Shock Mitigation in Additively Manufactured 316L Stainless Steel With Intentional Singular Pores
Taylor Sloop-Cabral, Georgia Institute of Technology
Additive manufacturing (AM) of stainless steels allows for tuning mechanical properties for unique functionalities. Stainless steel is a prime candidate material for use in a variety of applications due to its high strength, ductility, and corrosion resistance. AM fabricated stainless steel samples with strategically located pores are compared to AM fabricated samples with no porosity to determine the effects of intentional porosity on shock wave propagation and spall failure as well as the range of influence of large pores. The spall experiments were performed using an 80-mm gas gun and velocity profiles were obtained using multi-probe photon doppler velocimetry (PDV). Impacted samples were soft-recovered and analyzed post-shock using computerized tomography (CT) and electron backscatter diffraction to investigate void nucleation and coalescence in relation to pore locations. The presence of multiple pores within a single plane perpendicular to the impact direction have little to no void initiation in their vicinity. Additionally, pores placed farther apart had a large range of influence as compared to pores placed closer together, which suggests that shock mitigation from a singular pore compounds with those near it to further inhibit spall failure. However, multiple pores strategically placed in the same plane parallel to the impact direction results in extensive void initiation encroaching closely on the pre-existing pores. When the shock wave moves through multiple pores in succession, the shock mitigation is lessened, and more spall damage occurs.