Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 1...

Matgen4.2 – February 6, 2009– TR 1Reproduction ou diffusion interdite sans autorisation du

CEA

ODS steels – part I :ODS steels – part I :

manufacture, mechanical properties manufacture, mechanical properties

and oxidation behaviourand oxidation behaviour

Yann de Carlan, Jean Henry, Ana AlamoYann de Carlan, Jean Henry, Ana Alamo

Arnaud MonnierArnaud Monnier

Raphael Couturier, Emmanuel RigalRaphael Couturier, Emmanuel Rigal

Céline CabetCéline Cabet

Commissariat à l’Energie Atomique CEA, FRANCECommissariat à l’Energie Atomique CEA, FRANCE


CEA

OverviewOverview

Why ODS steels?

Manufacture

Observation and analysis

Microstructure control

Mechanical properties (+ radiation stability)

Welding techniques

Oxidation properties


CEA

Why ODS ?


CEA

Why ferritic ODS?Why ferritic ODS?

• Radiation resistance at high temperature

M. Inoue, JAEA, MATGENIV, 2007


CEA

Strengthening of alloys: ODS Strengthening of alloys: ODS principleprinciple

• Increase obstacles to dislocation glide– Precipitates or other dislocations

– Finer dispersoides and higher number density

lprecipitates

Clement, CEA

precitatesl

b 2

A


CEA

Manufacture


CEA

Overview of the powder metallurgy Overview of the powder metallurgy processprocess

Mechanical Alloying(MA)

Hot/cold Rolling

Attrition Mill

Intermediateheat treatment

Elemental orprealloyed powder

Hot Extrusion

Caningdegassing High Isostatic

Pressure

MachiningDrilling

Raw materialpowder

Mother tube

Y2O3 powderMA

powder

soft steel can

Annealing


CEA

Atomisation of an alloyAtomisation of an alloy

R. Lindau, FZK, GETMAT project

P91 steel

Powder sieving

SEM of atomized powder


CEA

Photo attritor + parameters

alloying parameters

- powder to ball ratio

- milling energy (-> rpm, cycling)

- milling time

R. Lindau, FZK, GETMAT project


CEA

Hot extrusion

soft steel

ODS steelODS steel

Hot extrusionHot extrusion

Y de Carlan, CEA


CEA

What happens during the process ?What happens during the process ?

Fe-18Cr-Ti Y2O3 , Y. De Carlan et al., ICRFM13, 2007

nano clusters< 10 nm

200nm

Before milling

After milling

12h milling – With Ti

12h millingno Ti

Mechanical alloying

Consolidation


CEA

M. Ratti et al., Boston, MRS 2008

Study by X Ray diffraction : Pre-alloyed powder + 10% of yttria

What happens during the process ?What happens during the process ?


CEA

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

26 31 36 41 46 51Angle 2.Théta

No

mb

re d

e co

up

s

Heat treatment 950°C/1h with titanium

Heat treatment 950°C/1h without titanium

Monoclinic base centered yttrium oxide peaks according to ICDD database

Body centered cubic yttrium oxide peaks according to ICDD database

Face centered cubic yttrium oxide peaks according to ICDD database

0

1000

2000

3000

4000

5000

6000

7000

26 31 36 41 46 51Angle 2.Théta

No

mb

re d

e co

up

s

48h milling without titanium

48h milling with titanium

After MA

What happens during the process?What happens during the process?

Study by X Ray diffraction : Pre-alloyed powder + 10% of yttria

After 1h @950°C

After MAFe peak

M. Ratti et al., Boston, MRS 2008


CEA 14

UT -BAT T EL L EO ak Ridge National Laboratory, U .S . Department of EnergyD. 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


CEA

M. Inoue, JAEA

Alternative process routesAlternative process routes


CEA

OCAS, GETMAT project

Alternative process routesAlternative process routes


CEA

Characterization


CEA

Optical microscopyOptical 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


CEA

0.46 Y

0.3 Ti

0.85 W

Microprobe analysis of as-manufactured Fe-18Cr-Ti-Y2O3 alloy

SEM, EDX and microprobeSEM, 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


CEA

TEM TEM

12Y1 ODS steel: bright- and dark-field TEM micrographs taken near beam direction B ~(1 2 2)

Y2O3 particle sizes are in the

range of a few tens of

nanometers in diameter

I.-S. Kim et al., JNM 280 (2000) 264-274


CEA 21

M.K. Miller et al., JNM, 2004

Nanometer scale precipitation in ferritic MA/ODS alloy MA957 after hot consolidation

Atom ProbeAtom Probe


CEA

Analysis by XRD and SANSAnalysis 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%Y2O3 and 10% Ti

M. Ratti et al., Boston, MRS, 2008, CEA

SANS of ODS steels with 0.3%Y2O3 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


