Microstructure and Mechanical Property of Al–Li Alloy Joint Formed by Electron Beam Welding with Filler Wire

The ER5183 is used as filler metal, and the Al–Li alloy is welded by electron beam welding. The microstructure and mechanical property of welded joint are investigated. Results show that, under the proper welding procedure, the joint with good appearance of weld is obtained. The fusion zone is mainly composed of α-Al matrix phase and some strengthening phases involving θ′(Al₂Cu), T₂(Al₆CuLi₃), T₁(Al₂CuLi) and δ′(Al₃Li). The grains in weldment are refined by the addition of electron beam scanning. Compared with that of the base metal (BM), the microhardness in weld zone is decreased to a certain extent. Under the welding condition of square wave electron beam scanning, the tensile strength of welded joint is 352.2 MPa, which is 70.2% of that of the BM. There exists obvious dimple morphology on the joint fracture surface, and it presents the characteristic of intergranular fracture.