钛/铝异种合金激光焊接研究

Research on laser welding of titanium/aluminum dissimilar alloy

钛、铝异种金属物化性能差异较大,焊接过程中易生成脆性金属间化合物,弱化接头性能,激光热输入量的控制是钛/铝异种合金焊接的关键。采用1 000 W光纤激光器对1 mm厚的LD2铝板和TC4钛板进行对接焊试验。试验重点研究焊接速度和激光偏置距离对热输入量的控制和分配,通过金相显微镜、SEM、EDS方法对焊缝微观组织和结构进行分析,利用拉伸试验机进行力学性能测试。研究结果表明,当激光作用在钛侧0.24 mm处,焊接速度为80 mm/s时,形成的金属间化合物仅2μm左右,获得了质量良好的焊接接头,断后伸长率为5.42%,抗拉强度可达242 MPa。

The physical and chemical properties of titanium and aluminum dissimilar metals are quite different.Brittle intermetallic compounds are easily formed during the welding process which weaken the joint performance.The control of laser heat input is the key to the welding of titanium and aluminum dissimilar alloys. In this paper,a 1 000 W fiber laser was used to perform butt welding on 1 mm thick LD2 aluminum plate and TC4 titanium plate. The experiment focuses on the control and distribution of the heat input quantity by adjusting welding speed and laser offset distance. The microstructure of the weld joint was analyzed by metallographic microscope,SEM,EDS. The tensile tester was used to test the mechanical properties. The results showed that the best performance of the joint was achieved with the laser applied at 0. 24 mm on the titanium side and the welding speed of 80 mm/s. The thickness of intermetallic compound formed was only about 2 μm,the tensile strength of the joint reached 242 MPa and the elongation rate of the joint reached 5. 42% in such welding condition.