chamber materials progress round robin materials refractory armored ferritic helium management

$: Chamber Materials Progress Round Robin Materials Refractory Armored Ferritic Helium Management$
1

OAK RIDGE NATIONAL LABORATORYU. S. DEPARTMENT OF ENERGY

Chamber Materials Progress

Round Robin MaterialsRefractory Armored Ferritic

Helium Management

J. Blanchard1, C. Blue,5 A. Federov2, N. Ghoniem3, S. Gilliam4, S. Gidcumb4,

J. D. Hunn5, S. O’Dell6, B. Patnaik4, N. Parikh4, G. R. Romanoski5,

S. Sharafat3, L. Snead5, T. Van Veen2

Delft Institute2, ORNL5, PPI6, UCLA3, UW1, UNC4

Presented at the High Average Laser Program Workshop

Georgia Institute of Technology

February 5-6, 2004

2


I still think everyone is getting what they need

Round Robin Materials

3


Facility Improvements : Implantation/Anneal

0

500

1000

1500

2000

2500

0 1 2 3 4 5

Minutes

0

2

4

6

8

10

• Upper annealing temperature

increased to 2500°C.

• System now fully automated.

Moving towards round-the-clock

operation (8 x 104 irr/anneal/day)

4


Facility Improvements : IR Thermal Fatigue

0

5

10

15

20

25

-200 0 200 400 600 800 1000Time (ms)

Heat flux (MW/m

2)

• Facility has been used for interfacial fatigue of W/LAF

• Previously 20 MW/m2 (time average), 20 msec pulse, 10 Hz, 10 cm2

5


Facility Improvements : IR Thermal Fatigue

• Now capable of 100 MW/m2 (time average), 2 msec pulse, 10 Hz, 5 cm2

• Phase 1 goal 1000 MW/m2 (time average), 0.1 msec pulse, 10 cm2

10

100

1000

104

0.001 0.01 0.1 1 10 100

Time (milliseconds)

IFE

~104 MW/m2

~ 10 μsec

IR upgrade

~102 / 2MW m ~ 2 msec

IR ThermalFatigueFacility~20 / 2MW m ~ 20 msec

> 0.1 / 2MJ m

~ 0.4 / 2MJ m

~ 0.2 / 2MJ m

6


Development of Armor

Fabrication process and repair

He management Mech. & thermal fatigue testing

“Engineered Structures”Ablation

Underlying Structurebonding (especially ODS)

high cycle fatiguecreep rupture

Armor/Structure Thermomechanicsdesign and armor thickness

detailed structural analysiis

thermal fatigue and FCG

Structure/Coolant Interface

corrosion/mass transfer/coating

2003 2004 2005 2006 2007

Development of W/LAF : Phase 1 Effort and Milestones

!!

!

!

} !

scoping optimization scaling

!

!scoping & modeling optimization

! !

7


Phase I : Helium Management

Objective: To understand parameters controlling helium diffusion in tungsten to develop armor with near zero helium retention.

Approach:

- Experimentally determine whether potential solutions exists. 04 Milestone.

- Get diffusion coefficients of ideal materials for modeling. 04 Milestone

- Define effect of microstructure, implantation, and anneal conditions, on retention of helium.

- Carry out diffusion modeling and determine if “engineered” structures are required. 04 Milestone.

-Phase I Goal : Perform long-term (>105 cycles, >1021 He/m2) IFE relevant implantation on candidate W/LAF

!

!

!

8


1x1021 (He/m2)

1.5 MeV He implanted polycrystalline W : 850C,flash annealed to 2000C.

Spallation Problem

2x1021 (He/m2)

5x1021 (He/m2) 10x1021 (He/m2)

9


Comparison of Polycrystalline, Single Crystal, and CVD W

0

100

200

300

400

500

12.8 13.0 13.2 13.4

Energy (MeV)

Proton Yield

single crystalpolycrystallineCVD

0

100

200

300

400

500

12.8 13.0 13.2 13.4Energy (MeV)

Proton Yield

single crystalpolycrystallineCVD

(a) 850°C implant, as-implanted

At 5 x 1020 He/m2 single crystal, polycrystalline, and CVD tungsten exhibited comparable helium retention.

Before and after annealing the proton yields collected by NRA were the same within a few percent.

(b) 850°C implant, 2000°C anneal

10


Step ImplantationsWhat happens when we approach IFE implant/anneal cycle?

0

500

1000

1500

2000

2500

0 1 2 3 4 5

Minutes

0

2

4

6

8

10

1.3 MeV He implantationPoly-X tungsten targetResistive Heating

A series of implantation to 1019 He/m2 for1, 10, 100 and 1000 cycles has been completedfor both single X and powder processed W.

