Effect of laser power on the morphology and porosity for 2195 Al-Li alloy fabricated by fiber-diode laser hybrid welding

Fiber-diode laser hybrid welding technology, which adequately combines the superiorities of both fiber and diode laser heat source, has great potential in the field of laser processing. In this paper, fiber-diode laser hybrid welding experiments were conducted for the 2195 Al-Li alloy. The effect of laser power on morphology and porosity was quantitatively investigated. The results show that fiber laser power has a significantly impact on the weld depth, while diode laser power has a significantly influence on the upper weld width. The regression model for predicting the cross-sectional area of weld seam was obtained. Besides, both fiber and diode laser play an important role in the control of porosity defects. The higher power of fiber laser is beneficial to reduce porosity. For 2195 Al-Li alloy with the thickness of 4mm, the high-temperature molten pool and large range of fiber-diode laser action region are formed at the fiber laser power of 3.0 kW and diode laser power between 2.5 kW and 3.0 kW, which results in the welded joint with the less porosity.