The Weldability of an Al-Li-Cu Alloy

The development of low-density aluminum-lithium alloys for aerospace applications provides industry with an attractive alternative to fiber-reinforced composites for reducing weight while maintaining the fabrication cost advantages of aluminum. In this study, gas metal arc (GMA), gas tungsten arc (GTA), and electron beam (EB) welding processes were used to evaluate the potential fusion weld-ability of alloy 2090 (Al-2.2 Li-2.7 Cu-0.12 Zr). The results indicate that, with proper filler alloy selection, 2090 may be easily welded with a low sensitivity to weld solidification cracking. The weld porosity of 2090, the source of which is hydrogen enriched surface oxides, may be eliminated by chemically or mechanically milling the surface prior to welding. The dominant modification in the heat-affected zone of 2090 weldments is dissolution of strengthening phases. This degradation is reduced by the use of high energy density heat sources, such as an electron beam, or post-weld thermal treatments.