Upload
others
View
4
Download
1
Embed Size (px)
Citation preview
2nd IAEA TM on Divertor, Suzhou, Nov. 13-16, 2017 R.Neu 1
Max-Planck-Institut für Plasmaphysik
1) Max-Planck-Institut für Plasmaphysik, 85748 Garching, Germany
2) Osram GmbH, SP PRE PLM DMET, 86830 Schwabmünchen, Germany
3) Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung – Plasmaphysik, 52425 Jülich, Germany
4) Technische Universität München, 85748 Garching, Germany
Tungsten Fibre-Reinforced Composites
for Advanced Plasma Facing
Components
J. Riesch1, J. Almanstötter2, M. Balden1, J. W. Coenen3, H.
Gietl1,4, T. Höschen1, Y. Mao3, A. v. Müller1,4, L. Raumann3,
R. Neu1,4 and the Wf/W-Team1,3
2nd IAEA TM on Divertor, Suzhou, Nov. 13-16, 2017 R.Neu 2
• Introduction
• W fibres and preforms
• Wf/W-composite
• Wf/Cu-composite
• Conclusions and outlook
Tungsten fibre-reinforced composites for
advanced plasma facing components
2nd IAEA TM on Divertor, Suzhou, Nov. 13-16, 2017 R.Neu 3
Introduction/Motivation
recrystallisation inherent brittleness
softening
Based on
S.J. Zinkle et al.,
FED 51-52
(2000) 55-71]
and
Timmis,
Mat. Ass. Rep.
(2012)
[G. Pintsuk et al.
FED 88 (2013)
1858]
deep cracking of ITER W
monoblock at 20 MW/m2
• Copper (Cu) based alloys (as for example CuCrZr) are foreseen as heat
sink, whereas as armour tungsten (W) based materials will be used.
• combining both materials in PFCs bears the difficulty that their optimum
operating temperatures do not overlap:
• W should be operated above 800°C
in order to be in a ductile state to avoid
brittle cracking under cyclic load,
• CuCrZr should be operated below 300°C to provide enough
mechanical strength.
2nd IAEA TM on Divertor, Suzhou, Nov. 13-16, 2017 R.Neu 4
Introduction/Motivation
• Copper (Cu) based alloys (as for example CuCrZr) are foreseen as heat
sink, whereas as armour tungsten (W) based materials will be used.
• combining both materials in PFCs bears the difficulty that their optimum
operating temperatures do not overlap:
• W should be operated above 800°C
in order to be in a ductile state to avoid
brittle cracking under cyclic load,
• CuCrZr should be operated below 300°C to provide enough
mechanical strength.
A remedy for both issues
– brittleness of W and degrading strength of CuCrZr –
could be the use of W fibres in W and Cu based composites
2nd IAEA TM on Divertor, Suzhou, Nov. 13-16, 2017 R.Neu 5
• Introduction
• W fibres and preforms
• Wf/W-composite
• Wf/Cu-composite
• Conclusions and outlook
Tungsten fibre-reinforced composites for
advanced plasma facing components
2nd IAEA TM on Divertor, Suzhou, Nov. 13-16, 2017 R.Neu 6
Performance of W-fibres
upper clamp +
load cell
laser spots
diode lasers
lower clamp +
manipulator
16 mm
translationstage
CCD +telecentric lens
W wire
epoxy glue
epoxy glue
[Riesch et al., Physica Scripta, 2016, T167, 014006]
W fibres: - are ductile already @ r.t.
