Effect of nanoscale precipitation on strengthening of ferritic ODS Fe–Cr–Al alloy

Abstract

The kinetics of Fe rich α and Cr rich α′ phase separation during aging of Fe–Cr–Al oxide dispersion strengthened alloys have been analysed with a combination of atom probe tomography and thermoelectric power measurements. The slight lattice parameter decrease measured by X-ray diffraction after thermal aging was associated with a lattice misfit between the emerging α and α′ domains. The elastic strain associated with this misfit and the different elastic moduli for the α and α′ phases would produce an increase in internal stresses that would retard the motion of dislocations and thus would be the main cause for the strengthening.