Discovering the nanoscale origins of localized corrosion in additive manufactured stainless steel 316L by liquid cell transmission electron microscopy

We use liquid cell scanning transmission electron microscopy (STEM) to directly characterize the nanoscale origins of corrosion initiation in Additive manufacturing (AM) 316 L stainless steel. Under applied anodic po-tentials, we found that the dislocation cellular boundaries were preferentially corroded and that regions of localize corrosion occurred along the cellular boundaries. We directly observed the earliest stages of corrosion by controlling the biasing parameters to decelerate the corrosion processes. The results show that highly localized corrosion occurs via inclusion dissolution along dislocation cell boundaries. More widespread corrosion initiates at the dislocation cell boundaries and spreads throughout the dislocation networks.

Automated summary

In this study, liquid cell scanning transmission electron microscopy (STEM) was used to characterize the nanoscale origins of corrosion initiation in AM 316 L stainless steel. It was found that the corrosion preferentially occurred at dislocation cellular boundaries and localized corrosion was observed along these boundaries. By controlling the biasing parameters, the earliest stages of corrosion were directly observed. The results indicate that highly localized corrosion was caused by inclusion dissolution along dislocation cell boundaries, and more widespread corrosion initiated at the dislocation cell boundaries and spread throughout the dislocation networks.