Comparison between the surface roughness and mechanical properties of AISI 316L samples produced via Laser Power Bed Fusion process using gas atomized and water atomized powders

Additive manufacturing (AM) has been widely investigated from the point of view of process optimization. This work focuses on Laser Powder Bed Fusion (LPBF); many aspects are discussed in the literature, such as the mechanical properties achievable or the process parameters influence. This work focuses on a particular material, AISI 316L, austenitic stainless steel, that attracted interest due to its wide use, mechanical properties, and corrosion resistance. The feedstock material has crucial relevance to obtain a product with desired properties. The atomizing process used to produce the powder provides the feedstock material with unique features; these features can influence various steps of the LPBF, such as the powder bed spreading or the consolidation of the component. Gas atomizing (GA) and water atomizing (WA) are the methods considered in this work. The powder produced shows different shapes and chemical compositions. As a consequence of the dissimilar properties of the powder, the final components can show different characteristics. The first part of the work is a literature review that analyzes the different features in the samples produced with two types of powder. The target is to cover a lack of literature due to the weak interest in water atomized powder. The second part consists of an experimental investigation in which two sets of samples are produced with the two types of powder. The components produced are analyzed to evaluate and compare the dimensional accuracy and the surface roughness. Furthermore, the measurements are direct to find the best set of process parameters that maximize the density. With the best set of processes, parameters are produced tensile samples and, after the tensile tests, it is possible to compare the mechanical properties achieved using the two types of powder.