Fracture Analysis of 316L Specimens Fabricated via Material Extrusion Additive Manufacturing: Influence of Building Orientation and Notch Acuity

Three-point bending tests were performed on notched specimens extracted from cuboids of 316L stainless steel produced via material extrusion additive manufacturing. The cuboids were printed vertically and horizontally on the printing platform to account for the building orientation effect on the mechanical performance. For each orientation, three notch sizes were considered. Overall, the specimens printed with building direction parallel to the loading direction outperformed the others. A significant notch size effect was observed in these specimens since the sharpest notch provoked a decrease in the peak load reached by the specimens in comparison with larger notches. On the contrary, this effect was less relevant among the other specimens, which presented a conspicuous amount of residual porosity that contributed to the premature failure. Further investigations were carried out to correlate the building orientation to the density of the parts and, ultimately, to the investigated mechanical properties. The ASED and TCD criteria were also applied to assess their accuracy in the failure prediction of the tested specimens.