CEA

Microstructure control


CEA

Chemical composition: Minor Alloying Chemical composition: Minor Alloying ElementsElements

• 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


CEA

Chemical composition: YChemical composition: Y22OO33 content content

• Effect of addition of Y2O3 in 13Cr-3W-0.5Ti on tensile properties at 650°C

• Effect of addition of Y2O3 in 13Cr-3W-0.5Ti on creep rupture strength at 650°C

Ukai S., JNM 204 (1993) 65-73


CEA

Chemical composition: Minor Alloying Chemical composition: Minor Alloying ElementsElements

• Effect of addition of Ti in 13Cr-3W-0.5Y2O3 on creep rupture strength at 650°C

Fig 4 Ukai JNM 1993

Ukai S., JNM 204 (1993) 65-73


CEA

Chemical composition: Excess of oxygenChemical composition: Excess of oxygen

• Effect of excess O in 13Cr-3W-0.5Ti-0.5Y2O3 on creep rupture strength at 650°C

Ukai S., JNM 204 (1993) 65-73


CEA

A. Alamo et al. , JNM 329–333 (2004) 333–337

0

2

4

6

8

10

12

-200 -100 0 100 200

MA957 - FG

MA957 - R

En

erg

y (

J)

Temperature (°C)

y = m1+(m1-2)*(exp((m0-m3)/m...

ErrorValue

4.440195.231m1

4.5467-69.209m3

7.777133.505m4

NA5339.8Chisq

NA0.96R

y = m1+(m1-2)*(exp((m0-m3)/m...

ErrorValue

0.9806419.307m1

7.0704-92.707m3

13.43653.445m4

NA241Chisq

NA0.94412R

y = m1+(m1-2)*(exp((m0-m3)/m...

ErrorValue

1.440718.466m1

5.8609-85.803m3

10.84725.805m4

NA428.06Chisq

NA0.88551R

y = m1+(m1-2)*(exp((m0-m3)/m...

ErrorValue

0.5646816.496m1

5.5712-52.641m3

9.303878.463m4

NA25.393Chisq

NA0.98789R

y = m1+(m1-2)*(exp((m0-m3)/m...

ErrorValue

3.62781.132m1

6.1215-44.722m3

10.98852.073m4

NA1863.4Chisq

NA0.97784R

y = m1+(m1-2)*(exp((m0-m3)/m...

ErrorValue

2.330495.171m1

2.6998-63.03m3

5.611938.161m4

NA730.7Chisq

NA0.99334R

y = m1+(m1-2)*(exp((m0-m3)/m...

ErrorValue

1.984789.937m1

1.9647-56.886m3

4.623923.364m4

NA874.73Chisq

NA0.99299R

y = m1+(m1-2)*(exp((m0-m3)/m...

ErrorValue

4.463495.489m1

5.9519-64.388m3

11.7950.604m4

NA2245.4Chisq

NA0.97778R

y = m1+(m1-2)*(exp((m0-m3)/m...

ErrorValue

2.087693.533m1

1.9009-60.158m3

4.160120.75m4

NA1031Chisq

NA0.99232R

y = m1+(m1-2)*(exp((m0-m3)/m...

ErrorValue

3.300889.182m1

4.2094-28.77m3

6.419334.721m4

NA1672.8Chisq

NA0.98763R

y = m1+(m1-2)*(exp((m0-m3)/m...

ErrorValue

2.758747.043m1

2.8259-96.955m3

5.320420.497m4

NA792.12Chisq

NA0.97332R

y = m1+(m1)*(exp((m0-m3)/m4)...

ErrorValue

0.313963.8357m1

3.5339-113.47m3

7.30713.118m4

NA9.603Chisq

NA0.93863R

USE (J)DBTT (°C)MA957

7.7- 110Fine Grains

9.2+ 60Recrystallised

RecrystallisedFine grains

Effect of the grain sizeEffect of the grain size

• Effect of MA957 ODS-alloy microstructure on– the impact properties– the tensile properties

fine grain


CEA

Mechanical properties


CEA

Creep properties (creep rupture time) Creep properties (creep rupture time)

A. Alamo et al., JNM 329–333 (2004) 333–337


CEA

Creep of high strength ODS alloysCreep of high strength ODS alloys


CEA

Welding


CEA

[email protected]

Basis of weldingBasis 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


CEA

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 weldingLiquid state weldingmelting of the base metal

change in the microstructure


CEA

SPS principle (3)

(3) www.ceramicindustry.com

Resistance welding principle (4)

(4) www.swantec.comResistance welding operation (5)(5) www.plasmo.eu

FSW principle (6)

(6) www.wikipedia.com

Solid state welding

retain the microstructure

Solid state wedlingSolid 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


CEA

Hot Isostatic PressureHot Isostatic Pressure

[email protected]

