2A14铝合金双轴肩搅拌摩擦焊工艺研究

Research on Process of Bobbin Tool Friction Stir Welding for 2A14 Aluminum Alloy

为了获得性能良好的焊接接头,对厚为5 mm的2A14-T6铝合金进行双轴肩搅拌摩擦焊(bobbin tool friction stir welding,BT-FSW)工艺研究。采用一种特殊设计的搅拌头,通过正交试验方法,对2A14铝合金进行BT-FSW焊接试验;利用光学显微镜和电子万能试验机分析不同焊接参数下焊缝的组织形态和力学性能,得出优化后的工艺试验窗口。研究表明:BT-FSW焊缝组织特征与常规FSW明显不同,呈"哑铃型",随着焊速的增加,抗拉强度与延伸率先增加后降低,最大的抗拉强度在焊速为250 mm/min时获得,其抗拉强度约为239 MPa,达到了母材强度的54%,延伸率仅为3.2%,接头断在有细微裂纹的地方。这项研究表明此工艺试验方案是切实可行的。

The research on process of bobbin tool friction stir welding for 5mm thick 2A14-T6 aluminum alloy was conducted to obtain better performance of the welded joints. A special designed stir heads were adopted, and Bobbin tool friction stir welding tests of 2A14 aluminum alloy were carried out by orthogonal test. Effect of different welding parameters on texture and mechanical properties of the welded joint was analyzed by using optical microscope and electronic universal testing machine to achieve the optimized process. Research shows that the macrostructure of BT-FSW is obviously different from that of conventional FSW, which is ＂ dumbbell-shaped＂ . With the increase of welding speed, the tensile strength and elongation first increase and then decrease. When the welding speed is 250 mm/min, the maximum tensile strength is obtained. The tensile strength is about 239 MPa, which reaches 54% of that of the base metal, and the elongation is only 3. 2%. The joints are broken in the presence of microcracks. This shows that the scheme of process test is feasible.