Microstructure and mechanical properties of laser beam welded Al-Li alloy 2060 with Al-Mg filler wire

Alloy 2060-T8 is a newly developed high-strength Al-Li alloy for applications in aircraft industry. Crack-free welds were obtained in laser beam welding with 5087 filler wire under optimized welding conditions. In this paper, fusion zone microstructure and joint mechanical properties were investigated. Microstructure typical for the weld metal consists of alpha-Al matrix with a few nanoscale precipitates inside and a coarse icosahedral quasi-crystalline T-2 phase at the dendritic and grain boundaries. The quasicrystalline occurred normally in Al-Li-Cu alloys with higher Li contents. Our investigations show that the icosahedral quasicrystalline phase T-2 phase forms in the laser-welded Al-Li alloy 2060 with lower Li content as a result of segregation and replacement of Mg element. The joint tensile strength in as-welded condition is around 317 MPa, about 63% of that of the base metal, and fracture occurs within the fusion zone. (C) 2015 Elsevier Ltd. All rights reserved.