f-

VANADIUM ALLOYS FOR STRUCTURAL APPLICATIONS IN FUSION SYSTEMS: AREVIEW OF VANADIUM ALLOY MECHANICAL AND PHYSICAL PROPERTIES*

B.A. Loomis I and D.L. Smith 2

IMaterials and Components Technology Division ANL/CP--737692Fusion Power Program

DE92 006973

.... Argonne National Laboratory9700 S. Cass Avenue

r;,"_,

Argonne, IL 60439, USA :i:;_,,,

December 16, 1991

The submitted manuscript has been authoredby a contractor of the U.S. Governmentunder contract No. W-31-109- ENG-38.

Accordingly, the U. S. Government retains anonexclusive, royalty-free license to publishor retoroduce the published form of thiscontribution, or allow others to do so, for

U. S. Government purposes.

DISCLAIMER

This report was prepared as an account of work sponsored by an agency of the United StatesGovernment. Neither the United States Government nor any agency thereof, nor any of their

employees, makes any warranty, express or implied, or assumes any legal liability or responsi-bility for the accuracy, completeness, or usefulness of any information, apparatus, product, orprocess disclosed, or represents that its use would not infringe privately owned rights. Refer-ence herein to any specific commercial product, process, or service by trade name, trademark,manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recom-

mendation, or favoring by the United States Government or any agency thereof. The views

and opinions of authors expressed herein do not necessarily state or reflect those of theUnited States Government or any agency thereof.

Submitted for inclusion in the proceedings of the Fifth Interna--tional Conference on Fusion Reactor Materials, Nover_ber 18-22,1991, Clearwater, Florida, USA.

*Work supported by the U.S. Department of Energy, Office of Fusion

Energy, under Contract W-31-109-Eng-38. MAST£R

1318TI]Ii]UTIONOFTttI,_[lfl_llt_,_lL_y!,_ Ir_: ,_,,..-.• _''I-,,1111 I _'4_

VANADIUM ALLOYS FOR STRUCTURAL APPLICATIONS IN FUSION SYSTEMS: AREVIEW OF VANADIUM ALLOY MECHANICAL AND PHYSICAL PROPERTIES*

B.A. Loomis I and D.L. Smith 2

IMaterials and Components Technology Division, 2Fusion Power Pro-gram , Argonne National Laboratory., 9700 S. Cass Av., Argonne,IL, USA.

The current knowledge is reviewed on (a) the effects ofneutron irradiation on tensile strength and ductility, ductile-brittle transition temperature, creep, fatigue, and swelling ofvanadium-base alloys, (b) the compatibility of vanadium-base al-loys with liquid lithium, water, and helium environments, and (c)the effects of hydrogen and helium on the physical and mechanicalproperties of vanadium alloys that are potential candidates forstructural materials applications in fusion systems. Also, phys-ical and mechanical properties issues are identified that havenot been adequately investigated in order to qualify a vanadium-base alloy for the structural material in experimental fusion de-vices and/or in fusion reactors.

i. Introduction

Vanadium-base alloys have significant advantages over othercandidate alloys, viz., austenitic and ferritic steels, for useas the structural material in experimental fusion devices, e.g.,a blanket module in the International Thermonuclear ExperimentalReactor (ITER), and/or for the first-wall in magnetic fusion re-actors (MFR). These advantages include intrinsically lower long-term neutron activation, neutron irradiation after-heat, neutron-induced helium and hydrogen transmutation rates, biological haz-ard potential, and thermal stress factor [1-5]. However, in or-der tG make use of these favorable neutronic and physical proper-ties of vanadium-base alloys for the structural material in fu-sion systems, these materials (and other candidate materials)must be resistant to neutron-induced swelling, creep, and em-brittlement and must be compatible with the reactor coolantand/or the reactor environment.

In this paper, we review our current knowledge on (a) theeffects of neutron irradiation on tensile strength and ductility,ductile-brittle transition temperature, creep, fatigue, andswelling of vanadium-base alloys, (b) the compatibility, i.e., O,N, C, and H transfer, of vanadium-base alloys with liquid lithi-um, water, and helium environments, and (c) the effects of hydro-gen and helium on the physical and mechanical properties of vana-dium alloys. The results of this review are utilized to recom-

mend alloys for additional experimental investigations. Also, anattempt is made to identify the major issues that have not beenadequately addressed in order to qualify a vanadium-base alloy asthe structural material for components in fusion systems, e.g., °an ITER blanket module, and/or for the first-wall in fusion re-actors.

*Work supported by the U.S. Department of Energy, Office ofFusion Energy, under Contract W-31-109-Eng-38.

2. Mechanical properties

2.1. Tensile

The tensile properties of neutron-irradiated vanadium-basealloys have been investigated by Braski [6-9], Loomis, et al[10,11], van Witzenburg and de Vries [12], Carlander, et al [13],Tanaka, et al [14], Wiffen [15], Bohm, et al [16], and Grossbeckand Horak [17]. The increase of yield stress and the total elon-gation of vanadium-base alloys after neutron irradiation at 420,520, and 600°C to _100 atom displacements per atom (dpa) reportedby these investigators are summarized in Figs. i and 2, respec-tively. The computed yield stress increase of the V-15Cr-5Tialloy on ion irradiation at 710-725°C to _175 dpa is also shown

in Fig. 1 [18]. The yield stress,.uo, of the unirradiated alloysreported by Loomis, et al [19,20] is shown in Fig. i.

The tensile-test data reported in Refs. [6-.17] and presentedin Fig. 1 show that the alloys undergo maximum irradiation har-dening, i.e., increase of yield stress, on neutron/ion irradia-tion at 40-50 dpa followed by a decrease of irradiation hardeningon irradiation to >50 dpa. The tensile-test data also s.how thatthe total elongation (Fig. 2) of the alloys decreases with irra-diation damage to _40 dpa and, with the exception of the V-20Tiand V-7.5Cr-15Ti alloys irradiated at 600°C, does not decreasefurther on irradiation to >40 dpa. With the exception of the V-15Cr-5Ti alloy, the total elongation of the alloys (420-600°C) at_100 dpa is >5%. The uniform elongation of the alloys jLs "_75% ofthe total elongation [10,11].

