On the tensile deformation characteristics and fracture behaviour of AA2024 fabricated by wire-arc directed energy deposition

Wire-arc directed energy deposition (waDED) is a versatile additive manufacturing (AM) technique that enables the production of large components with medium complexity and small-to-medium lot sizes, making it particularly suitable for aircraft construction. To elucidate the mechanical performance and application potential of waDED materials, the aircraft alloy AA2024 was evaluated in terms of its tensile stress-strain characteristics and fracture behaviour, using crack resistance, R-curve measurements. Compared to a reference wrought alloy, with 382.3-393.3 MPa yield strength and a fracture toughness of 37.0-44.3 MPa root m, the waDED AA2024 alloy exhibits values of 354.2-361.3 MPa and 29.1-30.2 MPa root m, respectively. While failure of the wrought material is primarily governed by transgranular fracture, crack growth of the AM alloy occurs through a combination of both inter-and transgranular failure, with micro-and mesostructural features promoting significant crack deflection. Despite the differences in failure mechanisms and the somewhat reduced mechanical performance of the AM fabricated alloy, our work indicates the potential for processing AA2024 using waDED and identifies areas for further optimization of its mechanical properties.