Post irradiation examination of nanoprecipitate stability and $\alpha$′ precipitation in an oxide dispersion strengthened Fe-12Cr-5Al alloy


Oxide dispersion strengthened (ODS) FeCrAl alloy (Fe-12Cr-5Al wt%) was neutron irradiated to 1.8 displacements per atom (dpa) at 215, 357, and 557 °C to investigate (Y,Al,O) nano-oxide stability and Cr-rich $\alpha$′ precipitate formation using atom probe tomography. The nano-oxide sizes remain unchanged after irradiation, but the compositions are dependent on irradiation temperature due to competition between ballistic dissolution and precipitate reformation. Cr-rich clusters observed after 357 °C irradiation have lower Cr contents (61 at.%) than equilibrium $\alpha$′, with a lower number density than wrought FeCrAl alloys. This suggests a suppression of $\alpha$′ precipitation due to the high sink strength of ODS FeCrAl.

In: Scripta Materialia, (162), pp. 94–98,