Elastic Property Anisotropy in Inconel 718 Alloy Specimens Fabricated by Wire Arc Additive Manufacturing

This study investigates the anisotropy of elastic properties in Inconel 718 alloy specimens fabricated via Wire Arc Additive Manufacturing (WAAM). The crystallographic texture of the specimens was characterized using inverse pole figures (IPF) obtained in three mutually orthogonal directions: the build direction (along the layer deposition), the transverse direction (the scanning direction), and the normal direction (perpendicular to both build and transverse directions). The analysis revealed that the texture is well-described by a combination of ideal orientations with some degree of dispersion. Based on the elastic constants of Inconel 718 single crystals and the pole density data derived from the IPF, the Young's modulus, shear modulus, and Poisson's ratio were calculated for each of the three orthogonal directions. The results demonstrate that the Young's modulus in the normal direction is, on average, 10-11% lower than in the build and transverse directions. Conversely, the shear modulus and Poisson's ratio exhibit higher values in the normal direction. The study concludes that crystallographic texture is the dominant factor contributing to the observed anisotropy in the mechanical properties of the WAAM-fabricated Inconel 718 specimens. Therefore, strategic control of crystallographic texture during WAAM processing offers a pathway to engineer components with a tailored, optimized combination of mechanical properties.