The effect of helium (implanted before irradiation) on thetensile properties of neutron-irradiated V-3Ti-Isi, V-5Ti, V-20TJ, V-15Cr-5Ti, and Vanstar-7 (v-gcr-3Fe-IZr) alloys has beeninvestigated by Braski [6-9], van Witzenburg and de Vries [12],Tanaka, et al [14], and Grossbeck and Horak [17]. The effect ofhelium (implanted by either cyclotron radiation or the "tritiumtrick") on the yield strength and total elongation of V-3Ti-lSi,V-20Ti, and V-5Ti alloys is shown in Fig. 3. Helium (i00 appm)implanted by cyclotron radiation in the V-3Ti-ISi and V-5Ti al-

loys does not have a significant effect on the tensile propertiesof these alloys on irradiation at 500, 600, and 700°C to =6 dpa[12] ; and helium (90-200 appm) implanted by cyclotron radiationin the V-20Ti alloy does not have a discernible effect on the

strength properties of this alloy after irradiation to =17 dpa at400, 575, and 700°C [14]. Whereas the ductility of the V-20Tialloy is not significantly affected by implanted helium on irra-diation at 400 and 575°C, the ductility of this alloy with im-planted helium is significantly lower after irradiation at 700°C[14]. In the case of the V-15Cr-5Ti alloy irradiated at 400-700°C to 30 dpa, there is no significant effect of cyclotron-implanted helium (80 appm) on tensile properties, although neu-tron irradiation increases the ductile-brittle transition temper-ature (DBTT), i.e., the temperature for transition from cleavageto ductile fracture, from <25°C to =625°C, resulting in signifi-cant reduction of ductility of the alloy [17].

Helium (82-480 appm) implanted by the "tritium-trick', proce-

%

dure in the V-3Ti-lSi alloy does not have a significant effect onthe tensile properties of this alloy after irradiation at 420,520, and 600°C to 40 dpa and at 420°C to 90 dpa [6-9]. The ef-fect of llelium (82-480 appm implanted by the "tritium-trick" pro-cedure) on the tensile properties of V-15Cr-STi and Vanstar-7

alloys on irradiation at 420, 520, and 600°C to 40-90 dpa wasalso investigated by Braski [6-9]. Irradiation hardening, whichresults in substantial increase of the yield strength and reduc-tion of total elongation, is the dominant effect that determines

the post-irradiation tensile properties of these alloys.

2.2. DBTT

The DBTTs of vanadium and vanadium-base alloys with Cr, Ti,and Si additions have been determined from Charpy impact tests onthese materials by Loomis and Smith [21] and Cannon, et al [22].The DBTT dependence of dehydrogenated, hydrogenated, and neutron-irradiated vanadium and vanadium-base alloys is shown in Fig. 4.These expermmental results show that vanadium alloys with Ti ad-ditions (0-20 wt.%) have a minimum DBTT (=-250°C) in an alloycontaining =5 wt.% Ti, that addition of up to 15 wt.% Cr to the

V-STi alloy results in a substantial increase (90-160°C) of theDBTT, and that Si additions (0.25-1.0 wt.%) to V-3Ti alloy resultin a significant increase (_60°C) in DBTT. In addition, the re-sults show that the presence of 400-1200 appm hydrogen in unal-loyed vanadium and vanadium alloys causes a significant increase(60-250°C) in DBTT. The DBTTs of V-5Ti, V-5Cr-5Ti, V-7Cr-5Ti,and V-10Ti alloys are least affected by hydrogen. Neutron irra-

diation of the alloys at 420°C to 41-44 dpa results in substan- 1tial increase (210-380°C) of DBTT. It is expected that the DBTT_

for irradiated V-5Ti and V-SCr-STi alloys will be significantlylower than the DBTT (40°C) determined for irradiated V-3Ti-lSialloy [21].

2.3. Creep

The creep and stress-rupture properties of unirradiated va-nadium and vanadium-base alloys have been reported by Diercks andLoomis [23], Schirra [24], Bohm and Schirra [25], Bajaj and Gold[26], Kainuma, et al [27], Van Thyne [28], Carlander [29], Bohm[30], and Tesk and Burke [31]. The effect of Ti, Cr, and Si al-loying additions on the stress-rupture time performance of vana-dium reported by these investigators is summarized in Fig. 5.Alloying of vanadium with up to =3 wt.% Ti produces significantstrengthening in creep, but further increases in Ti concentrationresult in substantial decrease in creep resistance [30]. The ad-dition of up to 15 wt.% Cr to the V-(3-5)Ti alloy also producessignificant strengthening in creep [23,24], whereas addition of 1wt.% Si to the V-3Ti alloy causes a significant decrease in thecreep strength of this alloy [23,25]. Experimental data on the

effect of neutron irradiation on the creep and stress-ruptureproperties of vanadium-base alloys are very limited and have onlybeen reported for V-20Ti [29], V-3Ti-lSi [30], and V-15Cr-5Ti[31] alloys. The stress-rupture data for these alloys are con-

sistent with the susceptibility of these alloys to irradiationhardening. The V-15Cr-5Ti alloy is susceptible to significantirradiation hardening (Fig.l, 600°C) and concomitant degradationof stress-r_pture time performance (Fig. 5), whereas the V-3Ti-iSi and V-20Ti alloys are less susceptible to irradiation harden-ing and exhibit minimal degradation of stress-rupture time per-formance on neutron irradiation (Fig. 5)

2.4. Fatigue

Experimental data on the response of vanadium-base alloys tofully reversed strain-controlled cyclic loading are limited to(fatigue) tests on the V-15Cr-5Ti alloy [32] and the unirradiatedand irradiated Vanstar-7,8,9 alloys [33]. The dependence of cy-cles-to-failure under cyclic loading on total strain range forthe V-15Cr-5Ti and Vanstar-7 alloys is shown in Fig. 6. The gen-eral data trends suggest that the V-15Cr-5Ti alloy has endurancelimits of =0.7% and 0.6% on cyclic loading at 550 and 650°C, res-pectively [32]. The endurance limit for the Vanstar-7,8,9 al-loys is =1.0% on cyclic loading at 400°C [33]. Neutron irradia-tion of the Vanstar-7,8,9 alloys to the damage levels shown inFig. 6 have little or no effect on the fatigue behavior of 'thesealloys [33].

