Improving the high-temperature properties of a new generation of Fe-Al-O oxide-precipitation-hardened steels

Increasing efficiency in power engineering is conditional on the improvement of the high-temperature properties of structuralmaterials. A new Fe-Al-O Oxide-Precipitation-Hardened (OPH) steel was developed by the authors to dissolve the requiredamount of O in the matrix during mechanical alloying and let a fine dispersion of Al oxides precipitate during the hot consoli-dation. Compared to oxide-dispersion-strengthened (ODS) ferritic steels, excellent oxidation resistance is guaranteed by using10 % Al in the matrix. To improve the high-temperature properties of OPH, a series of thermomechanical tests was performed toinvestigate the recrystallization and grain growth of the microstructures by metallographic analysis. The results show that theheat treatment has a significant influence on the mechanical properties of OPH as well as the microstructure andrecrystallization of the grains. It decreased the UTS to almost 25 % of the initial state, while causing plastic deformation. Also,grain growth was observed up to 16 %, even with no annealing and applied deformation, which shows a good structure-orientedmaterial.

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