Process planning of L-PBF of AISI 316L for improving surface quality and relating part integrity with microstructural characteristics Academic Article in Scopus uri icon

abstract

  • © 2020 Elsevier B.V.Surface finish and mechanical properties in additively manufactured parts are the foremost drivers for the optimization of the process. Both topics are often treated separately, but the industry is demanding product performance in the two dimensions. Within this context, this paper proposes a process planning workflow for the obtainment of calibrated ranges of parameters for AISI 316L samples, and to understand the relationship between the improved parameters, the surface quality and part integrity with the microstructural characteristics. Three principal methods of characterization, (1) Nanoindentation combined with Electron Backscatter Diffraction (EBSD), (2) non-contact profilometry by Focus Variation for surface texture and (3) X-Ray Computed Tomography (CT), were used to validate the influence of the overlap of the point distance (PD) and hatch distance (HD) in the fabrication process. From Nanoindentantion and EBSD, the obtained hardness and modulus of elasticity were correlated with the different grain sizes and the resulting crystallographic orientation product of the thermal history of the process. This characterization together with the surface texture and the CT scans results were used to estimate appropriate parameter combinations in terms of linear and Volumetric Energy Density. Finally, the microstructure was studied on samples with better surface quality (Sa = 9.4 ¿m), hardness and modulus of elasticity (4.59 GPa and 229.7 GPa respectively) where finer cellular/dendritic structures were found.

publication date

  • August 25, 2020