3. Physical properties

3.1. Swelling

The swelling of vanadium and vanadium-basealloys on neutronirradiation has been investigated by Braski [6-9], van Witzenburg[12], Carlander, et al [13], Tanaka, et al [14], Grossbeck andHorak [17], Matsui, et al [34], Loomis, et al [35-37], Bentleyand Wiffen [38], Takahashi, et al [39], and Ohnuki, et al[40,41]. The swelling data for vanadium and vanadium-base alloysirradiated at 420, 520, and 600°C reported by these investigatorsare summarized in Figs. 7, 8, and 9. Swelling values indicatedby open symbols in Figs. 7, 8, and 9 were determined from densitymeasurements on unirradiated and irradiated specimens.

The swelling dependence of vanadium and binary vanadium-basealloys on irradiation damage at 600°C is shown in Fig. 7. Thesedata show that undersize solute atoms, i.e., Fe, Cr, and Ni, in-crease swelling of vanadium whereas oversize solute atoms, i.e.,W, Mo, and Ti, decrease swelling of vanadium [12-14, 34-37, 40,41]. Titanium alloying additions (5-20 wt.%) are the most effec-tive in reducing the swelling of vanadium on neutron irradiation

at 600°C. The swelling of V-(5-20)Ti alloys is significantlyincreased by a 50 min. temperature excursion of +249°C during ir-radiation at 600°C [35,36].

The swelling dependence of V-(0-20)Ti alloys on Ti concen-tration on irradiation at 420, 520, and 600°C is shown in Fig. 8_The V-3Ti-(8.25-1.0)Si alloys undergo the highest (=2.5%) swell-ing of the V-Ti alloys with swelling of the V-Ti alloys generallydecreasing with increase of Ti concentration >3 wt.% [35-37].Although swelling of the V-3Ti-isi alloy on irradiation at 420°C

is increased (2X) by the presence of pre-implanted helium [6-9],the effect of helium on swelling of V-(0-20)Ti alloys is gener-ally minimal. Temperature excursions >600°C during irradiationat 600°C increase the swelling of V-(0-20)Ti alloys whereas atemperature excursion >520°C during irradiation at 520°C de-creases swelling of V-(0-20)Ti alloys. Swelling of the V-(0-20)Ti alloys on neutron irradiation to 114-124 dpa at 420°C, 50dpa at 520°C, and 84 dpa at 600°C is <0.05% per dpa, regardlessof the temperature excursions.

The swelling dependence of V-(0-i5)Cr-5Ti alloys on Cr con-centration on irradiation at 420, 520, and 600°C is shown in Fig.9. Swelling of the V-5Ti alloy generally increases with increaseof Cr concentration in the alloy [35-37]. Implanted helium hasno significant effect on the swelling of V-(0-15)Cr'5Ti alloys[6-9, 12, 17]. Temperature excursions during irradiation of theV-(0-15)Cr-5Ti alloys at 520 and 600°C cause a significant in-crease in swelling of these alloys. The swelling of these alloyson irradiation at 420°C to 124 dpa, 520°C to 50 dpa, and 600°C to84 dpa is <0.1% per dpa.

3.2. Corrosion in lithium, helium, and water

The dissolution behavior (corrosion) of vanadium-base alloysin flowing lithium (=i i/min) at 427-550°C has been investigatedby Chopra and Smith [42], Borgstedt, et al [43], and Loomis, etal [i0]. The weight losses of vanadium alloys exposed to lithium(482-550°C) containing either 20 wppm N or 12 wppm N are shown inFig. 10a. The alloy dissolution rates in lithium (482°C) con-taining 20 wppm N decrease in the order: V-3Ti-lSi, V-5Ti, V-15Cr-5Ti, V-12Cr-5Ti, V-7.5Cr-15Ti, and V-20Ti [42]. A similartrend of dissolution rates is also obtained on exposure of thesealloys to lithium (20 wppm N) at 427°C [42]. The dissolutionrates of the V-3Ti-lSi and V-15Cr-5Ti alloys are significantlyreduced on exposure to lithium containing 12 wppm N (Fig. 10a)[43]. Loomis, et al [i0] have reported that the dissolutionrates of vanadium alloys in lithium (482°C) containing 167 wppm Ndecrease in the order: V-20Ti, V-15Cr-5Ti, V-10Cr-10Ti, V-10Cr-5Ti, Vanstar-7, V-3Ti-0.5si, and V-7.5Cr-15Ti [I0].

The effect on tensile properties of vanadium alloys of expo-• sure to static and flowing lithium has been reported by Braski

[6] and Loomis, et al [i0]. The tensile properties of V-15Cr-5Ti, Vanstar-7, and V-3Ti-iSi alloys are virtually unchanged af-ter thermal aging (257 days) in static lithium (24 wppm N) at420, 520, and 600°C. However, Loomis, et al [I0] report a sig-nificant increase of yield strength (10-20%) and decrease oftotal elongation (1-6%) for V-15Cr-5Ti, V-10Cr-5Ti, V-7.5Cr-15Ti,V-3Ti-0.5Si, V-20Ti, and Vanstar-7 alloys on exposure (3400 hfs)to flowing lithium (167 wppm N) at 482°C.

