In-plane anisotropy of selective laser-melted stainless steel: The importance of the rotation angle increment and the limitation window

Abstract

The thorough description of the influence of the process conduct in powder-bed-based additive manufacturing on the mechanical properties of the fabricated components represents an ongoing challenge. A recent investigation highlighted that a minor safety feature, such as limiting the range of possible laser beam movements, to avoid interactions between the irradiation and emerging smoke and weld splashes, can cause a noteworthy alteration of the mechanical properties. In this study, the tensile characteristics of selective laser-melted stainless steel (1.4404, 316L) fabricated with two different process conducts were investigated, both of which yielded similar relative densities and surface hardness values. It was found that, besides these two characteristics, the tensile strength (yield and ultimate tensile strength) remained stable, whereas the linear elastic properties, as well as the breaking elongation, exhibited great fluctuations. The Young's modulus in the build-plane ranged from 151 to 208 GPa, and the breaking elongation ranged, respectively, from 33% to 43%. Furthermore, it has been found that this anisotropy is an adjustable characteristic and can be modified via two parameters, the rotation angle increment of the irradiation pathways between successive layers and their total admissible range, also referred to as the limitation window.