Recrystallization and Oxide Coarsening in Fe-10Al-4Cr Nanocomposite Strengthened with 5 vol.% of Various Mixed Oxides Based on Y, Al and Zr

The processing of coarse-grained creep-resistant oxide dispersion-strengthened (ODS) nanocomposites presents several challenges, e.g., the chemical composition of precipitated nanooxides and their resistance to coarsening. Precipitation of different types of nanooxides, such as mixed Y-Al, Y-Zr oxides, and Y 2 O 3 , is achieved by microalloying of the Fe-10Al-4Cr-4Y 2 O 3 nanocomposite (FeAlOY). To assess resistance to coarsening, different nanooxides are annealed at 1400 °C. The coarsening is evaluated through detailed microstructural characterization and hardness measurements. Both methods allow selection of the chemical composition of the FeAlOY, with nanooxides most resistant to coarsening, making them candidates for materials with the highest creep strength in long-term tests at temperatures > 1000°C. YAP and Y 2 O 3 nanooxides exhibit the best coarsening resistance, while FeAlOY with YAM nanooxides exhibit the poorest. The microalloying of the FeAlOY by Zr and Ti allowed spontaneous selection of oxide-forming elements. While all added Zr is chemically bound in Y-Zr mixed nanooxides, Ti does not participate in nanoprecipitate formation.