The dissolution rates and tensile properties of vanadiumalloys on exposure to lithium are strongly dependent on O, N, C,and H transfer between the alloys and lithium. Natesan [44],Loomis, et al [I0], and Hull, et al [45] have reported that theO, N, C, and H distribution coefficients for vanadium and vanadi-um alloys in lithium (400-600°C) are =I0 "z, 102 l0T and 10 "I, £

f

respectively.The increase in weight of V, V-STi, V-15Cr, and V-15Cr-5Ti

alloys on exposure to helium containing hydrogen (i vppm) and/orwater vapor (i-i0 vppm) at 450-650°C has been determined byLoomis and Wiggins [46]. The data obtained on exposure of the

alloys to a helium (i ppm H + 1 ppm H20 ) environment at 550°C areshown in Fig. 10b. These data clearly show that chromium in avanadium alloy is beneficial for a minimum increase-in-weight ina helium environment,

The weight losses of V-15Cr-5Ti, V-20Ti, and Vanstar-7alloys on exposure to flowing (i i/min), pressurized (8.3 MPa)water containing either 0.03, 0.19, or 4 wppm dissolved oxygenhave been determined by Diercks and Smith [47]. The weight-lossdata for the alloys in water (288°C) containing 0.19 wppm oxygenare shown in Fig. 10c. The V-15Cr-5Ti alloy exhibits lowerweight-loss rates in pressurized water at 288°C than Vanstar-7and V-20Ti alloys, viz., 0.003-0.005 mm/yr and 0.03-0.7 mm/yr.

3.3. Precipitates

The composition and structure of precipitates in unirradia-ted and irradiated vanadium-base alloys with Cr, Ti, and Si addi-tions have been reported by Schober and Braski [48], Chung, et al[49], Bohm [50], and Loomis, et al [51]. Schober and Braski[48], Chung, et al [49], and Bohm [50] report that the predomi-nant (i wt.%) precipitate in unirradiated V-15Cr-STi, V-3Ti-lSi,and V-20Ti alloyE_ is face-centered-cubic Ti(O,N,C) with variableO, N, and C ratios, which is formed by thermal processes duringcasting and heat treatment. The second most frequently observedprecipitate in these unirradiated alloys is face-centered-cubic

(CrQ.6Fe0.4)23C6 [48]. The Ti_S3, TiP, Tiss4, Ti2s , and Tic pre-cipltates are occasionally detected in these unirradiated alloys[48,49]. In the case of neutron-irradiated V-15Cr-5Ti, V-3Ti-

ISi, and V-20Ti alloys, hexagonal-close-pack Ti20 and T_(si,precipitates are observed [49], in addition to the intrlnsic, )3

P

thermally formed precipitates, i.e., primarily Ti(O,N,C) [49].Irradiation of the V-15Cr-5Ti alloy at 650°C with 4.0-MEV _I_+

ions results in formation of T_O precipitates according toLoomis, et al [51]. The Ti20 (formed on neutron irradiation) andTi30 precipitates are iso-structural and identical in atomicarrangement, except that oxygen vacancies in the latter aredistributed orderly in a superstructure of the former [49,51].

4. UTS, 1000-h rupture stress, DBTT, and swelling for V-Ti Alloys

The dependence of ultimate tensile strength (UTS) [30], I000h-rupture stress [30], DBTT (Fig. 4), and swelling (Fig. 8) of V-(0-20)Ti alloys on Ti concentration is shown in Fig. ii. Thesemechanical and physical properties for V-Ti alloys undergo sig-nificant changes at 3-5 wt.% Ti. Bohm attributes the change ofUTS and I000 h-rupture stress at 3-5 wt.% Ti to a minimum of

oxygen solubility and formation of finely dispersed, coherentprecipitates of TiO [50]. The coherency of TiO precipitates inV-Ti alloys is expected to decrease with increase of Ti concen-

L,

tration because of an increasing disparity of lattice constantsfor the alloy matrix and TiO precipitates [50]. The DBTT mini-mum and decrease of swelling of V-Ti alloys with >3 wt.% Ti mayalso be attributed to a decrease of coherency of TiO precipi-tates.

5. Vanadium alloys for ITER and M2R

The V-5Cr-5Ti alloy is recommended for the structural mater-

ial in experimental fusion systems, e.g., ITER, and magnetic fus-ion reactors and for additional investigation of the alloy physi-cal and mechanical properties. This recommendation is based on acombination of (I) low DBTT (<<25°C), (2) minimal effect (<I00°C)of hydrogen isotopes on DBTT, (3) low swelling (<0.05%/dpa, 420-600°C), (4) acceptable corrosion rate in lithium, helium, andwater, (5) high creep stre.ngth (250 MPa, 650°C), (6) irradiatedyield strength (450 MPa, 600°C), and (7) irradiated ductility(i0-15%, 420-600°C). It is expected that the physical and me-chanical properties of the. V-5Cr-5Ti alloy can be further im-proved by optimal thermal--mechanical treatment and O, N, C, andSi concentration.

6. Qualification issues

On the basis of the present review of mechanical and physi-cal properties for vanadium-base alloys, the major issues thathave not been adequately addressed in order to qualify a vanadi-um-base alloy as the structural material for components in fusionsystems are: (i) mechanical properties of components with gas-tungsten-arc (GTA) and/or electron-beam (EB) weld zones, (2) ef-fects of credible accident scenarios, e.g., rupture of first-wallin a MFR, on alloy physical and mechanical properties, (3) fu-sion-system life-time effects of plasma and coolant on alloy phy-sical and mechanical properties, and (4) susceptibility of alloycomponents with weld zones to fatigue, i.e., thermal cycling,failure.

References

[i] T. Noda, F. Abe, H. Araki and M. Okada, J. Nucl. Mater. 155-15v (1988)5si.

[2] R. Santos, J. Nucl. Mater. 155-157 (1988) 589.[3] S.J. Piet, H.G. Kraus, R.M. Neilson, Jr. and J.L. Jones, J.

Nucl. Mater. 141-143 (1986) 24.[4] F.L. Yaggee, E.R. Gilbert and J.W. Styles, J. Less-Comm.

