Table Of ContentORNL99/08051/lld
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DOE/ER-031 3/26
Distribution
Categories
UC-423, -424
FUSION MATERIALS
SEMIANNUAL PROGRESS REPORT
FOR THE PERIOD ENDING
June 30, 1999
Prepared for
DOE Office of Fusion Energy Sciences
(AT 602000 O)
DATE PUBLISHED: SEPTEMBER 1999
Prepared for
OAK RIDGE NATIONAL LABORATORY
Oak Ridge, Tennessee 37831
Managed by
Lockheed Martin Energy Research Corp.
for the
U.S. DEPARTMENT OF ENERGY
under Contract DE-AC05-960R22464
.
...
Ill
FOREWORD
This isthe tweny-sixth ina series of semiannual technical progress reports onfusion materials.
This report combines the full spectrum of research and development activities on both metallic
and non-metallic materials with primary emphasis onthe effects ofthe neutronic and chemical
environment on the properties and performance of materials for in-vessel components. This
effort forms one element ofthe materials program being conducted insupport ofthe Fusion
Energy Sciences Program ofthe U.S. Department of Energy. The other major element ofthe
program isconcerned with the interactions between reactor materials and the plasma and is
reported separately.
The Fusion Materials Program isa national effort involving several national laboratories,
universities, and industries. A large fraction ofthis work, particularly in relation to fission reactor
experiments, iscarried out collaboratively with our partners inJapan, Russia, and the European
Union. The purpose ofthis series of reports isto provide aworking technical record for the use
ofthe program participants, and to provide a means ofcommunicating the efforts of materials
scientists to the rest ofthe fusion community, both nationally and worldwide.
This report has been compiled and edited under the guidance of A. F. Rowcliffe by
Gabrielle Burn, Oak Ridge National Laboratory. Their efforts, and the efforts ofthe many
persons who made technical contributions, are gratefully acknowledged.
F.W. Wiffen
international and Technology Division
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,’
Reports previously listed inthis series areas follows:
DoE/ER-031 3/1 Period ending September 30, 1986
DOE/ER-0313/2 Period ending March 31, 1987
DoE/ER-031 3/3 Period ending September 30, 1987
DoE/ER-031 3/4 Period ending March 31, 1988
DoE/ER-031 3/5 Period ending September 30, 1988
DOE/ER-0313/6 Period ending March 31, 1989
DoE/ER-0313/7 Period ending September 30, 1989
DOE/ER-0313/8 Period ending March 31, 1990
DoE/ER-031 3/9 Period ending September 30, 1990
DoE/ER-031 3/1o Period ending March 31, 1991
DoE/ER-031 3/1i Period ending September 30, 1991
DOE/ER-0313/12 Period ending March 31, 1992
DoE/ER-0313/13 Period ending September 30, 1992
DoE/ER-031 3/14 Period ending March 31, 1993
DoE/ER-031 3/15 Period ending September 30, 1993
DOE/ER-031 3/16 Period ending March 31, 1994
DoE/ER-031 3/17 Period ending September 30, 1994
DOE/ER-031 3/18 Period ending March 31, 1995
DoE/ER-0313/19 Period ending December 31, 1995
DOE/ER-0313/20 Period ending June 30, 1996
DOE/ER-0313/21 Period ending December 31, 1996
DOE/ER-031 3/22 Period ending June 30, 1997
DO13ER-031 3/23 Period ending December 31, 1997
DOE/ER-031 3/24 Period ending June 30, 1998
DOE/ER-031 3/25 Period ending December 31, 1998
DoE/ER-031 3/100 Technical Evaluation of the Technology of Vanadium Alloys for Use as
Blanket Structural Materials in Fusion Power Systems
v
CONTENTS
1.0 VANADIUM ALLOYS “ 1
1.1 BIAXIALTHERMAL CREEP OFV-4Cr-4Ti AT 700”C AND800°C— R.J. Kurtzand
M. L. Hamilton (Pacific Northwest National Laboratory) 3
A study of the thermal creep properties of V-4Cr-4Ti is being performed using
pressurized tube specimens. Ina previous report relevant data on thermal creep of
vanadium alloys was reviewed to guide the selection of an initial test matrix.
