| Abstract Scope |
This study compares the irradiation response of additively manufactured (AM) 316H stainless steel (SS), produced via laser powder bed fusion, to conventionally manufactured (CM) 316H SS under identical proton irradiation conditions. Both materials were irradiated with 0.5 MeV H⁺ ions at room temperature up to a damage level of 6.0 displacements per atom (dpa), simulating conditions relevant to nuclear environments. Comprehensive characterization—via X-ray diffraction (XRD), scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and energy-dispersive X-ray spectroscopy (EDS)—was employed to evaluate microstructural and mechanical evolution.
XRD analysis revealed initially higher dislocation densities in AM SS due to its fabrication history. At low doses (0.6 dpa), AM SS exhibited a reduction in microstrain, suggesting defect annihilation or stress relaxation, while CM SS showed an increase. At higher doses (6.0 dpa), AM SS experienced increased microstrain and dislocation density, possibly due to defect saturation, whereas CM SS showed a decline—likely linked to radiation-induced disordering. Microhardness and tensile tests confirmed superior irradiation tolerance in AM SS, which exhibited lower embrittlement and strength degradation than CM SS.
Surface analysis showed AM SS retained elemental stability post-irradiation, with minimal Fe/Cr/Ni redistribution, while CM SS displayed significant surface degradation, grain fragmentation, and silicon/phosphorus enrichment. Distinct pore morphologies in AM SS contributed to localized radiation resistance mechanisms.
These findings highlight the enhanced radiation tolerance of AM 316H SS in near-surface regions, supporting its viability for demanding applications in nuclear and extreme irradiation environments. |