Prithwish Tarafder

Additive manufacturing (AM) is an innovative production approach that has gained significant attention due to its ability to overcome many limitations associated with traditional manufacturing techniques. As a consequence of efforts to optimize various AM processes, especially across different methods, a vast amount of data is either utilized (e.g., material properties, printer specifications, and process settings) or generated (e.g., monitoring data during printing, slicing strategies, and parameter configurations). Effectively managing, understanding, and retrieving information from this data remains a major challenge. The data often exhibits complex interrelationships and is distributed across heterogeneous sources, making it difficult for researchers and industry professionals to extract meaningful insights or make informed decisions. To address these challenges, we propose a knowledge‐based approach designed to support the structured management of AM data. The core of this approach is a modular ontology ( PBF‐AMP‐Onto ), which serves as a semantic foundation for integrating diverse data sources, enabling semantic querying, and supporting decision‐making systems. This ontology facilitates semantics‐aware data management, enhances the interpretability of AM processes, and contributes to the optimization of manufacturing outcomes. In this paper, we focus on one of the most advanced AM techniques, powder bed fusion (PBF), with a particular emphasis on electron beam (EB‐PBF). To validate the feasibility and practical utility of our approach, we constructed a knowledge graph using a workbench ( PBF‐AMP‐KG Workbench ) and based on our ontology using data from real‐world EB‐PBF use cases. We then demonstrate how domain‐relevant queries, such as those concerning process parameters, material behavior, and machine settings, can be answered efficiently using this knowledge graph, showcasing its potential to support researchers in navigating and leveraging AM data more effectively.

The microstructure and corrosion properties of electron beam powder bed fusion (EB-PBF)-fabricated 316L stainless steel are evaluated in the as-fabricated condition with and without the deposition of IN 625 coating. Different surface profiles were achieved by introducing layer thickness and a contour scan strategy as process variables. A potentiodynamic polarization test was used for corrosion testing, while state-of-the-art microstructural investigation techniques were employed to elucidate a possible link between the microstructure and corrosion properties of the samples. Results from this pilot study showed that the corrosion response was dictated by the combined effects of surface roughness, coating depth, coating morphology, and passive film characteristics. For specimens for which a contour scan strategy was not used, the coating hinted to an improved corrosion potential while it increased the corrosion rate for both layer thicknesses. On the contrary, for specimens where a contour scan was applied, as-fabricated samples trended towards better corrosion resistance than the coated samples. It is shown that the dross particles that are formed during EB-PBF processing influence the flattening mechanism of the coating, ultimately resulting in a coating deposit that is characterized by surface defects, microcracks, cavities, and incoherent splat boundaries.

Mechanical properties of powder bed fusion processed unalloyed copper are reported majorly in the as-fabricated condition, and the effect of post-processes, common to additive manufacturing, is not well documented. In this study, mechanical properties of unalloyed copper processed by electron beam powder bed fusion are characterized via room temperature quasi-static uniaxial tensile test and Vickers microhardness. Tensile samples were extracted both perpendicular and parallel to the build direction and assigned to three different conditions: as-fabricated, hot isostatic pressing (HIP), and vacuum annealing. In the as-fabricated condition, the highest UTS and lowest elongation were obtained in the samples oriented perpendicular to the build direction. These were observed to have clear trends between sample orientation caused primarily by the interdependencies between the epitaxial columnar grain morphology and dislocation movement during the tensile test. Texture was insignificant in the as-fabricated condition, and its effect on the mechanical properties was outweighed by the orientation anisotropy. The fractographs revealed a ductile mode of failure with varying dimple sizes where more shallow and finely spaced dimples were observed in the samples oriented perpendicular to the build direction. EDS maps reveal that grain boundary oxides coalesce and grow in HIP and vacuum-annealed specimens which are seen inside the ductile dimples and contribute to their increased ductility. Overall, for the post-process parameters chosen in this study, HIP was observed to slightly increase the sample’s density while vacuum annealing reduced the oxygen content in the specimens.