ODS steels part I : produce, mechanical properties and oxidation conduct

Ods steels part i manufacture mechanical properties and oxidation behaviour
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ODS steels – part I : make, mechanical properties and oxidation conduct Yann de Carlan, Jean Henry, Ana Alamo Arnaud Monnier Raphael Couturier, Emmanuel Rigal Céline Cabet Commissariat à l'Energie Atomique CEA, FRANCE

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Overview Why ODS steels? Produce Observation and investigation Microstructure control Mechanical properties (+ radiation security) Welding strategies Oxidation properties

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Why ODS ?

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Why ferritic ODS? Radiation resistance at high temperature M. Inoue, JAEA, MATGENIV, 2007

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Strengthening of amalgams: ODS rule Increase snags to disengagement float Precipitates or different separations Finer dispersoides and higher number thickness A Ds  l encourages Clement, CEA

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Manufacture

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Overview of the powder metallurgy prepare Caning degassing Mechanical Alloying (MA) Raw material powder High Isostatic Pressure Elemental or prealloyed powder delicate steel can MA powder Y 2 O 3 powder Attrition Mill Hot/icy Rolling Hot Extrusion Annealing Mother tube Machining Drilling Intermediate warmth treatment

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Atomisation of a composite R. Lindau, FZK, GETMAT extend P91 steel SEM of atomized Powder sieving

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Photo attritor + parameters R. Lindau, FZK, GETMAT extend alloying parameters - powder to ball proportion - processing vitality (- > rpm, cycling) - processing time

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Hot expulsion Y de Carlan, CEA Hot expulsion ODS steel delicate steel

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What occurs amid the procedure ? Mechanical alloying Consolidation 12h processing – With Ti 200nm 12h processing no Ti Before processing nano groups < 10 nm After processing Fe-18Cr-Ti Y 2 O 3 , Y. De Carlan et al., ICRFM13, 2007

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What occurs amid the procedure ? Think about by X Ray diffraction : Pre-alloyed powder + 10% of yttria M. Ratti et al., Boston, MRS 2008

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7000 6000 5000 48h processing with titanium 4000 48h processing without titanium Nombre de upsets 3000 2000 1000 0 Angle 2.Théta 26 31 36 41 46 51 What occurs amid the procedure? Examine by X Ray diffraction : Pre-alloyed powder + 10% of yttria Fe top After MA After MA After 1h @950°C M. Ratti et al., Boston, MRS 2008

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Characterization by Tomographic Atom Probe Consolidation 1100°C M.K. Mill operator, D.T. Hoelzer, E.A. Kenik, K.F. Russell, Nanometer scale precipitation in ferritic MA/ODS composite MA957, Journal of atomic materials 2004 UT - BAT T EL L E O ak Ridge National Laboratory, U .S . Branch of Energy D. Hoelzer After mechanical alloying After solidification 14

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Alternative process courses M. Inoue, JAEA

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Alternative process courses OCAS, GETMAT extend

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Characterization

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Optical microscopy General microstructure Optical micrographs of the general microstructure of MA957 in the (an) as-got condition and in the wake of tempering at 1300°C for (b) 1 h and (c) 24 h M.K. Mill operator et al., JNM 329–333 (2004) 338–341

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0.85 W 0.46 Y 0.3 Ti SEM, EDX and microprobe Grain size and morphology Structure homogeneity SEM picture of MA957 recrystallized grains acquired after twisting by icy drawing and recrystallization warm treatment at 1100°C Microprobe examination of as-fabricated Fe-18Cr-Ti-Y 2 O 3 combination Y de Carlan, CEA A. Alamo et al., JNM 329–333 (2004) 333–337, CEA

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TEM 12Y1 ODS steel: brilliant and dim field TEM micrographs taken close bar heading B ~(1 2) Y 2 O 3 molecule sizes are in the scope of a couple of many nanometers in width I.- S. Kim et al., JNM 280 (2000) 264-274

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Atom Probe Nanometer scale precipitation in ferritic MA/ODS combination MA957 after hot union M.K. Mill operator et al., JNM, 2004 21

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Analysis by XRD and SANS Nature of solidified stages Particles size and appropriation SANS of ODS steels with 0.3%Y 2 O 3 and 10%Ti at RT under attractive field (2 Teslas) opposite to the occurrence neutron shaft course, in a scope of disseminating vectors going from 0 to 0.16 nm - 1 XRD of ODS steels with 0.3%Y 2 O 3 and 10% Ti real pinnacle of Fe as per ICDD db M. Ratti et al., Boston, MRS, 2008, CEA M. Ratti et al., ICRFM13, 2007

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Microstructure control

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Ti is the best component to refine the dispersoid sizes Precipitation of Ti-Y-O (C) nanoscale bunches Chemical creation: Minor Alloying Elements Refinement of dispersoids size by Minor Alloying Elements AP-FIM with 3D mapping MA/ODS12-YWT Larson D.J. et al., Scripta Mater. 44 (2001) 359-364, ORNL Inoue M., JAEA, MATGENIV, 2007

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Chemical organization: Y 2 O 3 content Effect of expansion of Y 2 O 3 in 13Cr-3W-0.5Ti on elastic properties at 650°C Effect of expansion of Y 2 O 3 in 13Cr-3W-0.5Ti on crawl crack quality at 650°C Ukai S., JNM 204 (1993) 65-73