Met. 19 (1969) 39.[5] D.L. Smith,. B.A. Loomis and D.R. Diercks, J. Nucl. Mater.

135 (1985) 125.

[6] D.N. Braski, in: Influence of Radiation on Material Proper-ties, Seattle, WA, 1986, ASTM STP 956, p. 271.

[7] D.N. Braski, J. Nucl. Mater. 141-143 (1986) 1125.[8] D.N. Braski, in: Fusion Reactor Materials, Semiannual Pro-

gress Report for Period Ending SepteI_er 30, 1987, DOE/ER-0313/3, Oak Ridge National Laboratory, Oak Ridge, TN,

p. 235.

[9] D.N. Braski, in: Reduced Activation Materials for Fusion

Reactors, Andover, MA, 1988, ASTM STP 3.047, p.161.

[i0] B.A. Loomis, A.B. Hull and D.L. Smith, J. Nucl. Mater. 179-

181 (1991)148.[ii] B.A. Loomis and D.L. Smith, in: Fusion Reactor Materials,

Semiannual Progress Report for Period Ending September 30,

1989, DOE/ER-0313/7, Oak Ridge National Laboratory, OakRidge, TN, p. 203.

[12] W. van Witzenburg and E. de Vries, to be published in:

Effects of Radiation on Materials, ASTM STP 1125, Nashville,TN, June 17-21, 1990.

[13] R. Carlander, S.D. Harkness and A.T. Santhanam, in: Effects

of Radiation on Substructure and Mechanical Properties of

Metals and Alloys, Los Angeles, CA, 1972, ASTM STP 529,p. 399.

[14] M.P. Tanaka, E.E. Bloom and J.A. Horak, J. Nucl. Mater. 103-

104 (1981)895.[15] F.W. Wiffen, in: Defects and Defect Clusters in B.C.C. Me-

tals and Their Alloys, Nuclear Metallurgy, Vol. 18, 1973,p. 176.

[16] H. Bohm, W. Dienst, H. Hauck and H.J. Laue, in: The Effects

of Radiation on Structural Materials, Atlantic City, N.J.,1966, ASTM STP 426, p. 95.

[17] M.Lo Grossbeck and J.A. Horak, in: Influence of Radiation on

Material Properties, Seattle, WA, 1986, ASTM STP 956,p. 291.

[18] B.A. Loomis, B.J. Kestel and D.L. Smith, J. Nucl. Mater.155-157(1988)1305.

[19] B.A. Loomis, R.H. Lee, D.L. Smith and J.R. Peterson, J.

Nucl. Mater. 155-157 (1988) 631.

[20] B.A. Loomis, L.J. Nowicki and D.L. Smith, in: Fusion Reactor

Materials, Semiannual Progress Report for Period EndingMarch 31, 1991, DOE/ER-0313/10, Oak Ridge National Labora--tory, Oak Ridge, TN, p. 145.

[21] B.A. Loomis and D.L. Smith, J. Nucl. Mater. 179-181 (1991)783.

[22] N.S. Cannon, M.L. Hamilton, A.M. Ermi, D.S. Gelles and W.L.

Hu, J. Nucl. Mater. 155-157 (1988) 987.

[23] D.R. Diercks and B.A. Loomis, J. Nucl. Mater. 141-143 (1986)1117.

[24] M. Schirra, Creep and Creep-Rupture Behavior of V_adium

Based Alloys, United States-Euratom Fast Reactor ExchangeProgram, EURFNR-1449_ April, i_77.

[25] H. Bohm and M. Schirra, J. Less-Comm. Met. 12 (1967) 280.

[26] R. Bajaj and R.E. Gold, in: Alloy Development for Irradia-

tion Performance, Semiannual Progress Report for Period End-

ing March 31, 1983, DOE/ER-0045/10, Oak Ridge iTational La-

boratory, Oak Ridge, TN, p.74.

T Suzuki and R Watanabe, J Less-[27] T. Kainuma, N. Iwao, . . .

Conua. Met. 86 (1982)263.

[28] R.J. Van Thyne, in: Reactive Metals, Vol. 2, Buffalo, N.Y.,1958, p.415.

[29] R. Carlander, in: Quarterly Progress Report, Irradiation

III

Effects on Structural Materials, February, March, April,1968, BNWL-790, p. 3.7.

[30] H. Bohm, in: Defects and Defect Clusters in B.C.C. Metals

and Their Alloys, Nuclear Metallurgy, Vol. 18, 1973, p. 163.

[31] J.A. Tesk and W.F. Burke, ANL Reactor Development ProgressReport, ANL 7553, February, 1969, p. 85.

[32] K.C. Liu, J. Nucl. Mater. 103-104 (1981) 913.[33] G.E. Korth and R.E. Schmunk, in: Effects of Radiation on

Structural• Materials, Richland, WA, 1978, ASTM STP 683, p.466.

[34] H_ Matsui, D.S. Gelles and Y. Kohno, to be published in:

Effects of Radiation on Materials, ASTM STP 1125, Nashville,TN, June 17-21, 1990.

[35] B.A. Loomis, D.L. Smith and F.A. Garner, J. Nucl. Mater.179-181(1991)771.

[36] B.A. Loomis, D.L. Smith and F.A. Garner, in: Fusion Reactor

Materials Semiannual Progress Report for Period Ending March

31, 1989, DOE/ER-0313/6, Oak Ridge National Laboratory, OakRidge, TN, p. 339.

[37] B.A. Loomis and D.L. Smith, to be published in: Proceedings

of Ninth Topical Meeting on the Technology of Fusion Energy,October 7-11, 1990, Oak Brook, IL.

[38] J. Bentley and F.W. Wiffen, Nucl. Technol. 30 (1976) 376.

[39] H. Takahashi, S. Ohnuki and T. Takeyama, J. Nucl. Mater. 96(1981) 233.

[40] S. Ohnuki, H. Takahashi, H. Kinoshita and R. Nagasaki, J.Nucl. Mater. 155-157 (1988) 935.

