! Introduction.! Production of ODS alloys.! Mechanical tests.! EBSD measurements.! Outlook

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1 Contents Investigation on different oxides as candidates for nano-sized ODS particles in reduced-activation ferritic (RAF) steels Jan Hoffmann! Introduction!! Mechanical tests! EBSD measurements! Outlook 2 Introduction! What are ODS alloys? Oxide Disperions-Strengthened alloys Nano-sized oxide-particles 10-20nm + good corrosion-resistance + excellent high-temperature properties ++ improved creep-strength - material tends to be brittle - high production costs (TEM High-Angle-Annular-Dark-Field Image) 3 4

2 100 Mpa 1100 C 5 6 Compacting of the powders containing the different oxides:! HIP at 1100 C / 100 MPa for 2 hours! Hot-rolling at 1100 C! Reduction from 45 mm diameter to 6 mm thickness! 5 passes needed for final shape, with reheating after each pass 100 Mpa 1100 C 7 TU Clausthal 8

3 Production-parameters: No. composition milling-speed milling-time 1 + La 2 O / h 2 + Ce 2 O / h 3 + MgO 1200 / h 4 + ZrO / h 5 + Fe 2 Y 1200 / h Ref / h! milling in argon-atmosphere! ball to powder ration 10:1 (2000g : 200g)! complete produktion in argon (glove-box) Characterization (FIB/TEM) HAADF + TEM BF* 9 FIB + La 2 O 3 rolled D. Armstrong Univ. Oxford *GRC - Physical Metallurgy 2011, August 3., Boston, USA 10 Characterization (microstructure) Characterization (oxides) TEM BF 90 RD! clearly visible rolling texture! grain size approx. 400 to 800 nm width, but micrometer-sized length 11 TEM BF TEM DF 90 RD! formatation of ODS particles with La 2 O 3! fine distribution of the oxides (inside grains 1 and on GB 2 ) 12 TEM DF

4 Prof. Dr. Max Mustermann Musterfakultät Characterization (oxides) KIT 13Cr 1W 0.3Y2O3 ODS hot rolled 1100oC + Y2O3 Step size: 80 nm Average CI: 0.57 (after clean up) TEM DF 90 RD! formatation of ODS particles with La2O3! fine distribution of the oxides (inside grains1 and on GB2) KIT 13Cr 1W 0.3Y2O3 ODS hot rolled 1100oC Results from! A bimodal grain size distribution is visible! Grains with <110> parallel to the rolling direction! Predominance of {001} <110> rotated cube (α-fiber) (typical texture in bcc metals) 15 16

5 2 Mechanical tests (charpy-impact test) KAM Kernel Average Misorienation Map Fine recrystallized grains are surrounded by coarser elongated ones All specimens in LT- orientation Mechanical tests (charpy-impact test) Mechanical tests (charpy-impact test) RT RT MgO MgO 300 C 19 20

6 Mechanical tests (tensile tests yield strength) Mechanical tests (tensile tests total elongation)! Y-containing alloys show the best results! Most alloys perform in a similar way Comparison of 12Cr, 13Cr and 14Cr ODS Conclusion and Outlook Alternative oxides for ODS steels GETMAT 12Cr2W0.3Ti 0.2 Y 2O 3 ORNL 12Cr3W0.4Ti 0.25 Y 2O 3 14Cr3W0.4Ti 0.25 Y 2O 3 KIT 13Cr1W0.3Ti 0.3 Y 2O 3 13Cr1W0.3Ti 0.3 La 2O 3 13Cr1W0.3Ti 0.3 Ce 2O 3 13Cr1W0.3Ti 0.3 Fe 2Y! Performance in tensile tests is comparable to alloys produced at other facilities 23! Formation of nano-oxides is possible with alternative oxides! Tensile properties of different oxides are comparable to yttrium-alloys! Improved charpy-impact properties for Ce 2 O 3 and MgO Outlook! Detailed TEM Characterization of nano-oxides is still in progress! EBSD mappings of selected oxides (other than ) 24

7 Conclusion and Outlook planned work at the Materials Department FIB (Channeling) microstructure char. EBSD on rolled and extruded materials 4-point-beding-tests (fracture-toughness) Thank you for your a,en.on! 25 26