Influence of position and building orientation on the static properties of LPBF specimens in 17-4 PH stainless steel

Abstract

Laser Powder Bed Fusion (LPBF) is among the most valid solutions for Additive Manufacturing thanks to its high flexibility and accuracy, even though LPBF products can present mechanical properties negatively affected by anisotropic grain morphologies, porosity and heterogeneous solute distribution.Growth direction of parts has a clear effect on mechanical properties. Although the subject has been addressed in literature by numerous Authors, many conflicting results can be found. This work is aimed at providing further knowledge in this regard, even assessing the influence of the building position over the building plate, in case of LPBF of 17-4 PH stainless steel powder in full-melting mode. The investigation comprised static tensile tests to assess the influence of building direction (0° or 90°) and position of specimens on the building plate. Scanning Electron Microscope (SEM) observations were made on specimens after tests so to observe the fracture surfaces and, eventually, statistical evidences were provided to support the conclusions of the work.