Depositing large components (.10 kg) in titanium, aluminium, steel and other metals is possible using Wire þ Arc Additive Manufacturing. This technology adopts arc welding tools and wire as feedstock for additive manufacturing purposes. High deposition rates, low material and equipment costs, and good structural integrity make Wire þ Arc Additive Manufacturing a suitable candidate for replacing the current method of manufacturing from solid billets or large forgings, especially with regards to low and medium complexity parts. A variety of components have been successfully manufactured with this process, including Ti-6Al-4V spars and landing gear assemblies, aluminium wing ribs, steel wind tunnel models and cones. Strategies on how to manage residual stress, improve mechanical properties and eliminate defects such as porosity are suggested. Finally, the benefits of non-destructive testing, online monitoring and in situ machining are discussed.

Wire and Arc Additive Layer Manufacturing (WAALM) is gaining increasing popularity as the process allows the production of large custom-made metal workpieces with high deposition rates. The high power input of the welding process, causes significant residual stress and distortion of the workpiece. This paper describes the thermo-mechanical behaviour of the multi-layer wall structure made by the WAALM process. A 3D thermoelastic-plastic transient model and a model based on an advanced steady-state thermal analysis are employed in this study. The temperature simulations and distortion predictions are verified by comparing with the experimental results from thermo-couples and laser scanners, while the residual stresses are verified with the neutron diffraction strain scanner ENGIN-X. The stress across the deposited wall is found uniform with very little influence of the preceding layers on the following layers. The stress redistributed after unclamping with a much lower value at the top of the wall than at the interface due to the bending distortion of the sample. The FEM model based on the steady-state thermal model shows a significant advantage on the computational time.

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Wire + Arc Additive Manufacture (WAAM) attracts great interest from the aerospace industry for producing components with aluminum alloys, particularly Al-Cu alloy of the 2000 series such as 2219 alloy. However the application is restricted by the low strength properties of the as-deposited WAAM metal. In this study two strengthening methods were investigatedinter-layer cold working and post-deposition heat treatment. Straight wall samples were prepared with 2319 aluminum alloy wire. Inter-layer rolling with loads of 15kN, 30kN and 45kN were employed during deposition. The ultimate tensile strength (UTS) and yield strength (YS) of the inter-layer rolled alloy with 45 kN load can achieve 314 MPa and 244 MPa respectively. The influence of post-deposition T6 heat treatment was investigated on the WAAM alloy with or without rolling. Compared with inter-layer rolling, post-deposition heat treatment can provide much greater enhancement of the strength. After T6 treatment, the UTS and YS of both of the as-deposited and 45 kN rolled alloys exceeded 450 MPa and 305 MPa respectively, which are higher than the properties of the wrought 2219-T6 alloy. The strengthening mechanisms of this additively manufactured Al-6.3Cu alloys were investigated through microstructure analysis.