US3597193A - Vanadium base alloy - Google Patents

Vanadium base alloy Download PDF

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Publication number
US3597193A
US3597193A US623697A US3597193DA US3597193A US 3597193 A US3597193 A US 3597193A US 623697 A US623697 A US 623697A US 3597193D A US3597193D A US 3597193DA US 3597193 A US3597193 A US 3597193A
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alloys
zirconium
vanadium
alloy
carbon
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US623697A
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William Pollack
Richard T Begley
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CBS Corp
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Westinghouse Electric Corp
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C27/00—Alloys based on rhenium or a refractory metal not mentioned in groups C22C14/00 or C22C16/00
    • C22C27/02—Alloys based on vanadium, niobium, or tantalum
    • C22C27/025—Alloys based on vanadium, niobium, or tantalum alloys based on vanadium

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  • Fast breeder reactors operate at temperatures of from 550 C. to 800 C., usually about 600 C. to 700 C., with sodium metal or NAK metal circulating therethrough.
  • the development of fast breeder reactors employing the liquid alkali metals is dependent among other things upon the availability of alloys which can withstand the rigorous environment in which they are employed; particularly capable of withstanding high operating stresses and the corrosive efifects of the liquid alkali metals at high operating temperatures of from 550 C. to 800 C. Alloys subjected to the operating conditions of a fast breeder reactor must have a combination of properties including good fabricability, strength at elevated temperatures of from 550 C. to 800 C., good resistance to creep deformation at these elevated temperatures, and corrosion resistance to the liquid alkali metals at such temperatures. It is necessary that the alloys not affect detrimentally the operation of a breeder reactor when used as cladding and structural components.
  • Unalloyed vanadium does not have the desired high temperature strength (700 to 800 C.) and corrosion resistance properties necessary for employment as fuel cladding for a fast breeder reactor.
  • vanadium base alloys containing reactive metal additions such as zirconium and titanium have been developed, such alloys have high creep rates and are useful primarily for short time applications at high temperatures and reasonable loads; that is, for periods of use of from to 100 hours at 700 C.
  • High tensile strength is not necessarily indicative of good resistance to creep deformation.
  • Various vanadium base alloys containing 40 to 50% titanium as a major alloying component have displayed attractive tensile properties at elevated temperatures for short time applications, but'the creep rate is excessively high.
  • Other vanadium base alloys having high creep strength properties are so heavily alloyed that the compositions for the most part are unsuitable for use as a cladding material for fast breeder reactors.
  • fuel cladding material for fast breeder reactors having the desired combination of properties of good corrosion resistance at elevated temperatures, particularly to alkali metals, high tensile strength, and good resistance to creep deforma- 3,597,193 Patented Aug. 3, 1971 tion at elevated temperatures over extended periods of time.
  • vanadium base alloys may be employed as cladding for fuel material for fast breeder reactors which alloys have outstanding resistance to creep deformation at 700 to 800 C. for extensive periods of time, good tensile strength at these elevated temperatures and go d fabricability.
  • FIG. 1 is a graph showing creep curves of typical vanadium base alloys at 700 C.
  • FIG. 2 is a graph showing creep curves of typical vanadium base alloys at 800 C.
  • the vanadium base alloys of this invention contain both solid solution hardeners and a dispersed second phase comprising complex carbides, nitrides, and oxides which restrict dislocation motion and grain boundary movement and thereby improve the resistance of alloys to creep deformation.
  • the vanadium base alloys of the present invention are composed of zirconium from about 1% to 4%, carbon in amounts of 0.02 to 0.1%, nitrogen in amounts of up to 0.05 and a solid solution hardener in amounts of from 3% to 20% of at least one of the elements selected from a group consisting of chromium, columbium, iron, nickel, molybdenum, titanium, tantalum and tungsten. More specifically stated, the vanadium-base alloys com prise, by weight, from about 1% to 4% zirconium, from 3% to 20% of at least one element selected from the group consisting of chromium, columbium, tungsten, molybdenum, iron, nickel, and tantalum.
  • the zirconium content may be replaced either wholly or in part by titanium and/ or equimolar proportions of hafnium. It is preferred that chromium when present does not exceed about 12%; columbium when present does not exceed about 12%; tungsten when present does not exceed 12%, and preferably is present with a nearly equal amount of chromium; molybdenum when present does not exceed 9%, and preferably with chromium being present when the molybdenum exceeds about 3%; iron when present does not exceed 8%; nickel when present does not exceed 3% and tantalum when present does not exceed 12%. Iron gives good results when present with nickel.
  • Carbon and nitrogen are present in amounts of from 0.02% to 0.1% C., and from 0.001% to 0.05% N.
  • the atomic ratio of zirconium to carbon and/or nitrogen ranges from about 1.5:1 to 2:1.
  • Oxygen is present from trace amounts to about 0.1% and, at most, not exceeding 0.15
  • Aluminum may be present in amounts of up to 2%.
  • the balance is essentially vanadium, except for traces of incidental impurities such as silicon, manganese, phosphorus, etc. not exceeding a total of 0.5%.
  • the zirconium is preferably low in hafnium.
  • a small trace of hafnium may be present.
  • other applications particularly removed from the nuclear reaction zone proper,
  • the zirconium may be normal zirconium With up to 3% hafnium present. Also hafnium may replace the zirconium on an atom for atom basis for high temperature application not involving nuclear reactions.
  • Improved creep resistance properties in the alloys of this invention are obtained by introducing the specified amounts of zirconium which combine with the recited amounts of carbon, oxygen and nitrogen to form precipitates of zirconium carbide, zirconium nitride, and zirconium oxide on precipitation hardening.
  • Small amounts of titanium may be substituted either fully or partially for zirconium and the precipitates of titanium carbide, oxide and nitride will also form.
  • alloys having two phases each of which contributes to the creep resistance namely, solid solution of vanadium with one or more of the elements selected from the group consisting of columbium, chromium, tungsten, molybdenum, iron, titanium, nickel, and tantalum as substitutional solutes, and a dis-