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Chemical structure: Minor Alloying Elements Effect of expansion of Ti in 13Cr-3W-0.5Y 2 O 3 on crawl break quality at 650°C Fig 4 Ukai JNM 1993 Ukai S., JNM 204 (1993) 65-73

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Chemical sythesis: Excess of oxygen Effect of abundance O in 13Cr-3W-0.5Ti-0.5Y 2 O 3 on crawl burst quality at 650°C Ukai S., JNM 204 (1993) 65-73

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Effect of the grain estimate Effect of MA957 ODS-composite microstructure on the effect properties the malleable properties fine grain A. Alamo et al. , JNM 329–333 (2004) 333–337

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Mechanical properties

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Creep properties (crawl crack time) A. Alamo et al., JNM 329–333 (2004) 333–337

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Creep of high quality ODS amalgams

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Welding

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Basis of Welding of two metallic pieces = production of a metal security between the iotas of the 2 sections Weld must be as mechanically solid as the base metal HT quality is because of the uniform scattering of nanoscale oxide particles  welding operation needs to hold the nanostructure no reallocation of the dispersoids no collection of the dispersoids no adjustment in the underlying microstructure fluid state welding strong state welding arnaud.monnier@cea.fr

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Liquid state welding liquefying of the base metal change in the microstructure Arc welding: GTAW (Gas Tungsten Arc Welding) GMAW (Gas Metal Arc Welding): MIG (Metal Inert Gas) or MAG (Metal Active Gas) Electron pillar welding, laser welding GTAW welder (2) GTAW standard (2) GTAW gear (1) GMAW (1) (1) CEA/DEN/DANS/DM2S/SEMT/LTA (2) www.wikipedia.com GTAW weld in restricted hole (1) electron bar hardware (1)

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Solid state wedling Solid state welding hold the microstructure Solid state welding + atomic imperatives: huge scale, glove box working HIP (Hot Isostatic Pressing) SPS (Spark Plasma Sintering) Friction Stir Welding, Resistance Welding FSW rule (6) Resistance welding guideline (4) SPS rule (3) (3) www.ceramicindustry.com (4) www.swantec.com Resistance welding operation (5) (5) www.plasmo.eu (6) www.wikipedia.com

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Hot Isostatic Pressure Surface molding: Degreasing, corrosive cleaning, mechanical cleaning, ionic sputtering, covering… Canning: in a steel container (welded by GTAW) Degassing of the can (P ~ 10 - 5 mbar) Closing of the can, gas-snugness HIP cycling : ~1000 °C/1000 bar/1 h Removal of the can: machining, substance disintegration emmanuel.rigal@cea.fr

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High Isostatic Pressing Mockup: upper plate emmanuel.rigal@cea.fr Mockup: first divider Mockup: cooling plate Eurofer joint

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Spark Plasma Sintering (SPS) raphael.couturier@cea.fr, CEA Université de Bourgogne SPS rule INSA Lyon

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Resistance welding www.cea.fr Resistance welding gadget of CEA/DEN/DANS/DM2S/SEMT/LTA arnaud.monnier@cea.fr

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Resistance welding – portrayal of the weld hardness of the weld = hardness of the base metal requirements for precise investigation of the dispersoid size and assignment arnaud.monnier@cea.fr

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Characterization of ODS weld How to describe an ODS weld? Normal techniques to describe a weld SEM, EDS investigation, hardness profile Do not permit watching nanoscale dispersoids Methods to portray an ODS TEM, nano-space, SANS Do not permit checking for the weld homogeneity + in fact hard to perform

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Oxidation properties

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Example of business ODS chromia-shaping alumina-framing

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Y is a RE !!! Enhance the oxidation and erosion properties  longer administration life RE = Reactive Element powerful when included as metal or amalgam oxide dispersoids (ODS) ionic implantation surface covering Fe-24Cr 800°C, air

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alumina scale spalls out insurance is lost 12Cr-2W ODS (0.24 Y 2 O 3 ) FMS 12Cr-2W Oxidation in dry air at 650°C for 2000hrs Improvement of the oxidation properties Surface oxide thickness Mass pick up Spallation

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Influence on the scale arrangement Chromia shaping Alumina framing Decrease of the basic Cr% for chromia development Promote -Al 2 O 3 (no short lived θ - Al 2 O 3 ) Decreases the length of brief oxidation (lessens the base metal oxidation) 12Cr steel oxidized at 1300°C in dry air for 50h

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O 2 O 2 O Cr no Y Wagner hypothesis O 2 O Y 2 O 3  bull  bull 2 t Influence on the scale development Chromia shaping Alumina framing Supress outward dissemination of metal cation Decrease the oxidation rate (illustrative steady) Possible change in the oxidation energy (from explanatory to subparabolic)

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2µm Influence on the scale microstructure and grip Chromia shaping Alumina shaping Increase bond  spallation resistance Increase the scale compacity and abatement the oxide grain estimate Supress the pores at the combination/scale interface FeCrAl oxidized at 1300°C for 100h Al 2 O 3 scattering Tb 4 O 7 scattering

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Which is the ideal RE amount? No commonsense govern It relies on upon Chemical nature of the RE Size and dispersion Chemical association with Ti, C, N Fabrication procedure

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