Microstructural evolution and corrosion behavior of Sanicro 28 during thermomechanical processing

Abstract The corrosion behavior of Sanicro 28 superalloy with different microstructures is investigated. Potentiodynamic polarization measurements are performed to evaluate the corrosion behavior. The corrosion resistance is found to depend primary on the residual strain level and deformation structures. Annealing the cold-rolled microstructure between 850 °C and 950 °C leads to galvanic corrosion due to the precipitation of Cr and Mo rich sigma phase and M23C6 carbides. Samples with high volume fraction of annealing twins exhibit a higher corrosion resistance. Finally, grains with deformation texture components near {110} planes have the highest surface energy and lowest dissolution rate.