Effects of Porosity on Spall Failure of Additively Manufactured 316L Stainless Steel

Additive manufacturing (AM) of stainless steels allows for tuning of mechanical properties for unique functionalities, and stainless steel is a prime candidate for use in many applications due to its existing high strength, ductility, and corrosion resistance. AM fabricated 316L stainless steel samples with intentionally random pore placement are compared to samples with known pore placement to study the interaction of the shock wave with individual and grouped pores. Velocity profiles were obtained using photon doppler velocimetry (PDV) probes placed strategically along the location of the known pores to understand the limits of local influence for the known pores. Postmortem characterization of soft-recovered samples using electron backscatter diffraction and transmission electron microscopy was performed to investigate the strain accommodation around pores. It is observed that shock wave fronts are highly dispersed and slow as they propagate through the pore due to strain accommodation around individual pores. As a result, there is shifting of the spall plane away from the impact face. This slow wave front also results in a slow rise time and la