Upload
others
View
6
Download
0
Embed Size (px)
Citation preview
30.10.2009 1
IRRADIATION EMBRITTLEMENT CHARACTERIZATION OF THE EUROFER
97 MATERIAL
M. Kytka, M. Brumovsky
and M. FalcnikNuclear Research Institute Rez plc,
Vltavska 130, 250 68 Rez near Prague, Czech Republic
30.10.2009 2
Introduction
The paper summarizes results of irradiation embrittlement
study of EUROFER 97 material that has been proposed as one candidate for future GEN IV reactors.
Test specimens were manufactured from base metal EUROFER 97 as well as from weld metal and tested in initial unirradiated
condition and also after irradiation to reach approx. 2.5 dpa
.
Sub-sized TPB (3x4 mm) specimens were tested to determine static and dynamic fracture toughness.
The main objective: comparison of unirradiated
and irradiated properties as well as changes in transition temperature shifts of these material parameters.
The investigation has been performed in the frame of EFDA project on „Tritium Breeding and Materials“, Task TW2.
30.10.2009 3
Material and Specimens
Micro-TPB samples (W=4mm, B=3mm) were prepared by machining from plates of 14 mm thickness. Static fracture toughness specimens have been side grooved.
Materials:– BASE METAL: Reduced activation martensitic
steel EUROFER 97
(steel plates of 300x300x14mm).– WELD METAL: A weld joint was prepared from two plates
14x90x300mm by TIG method in CEA Saclay.
Tab. 1 The chemical composition of EUROFER 97 in w%:C Mn Si P S Cu Ni Cr Ti Zr
0.11 0.47 0.040 0.005 0.004 0.0016 0.022 8.82 0.005 <0.005
B As O N V W Mo Ta Nb Co<0.001 <0.005 0.001 0.0034 0.20 1.09 <0.005 <0.005 0.0016 0.006
30.10.2009 4
Irradiation
1
Material specimens were irradiated in the Chouca
rig (irradiation rig with a controlled temperature and inert gas) in the core of the LVR-15 experimental reactor in the Nuclear Research Institute Rez
plc. for 8 irradiation cycles (21 days each) at max. 235
°C.
Neutron fluence
was equivalent to approx. 2.5 dpa
(1.5 x 1021
n.m-2, E >1 MeV).
30.10.2009 5
Irradiation 2
Fig. 1 Average neutron fluences (individual blocks of specimens inthe irradiation rig)
0,0
0,5
1,0
1,5
2,0
2,5
3,0
0 100 200 300 400Position (mm)
Neu
tron
fluen
ce (1
0 21n.
m -2
)E > 0.5 MeVE > 1. MeV
Blocks of specimens forstatic/dynamic FT
30.10.2009 6
Procedure
1
Testing end evaluation of the results has been performed in accord with:
Dynamic fracture toughness– EN 10045-1 Metallic materials-Charpy
impact test-Part 1
– ISO 14556 Steel-Charpy-V notch pendulum impact test-Instrumented test
– ESIS TC5 Proposed standard method for instrumented impact testing of sub-sized Charpy-V notch specimen of steels (Draft 10)
– ASTM E 1921-05 (obtained reference transition temperatures are not in compliance with the requirements of the method)
Static fracture toughness– ASTM E 1820-01– ASTM E 1921-05 (invalid reference temperature To)– Additional evaluation of J-R
test in upper shelf in agreement with CSN
420347 (Czech national testing method) and ESIS P2/91D procedure
30.10.2009 7
Procedure
2
Transition temperatures :
Static and dynamic fracture toughness
– Transition temperature T100
at KJC
=100 MPa.m1/2
– Reference temperature To
(ASTM E 1921-05)
TaJC eaKK 1
0min
7030
ln)019.01( )(
0medJCK
T
30.10.2009 8
RESULTS: Dynamic fracture toughness 1
0
100
200
300
400
-200 -150 -100 -50 0 50 100 150 200
Temperature (oC)
K JC
(MPa
.m1/
2 )
Initial Initial Irradiated (2.31 dpa) Irradiated (2.31 dpa)
Weld metalT100= -13,3oC (initial)T100= +48,3 oC (2.31 dpa)
Micro TPB specimens (3x4mm) –
no side grooves
Roell
Amsler
RKP 50 impact tester (nominal capacity of 50 J,
max.testing energy 6,29 J)
Impact velocity : 1,36
m/s
0
100
200
300
400
-200 -150 -100 -50 0 50 100 150 200
Temperature (oC)
K JC (
MPa
.m1/
2 )
Initial initial Irradiated (2.43 dpa) Irradiated (2.43 dpa)
BM Eurofer 97T100= -41,5oC (initial)T100= +71,5 oC (2.43 dpa)
30.10.2009 9
RESULTS: Dynamic fracture toughness 2
0
100
200
300
400
-200 -150 -100 -50 0 50 100 150 200Temperature (oC)
K JC
(1T)
(MPa
.m1/
2 )KJC(1T)MASTER CURVEKJC(0,05)KJC(0,95)KJC(1T)-invalid valuesKJC(1T)-invalid values
EUROFER 97Weld metal - unirradiatedTo = +2,0 oCSum ni = 0,39
WELD METAL - the obtained reference temperatures To are not in compliance with the requirements of ASTM E 1921-05.
