Michael Heiden¹, Dan Tung¹, David Saiz¹, Bradley Jared¹; ¹Sandia National Laboratories

In the quest for developing more consistent and reliable additively manufactured (AM) parts, it’s known that surface roughness and porosity negatively affect mechanical performance. However, predicting how an AM part will perform and where it will fracture is still an unknown. In this study, electrical discharge machining (wire-EDM) was used to cut tensile samples out of blocks of 316L stainless steel, printed using laser-powder bed fusion (L-PBF). With the reduction of roughness and sites for surface crack initiation, failure mechanisms could be identified in various orientations. UTS, YS, and ductility all increased, except for two orientations. Positioning in the build chamber and angle of parts were found to contribute significantly to changes in microstructure, fracture site, crystallographic texture, hardness, and porosity. How slight changes to build orientation and post-processing can affect resulting mechanical performance will be discussed.SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525.