径向迁移距离变小，迁移至母材中的颗粒状铜增多。在焊缝截面，搅拌针越长上层金属向下迁移距离越小。在焊缝轴肩摩擦平面，搅拌针越长，金属沿径向迁移的距离越大，在铝铜界面平面，搅拌针越长，金属流动性越差，沿径向迁移的距离更小且更不均匀。

关键词：搅拌摩擦焊；铝铜搭接；搅拌针长度；塑性迁移

Abstract：The 1060 aluminum alloy and the T2 copper have been widely used in the industry for their good physical and mechanical property. The connection of the dissimilar copper and aluminum metal has been one of the research focuses all over the world. As a method for solid-phase connection, FSW was usually used in connecting the nonferrous metals like aluminum, magnesium, copper, etc. The lap FSW of copper and aluminum is now still in the experimental phase. And it is rear of the report concerning the metal migration behavior in copper-aluminum lap welds. So, there is a foundational meaning for the promotion of 1060 aluminum alloy and T2 copper to study and reform the process of Al-Cu lap FSW.

In this paper, 1060 aluminum alloy sheet with thickness of 6mm and 2mm T2 copper plate were tested by friction stir welding. The optimum process parameters were determined by changing the welding process parameters and comparing the experimental results. And the effect of the length of the needle on the migration behavior of the joint metal was studied by friction stir welding test of aluminum and copper under the optimal welding parameters.

The macro-migration of the metal in the cross-section, vertical-section, shoulder friction plane and Al-Cu interface plane of the joint were studied in this paper. It was founded that, the metal migration in the thickness direction can be pided into three areas. The plastic metal moved in the horizontal circle motion in shoulder affected zone and moved in convection vertically in the turbulent flow area. In nugget area, it moved in an ellipsoid circulation. In the shoulder plane, the plastic metal on the one hand migrated along radial direction in the advancing side, on the other hand, it moved along the welding direction pushed by the shoulder. On the edge of the shoulder, the metal in the advancing side moved forward and the metal in the retreating side was rolled into shoulder area, migrated along radius and bypassed the pin then moved forward. In the interface plane, large amount of copper and aluminum migrated in opposite direction and formed the mixture structure, which then moved in a short distance along radius. The second welding reduced the amount of mixture in the turbulent flow area in section, shortened the migration distance in the downward direction, shortened the distance in radial direction in interface plane, and increased the amount of granular copper migrated into the base metal. In the weld section, the longer the pin, the shorter the move distance in vertical direction. In the shoulder plane, the longer pin increased the migration distance in radial direction. In the interface plane, the longer pin worsened the liquidity of metal and resulted in the shorter and uneven migration distance in radial direction.