钛、铝异种金属物化性能差异较大, 焊接过程中易生成较厚的脆性金属间化合物, 弱化接头性能, 激光焊接速度是钛、铝异种金属焊接的关键。采用1 000 W光纤激光器对1 mm厚的LD2铝板和TC4钛板进行对接焊实验。实验重点研究激光焊接速度对脆性金属间化合物厚度的影响, 从热力学条件出发解释生成金属间化合物的可能性, 与XRD检测结果一致, 研究表明, 焊接速度为20 mm/s时, 生成14 μm左右厚的金属间化合物Ti3Al和TiAl, 抗拉强度仅有173 MPa; 当焊接速度为80 mm/s时, 获得了良好的焊接接头, 生成了4 μm左右的TiAl3化合物, 断裂伸长率为.42%, 最大抗拉强度可达242 MPa。

The difference of physical and chemical properties of Ti and Al dissimilar metals is great. During the welding process, thick brittle intermetallic compounds are easy to be produced, and the properties of joints are weakened. The speed of laser welding is the key to the welding of Ti and Al dissimilar metals. The butt welding experiment of 1 mm thick LD2 Aluminum plate and TC4 Titanium plate by 1 000 W fiber laser is carried out. The experiment focuses on the influence of laser welding speed on the thickness of intermetallic compounds, the possibility of the formation of intermetallic compounds is explained from the thermodynamic conditions, consistent with the XRD test results, the results show that when the welding speed is 20 mm/s, generating about 14 μm thick intermetallic compounds Ti3Al and TiAl, the tensile strength is only 173 MPa; when the welding speed is 80 mm/s, a good welded joint is obtained, TiAl3 compound around 4μm is formed, the elongation at break is 5.42%, the maximum tensile strength of up to 242 MPa.