• 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


CEA

Mockup: upper plate

Mockup: first wall Mockup:

cooling plate

Eurofer joint

High Isostatic PressingHigh Isostatic Pressing

[email protected]


CEA

INSA Lyon

Spark Plasma Sintering (SPS)Spark Plasma Sintering (SPS)

[email protected], CEA

Université de Bourgogne

SPS principle


CEA

www.cea.fr

Resistance welding device of CEA/DEN/DANS/DM2S/SEMT/LTA

[email protected]

Resistance weldingResistance welding


CEA

hardness of the weld = hardness of the base metal

needs for accurate analysis of the dispersoid size and allocation

Resistance welding – characterization of the Resistance welding – characterization of the weldweld

[email protected]


CEA

Characterization of ODS weldCharacterization 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


CEA

Oxidation properties


CEA

Example of commercial ODSExample of commercial ODS

from Fe Ni Cr Al Ti Mo W others C Y2O3

MA 956 INCO base 20 4,5 0,5 0,5

PM 2000 Plansee base 20 5,5 0,5 0,5

ODM 751 Dour Metal base 16,5 4,5 0,6 1,5 0,5

MA 957 INCO base 14 1 0,3 0,25

MA758 INCO base 30 0,3 0,5 0,05 0,6

MA754 INCO base 20 0,3 0,5 0,05 0,6

PM 1000 Plansee base 20 0,3 0,5 0,6

MA760 INCO base 20 6 2 3,5 Zr 0,15 0,05 0,95

PM 3030 Plansee base 17 6 2 3,5 Ta 2 Si 0,95 1,1

MA757E INCO 0,5 base 16,8 4 0,5 0,06 0,7

HDA-8077 Cabot base 15,7 4,2 0,06 Y :1,6

MA6000 (') INCO base 15 4,5 2 2 2 Ta 2 Zr 0,15 0,05 1,1

MA753 (') INCO base 20 1 2,2 0,05 1,3

alumina-formingchromia-forming


CEA

Y is a RE !!!Y is a RE !!!

• Improve the oxidation and corrosion properties longer service life

• RE = Reactive Elementeffective when added as

– metal or alloy

– oxide dispersoids (ODS)

– ionic implantation

– surface coating

Fe-24Cr800°C, air


CEA

Improvement of the oxidation propertiesImprovement of the oxidation properties

• Surface oxide thickness

Oxidation in dry air at 650°C for 2000hrs

12Cr-2W ODS (0.24 Y2O3) FMS 12Cr-2W

• Mass gain

• Spallation

alumina scale spalls out

protection is lost


CEA

Influence on the scale formationInfluence on the scale formation

• Decrease of the critical Cr% for chromia formation

Alumina forming Chromia forming

• Promote -Al2O3 (no transitory θ-Al2O3)

• Decreases the duration of transitory oxidation(reduces the base metal oxidation)

Fe-Cr Co-Cr Ni-Cr

no Y 20%Cr 25%Cr 35%Cr

Y2O3 10-13% Cr

12Cr steel oxidized at 1300°C in dry air for 50h


CEA

Influence on the scale growthInfluence on the scale growth

• Supress outward diffusion of metal cation


O2

OY2O3

Cr

O2 O2

O

no Y

RT

Eexp.DDk

t.k

ap

pox

ox

t

ox2

t

Wagner theory

• Decrease the oxidation rate (parabolic constant)

• Possible change in the oxidation kinetics (from parabolic to subparabolic)


CEA

Influence on the scale microstructure and Influence on the scale microstructure and adhesionadhesion

• Increase adhesion spallation resistance


• Increase the scale compacity and decrease the oxide grain size

• Supress the pores at the alloy/scale interface

2µm

Al2O3 dispersion Tb4O7 dispersion

FeCrAl oxidized at 1300°C for 100h


CEA

Which is the optimum RE quantity?Which is the optimum RE quantity?

• No practical rule• It depends on

– Chemical nature of the RE

– Size and distribution

– Chemical interactionwith Ti, C, N

– Fabrication technique


CEA

Temperature range for ODS useTemperature range for ODS use

800°C 950°C 1200°C1300°C

evaporation

breakaway oxidation

Ni-CrFe-Cr Ni-Cr-Al

Fe-Cr-Al

evaporationoxidation rate

spallation

spallationbreakaway oxidation

Fe-12Cr

PM2000 tested in air at 1200°C for 1825 h, cycling at RT every 48h


CEA

ConclusionConclusion

• 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


CEA

Conclusion cont.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

Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 1...

Documents

Transcript of Reproduction ou diffusion interdite sans autorisation du CEA Matgen4.2 – February 6, 2009– TR 1...