[41] S. Ohnuki, D.S. Gelles, B.A. Loomis, F.A. Garner and H.

Takahashi, J. Nucl. Mater. 179-181 (1991) 775.

[42] O.K. Chopra and D.L. Smith, J. Nucl. Mater. 155-157 (1988)683.

[43] H.U. Borgstedt, M. Grundmann, J. Konys and Z. Peric, J.Nucl. Mater. 155-157 (1988) 690.

[44] K. Natesan, J. Nucl. Mater. 115 (1983) 251.

[45] A.B. Hull, O.K. Chopra, B. Loomis and D. Smith, J. Nuc!.Mater. 179-181 (1991) 824.

[46] B.A. Loomis and G. Wiggins, J. Nucl. Mater. 122-123 (1984)693.

[47] D.R. Diercks and D.L. smith, J. Nucl. Mater. 141-143 (1986)617.

[48] T. Schober and D.N. Braski, Met. Trans. 20A (1989) 1927.

[49] H.M. Chung, B.A. Loomis and D.L. Smith, to be published in:

Reactor Materials (ICFRM-5), November 17-22, 1991, Clearwa-ter, FL., J. Nucl. Mater.

[50] H. Bohm, in: Second International Conference on the Strengthof Metals and Alloys, Vol. i, ASM, 1970, p. 341.

[51] B.A. Loomis, B.J. Kestel and S.B. Gerber, in: Radiation-In-

duced Changes in Microstructure, Seattle, WA, 1987, ASTM STP955, p. 730.

Figure Captions:

Fig. i. Dependence of increase of yield stress of vanadium-basealloys at 420, 520, 600, and 710-725°C on neutron/ion irradiationdamage; and yield stress, ao, of unirradiated alloys.

Fig. 2. Dependence of tensile ductility of vanadium-base alloysat 420,520,and 600°C on irradiation damage.

Fig. 3. Effect of helium on tensile yield strength and ductilityof irradiated vanadium-base alloys.

Fig. 4. Effects of hydrogen and irradiation damage on the DBTT(Charpy impact loading) of vanadium and vanadium-base alloys.

Fig. 5. Dependence of rupture time on stress (creep deformation)for vanadium and vanadium-base alloys at 650°C.

Fig. 6. Dependence of cycles-to-failure on total strain range(fatigue deformation) for vanadium alloys.

Fig. 7. Dependence of swelling of vanadium and binary vanadium-base alloys irradiated at 600°C on irradiation damage.

Fig. 8. Dependence of swelling of V-(0-20)Ti alloys irradiated at420, 520, and 600°C on titanium concentration.

Fig. 9. Dependence of swelling of V-(0-15)Cr-STi alloys irradia-ted at 420, 520, and 600°C on chromium concentration.

Fig. i0. Dependence of weight loss (increase) of vanadium and va-nadium-base alloys on exposure time in (a) lithium, (b) water,and (c) helium environments.

Fig. II. Dependence of UTS, stress-1000 h rupture time, DBTT, andswelling of V-(0-20)Ti alloys on Ti concentration.

i

500 ; ' ' ' " ' ' ; ='_J!800 °e_ 400 C ,

-3OO -_

' _ }V- 15Cr-STi t: °

. "--r1._C'--6_ '_""_ 200

m

") V- 1,ICr- 5"i'iI

o II// __"_e,_} v-3_-is; -o

100 -"_"'v loc_,,,

b. }/' / _- _-"-"-'ml, 1 Vcn_4cr-7- - V-7 =Cr-I=Tic 0 - -) ""

. • . V- ;.OTilcn Irrc=Rctlon (7_0-725 C)

I , • . I . . ! I . l ' I I '

I ' " ' ' I ''' ' ' I ' _ J I '

: 9 o700 L 5-0 C

o 6o0 _.

_V-15Cr-STI "--"b°

400

"_ ) V- 14Cr-5TJ

)v-3_-is_

o 200 _//o • _) V-,CC,-_T_ "c

b ioor- )V-7.5C:- 15]]

0 L_'" "'V-;ZOT_' ' ! • • I I , .. . ! .

0

420 C_" 6oo2_"-" JV_n.tcr-7b 500 - ,_

._ m-- o

_n 400 - _,)V-3Ti-ISi • e-V-

) V-14Cr-5Ti Y- _"

"o 300 - _u:")" I_-V 1OCt 5,,,,.-.. •

0 200 - IV-7.5Cr-15Ti "oV-2OTi .__>.-o

100 -%..

tj p

0 -t! _ ' ' ! _ ! ' t., _ ! : _ .

0 .50 1O0 150 200Irrcdictic,n Dcrncce (DPA)

- < .

35i| , , i I

..30 6GO°C

° i"£ 20

° 1z 15 tc . ".uV- I CC:-STT _

")" '" : ._,v-_-1 _:;.- • J"°°%

I-- ..... V- 15C:-6TJ -]

CpV-7._.:-, 15TJ

5 - " .=} Vcn_t:r-7 _

J/

0 ", . , ' . , . 4

I I 1 I j

"50 J

I

520'_C ]I

25 l

= 1-£ 20 "l

4c_ : -.,_, V-2OTi(3

1 5 ,." .-_, V-7.5C:- 15_ -

_ V- 1CCr-STi0_- 10 • -: N v-.Tri- Is; "IV- 15C:-6TJ

_}V- 14Cr-57i

5

- ,._Von:tct-7

0 ' ' ' ' ' , , ' , Jl

I ' ' I i " ' ' I ' ' 4

t5o _

,:." 42°°c !I1.

