Evaluation of Corrosion Performance of Friction Stir Processed Magnesium Alloys Using Multimodal Analysis Across Length Scales

Friction stir processingFriction Stir Processing (FSP) (FSP) homogenizes and refines the microstructureMicrostructure through severe plastic deformationPlastic deformation. Previous studies have demonstrated that the processed zone is more corrosionCorrosion-resistant as compared to the base Mg alloyMagnesium alloys (Mg alloys). However, the corrosion behavior of the microstructureMicrostructure immediately adjacent to the processed zone, and how it affects the base material under corrosive environments has received little attention. In this study, we have used a multimodalMultimodal analysis corrosion measurement system to investigate the corrosion behavior of the surface and cross section of FSP AZ31 and AZ91 Mg alloy plates by imaging the sample, acquiring electrochemical data, and collecting evolved hydrogen. Additionally, scanning electrochemical cell microscopy (SECCM) was employed to study variations in localized corrosionCorrosion behavior from the base metal into the stir zone from the advancing and retreating sides. Microscopy was employed to identify the microstructural cause for the enhanced susceptibility to corrosion in the heat-affected zone and base material.