Experimental details and results for exposure times of 1523 h at700”C and 1784 h
at 800”C were also covered. This report provides additional results for exposure
times upto approximately 4000”C.
1.2 MICROSTRUCTURAL EXAMINATION OFV-4Cr-4Ti PRESSURIZEDTUBES—
D.S. Genes,M. L.Hamilton, and R.J. Kurtz (Pacific Northwest National Laboratory) 11
Failedthermal creep pressurized tubes of V-4Cr-4Ti tested at700 and 800”C have
been examined using optical microscopy, scanning electron microscopy, and
transmission electron microscopy in order to understand failure and creep
mechanisms. Results show extensive thinning was controlled by dislocation c limb.
Dislocation cell structure was not well developed, Ti02 particles developed complex
dislocation tangles and evidence for development of fine precipitation during creep
was found.
1.3 UNIAXIAL CREEP BEHAVIOR OFV-Cr-Ti ALLOYS — K.Natesan, W. K.Soppet,
and D.L. Rink (Argonne National Laboratory) 20
A systematic study has been initiated atArgonne National Laboratory to evaluate the
uniaxial creep behavior ofV-Cr-Ti alloys asafunction of temperature inthe range of
650-800”C and atapplied stress levelsinthe range of 75-380 MPa. At present, the
principal effort has focused on the V-4Cr-4Ti alloy of heat identified as BL-71;
however, another heat ofsimilar alloy from general Atomics (GA)willalso be used in
the study.
1.4 HIGH TEMPERATURE TENSILE PROPERTIES AND DEFORMATION BEHAVIOR
OF V-4Cr-4Ti — A. F. Rowcliffe, D.T. Hoelzer, and S.J.Zinkle (Oak Ridge National
Laboratory 25
The tensile deformation behavior ofV-4Cr-4Ti has been determined over the range
20 to 800°C for strain rates in the range 10-’/s to 10-5/s. Changes in the strain rate
sensitivity of stress parameters are linked tothe existence of three different regimes
of deformation, namely, Ltiders extension, dislocation glide/strain hardening, and
dislocation creep.
vi
1.5 EFFECT OFORIENTATION ON EFFECTIVE TOUGHNESS-TEMPERATURE
CURVES INV-4Cr-4Ti — E.Donahue, G. R.Odette, and G. E.Lucas (University of
California, Santa Barbara) 33
Fracture tests were performed on fatigue precracked, 20% sidegrooved 0.26T
compact tension specimens in LT and TL orientations under static loading
conditions over temperatures ranging from –196 to -1 10“C. The effective
toughness-temperature I-QT)curves were similarfor both LT and TL orientations.
The corresponding 100 MPa~m transition temperature was estimated to be about
–155°C. Additional tests to evaluate effects of specimen size, orientation, and
material fabrication history onthe K-T curves are underway.
1.6 STUDY OF IRRADIATION CREEPOFVANADIUMALLOYS— H.Tsai, R.V. Strain,
M. C. Billone,T. S. Bray, and D.L.Smith (Argonne National Laboratory) 36
Thin-wall tubing produced from the 832665 (500 kg) heat of V-4 Cr-4
wL70 wt.!40 Ti
material was formed into pressurized tube specimens and irradiated inthe HFIRRB-
12J experiment to study irradiation creep. Irradiation and the required cool-down
following irradiation have been completed and disassembly of the vehicle is under
way. Calculated dose for the specimens ranged from 5.5 to 6.0 dpa and the
calculated irradiation temperatures were 400 to 500°C.
1.7 FRACTOGRAPHY RESULTS FORV-ALLOY TENSILE SPECIMENS IRRADIATED
INTHE BOR-60ATR,AND F17F REACTORS—T. S.Bray, H.Tsai, R.V. Strain,
M. C. Billone, and D.L.Smith (Argonne National Laboratory) 38
Fractography studies were conducted on. numerous V-alloy specimens. These
specimens had been irradiated in the ATR, FfTF, and BOR-60 reactors at
temperatures ranging from 273to 600”C and damage doses from 41 to 51 dpa. The
results of the fractography studies show the medium dose (17 to 19 dpa), low
irradiation temperature materials irradiated inBOR-60to have mostly ductile fractures
but with low areal reduction. The low dose (-4 dpa) ATR samples display a wide
range of areal reductions with mostly ductile fractures. The fractography results for
the FFIT samples with irradiation temperatures from 520 to 600”C and damage
doses from 41 to 51 dpa show a wide range of reductions in area and all ductile
fractures. Side-view observations revealed evidence of slip bands that are typically
associated with dislocation channeling.
