1. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 1 ODS steels – part I : manufacture, mechanical properties and oxidation behaviour Yann de Carlan, Jean Henry, Ana Alamo Arnaud Monnier Raphael Couturier, Emmanuel Rigal Céline Cabet Commissariat à l’Energie Atomique CEA, FRANCE

2. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 2 Overview Why ODS steels? Manufacture Observation and analysis Microstructure control Mechanical properties (+ radiation stability) Welding techniques Oxidation properties

3. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 3 Why ODS ?

4. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 4 Why ferritic ODS? Radiation resistance at high temperature M. Inoue, JAEA, MATGENIV, 2007

5. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 5 Strengthening of alloys: ODS principle Increase obstacles to dislocation glide –Precipitates or other dislocations –Finer dispersoides and higher number density l precipitates Clement, CEA  A

6. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 6 Manufacture

7. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 7 Overview of the powder metallurgy process Mechanical Alloying (MA) Hot/cold Rolling Attrition Mill Intermediate heat treatment Elemental or prealloyed powder Hot Extrusion Caning degassing High Isostatic Pressure Machining Drilling Raw material powder Mother tube Y 2 O 3 powder MA powder soft steel can Annealing

8. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 8 Atomisation of an alloy R. Lindau, FZK, GETMAT project P91 steel Powder sieving SEM of atomized powder

9. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 9 Photo attritor + parameters alloying parameters - powder to ball ratio - milling energy (-> rpm, cycling) - milling time R. Lindau, FZK, GETMAT project

10. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 10 Hot extrusion soft steel ODS steel Hot extrusion Y de Carlan, CEA

11. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 11 What happens during the process ? Fe-18Cr-Ti Y 2 O 3, Y. De Carlan et al., ICRFM13, 2007 nano clusters < 10 nm 200nm Before milling After milling 12h milling – With Ti 12h milling no Ti Mechanical alloying Consolidation

12. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 12 M. Ratti et al., Boston, MRS 2008 Study by X Ray diffraction : Pre-alloyed powder + 10% of yttria What happens during the process ?

13. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 13 0 1000 2000 3000 4000 5000 6000 7000 263136414651 Angle 2.Théta Nombre de coups 48h milling without titanium 48h milling with titanium After MA What happens during the process? Study by X Ray diffraction : Pre-alloyed powder + 10% of yttria After 1h @950°C After MA Fe peak M. Ratti et al., Boston, MRS 2008

14. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 14 14 UT -BAT T EL L E O ak Ridge National Laboratory, U.S. Department of Energy D. Hoelzer After consolidationAfter mechanical alloying Characterization by Tomographic Atom Probe M.K. Miller, D.T. Hoelzer, E.A. Kenik, K.F. Russell, Nanometer scale precipitation in ferritic MA/ODS alloy MA957, Journal of nuclear materials 2004 Consolidation 1100°C

15. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 15 M. Inoue, JAEA Alternative process routes

16. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 16 OCAS, GETMAT project Alternative process routes

17. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 17 Characterization

18. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 18 Optical microscopy General microstructure M.K. Miller et al., JNM 329–333 (2004) 338–341 Optical micrographs of the general microstructure of MA957 in the (a) as- received condition and after annealing at 1300°C for (b) 1 h and (c) 24 h

19. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 19 0.46 Y 0.3 Ti 0.85 W Microprobe analysis of as- manufactured Fe-18Cr-Ti-Y 2 O 3 alloy SEM, EDX and microprobe Y de Carlan, CEA Grain size and morphology Structure homogeneity SEM picture of MA957 recrystallized grains obtained after deformation by cold-drawing and recrystallization heat treatment at 1100°C A. Alamo et al., JNM 329–333 (2004) 333–337, CEA

20. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 20 TEM 12Y1 ODS steel: bright- and dark-field TEM micrographs taken near beam direction B ~(1 2 2) Y 2 O 3 particle sizes are in the range of a few tens of nanometers in diameter I.-S. Kim et al., JNM 280 (2000) 264-274

21. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 21 21 M.K. Miller et al., JNM, 2004 Nanometer scale precipitation in ferritic MA/ODS alloy MA957 after hot consolidation Atom Probe

22. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 22 Analysis by XRD and SANS Nature of crystallized phases Particles size and distribution major peak of Fe according to ICDD db XRD of ODS steels with 0.3%Y 2 O 3 and 10% Ti M. Ratti et al., Boston, MRS, 2008, CEA SANS of ODS steels with 0.3%Y 2 O 3 and 10%Ti at RT under magnetic field (2 Teslas) perpendicular to the incident neutron beam direction, in a range of scattering vectors going from 0 to 0.16 nm -1 M. Ratti et al., ICRFM13, 2007

23. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 23 Microstructure control

24. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 24 Chemical composition: Minor Alloying Elements Ti is the most effective element to refine the dispersoid sizes Precipitation of Ti-Y-O (C) nanoscale clusters Larson D.J. et al., Scripta Mater. 44 (2001) 359-364, ORNL Refinement of dispersoids size by Minor Alloying Elements AP-FIM with 3D mapping MA/ODS12-YWT Inoue M., JAEA, MATGENIV, 2007

25. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 25 Chemical composition: Y 2 O 3 content Effect of addition of Y 2 O 3 in 13Cr-3W-0.5Ti on tensile properties at 650°C Effect of addition of Y 2 O 3 in 13Cr-3W-0.5Ti on creep rupture strength at 650°C Ukai S., JNM 204 (1993) 65-73

26. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 26 Chemical composition: Minor Alloying Elements Effect of addition of Ti in 13Cr-3W-0.5Y 2 O 3 on creep rupture strength at 650°C Fig 4 Ukai JNM 1993 Ukai S., JNM 204 (1993) 65-73

27. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 27 Chemical composition: Excess of oxygen Effect of excess O in 13Cr-3W-0.5Ti-0.5Y 2 O 3 on creep rupture strength at 650°C Ukai S., JNM 204 (1993) 65-73

28. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 28 A. Alamo et al., JNM 329–333 (2004) 333–337 Effect of the grain size Effect of MA957 ODS-alloy microstructure on – the impact properties – the tensile properties fine grain

29. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 29 Mechanical properties

30. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 30 Creep properties (creep rupture time) A. Alamo et al., JNM 329–333 (2004) 333–337

31. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 31 Creep of high strength ODS alloys

32. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 32 Welding

33. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 33 arnaud.monnier@cea.fr Basis of welding Welding of two metallic pieces = creation of a metal bond between the atoms of the 2 parts Weld must be as mechanically strong as the base metal HT strength is due to the uniform dispersion of nanoscale oxide particles  welding operation has to retain the nanostructure no reallocation of the dispersoids no aggregation of the dispersoids no change in the initial microstructure solid state weldingliquid state welding

34. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 34 Arc welding: -GTAW (Gas Tungsten Arc Welding) -GMAW (Gas Metal Arc Welding): MIG (Metal Inert Gas) or MAG (Metal Active Gas) Electron beam welding, laser welding GMAW (1) GTAW principle (2) GTAW equipment (1) GTAW welder (2) GTAW weld in narrow gap (1) electron beam equipment (1) (1) CEA/DEN/DANS/DM2S/SEMT/LTA (2) www.wikipedia.com Liquid state welding melting of the base metal change in the microstructure

35. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 35 SPS principle (3) (3) www.ceramicindustry.com Resistance welding principle (4) (4) www.swantec.com Resistance welding operation (5) (5) www.plasmo.eu FSW principle (6) (6) www.wikipedia.com Solid state welding retain the microstructure Solid state wedling Solid state welding + nuclear constraints: large scale, glove box working –HIP (Hot Isostatic Pressing) –SPS (Spark Plasma Sintering) –Friction Stir Welding, Resistance Welding

36. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 36 Hot Isostatic Pressure emmanuel.rigal@cea.fr Surface conditioning: –Degreasing, acid cleaning, mechanical cleaning, ionic sputtering, coating… Canning: –in a steel capsule (welded by GTAW) Degassing of the can (P ~ 10 -5 mbar) Closing of the can, gas-tightness HIP cycling : ~1000 °C/1000 bar/1 h Removal of the can: –machining, chemical dissolution

37. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 37 Mockup: upper plate Mockup: first wall Mockup: cooling plate Eurofer joint High Isostatic Pressing emmanuel.rigal@cea.fr

38. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 38 INSA Lyon Spark Plasma Sintering (SPS) raphael.couturier@cea.fr, CEA Université de Bourgogne SPS principle

39. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 39 www.cea.fr Resistance welding device of CEA/DEN/DANS/DM2S/SEMT/LTA arnaud.monnier@cea.fr Resistance welding

40. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 40  hardness of the weld = hardness of the base metal  needs for accurate analysis of the dispersoid size and allocation Resistance welding – characterization of the weld arnaud.monnier@cea.fr

41. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 41 Characterization of ODS weld How to characterize an ODS weld? Usual methods to characterize a weld –SEM, EDS analysis, hardness profile –Do not allow observing nanoscale dispersoids Methods to characterize an ODS –TEM, nano-indentation, SANS –Do not allow checking for the weld homogeneity –+ technically difficult to perform

42. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 42 Oxidation properties

43. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 43 Example of commercial ODS fromFeNiCrAlTiMoWothersCY2O3Y2O3 MA 956INCObase204,50,5 PM 2000Planseebase205,50,5 ODM 751Dour Metalbase16,54,50,61,50,5 MA 957INCObase1410,30,25 MA758INCObase300,30,50,050,6 MA754INCObase200,30,50,050,6 PM 1000Planseebase200,30,50,6 MA760INCObase20623,5Zr 0,150,050,95 PM 3030Planseebase17623,5Ta 2 Si 0,951,1 MA757EINCO0,5base16,840,50,060,7 HDA-8077Cabotbase15,74,20,06Y :1,6 MA6000 (  ') INCObase154,5222Ta 2 Zr 0,150,051,1 MA753 (  ') INCObase2012,20,051,3 alumina-formingchromia-forming

44. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 44 Y is a RE !!! Improve the oxidation and corrosion properties  longer service life RE = Reactive Element effective when added as –metal or alloy –oxide dispersoids (ODS) –ionic implantation –surface coating Fe-24Cr 800°C, air

45. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 45 Improvement of the oxidation properties Surface oxide thickness Oxidation in dry air at 650°C for 2000hrs 12Cr-2W ODS (0.24 Y 2 O 3 )FMS 12Cr-2W Mass gain Spallation alumina scale spalls out protection is lost

46. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 46 Influence on the scale formation Decrease of the critical Cr% for chromia formation Alumina forming Chromia forming Promote  -Al 2 O 3 (no transitory θ-Al 2 O 3 ) Decreases the duration of transitory oxidation (reduces the base metal oxidation) Fe-CrCo-CrNi-Cr no Y20%Cr25%Cr35%Cr Y2O3Y2O3 10-13% Cr 12Cr steel oxidized at 1300°C in dry air for 50h

47. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 47 Influence on the scale growth Supress outward diffusion of metal cation Alumina forming Chromia forming O2O2 O Y2O3Y2O3 Cr O2O2 O2O2 O no Y  ox t  ox 2 t Wagner theory Decrease the oxidation rate (parabolic constant) Possible change in the oxidation kinetics (from parabolic to subparabolic)

48. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 48 Influence on the scale microstructure and adhesion Increase adhesion  spallation resistance Alumina forming Chromia forming Increase the scale compacity and decrease the oxide grain size Supress the pores at the alloy/scale interface 2µm Al 2 O 3 dispersion Tb 4 O 7 dispersion FeCrAl oxidized at 1300°C for 100h

49. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 49 Which is the optimum RE quantity? No practical rule It depends on –Chemical nature of the RE –Size and distribution –Chemical interaction with Ti, C, N –Fabrication technique

50. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 50 Temperature range for ODS use 800°C950°C1200°C1300°C evaporation breakaway oxidation Ni-Cr Fe- Cr Ni-Cr-Al Fe-Cr-Al evaporation oxidation rate spallation breakaway oxidation Fe-12Cr PM2000 tested in air at 1200°C for 1825 h, cycling at RT every 48h

51. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 51 Conclusion Gen IV systems are highly demanding toward structural materials: high temperature, extended service life, high neutron dose, corrosive environment…  ODS steels and alloys could met these high level requirements especially for –SFR cladding –VHTR heat exchanger or GT-MHR turbine –GFR cladding Oxide dispersion strengthening –Nanoscale particles = obstacle to dislocation glide –Superior HT strength

52. Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 52 Conclusion cont. ODS can be produced via powder metallurgy processes –Fabrication route and parameters impact microstructure and properties of the final ODS product ODS can be characterized by –Microscopy, SEM, microprobe analysis  global microstructure –TEM, AP-FIM, DRX, SANS  dispersoids ODS welding –Solid state welding processes are to be used (resistance welding) ODS oxidation properties –Y is a Reactive Element that improves HT oxidation properties –Chromia-forming alloy: lower oxidation rate –Alumina forming alloys: improved spallation resistance