Investigation on microstructure and corrosion behavior of selective laser melted 316L stainless steel at various high-speed deformation levels
Shaohua Zhang, Lijing Wang, Baosheng Liu, Yinghui Wei, Lifeng Hou, Pengpeng Wu, Xiaoxia Ren, Yuezhong Zhang, Hui‐Hu Lu
Abstract
This study examines the impact of high-speed cold rolling deformation on the microstructure and corrosion resistance of selectively laser melted (SLMed) 316L stainless steel after solution treatment at 1100°C for 0.25 hours in a simulated proton exchange membrane fuel cell (PEMFC) cathode environment. The research aims to elucidate the mechanism by which high-speed plastic deformation affects the corrosion resistance of bipolar plates during operation, thereby providing theoretical foundations for the design of metallic bipolar plate materials and ensuring the safe operation of fuel cells. The findings demonstrate that a high-speed deformation rate of 50% substantially improves corrosion resistance, largely attributable to the elevated presence of low-ΣCSL grain boundaries accounting for 49.4%, thereby improving grain boundary stability and reducing corrosion susceptibility. Additionally, optimized dislocation density and an elevated O 2- /OH - ratio of 0.69 contribute to a more effective passive film with superior protective properties. In contrast, excessively high-speed deformation at 70% leads to deteriorated corrosion resistance, as the formation of martensite promotes micro-galvanic corrosion, while the reduced Cr 2 O 3 content in the passive film weakens its protective properties.