Effect of unit cell size and geometry on corrosion of 316L lattice structures fabricated by laser powder bed fusion

An open dataset for the paper with the same title: "Effect of unit cell size and geometry on corrosion of 316L lattice structures fabricated by laser powder bed fusion".

The dataset contains, for example, 3D models, original and analyzed microCT data, video visualizations, tensile testing .csv files, microscopy images, and code resources. Selected works are presented as part of the paper.

Abstract:

Laser powder bed fusion (LPBF) has become an established method for manufacturing end-use metal components. Exploiting the geometric freedom of additive manufacturing (AM) with lattice structures offers broad possibilities for part optimization and enables performance enhancements across industry sectors. However, part shape and feature size have been found to locally affect residual stresses, melt pool cooling rates, microstructure, and thus the mechanical properties of components. There are no prior studies on the influence of the feature size and shape on corrosion. Using AM-produced parts in critical applications necessitates a better understanding of the long-term performance of optimized parts in demanding environments. This study examines the effects of the lattice unit cell size and shape on the corrosion susceptibility and spatial localization.

The susceptibility of submillimeter LPBF-fabricated 316L stainless steel lattice structures to localized corrosion was investigated by conducting a 21-day immersion corrosion test (aqueous 3.5wt% NaCl solution). Schoen gyroid and Schwarz diamond triply periodic minimal surface lattices were manufactured with three unit cell sizes and wall thicknesses (0.867, 0.515, and 0.323 mm). The nominal surface and cross-sectional areas were the same for the two geometries. X-ray computed tomography scans before and after the corrosion test were analyzed for volumetric losses, and the mechanical properties of the samples were evaluated by comparing with those reported in the literature. The registration of tomography data and indexing of mass loss volumes, using open-source software, is fully disclosed.

Three out of five of the 0.323 mm wall thickness lattices displayed visually aggressive pitting. Based on the microcomputed tomography data, the mass losses were localized either in the entrapped powder particles or partially melted surface globules. Corrosion did not occur in the dense base material. The total mass losses ranged from 8 to 19 mg. Despite visual indications to support a higher susceptibility for the smallest lattice sizes, the mass loss values did not confirm this conclusion.

Version 1.1: 'Microstructure.zip' was revised. Metallographic preparation and Beraha II etching was redone for selected samples. New images and grain size (and grain distribution) measurements were added.