11


0

20

40

60

80

100

120

140

160

12.8 13.0 13.2 13.4

Energy (MeV)

Proton Yield

1 step as-implanted

1 step annealed

10 steps

100 steps

1000 steps

Proton spectra for polycrystalline (a) and single crystal (b) tungsten implanted at 850C and flash annealed at 2000C in 1, 10, 100, and 1000 cycles to reach a total dose of 1019 He/m2. The sample implanted with the total dose in one step was analyzed before and after the 2000C anneal.

0

10

20

30

40

50

12.8 13.0 13.2 13.4

Energy (MeV)

Proton Yield

1 step asimplanted

1 step annealed

10 steps

100 steps

1000 steps

(a) (b)

Step ImplantationsWhat happens when we approach IFE implant/anneal cycle?

In both single and polycrystalline tungsten the helium dose per cycle affects retention significantly.

Single crystal releases helium more easily than polycrystalline.

12


0

50

100

150

200

250

300

350

400

12.8 12.9 13 13.1 13.2 13.3 13.4 13.5

Energy (MeV)

Proton Yield

1000 steps (850/2000)

1 step as-implanted (850)

1 step annealed (850/2000)

100 steps (850/2500)

Effect of Annealing Temperature on Retention: Single-X W

Single crystal annealed at 2500°C shows significantly less helium retention than the 2000°C anneal.

Temperature plays a significant role when comparing the step sizes and the two different annealing temperatures.

13


04 Milestone : Go/No Go on helium management. Is there the potential to defeat the spallation problem?

Where are we ???

!

• Even though we have an extremely high fluence of helium, due to the small implant “packets” and the extreme annealing associated with the fusion event, difficult to diffuse helium clusters are not formed in single crystal W and the helium is released. We’re good to Go?

• What is now needed:

- Determine effective diffusivity needed for modeling.

- Determine the annealing kinetics and carry out rapid

implant/anneal experiments.(current experiments have long anneal)

- Continue to define role of microstructure on retention.

(as seen from the polyX W results, real structures may spall.)

- Carry out high-cycle implantations (105 anneal/implantation)

- Include effects of hydrogen.

14


Phase I : Fabrication Process and RepairTungsten Armored Low Activation Ferritic Steel

Objective: select and optimize methods for bonding tungsten to LAF steel and assess the integrity of these coatings under HAPL-relevant thermal fatigue conditions.

Approach: - Evaluate methods for applying tungsten coatings to substrates. Fabricate and

study adherence and thermal stability. Is there a viable material? FY-04 Milestone.

- Given W thickness, model interface fatigue stresses and fatigue crack growth performance of underlying LAF. FY-04 Milestone.

- Screen coupon coatings using thermal fatigue facility. Select candidate monolithic armor system or move to “engineered structure.” FY-05 Milestone.

- Phase 1 Endpoint : Perform scaling studies and carry out prototype thermal fatigue at IFE relevant conditions:

> 105 cycles, <100μs pulse width > 103 MW/m2 (during pulse) > 10 cm2 sample face

!

!

!

15


Viable W/Low Activation Ferritic?Screening material processing options.

Infrared fusion of tungsten powder

Diffusion bonding of tungsten foil

Vacuum plasma spraying powder

Alternative approaches, e.g., CVD

Processing Method Method of Screening

Thermal stability of interface

Thermal Fatigue

Interfacial Strength

16







Processing Method

IR processing: 2350W/cm2 (Flash: 6sec)• Initial runs showed promise, though somewhat

non-uniform surface. Considered back-up.

17







Processing Method

• Initial runs showed promise: high-thermal

conductivity and good uniformity. Cracks

were present due to CTE mismatch and

phase change. Considered back-up.

18


Vacuum Plasma Spraying of Tungsten Powders

Coating Conditions Post-Spray TreatmentFeed Gas Argon / Hydrogen

100 – 300 torrNone H anneal

800C/4hH anneal + HIP800C/4h/30ksi

100µm tungsten only (-45/+20µm)600ºC Preheat – Mach 2-3

5 samples 5 samples 5 samples

100μm tungsten only (-45/+20µm)No Preheat – Mach 1


100μm tungsten only (-45/+20µm)600C Preheat - Mach 1


200μm-thick graded layer of 50% steel blended with 50% tungsten plus100μm-thick tungsten top coat (-

45/+20μm).No preheat –Mach 1


300µm-thick tungsten only (-45/+20μm)No preheat -Mach 1


100µm-thick tungsten only (-20µm)No Preheat - Mach 1


VPS coatings were produced at Plasma Processes of Huntsville, Alabama

Preliminary VPS coating looked promising.

An array of coatings were then ordered for evaluation

19


VPS Tungsten on F82H Steel : Post-Spray Treatments

Post-spray hydrogen anneal at 800°C/4hrs provides stress relief. Annealing limited to 800°C due to steel substrate. Temps of 1700°C required for sintering VPS W coatings may be achieved with IR processing.

