Characterization and Corrosion Resistance Behavior of Shape Memory Stainless Steel Developed by Alternate Routes

The microstructural characterization and corrosion resistance behavior of Fe-Mn-Si-Cr-Ni alloy with shape memory effect was studied under different mechanical processing conditions and heat treatments, which were produced using conventional casting and routing methods to reduce costs and make production viable. Microstructural characterization was performed with electron microscopy and x-ray diffraction techniques, electrochemical tests with polarization, and thermogravimetry techniques. The cast condition presented a dendritic structure and the presence of the secondary phases: ferrite-delta and Chi-X phase. The heat treatment eliminated phases, reincorporated elements in the matrix, and increased the austenitic grain. After the hot rolling process, the alloy exhibited a refined microstructure with recrystallized austenitic grains. The heat-treated condition presented better oxidation resistance than the other conditions, while the hot-rolled condition showed repassivation of the pits, raising them to higher levels. All conditions presented low corrosion resistance in environments containing chloride ions.