Microstructural and mechanical implications of manufacturing AA2024 hybrid structures by sheet metal forming and wire-arc directed energy deposition

This paper presents the characterisation of hybrid structures manufactured by modifying AA2024 profiles using wire-arc directed energy deposition. The produced structures are characterised using various methods to investigate the properties of the deposited material, the region affected by wire-arc directed energy deposition, and the hybrid component as a whole. Ultimate tensile strength of up to 458 MPa and a hardness of 148 HV0.1 are achieved with the additive AA2024 material. Mechanical characterisation of the process-affected profiles shows that low heat input has a limited impact on sheet material properties, in contrast to the more pronounced effects observed under high heat input conditions. With the substrate stabilised by a pre-heat treatment step and modified by a low heat input process, a yield strength of 310 MPa, an ultimate tensile strength of 451 MPa, and a fracture strain of 11.1% are achieved. Metallographic and mechanical characterisation of the complete hybrid structures reveals crack-free components. In summary, controlling the heat input is essential for minimising undesirable effects such as ageing, micro-segregation, micro-shrinkage, and porosity during the fabrication of hybrid structures. This study demonstrates the feasibility of producing components with excellent mechanical properties using wire-arc directed energy deposition, even for alloys susceptible to hot cracking, thereby highlighting the potential for future applications.