Authors: Alberto Meza, Eric Macía, Andrea García-Junceda, Luis Antonio Díaz, Paul Chekhonin, Eberhard Altstadt, Marta Serrano, María Eugenia Rabanal, Mónica Campos

Article published on: Metals



In this research, four ODS steels were produced through the addition of a nano complex oxide (Y-Ti-Zr-O) and B.

The ODS steels were successfully processed by using MA to mill the powders and by using SPS as a consolidation technique. It is demonstrated that:

The use of a unique precursor of oxide formers (Y-Ti-Zr-O) resulted in a better control of nano precipitates composition when preparing a F-ODS steel, thereby improving the precipitation of specific oxides containing Zr that led to a strengthened microstructure.
A good precipitation morphologies (in the order of 1022 ox/m3) of the nano oxides was achieved, which may guarantee a fine pinning effect of the oxides over the dislocations and grain boundaries.
The selected parameters in the SPS technique fully densified the milled powders while avoiding an excessive grain growth during the consolidation stage and maintaining a high density of dislocation. All of this occurred without the necessity of post heat or thermo-mechanical treatments.
The tailored microstructure affected the final mechanical behavior of the material. The best values of microhardness and UTS were achieved for the 14Al-X-ODS and 14Al-X-ODS-B compositions (with increments of 50 HV0.2 and 200 MPa, respectively, in comparison with the reference composition), which were the ones that included the Y-Ti-Zr-O compound in their composition.
Small punch tests demonstrated the outstanding performance of 14Al-X-ODS and 14Al-X-ODS-B, achieving similar or better results than the GETMAT material when the tests were performed at high temperatures.
The mechanical behavior of the materials evaluated at room and high temperatures (500 °C) showed very promising and optimum values, comparable to the ones obtained in ODS steels developed with a more complex route.