On the Influence of Geometrical Features on Residual Stresses in Additively Manufactured 316L for Lightweight Engineering

Additive manufacturing, particularly the Laser Beam Powder Bed Fusion (PBF-LB) process, is increasingly utilized in both scientific research and industrial applications due to its ability to produce complex and customized metal parts. However, the PBF-LB process introduces unique thermal histories to the manufactured parts because of the localized heat input. This results in a distinctive residual stress distributions and complex microstructures. These play a critical role in the fatigue performance of components.

The possibility of AM to create components with high design freedom, offers a considerable potential for lightweight engineering. This potential can be further enhanced by combining the AM process with topology optimization during the design of components.

This study aims to provide a deeper understanding of the relationship between geometrical features and residual stresses. Therefore, typical geometries, as they often result from topology optimization algorithms, were identified and manufactured from 316L stainless steel with the LB-PBF process. For these geometries, like Y-struts or different node shapes, the near-surface residual stress distributions were characterized.

The AM-process also has an impact on the mechanical properties of components. Due to the directed buildup of parts, texture effects may occur. These can also have an effect on the macroscopic mechanical properties of components. Especially in lightweight engineering, these effects need to be considered in the design process. In this study, the texture of the material was determined with non-destructive ultrasound phase spectroscopy as well as with conventional mechanical methods.