1.8 IMPURITY STUDIESOF GASTUNGSTEN ARCWELDINGOFVANADIUMALLOYS—
M. L. Grossbeck andJ. F.King (Oak Ridge National Laboratory) 44
An improved getler system has been installed on the welding glove box since
progress was last reported. Gastungsten arc (GTA)welds using both oxygen and
hydrogen getters resulted invery low oxygen levels butvery high hydrogen levels in
V-4Cr-4Ti. Charpy impact testing, nonetheless, determined a DB1’T lower than
previously achieved. The first weld with a DBIT at room temperature was made.
Erratic results following post-weld heat treatments or low-temperature outgassing
treatments were previously attributed to hydrogen cracking. Itis now believed that
this behavior is not so erratic and might result from precipitation. Transmission
electron microscope studies have been initiated to study the unusual behavior.
vii
1.9 IMPROVEMENT OF LASERWELD QUALITY OFV-Cr-TiALLOYS — Z Xu,
C. B. Reed, K. Natesan, and D.L.Sinith (Argonne National Laborato~) 49
During this report period, the use of aYAGlaser to weld sheet materials of V-Cr-Ti
alloys has focused on (a) development of optimal laser welding parameters to
produce deep penetration and defect-free welds, (b) integration of a custom-
designed environmental control box (ECB) into the laser system to control the
oxygen uptake during the processing, (c) examination of the porosity on
longitudinally sectioned welds, and (d) analysis for oxygen content of the welds. An
innovative method has been developed to obtain deep penetration and oxygen
contamination free welds.
1.10 DIFFUSION BONDING OFVANADIUMALLOYS— Z.Xu, D.L.Smith, and C.B. Reed
(Argonne National Laboratory) 54
Preliminary investigations are in progress to evaluate the potential of diffusion
bonding processes for joining vanadium-base alloys. Diffusion bonds were
prepared on 3.8 mmthick V-4Cr-4Ti alloy plate on a50 KVA welder with a range of
process parameters. Preliminary microstructural analyses conducted on the test
samples indicated that bonding was achieved for a range of process parameters.
1.11 DEVELOPMENT OF ELECTRICALLY INSULATINGCaOCOATINGS—
K. Natesan, M. Uz,and S.Wieder (Argonne National Laboratory) 57
A systematic vapor transport study has been in progress to develop electrically
insulating CaO coatings that are compatible with use in a liquid Li environment.
Several experiments were conducted to study how the deposition of Caon V-4Cr-
4Ti substrate alloys isaffected by variations in process temperature and time, and
specimen locations, surface preparation, and pretreatment. During this reporting
period, several specimens were prepared with a coating of CaO by thermal/chemical
deposition and measurements were made of the electrical resistance of several
CaO-coated specimens before and after exposure to an Lienvironment.
2.0 SILICON CARBIDE COMPOSITE MATERIALS 63
2.1 M~HODS FORJOININGSILICONCARBIDECOMPOSITESFORHIGH
TEMPERATURE STRUCTURAL APPLICATIONS — C.A. Lewinsohn, R. H.Jones,
.
(Pacific Northwest National Laboratory), M. Singh (NASALewis Research Center),
T. Shibayama (Center for Advanced Research of Energy Technology, Hokkaido
University), T. Hinoki, M.Ando, Y. Katoh, andA. Kohyama (Institute ofAdvanced
Energy, Kyoto University) 65
Joining methods are required to allow affordable fabrication of large or complex
SiC/SiC components for fusion energy systems. Previous anaIysisof the criteria for
successful and functional joints indicates that reactor-formed and polymer-derived
silicon carbide should be considered as candidate joint materials. This report
summarizes preliminary mechanical properties of silicon carbide joints formed by a
reaction-based approach. Both the test methods and materials are preliminary in
design and require further optimization. The values of the room temperature
strength of the joints, tested inflexure, are one-third to one-quarter the expected
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