Effect of cold rolling rates on microstructure and corrosion behavior of selective laser melted 316L austenitic stainless steel bipolar plates

The effect of varying cold rolling deformation rates on the microstructure and corrosion behavior of selective laser melted (SLMed) 316L austenitic stainless steel (ASS) was investigated using electron backscattered diffraction and electrochemical tests. The results indicate that cold deformation results in an increase in the fraction of low-angle grain boundaries (LAGBs), which significantly enhances corrosion resistance of SLMed 316L ASS. In contrast, the increase of dislocation density and the martensite phase resulting from high-speed deformation negatively impact corrosion resistance of SLMed 316L ASS in the simulated cathodic environment of proton exchange membrane fuel cells (PEMFCs). In addition, different cold deformation rates correspond to different compositions of passive films, with the low-speed deformed sample showing a greater proportion of chromium oxides and O 2− /OH − ratio compared to both the un-deformed and high-speed deformed samples.