| Porosity in fiber laser formation of 5A06 aluminum alloy
Yangchun Yu, Chunming Wang, Xiyuan Hu, Jun Wang, Shengfu Yu
The Journal of Mechanical Science and Technology, vol. 24, no. 5, pp.1077-1082, 2010
Abstract : The mechanism of porosity formation and its suppression methods in laser formation of aluminum alloy have been studied using a
4kW fiber laser to weld 5A06 aluminum alloy with SAl-Mg5 filler. It was found that the porosity formation is closely related to the stability
of the keyhole and fluctuation of the molten pool in the laser welding aluminum alloy. The filling wire increased the instability of
the keyhole and weld pool, thus further increasing the amount of gas cavities in the joint. Prefabrication of a suitable gap for the butt joint
can provide a natural passage for the flow of the liquid metal, which can weaken, and even completely eliminate the disturbance of the
filling wire on the formation of keyhole. The gap can also provide a passage for the escape of the bubble. Thus, this method can greatly
decrease the sheet’s susceptibility to porosity. Moreover, for a thin sheet, if the power of the laser is sufficient to form a keyhole with
stable penetration through the weld sheet, a weld bead without porosity can also be obtained because closing the keyhole is almost
impossible.
Keyword : Aluminum alloy; Fiber laser; Filler wire; Laser formation; Poros |
