Substantially Higher Corrosion Resistance in AE42 Magnesium Alloy through Corrosion Layer Stabilization by ECAP Treatment

The corrosion properties of magnesium alloy AE42, just extruded and with posterior eight passes through equal channel angular pressing after extrusion, were investigated in 0.1 M NaCl by electrochemical impedance spectroscopy. The obtained samples were compared using scanning electron microscopy micrographs of the corrosion layers created on the surface of the specimens. The background of the substantial higher corrosion resistance of the samples after equal channel angular pressing treatment was found to be the much thicker and stable corrosion layer and smaller separating fragments in comparison with the just extruded samples. The lowering of the grain size by severe plastic deformation, especially by the equal channel angular pressing treatment was found to be also responsible for the enhancement of the corrosion resistance in AE42 class of magnesium alloys.