Investigating the influence of microstructure on corrosion susceptibility: A multiscale electron microscopy approach

Abstract

In recent years, researchers have been leveraging developments in novel experimental methods and automated processing and analysis to establish processing-structure-property links in a more robust and statistical manner. One prime area that would benefit from such an approach is corrosion studies. Corrosion is an important societal issue with a broad and varied impact, and the corrosion-related maintenance and repair imposes a large expense on the global economy. This makes it important to better understand and predict corrosion behavior in order to design superior corrosion resistant materials. This work investigates the role of local microstructure in determining the corrosion behavior of materials, at the mesoscale and the nanoscale, through the combination of automated image processing and rapid, detailed characterization. This work is divided into two parts. At the mesoscale, detailed microstructural characterization through SEM and EBSD analysis is combined with automated image processing to develop first order correlations between pit initiation and grain orientation, intermetallic particle proximity, grain boundary proximity, and local dislocation density in 5083 aluminum. At the nanoscale, in situ TEM oxidation investigations of Fe thin films are combined with automated image processing to track dynamic processes in real time. Information on oxidation front propagation behavior and kinetics, as well as crystallographic evolution, is extracted. These findings improve the understanding of the influence of microstructure on corrosion and lay the groundwork for further developments of these methodologies.