Post spray hot isostatic pressing 800°C / 35ksi achieved some densification of the coating (enhancing thermal conductivity.)

As Sprayed Hot Isostatic Pressing

20


Microstructural stability of F82H will limit the interface temperature to under 900C

Coarsening of carbides above 800C and dissolution around 900C will degrade mechanical properties.

The alpha – gamma - alpha phase transformation will impart large strains at the interface.

A critical thickness of tungsten will be required to dissipate the heat pulses to maintain the interface in an acceptable temperature regime.

Furnace cycling experiments will be performed to better understand interface stability.

21


VPS coatings were produced with W/steel intermediate layer to minimize thermal strain mismatch.

Blended constituents will result in an average thermal expansion.

The intermediate layer is rather heterogeneous due to the coarse size of available steel powder.

Significant porosity will impart compliance to the coating (but

reduce conductivity.)

22


04 Milestone : Go/No Go on tungsten armor. Is there a viable material?

!

Where are we ???

• All coating studied had promise. Vacuum plasma sprayed W on F82H

low activation ferritic is being focused on.

• Previous thermal fatigue showed promise.

• Long-term stability of interface is still required, but it looks like a Go.

IR Thermal Fatigue Facility

Rep rate: 10Hz, 1000 cyclesMax. flux: 20.9MW/m2 (20ms)Min. flux: 0.5MW/m2(80ms)

Substrate temp. (bottom): 600 ºC0

5

10

15

20

25

-200 0 200 400 600 800 1000Time (ms)

Heat flux (MW/m

2)

23


Questions ???

24


Moving Towards Phase IIMaterials Development

February 6, 2004Georgia Institute of Technology

25


Development of Armor

Fabrication process and repair

He management Mech. & thermal fatigue testing

“Engineered Structures”Ablation

Underlying Structurebonding (especially ODS)

high cycle fatiguecreep rupture

Armor/Structure Thermomechanicsdesign and armor thickness

detailed structural analysiis

thermal fatigue and FCG

Structure/Coolant Interface

corrosion/mass transfer/coating

2003 2004 2005 2006 2007

Development of W/LAF : Phase 1 Effort and Milestones

!!

!

!

} !

scoping optimization scaling

!

!scoping & modeling optimization

! !

26


Phase I (~5-6 years)- Mission Oriented R & D• Develop required science & technology.

Phase II (~8-9 years)-Integrate d Research Experiment (IRE)• Essential reactor coμ ponents operate together with required efficiency and precision.• Includes a full-scale laser μ odule.• Includes μ ore coμ prehensive R & D in target fabrication, μ aterials, and power plant

design.

Phas e III (~10 years)- Engineering Tes t facility (ETF)• Therμ onuclear gain.• Validate μaterials & coμ ponents for a fusion systeμ.• Could also deμ onstrate fusion electrical power.

HAPL Program Plan

27


• At the end of Phase 1 (constant dollars), assuming that a flat-plate or simple “engineered” armored structure appears workable, we will have materials ready for serious development.

--there is a concern that significant time at the beginning of Phase 2 will be eaten optimizing a material, delaying the time consuming effort of property testing and proof testing.

• At what point do we need irradiation data? There is fair data on LAF, but no data on its fatigue properties. The behavior of this tungsten, and the W/LAF interface is essentially not known. Can we wait until the end of Phase 2 for bad news here?

• As we move towards Phase 2, the issue of fatigue will require seriously studied. High-cycle thermomechanical fatigue of prototype size component will be necessary. As this is very time consuming, any delay in delivery of the candidate armor will lengthen Phase 2.

• Leading up to Phase 2 we should include in the MWG a specialist in design of vibrating structures and one on NDE.

• Code qualifications may bite us.

• Following Rene’s logic, we need qualified primary candidate at least two years prior to ETF. Is there enough time?

28


29


30


ComputerLabVIEW

DAQ Card

Power Controller

Cup Control

Infrared Thermometer

SampleControls implant dose

Reads sample temperature

Controls sample temperature

Current Integrator

(Faraday Cup)

Current Integrator

(BPM)

Automation Hardware Schematic

31


Thermal Fatigue Test Plan

Test Conditions2003 2004 2005 2006

Test Article specimen specimen specimen Mock-ups

Area Tested (cm2) 2 2 2 100

Maximum Flux (MW/m2)

21 30 30

Pulse Width (ms) 10 10 10 0.1

Rep Rate (Hz) 10 10 10 ?

Duration (cycles) 1K 10K to 100K 10K to 100K 10K to 100K

Substrate Temperature ©

600°C 600°C 600°C LAF800°C ODS

600°C LAF

Diagnostics Back face T Back face TSurface T

Back Face TSurface T

Flux

chamber materials progress round robin materials refractory armored ferritic helium management

Documents