- no embrittlement < 2200 K
- yield strength increases with
decreasing fibre diameter
2nd IAEA TM on Divertor, Suzhou, Nov. 13-16, 2017 R.Neu 7
[Riesch et al., Physica Scripta, T170 (2017) 014032]
use thinner W fibres
(higher deformation)
- higher tensile strength
- more flexible
development of W-yarn
W fibres with PVA enwinding
[Coenen et al., ICFRM]
Performance of W-fibres
2nd IAEA TM on Divertor, Suzhou, Nov. 13-16, 2017 R.Neu 8
Preforms for Wf/W
flat W fibre textiles for layered deposition of Wf /W-samples,
optimum parameters defined:
- 150/50 µm warp/weft wire, 600 mm width,
- eventually yarn to reduce height & stiffness of textile ( higher fibre fraction)
0
282
141
µm
230-250 µm
100-150 µm
warp
150 µm
weft 70 µm
2nd IAEA TM on Divertor, Suzhou, Nov. 13-16, 2017 R.Neu 9
Preforms for Wf/Cu tubes
braided cylindrical preform (23
layers)
5000 μm high strength W
fibres (∅: 50 µm)
• tubular fabrics of multi-layered W fibres for Wf /Cu-tubes by braiding (~m)
• optimisation of wire thickness (50 µm), braiding angle (77°) and layer
number (23) successfully completed
• yarns can further optimize performance (easily to be infiltrated)
2nd IAEA TM on Divertor, Suzhou, Nov. 13-16, 2017 R.Neu 10
• Introduction
• W fibres and preforms
• Wf/W-composite
• Wf/Cu-composite
• Conclusions and outlook
Tungsten fibre-reinforced composites for
advanced plasma facing components
2nd IAEA TM on Divertor, Suzhou, Nov. 13-16, 2017 R.Neu 11
Wf/W – state of the art
Principle
Synthesis
Chemical
Vapour
Deposition
(CVD-Wf/W using WF6)
powder metallurgy (PM-Wf/W)
presentation by Y. Mao
Matrix
Fibre:
drawn
W-wire Interface
2nd IAEA TM on Divertor, Suzhou, Nov. 13-16, 2017 R.Neu 12
Artificial
notch First fibre layer
half cut
Mechanical Properties of Wf / W
• Multi-fibre composite (150 µm)
W-CVD layered deposition
Polished
ca. 3 mm x 2 mm x 10 mm
• as fabricated and
embrittled (2000 K, 30 min) Wf / W
2 mm
• stepwise 3-point bending +
in-situ surface observation in SEM (ESI)
2nd IAEA TM on Divertor, Suzhou, Nov. 13-16, 2017 R.Neu 13
2 mm
• stepwise 3-point bending +
in-situ surface observation in SEM (ESI)
Mechanical Properties of Wf / W
• Multi-fibre composite (150 µm)
W-CVD layered deposition
Polished
ca. 3 mm x 2 mm x 10 mm
• as fabricated and
embrittled (2000 K, 30 min) Wf / W
ductile fibre
strength 2900 MPa,
fracture strain 2%
brittle fibre
strength 900 MPa,
fracture strain 0.2 %
matrix failure
= bulk material failure
Lo
ad
[N
]
Displacement [µm]
rising load
bearing capacity
no catastrophic
failure
2nd IAEA TM on Divertor, Suzhou, Nov. 13-16, 2017 R.Neu 14
Cyclic tensile testing of WfW in as-fabricated condition
Fibre orientation
2nd IAEA TM on Divertor, Suzhou, Nov. 13-16, 2017 R.Neu 15
10.000
Cycles 10.000 Cycles
without further damage
115 Overload Cycles
without catastrophic failure
10.000 Cycles @ 60% 10.000 Cycles @ 70% 10.000 Cycles @ 80% 10.000 Cycles @ 90% 10.000 Cycles @ 100%
𝒍
𝒍
𝒍
𝒍
𝒍
𝟐𝒍
𝒍
𝒍
𝒍 ≈ 𝒄𝒐𝒏𝒔𝒕
damage tolerance
H. Gietl
FED 2017
Cyclic tensile testing of WfW in as-fabricated condition
2nd IAEA TM on Divertor, Suzhou, Nov. 13-16, 2017 R.Neu 16
Preliminary FEM analysis of thermal behaviour of Wf /W-composite
therm. conductivity
fibres
100% 50% 10%
fibre volume
fraction:
13%
(Ø0.25mm)
Tmax
surface
2146 219
5
227
0
Tmax fibres 1959 201
1
209
5
fibre volume
fraction:
33% (Ø0.4
mm)
Tmax
surface
2146 229
0
258
9
Tmax fibres 2033 218
3
249
1
debonding length (mm) 0 2 10
fibre volume fraction: 13% (Ø0.25mm)
Tmax surface 2146 2149 2161
Tmax fibres 1959 1961 1974
Maximum temperatures (°C) for different thermal conductivities /
debonding lengths of W fibres
FEM (Abaqus) simulations,
actively cooled component,
20 MW/m² loading
model
fibre
layers
2nd IAEA TM on Divertor, Suzhou, Nov. 13-16, 2017 R.Neu 17
Upscaling of CVD process for Wf/W production
rotatable supply and CVD target
W(CO)6 ‚shower‘
60 mm
Wf/W sample Wf preform
2nd IAEA TM on Divertor, Suzhou, Nov. 13-16, 2017 R.Neu 18
• Introduction
• W fibres and preforms
• Wf/W-composite
• Wf/Cu-composite
• Conclusions and outlook
Tungsten fibre-reinforced composites for
advanced plasma facing components
2nd IAEA TM on Divertor, Suzhou, Nov. 13-16, 2017 R.Neu 19
(hoop)
at 300°C
(W/(m·K))
265
274
283
318
calculated stress-strain behaviour
W fibre-reinforced Cu composites
(a) transversal
(b) axial microsections
of a Wf/Cu heat sink pipe
Manufacturing of W fibre-reinforced Cu composite by means of liquid Cu
melt infiltration in a carbon-free environment!