  • Another desirable vanadium base alloy of this invention contains from 6 to 12% chromium, from 2 to 6% iron, from 1 to 4% zirconium, and suflicient carbon and/ or nitrogen to constitute a zirconium to carbon atom ratio ranging from 1.5 :1 to 2:1, and up to 1500 parts per million of residual oxygen.
  • Still another useful alloy of this invention having a vanadium base contains from 4 to 9% iron, from 4 to 8% columbium, from 1 to 4% zirconium, and sufficient carbon and/or nitrogen to constitute a zirconium to carbon and nitrogen atom ratio ranging from 1.5:1 to 2:1, and up to 1500 parts per million of residual oxygen.
  • another useful alloy of this invention having a vanadium base contains from 6 to 12% chromium, from 6 to 12% tantalum, from 1 to 4% zirconium, sufficient carbon and/ or nitrogen to constitute a zirconium to carbon and nitrogen atom ratio ranging from 1.5 :l to 2:1, and up to 1500 parts per million of residual oxygen.
  • zirconium carbide zirconium nitride, and zirconium oxide.
  • the zirconium also acts as an oxygen getter for increasing corrosion resistance at elevated temperatures. Without zirconium and/ or titanium or hafnium being present, the carbon, oxygen, and nitrogen would combine with vanadium interstitially that would decrease fabricability of the vanadium.
  • One useful group of alloys of this invention contain the foregoing elements in the ranges of, by weight, from 5 to 12% columbium (niobium), from 1 to 4% zirconium, carbon, and nitrogen to constitute a zirconium to carbon and nitrogen atom ratio ranging from 1 /2:1 to 2:1, and up to 1500 parts per million of residual oxygen.
  • Another useful alloy having a vanadium base contains elements in the range of, by weight, from 6 to 12% chromium, from 6 to 12% tungsten, from 1 to 4% zirconium, suflicient carbon and/0r nitrogen to constitute a zirconium to carbon and nitrogen atom ratio ranging from 1 /2 :1 to 2:1, and up to 1500 parts per million of residual oxygen.
  • Another useful alloy of this invention having a vanadium base contains from 6 to 12% chromium, 3 to 9% molybdenum, from 1 to 4% zirconium, suflicient carbon and nitrogen to constitute a zirconium to carbon and nitrogen atom ratio ranging from 1 /2 to 2, and up to 1500 parts per million of residual oxygen.
  • the nitrogen content of the alloys is residual nitrogen present in the alloy constituents or introduced during melting.
  • an analysis is made to determine the nitrogen and carbon present and additional carbon is then added in an amount to make up the indicated 1 /2 :1 to 2:1 atom ratio of zirconium to total carbon and nitrogen.
  • the Table I also includes two meritorious vanadium base high titanium alloys for comparative purposes; these alloys have attractive tensile properties at elevated temperatures.
  • the quantities in Table I are expressed in weight percent.
  • Each of the exemplary alloys A to W of Table I has a substantial merit in its own right.
  • Each of these alloys is representative of a difierent composition within the broad invention.
  • the alloys used in Tables I and II were prepared by double arc melting of consumable electrodes in a partial pressure of atmosphere of argon. However, the ingots of the alloys may also be prepared by other means such as non-consumable arc melting of electron beam melting techniques.
  • Test specimens for the alloys may be prepared in a number of ways. A typical method used here for all the alloys was to initially hot work an ingot of from 1.5 to 2.5 inches diameter by forging to effect a 50% reduction at about 1000" C. The specimen was then rolled at about 500 C. to effect a 50% to 75% reduction and then cold work the specimen to final size of 0.042 inch sheet. The test specimens were then heat treated above 1200 C. for about one hour to produce a relatively coarse grain size of 3 to 5 ASTM.
  • the alloys of this invention have superior creep resistance properties compared to those of the best known binary vanadium titanium alloys under similar test conditions.
  • the high creep resistance exhibited by these alloys is attributable in part to the dispersed second phase faces of the carbides and nitrides of zirconium which inhibit dislocation motion and grain boundary movement and thereby decreases the creep rate.
  • the alloys of this invention contain relatively low substitutional solutes as compared with the binary vanadium titanium alloys.
  • the amounts of substitutional solute elements present in the alloys is an important consideration because fabricability is influenced by the amount of such solid solution strengtheners present. Nuclear characteristics (i.e. breeding rating, etc. are degraded by large additions of substitutional solutes having high nuclear cross-section.
  • the alloys of the present invention combine solid solution and dispersed phase strengthening to achieve high strength and high temperatures.
  • Vanadium base alloys which have been previously commercially available contain a high level of interstitials which tend to seriously degrade their fabricability.
  • zirconium and titanium combine with the interstitals carbon, oxygen, and nitrogen to form stable carbides, oxides, and nitrides which form the basis of the dispersed strengthening.
  • the zirconium Prior to precipitation hardening, the zirconium, for example, does not adversely affect fabricability.
  • the addition of zirconium permits oxygen levels of 1500 parts per million in the 'vanadium base materials without sacrificing fabricability.
  • Sufiicient interstitial carbon is added to the base alloy in order to attain a sufiicient volume fraction of dispersoid which contributes to the creep resistance of the alloy but does not reduce fabricability prior to precipitation hardening.
  • Alloys can be wrought into bolts, rods, tubes, and sheets for use in elevated temperature conditions such as in a fast breeder reactor.
  • a vanadium-base alloy consisting essentially of, by weight, from about 1% to 4% zirconium, from 3% to 20% of at least one element selected from the group consisting of columbium, chromium, tungsten, molybdenum, iron, nickel, titanium, and tantalum, from 0.02% to 0.1% carbon, from 0.001% to 0.05% nitrogen, the atomic ratio of zirconium to total carbon and nitrogen ranging from about 1.521 to 2:1, up to 0.15% oxygen, and the balance being essentially vanadium.
  • the alloy of claim 3 comprising about 10% columbium.
  • the alloy of claim 3 comprising about 8.48% chromium, and from about 6% to 12% tungsten.
  • the alloy of claim comprising about tungsten.
  • the alloy of claim 3 comprising about 9% chromium, and from about 3% to 9% molybdenum.
  • the alloy of claim 7 comprising about 5.48% molybdenum.
  • the alloy of claim 3 comprising about 9% chromium, and from about 2% to 6% iron.
  • the alloy of claim 3 comprising at least one element selected from the group consisting of to 3% nickel, 4 to 8% columbium, and about 6.5% iron.
  • the alloy of claim 10 comprising about 1.7% nickel.
  • the alloy of claim 10 comprising about 5.3% columbium.
  • the alloy of claim 3 comprising about 8.49% chromium, and from about 6% to 12% tantalum.
  • the alloy of claim 13 comprising about 9.85% tantalum.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Heat Treatment Of Steel (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)
US623697A 1967-03-16 1967-03-16 Vanadium base alloy Expired - Lifetime US3597193A (en)

