Residual Stresses at Critical Locations in Additively-Manufactured Components

Adopting additively-manufactured components in conventional supply chains requires an understanding of residual stress effects on typical component quality: dimensional accuracy, mechanical strength, and fatigue performance. Residual stresses are central to these elements of component quality; however, they vary significantly at different locations in additively-manufactured parts. Multiple methods are used to assess residual stresses at critical locations including the build/baseplate interface, the near surface layers, between layers, and typical planes of interest. Exploratory measurements on laser engineering net shaping (LENS) and powder bed fusion (PBF) bosses are performed using the contour method and slitting method. Steep stress gradients and high stresses with limits approaching the material yield strength are reported. These stresses are often compressive at the component interior and tensile near the outer surfaces. Future work is planned to investigate repeatability of both the measurement methods and the ADDITIVE manufacturing processes.