?20 ' 1

15 v-2o_

_uV-ICCr-STi

"".- ,T)V-14C:-5_

5 L 'y_ o-------,vo,,_t=:-7- 4,> V'-.3T;-- I ._i

\-"7 "_ , .'_V- 15Ct-5Ti

0 -, , . , , , . ! ,

0 50 100 150 200Irrcdic_icn Ocmcce (DPA)

1200 --- ------- o_=_ _.,,J

V-..-_-1'q : - 90 ¢::m H= "Ia_ np._" = - lCO c::m H,j...... _- I:: ¢:_m He I

,-, 1000 ,-----"- zoo_-:_,_._I'] -"--- : - a4o c::m He -Ili •- C?_!cc._._,)I

v-_-,__*111 _--T,_u,_c_..)]4,_ OPk I"] I "1

_- aoo ,, _-__ -141 v 2o_" /

_ _oo _-=-'-_I_,! I_II:- v;_ JI ;I , I :ZIi:t IHII:.- ,

_oori_Iii'rI'NII-:r:!I,]_ _ : , ,.'I . :-" ": _=

Lr'__'"_'"-'"-I_1!111_lliI!iIi_Jii_1_| ;CO _CO7C0 4,::_ZO _ca 4;0 4_0 575 700 .(_0 _cO 7C=

" V-ZOT_" J22 17_A i

I

20 " v-._" j. V-_Ti-I_" 6._.t:_A 3

18 '-__ l

v ' .. V-_7",,- 1_"

o I_. _ _ _

c_ 12 - _ _,.

° " : _i_ _! ,_iri 10 - _ 'i ..,_ . _ ,]'-

_- " "_ _"-=-.-';,_ _ _ 76 - _ so=_ = . _

• _ _ ,._ _ __. _ _ _ _ ., ,_ _," ,_

2- _ _ r,4 L.=•", n L= _ "i

¢

IrrcdTc_icn/Q es_,Tempera_,ure (°C)

' ' I .... I .... I .... I ' _ ' ' I ....

400 - V and V-Cr-Ti Alloys e(--,) t

/ "IOo 50- V-lT1

C - <30 cppm H / 45- V-3Ti-O._Si300 , 400-1200 c_m H /. 42- V-3Ti-1Si

j-• 41-'-.4D_A (_.2OQC) / . 46 V-ST1

/ 47-- V- 5Cr--ZTi

() LD._" 200 12- v-lc_

o_ J 49- V-7Cr-._,T]

43- V- 1CCr-.=.=Ti

1 O0 15- V-2OTi

>, 44- V-I GCr- iOTio_..

_ x /J ] 24- V-14Cr-STi

G _/ __. (,G) ._ "I - v--I5Cr-_.Tir- 0 ,,,,_,..__ / 21 - V- 1_.Cr-=_Z .tj :) '

1O- V-7.2Cr- i _.T_

- oo- ./A _=) "I

- 200 (:'% c-5)(-,_)T"-----___:) -7, , , I .... ! .... I .... I , r ' , I .... 1

0 5 10 15 20 250.95

Cc:+ (CTx) (wt.%)

600 ,,_1o

650 C

V- 13Ct-3Ti

400* I

"_" V-15Cr-5Ti "]O

JO_

_-" 300cn + V-3Ti /O3 J(U._- X V-3Ti- ISi

• (/3

200 V-STi

100 x - V-2OTi (12 dpc) V

* - V-15Cr-BTi (0.1 d',po) _ V-1OTi __.JV-7.SCr- I

+ - V-3Ti-ISi (6 dF.c) _ V-2OTi

0 ........ I ........ I , , ....,,,F ,,, ,!,,_I _ , ;, ,,

10 o 101 102 103 10 _, 105

Time (Hours)

........ i ........ I ........ t ..... '"1 ' '

\ -+oo°c-O\ 0 - Vanstar-7, Unirradiated

\ • - Vanstar-7, Iorradia_ed (dpa)

0 - L \ -550 C-O _ A - V-15Cr-5Ti, Unirradiated

l-

C 2 ,,,C_2

.5o

CO ,_ _°_L"\ \ :I

+ (o.+)o\ _ 7q

O I I , ,I I' , ' ''''' , I ltlvfl I I _ It,lt[ I I "J

-- 10 2 10 3 10 4 10 5 10 6

Cycles to Failure

100

80 - V and V Binary Alloys "1

60 600°C " / -I

"-" / o-15)Cr'. -

40 --=-_- v-(_ -iIo 20 ]/

q.. / / _ V- 1.2NI Z

,4

o_..I

0

E, 5 -.E V" . -_,, V- £W

_= 2 v--"'v°•rf)

1 _ V-(5-20)TiI

0 q0 .(" 50 rain Gt +24.9 ° ] V-(S-20)Ti], , , , , c'l , , , I

0 20 40 60 80 100Irradiction Damage (dpa)

4',0 [' i" |' i * i, 1, i , i, 1. i. i, i • i •

/ E, nn - 1-I0 d;= o /r C . • - I-'--21dr.=(.=0rnina_,+7.05C) l

3.5 I- -" . • - ._'-_.0 _:: // _ - 7_-77 d:= (._0 mln at +2;_.-C) "]l" x . "e - E-' c== i

3.0 [ (t_ , (+_. u.:- c:: + (;co-=,co a==m He (TZ:,,4)

[_ .= (o-N-c. s;) _;:_-_.- 2.5

.oL \.+ ]- "" "_ 1.5

I. +_'__._ I / ___ i-i

I I (:'::-----=I I (::lo--"t:l ! t /

(,:_.:;l(.'=":.) ' (':7°':=°i, , (::_'::') t (l:7,:;.,;=l,'. ........ I , , . i

- - O 2_-3rJ _:: (._0 m_n c: + _ "%".3._ e.. I - 22-;0 dT.c ": "-

I:: - EO _:: J

_ 3.0 ; (_ e:= + (_.2-ico)::.=m _-. G'::.,'I(o+,+c.s;).,,_.-,_ :']

•'- ]

._ 2s /'1<- 20 _2oc lI °

"" 1.5 "" e J

'= 1.0 Z _'-'-" -OJ

.o, I_ _ _ .

.... .