To+/-50oC
KJC limit (M=30)
30.10.2009 10
RESULTS: Static
fracture toughness 1
0
100
200
300
400
-200 -150 -100 -50 0 50 100 150 200
Temperature (oC)
K JC
(MPa
.m1/
2 )
Initial Initial Irradiated (2.31 dpa) Irradiated (2.31 dpa)
Weld metalT100= -118,1oC (initial)T100= -34,6 oC (2.31 dpa)
Micro TPB specimens (3x4mm) –
20% side grooved
Instron
1342,
load cell capacity 50 kN
Load point displacement has been measured using LVDT gauges
0
100
200
300
400
500
-200 -150 -100 -50 0 50 100 150 200
Temperature (oC)
K JC (
MPa
.m1/
2 )
Initial initial Irradiated (2.43 dpa) Irradiated (2.43 dpa)
BM Eurofer 97T100= -126,6oC (initial)T100= -16,7 oC (2.43 dpa)
30.10.2009 11
RESULTS: Static fracture toughness 2
0
100
200
300
400
-200 -150 -100 -50 0 50 100 150 200Temperature (oC)
K JC
(1T)
(MPa
.m1/
2 )KJC(1T)MASTER CURVEKJC(0,05)KJC(0,95)KJC(1T)-invalid valuesKJC(1T)-invalid values
EUROFER 97Base metal - irradiatedTo = +6,1oCSum ni = 0,52
All the obtained reference temperatures To are not in compliance with the requirements of ASTM E 1921-05.
To+/-50oC
KJC limit (M=30)
30.10.2009 12
RESULTS: Static
fracture toughness 3
J-R test in upper shelf have been performed in accord with ASTM E 1820-
01.
Because of small dimension of Micro-TPB samples, ASTM as well
as
ESIS/CSN qualification of the JQ
validity was not been satisfied.
From comparison of J-R curves it
is seen that JQ
values were reduced by approx. 50 % for BM and 30% for WM.
Low sensitivity of weld metal to neutron irradiation embrittlement
in
comparison of Eurofer
97 base metal.
Eurofer97 Base material, T=+24 oC
0
100
200
300
400
500
600
700
0,00 0,10 0,20 0,30 0,40 0,50 0,60 0,70
Crack growth (mm)
J-in
tegr
al (k
J.m
-2)
B220-unirradiated
B220-unirradiated
B221-unirradiated
B221-unirradiated
A45-unirradiated
A45-unirradiated
A46-unirradiated
A46-unirradiated
B310-irradiated
B310-irradiated
B311-irradiated
B311-irradiated
B312-irradiated
B312-irradiated
Eurofer97 Weld metal, T=+24 oC
0
100
200
300
400
500
600
700
0,00 0,10 0,20 0,30 0,40 0,50 0,60 0,70
Crack growth (mm)
J-in
tegr
al (k
J.m
-2)
U1-210unirradiatedU1-210unirradiatedU1-310unirradiatedU1-310unirradiatedU1-117unirradiatedU1-117unirradiatedU1-28 irradiated
U1-28 irradiated
U1-29 irradiated
U1-29 irradiated
U1-31 irradiated
U1-31 irradiated
30.10.2009 13
SUMMARYTransition temperature shifts
*… Invalid value of To (ASTM E1921-05). Maximum KJC capacity (M=30) has not been fulfilled + results outside To+/-50 oC.
Low sensitivity of weld metal to neutron irradiation embrittlementin comparison of Eurofer 97 base metal.
Specimen set
Displ. per atom(dpa)
Dynamic fracturetoughness
Static fracturetoughness
ΔT100
(oC)ΔT0
(oC)ΔT100
(oC)ΔT0
(oC)
BM 2.43 113.0 122.6 109.9 101,6*
WM 2.31 61.6 74.7* 83.5 99.0*
113.0
61.6
109.9
83.5
30.10.2009 14
SUMMARY Effect of specimen size and geometry on To
Static fracture toughness results
Eurofer
97 BM
To
determined according to ASTM E1921-05
Transition temperature To
appears to be in-dependent on specimen size and geometry.
Good agreement of NRI INVALID To
values in comparison with the other data [1,2]
-150
-100
-50
0
50
100
150
200
0 2 4 6 8 10
Dose (dpa)
T o (o C
)
CT B=5mm (NRG) CT B=10mm (NRG)TPB B=10mm (SCK) TPB B=3mm (NRI)
Data from:[1]Final report for EFDA project Task2[2]E. Gaganidze: Assessmemt of Fracture Mechanical and Impact Experiments of Irradiated Eurofer97 and RAFM Steels. Barcelona, 2007.
DoseAATo exp121
A1 =-107.4 oC, A2 =297.8 oC,τ=4.23 dpa [2]
30.10.2009 15
SUMMARY Shift in transition temperature To
Static and dynamic fracture toughness results Eurofer
97 BM
To
determined according to ASTM E1921-05
Good agreement of NRI INVALID To
values in comparison with the other data [1,2]
Dynamic fracture toughness shift do not differ significantly in comparison with static fracture temperature shifts
0
50
100
150
200
250
300
0 2 4 6 8 10Dose (dpa)
Shift
To
(o C)
100mm bar (SCK) 8+14mm plate (NRG)25mm plate (NRG) SFT To 14mm plate (NRI)SFT T100 14mm plate (NRI) DFT To 14mm plate (NRI)DFT T100 14mm plate (NRI)
Data from:[1]Final report for EFDA project Task2[2]E. Gaganidze: Assessmemt of Fracture Mechanical and Impact Experiments of Irradiated Eurofer97 and RAFM Steels. Barcelona, 2007.
DoseATo exp1
A1 =268.9 oC, τ=3.58 dpa [2]
30.10.2009 16
CONCLUSIONS
Low sensitivity of weld metal to neutron irradiation embrittlement
in comparison of Eurofer
97 base metal.
Transition temperature To
appears to be in-dependent on specimen size and geometry.
Dynamic fracture toughness shift do not differ significantly in comparison with static fracture temperature shifts.
Additional testing : It will be performed impact testing on un-irradiated and irradiated sub-sized Charpy-V specimens (3x4 mm).