[A. v. Müller FED 124 (2017) 455]
Property Estimation
(Digimat Calculations):
relating micro & macro properties
by averaging quantities over
representative volume element (RVE)
[A. v. Müller ICFRM 2017]
2nd IAEA TM on Divertor, Suzhou, Nov. 13-16, 2017 R.Neu 20
Performance of Wf/Cu composites
100 µm
fracture surface of a W fibre-reinforced Cu pipe specimen:
Cu infiltrated W fibre braiding; axial tensile test at room temperature
necking of W fibres plainly visible
ductile failure of both Cu matrix & W fibrous reinforcements
(already at room temperature)
2nd IAEA TM on Divertor, Suzhou, Nov. 13-16, 2017 R.Neu 21
Performance of mock-ups with Wf/Cu heatsink
HHF testing (GLADIS) of W fibre-reinforced Cu heat sink pipe
successful HHF testing up to 25 MW/m2
indicates good material performance
HHF testing (GLADIS) of monoblock-type mock-up
with W fibre-reinforced Cu heat sink pipe
W fibre-reinforced Cu
pipe before HHF testing
W fibre-reinforced Cu pipe
during HHF testing
W fibre-reinforced Cu pipe
after HHF testing
brazed joint between W monoblocks and
W fibre-reinforced Cu heat sink pipe
successful HHF testing up to 300 load cycles
at 20 MW/m2 without indication of failure
Monoblock-type PFC mock-up
with W fibre-reinforced Cu heat
sink pipe
2nd IAEA TM on Divertor, Suzhou, Nov. 13-16, 2017 R.Neu 22
• Introduction
• W fibres and preforms
• Wf/W-composite
• Wf/Cu-composite
• Conclusions and outlook
Tungsten fibre-reinforced composites for
advanced plasma facing components
2nd IAEA TM on Divertor, Suzhou, Nov. 13-16, 2017 R.Neu 23
Conclusions
• industrial textile processing of W fibres to cylindrical braiding and
flat textiles has been demonstrated
• large scale composites have been produced by layered chemical
vapour deposition (Wf/W ) and infiltration (Wf/Cu)
• Wf/W composites show high toughness and damage tolerance in
cyclic loading even at room temperature
(K-doped fibres resistive against embrittlement up to 1900 C)
• liquid Cu melt infiltration of W fibre preforms is feasible in industrial
environment
• property estimation indicates clearly the potential of Wf/Cu as
advanced heat sink material for DEMO PFCs
• mock-up with Wf/Cu heatsink successful tested @ 20 MW/m²
W fibre reinforcement strongly increases operational temperatures
of W and Cu (& reduced stresses when used in combination!)
2nd IAEA TM on Divertor, Suzhou, Nov. 13-16, 2017 R.Neu 24
Conclusions
recrystallisation inherent brittleness
ductile fibres &
bridging/pull-out if embrittled K doped
fibres
Wf/CuCrZr
softening
2nd IAEA TM on Divertor, Suzhou, Nov. 13-16, 2017 R.Neu 25
Outlook / Development Plan
design & fabrication of wall mock-up (Wf/W)
proof of concept
HHF testing under relevant test conditions (Wf/Cu)
validation
fusion environment interaction / irradiation studies
component validation in relevant environment
application in ASDEX Upgrade
(manipulator & wall tile)
prototype demonstration in relevant environment
Technology
Readiness
Level (TRL) Idea
Application
PFC in
DEMO
After [Riesch et al., Physica Scripta, 2016, T167, 014006]
Current
status
2nd IAEA TM on Divertor, Suzhou, Nov. 13-16, 2017 R.Neu 26
Tungsten manufactured by means of laser beam melting
A.v.Müller, 6th Int. Conf. on Additive
Technologies iCAT 2016, Nürnberg
Small samples produced by
from pure tungsten
Reduce cracks by improved process using higher temperature of W substrate!
2nd IAEA TM on Divertor, Suzhou, Nov. 13-16, 2017 R.Neu 27
Tungsten manufactured by means of laser beam melting
A.v.Müller, 6th Int. Conf. on Additive Technologies iCAT 2016, Nürnberg