..3 5 O . • - 3_:-'_. _:: 4

_ =-----, _ . • . _ , I _':: CTE:.t)' j""" 3.0 _ c'T,_ii, I_ iii c:: + a2- _i

_" _ 2C0 c::m /.._ .(,;-..<=l .- _ (o+N+C.Sl) _,.+CTF_!<I)]'2.5 " '- (-1

•"- . ¢' \ I?" 2.0 _(,,,_<'-_l_ i o "io , 420 C -

_. C' t

61.5 =;\t i;:_ 1.O _,,,,,.<=_(\\ //°.'*\u_ : \-c I /_\ . _ ](I :::.1.':)

III ; / , . •:L,/l J I

, ,_-'-=-:)l+:_,o:,:) /!:-7°:,°:_ , !,:-::-'-:},ti .', I i ! ' l , . , t , .

0 2 4 E 8, 10 12 14 16 18 20 22 2-'.Tiicn_,,,-'r,, Concer, trction (WL,%)

/.

f ....... ° lic - l'-Zll =:= rc__.rain :: -_C5 C',_, . x - 40-.=0 ¢:=

r -°7 _ - 73-77 ¢:= [53 enin =" _-_-£ '=, (:::_ :_o

- 4G-=.._ :==._-"a=c3(TE!,4)_'_ E / "" - e:-. + v-'-;ca :-:_ _ (_.._) / /II) (11

° t.J 13".=" m',/ --

• "_ 2 -',::::._-'::I_----'_ _'- -I

5'3 _'//" 1

. _(lll I

0 (_, - , -I'' I I ! I I I ! I

P I I I i i * i i I

II= - 21-20 c:: (_.Ornln:'.+ ...), v - 21 d:: "l, _ - aO-=O c:= /e ---1.00 0 •- = :c :-:,,rP'-.2_l- :{ -. 4G-.:O ¢:= ITEM) -]

'e': - "-'-;C,Oc=:m H= (TE,Li) I--, j

,--,_ (e) " _'_ (C;N+C. S;) ,'==m '

0.75 520 C " -_o,

o _ _ (:::;_) |O. 50 F.=-=2.....---''/ _re_:::==_uj/,,°::.,,:ol

_ =...i "-¢-- _ =_"°' =' 1- " I_ • _

• 0.25 - _ . /

10.00 (_' _--' -I 1 ! I I l I I I

I ' i -- 4i " i i i I J.. - C -IC _i.. /2.25 c - ._2 : = _;=

v - 73-7"7 c_:: ]

_,, 2.00 • +. ,. - ,_o._:._:'-d:c(_;.i)) _'"=":":q(,1._+t(_} - d:: + 7-'.'300c.:pm He (TEhl) v(1,:o.z"o)}

-_ 1.75 (o+'_.c. s;) ,.;;,_ _ _:::-';°_q

?o 1.25- ' .

.c:0.75

0.25 - _------- . -,-- A J

I

I0.00 , , , , , , , , . ,,, q

0 2 z E _ 10 12 lZ 15Chrcmiu'_,. Ccnce.qlrcUon (Wt.%)

f < ":',

i

12 lT V--_T_-ISi , . . , , . . . ,

• - io - V-5Ti• - V-1.,'Cr-_Ti

10 w - V-12Cr-5Ti• - v-7._cr-1_n 4E2-5._0 C -_lm - V-2OTi -I-"- - V-1':Cr-ST] • l.

_" - - V-3Ti-iEi / '_E 8 _..=

z_ , A ] 12 wppm N in Li

6 2I

_ 4 A

f: t0 _

•"Corrosion oF Mctericis in Helium Environment

28 i ' ' ' _ ' ' . , .... , . • • , . . . , .' ' I

J

24 v -_

I..-. "1

E 2O • i

V-ST_--, 15 / / "i

12.E -io !

8 v-i

,_ // .._ v-;_c; "i'- i}u I/ / hT-=.

FC._ . Io5:.oc Cb)

0 Helium + 1 vp.=m Hydrc_en + 1 vppm Wcter| I l I 1 l t ; ! ' . • ! . , ' ! .. t , _ . . . I

Wet_r Ccrrosion of" Vcncdium Alloys250

..... J ' ' _ I ' ' ' I'''''''''' 2=.EOC

,-, 200 o - v-_c:-sn i _ Jo - V-2OT} / _ 4E ii - Vcnst:r-7 // .I

_5o •

@

•_" 5O

1" | _ t : ! , , , 1 _ _ _ I . , , I . , . I ;. ,

0 400 800 12r-O 1600 2000 2400'

Ex',,,sure_... Tirr,.e (Hcurs)

ii

I

600 _ i , i , t , i , | . | . , , i i t , | , i . , •o

• 650 C ._

500 _Ten.'ile SLren_',h -

._ 4oo ,#-

° tm 300In

IOC0 Hcur Rupture

__I " I100 "

0 -' ! , .L . ! , q . I . t : t . f , I r ! , t . i .

' i ' i ' I ' i i i • _ ' i ' i ' I ' i ' I ' _ ' -IO - <30 ar.:m H 1® - 400-12g0 c::m H

50 2

° ?"6" °

I::: -5o

° 3>,

E -ioo i

°0- - t-

C_)

-150- o

-2oo _'_ J'.ti ! I ! T ! J ! _ ! : I z ! , I L l , ! , ! • ! ,

' i '" I ' i ' l ' i • l ' i ' i ' ' , ' I ' _ ' I

._[_ 0 , • 36-46 dpa /

3.5 -- _ . _ 73-8_ d=_ "I13 , " 114-12" d_al

_,, ,, _ . , . .L . _ d;a CrE._.O1"_" 3.0 " (_r3.c*J. _1 , c',_ d_a + 82- ..J'- .,,_,.:,_} _ (O+N+C,si) 200 c=;m I

• ,_ _ - He (TEM) "I2.5 (') /

. o_ "]2.0 - 420°C /

• 0

1.5 1

5 J

1(m_: 1.0 i(,,'_.eo) (0.5

0.0 - v,--'l'*"- " T _._T

0 2 4 6 E 10 12 14 16 18 20 22 24

Ti_cnium C_.ncentrotion(Wt.Z)