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US (1) US3597193A (de)
BE (1) BE712164A (de)
CH (1) CH499625A (de)
DE (1) DE1608223A1 (de)
FR (1) FR1559945A (de)
GB (1) GB1218605A (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3850584A (en) * 1970-03-07 1974-11-26 Metallgesellschaft Ag Fuel element can for a nuclear reactor
US10109382B2 (en) 2017-02-13 2018-10-23 Terrapower, Llc Steel-vanadium alloy cladding for fuel element
US10311981B2 (en) * 2017-02-13 2019-06-04 Terrapower, Llc Steel-vanadium alloy cladding for fuel element
CN111139387A (zh) * 2019-12-26 2020-05-12 西安交通大学 一种力学性能优良的钒合金材料及其制备方法
US11133114B2 (en) * 2017-02-13 2021-09-28 Terrapower Llc Steel-vanadium alloy cladding for fuel element

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1758402C2 (de) * 1968-05-25 1973-01-04 Gesellschaft Fuer Kernforschung Mbh, 7500 Karlsruhe Vanadiumlegierung

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3850584A (en) * 1970-03-07 1974-11-26 Metallgesellschaft Ag Fuel element can for a nuclear reactor
US10109382B2 (en) 2017-02-13 2018-10-23 Terrapower, Llc Steel-vanadium alloy cladding for fuel element
US10311981B2 (en) * 2017-02-13 2019-06-04 Terrapower, Llc Steel-vanadium alloy cladding for fuel element
US11133114B2 (en) * 2017-02-13 2021-09-28 Terrapower Llc Steel-vanadium alloy cladding for fuel element
CN111139387A (zh) * 2019-12-26 2020-05-12 西安交通大学 一种力学性能优良的钒合金材料及其制备方法
CN111139387B (zh) * 2019-12-26 2021-05-28 西安交通大学 一种力学性能优良的钒合金材料及其制备方法

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CH499625A (de) 1970-11-30
DE1608223A1 (de) 1970-12-03
BE712164A (de) 1968-09-16
GB1218605A (en) 1971-01-06
FR1559945A (de) 1969-03-14

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