Effect of deformation treatment on corrosion properties of Fe-Mn-Si shape memory alloys

This study examines the corrosion response and microstructural evolution of Fe-15.5Mn-5.5Si-8.2Cr-5.5Ni shape memory alloy subjected to varying pre-deformation levels. Experimental findings reveal that pre-strain promotes stress-induced transformation of austenite into ε-martensite, which nucleates preferentially at austenite grain boundaries. A significant rise in dislocation density is observed near grain boundaries and phase interfaces, contributing to localized corrosion. As a result, the alloy exhibits increased susceptibility to corrosion with greater pre-deformation, demonstrating a clear deterioration in overall corrosion resistance. • ε-martensite initially forms and grows at the grain boundaries. • Corrosion resistance progressively diminishes as the degree of pre-strain deformation increases. • Localised dissolution and repair phenomena occur on the surface of pre-deformed specimens.