29th Symposium on Fusion Technology (SOFT 2016)

P3.190 Survey of oxide candidate for advanced 9%, 14% and 17%Cr ODS steels for fusion applications

7 Sep 2016, 11:00

1h 20m

Foyer 2A (2nd floor), 3A (3rd floor) (Prague Congress Centre)

Board: 190

Poster I. Materials Technology P3 Poster session

Speaker

Hynek Hadraba (Institute of Physics of Materials)

Description

The structural components used for construction of future generation of fission reactors and fusion reactors will undergo demanding service conditions as high neutron doses, high temperature and extremely corrosive environment. The nano-structured oxide dispersion steels (ODS) containing small amounts of homogeneously dispersed nano-size yttria particles were developed as structural material for fast breeder reactors. Three classes of prospective structural ODS steels can be identified: ferritic-martensitic 9%Cr steel and ferritic 14%Cr and 17%Cr steels. The aim of this work was to find new candidate low-activation ODS steels strengthened by alternative nano-sized oxides. The 9Cr-1W, 14Cr-2W and 17Cr-1Mo ODS steels containing oxides based on Y, Al, Zr, Ti and Ca were prepared by mechanical alloying from atomic powders. The oxide dispersion was created alternatively by controlled oxidation powder during mechanical alloying process. Fully dense steels were obtained after densification of prepared powders by spark-plasma-sintering process. Structural and mechanical properties of the new candidate ODS steels were compared to conventional oxide-free steels and ODS steels strengthened by direct adding of relevant oxides. The new procedure for preparation of nano-structured ODS steels was developed based on internal oxidation of oxide-trapping atoms. The oxides were created from oxygen and Y, Al, Zr, Ti and Ca atoms added to the alloy during mechanical alloying of the powder. Oxide distribution increases tensile yield strength and ultimate tensile strength both at room and elevated temperature without distinct deterioration of plasticity.