Investigation of microstructure, hardness and residual stresses of wire and arc additive manufactured 6061 aluminium alloy

Wire and arc additive manufacturing cold metal transfer® enable the defect-free soldering of poorly weldable alloys, such as AA6061. Thin-walls have been successfully built with two deposition strategies that is either a back forth movement torch (alternate vectors) or repeating along one direction (unidirectional vectors). The obtained macro- micro-structures are highly dependent on WAAM process parameters strategy. Both produce stacked structures consisting successive alternating layers columnar equiaxial grains. AA6061 alloy contains iron-rich intermetallic compounds β-phase. precipitates latter melted during leading to an even higher hardness compared commercial T6 material. At nanoscale, Transmission Electron Microscopy analyses reveal β’ phase, β’’ phase small dispersoids at state, well multitude phases (L, Q’) in studied It shows coexistence β’’- β’- phases. conventional treatment applied material resulted slight over-ageing this Neutron diffraction has used for residual stress measurements showing tensile stresses (up 130 MPa) parts compressive −80 substrate. Despite difference between generated microstructure (grain shape orientation subsequent crystallographic texture) by building strategies, no significant variation observed their mechanical properties.