The evolution of dislocation densities in tempered martensite ferritic steels during long-term aging and creep was monitored. Scanning transmission electron microscopy, in combination with a high-angle annular dark-field detection, was used to study dislocations in a 12% Cr steel. During aging, the dislocation density quickly decreases by a factor 2 and then remains constant. Long-term creep results in an initial decrease by a factor 10, and after this sharp drop, the dislocation density continues to decrease.

How Dislocation Substructures Evolve during Long-Term Creep of a 12%Cr Tempered Martensitic Ferritic Steel. J.Pešička, A.Aghajani, C.Somsen, A.Hartmaier, G.Eggeler: Scripta Materialia, 2010, 62[6], 353-6