Electrochemical-controlled Characterization of the Corrosion Fatigue Behavior of Creep-resistant Magnesium Alloys DieMag422 and AE42

Magnesium alloys offer a high potential for lightweight construction, however their application range is limited due to their low corrosion resistance. In the present study the corrosion fatigue behaviors of the creep-resistant alloys DieMag422 and AE42 were characterized and compared. In this context, fatigue properties of specimens in sodium chloride solutions as well as under simultaneous galvanostatic anodic polarization were assessed in constant amplitude tests. The results were correlated with the corrosion behavior of the alloys, which was investigated in instrumented immersion tests. Corrosion- and deformation-induced changes in microstructure were observed by light and scanning electron microscopy, yielding a structure-property relationship for a comprehensive understanding of corrosion fatigue processes. The reduction of the corrosion fatigue strength with increasing corrosion impact could be quantitatively correlated with the adjusted corrosion rates. However, different corrosion morphologies between both materials were found, leading to varying influence on the corrosion fatigue behavior.