Classifications

• • 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
• • G—PHYSICS
  • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
  • G21C—NUCLEAR REACTORS
  • G21C3/00—Reactor fuel elements and their assemblies; Selection of substances for use as reactor fuel elements
  • G21C3/02—Fuel elements
  • G21C3/04—Constructional details
  • G21C3/06—Casings; Jackets
  • G21C3/07—Casings; Jackets characterised by their material, e.g. alloys
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E30/00—Energy generation of nuclear origin
  • Y02E30/30—Nuclear fission reactors
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S376/00—Induced nuclear reactions: processes, systems, and elements
  • Y10S376/90—Particular material or material shapes for fission reactors

Definitions

• This invention relates to a vanadium-base alloy which is free of columbium and has low contents of titanium and/or zirconium and/or hafnium.
• the vanadium-base alloy according to the invention containing less than 2.8 percent titanium and/or zirconium and/or hafnium can be used in nuclear reactors as a structural material or for cladding fuel elements.
• Vanadium-base alloys are known which consist substantially of -60 percent columbium, 3-25 percent titanium, balance vanadium (Canadian Pat. No. 716,521). Owing to their mechanical properties at elevated temperatures and their high resistance to corrosion in aqueous and gaseous fluids they are used as a material for propulsion systems of aircraft and spacecraft and for nuclear reactors.
• Binary vanadium-base alloys are known which contain 5 percent titanium or 2.8 percent titanium (Journal of the Less Common Metals, Vol. 12, 1967, pages 280-93). The vanadium-base alloy containing 5 percent titanium has shown good creep-rupture properties in tests carried out for as much as 1,000 hours.
• At least one of the elements titanium, zirconium or hafnium in an amount of 0.1 percent to less than 2.8 percent, preferably 1-2.5 percent, balance vanadium in conjunction with 400-4,000 p.p.m. oxygen, 100-1,500 p.p.m. nitrogen, and 100-1,500 p.p.m. carbon, the total of oxygen, nitrogen and carbon being not in excess of 5,000 p.p.m., and with small amounts of usual metallic impurities, such as nickel, iron, chromium and copper, which are due to the manufacturing process.
• the term usual metallic impurities relates to such p.p.m., which are contained in the vanadium as a result of the manufacturing conditions.
• Each of these impurities is present in an amount not in excess of 1,000 p.p.m. e.g., up to 700 p.p.m. of each of the elements iron, chromium and nickel and up to 300 p.p.m. copper.
• the elements titanium, zirconium and hafnium may be present individually or jointly in the content range according to the invention.
• Con tents of zirconium and/or hafnium in conjunction with titaniurn increase the resistance to oxidation.
• Vanadium-base alloys which contain zirconium and/or hafnium have, e.g., the composition:
• the vanadium-base alloys in the composition range according to the invention contain as nonmetallic substances the elements carbon, nitrogen and oxygen in amounts totaling not more than 5,000 p.p.m. These elements amount preferably to 200-600 p.p.m. carbon, 200-600 p.p.m. nitrogen and 400-1500 p.p.m. oxygen.
• the inherent embrittling action of these elements on the vanadium-base alloy is largely eliminated by the addition of titanium, zirconium and/or hafnium.
• the hard phases which are thus formed result also in a grain refinement and in an improved creep-rupture strength.
• oxygen has a particularly important function, as is apparent from the following creep-rupture data:
• each of the two alloys contained 300-500 p.p.m. nitrogen, 300-500 p.p.m. carbon and the following impurities which were due to the manufacturing process: 300 p.p.m. iron, 300 p.p.m. nickel, 300 p.p.m. chromium, 100 p.p.m. copper.
• Germanium may be used alone or in conjunction with silicon.
• An alloy which has shown particularly desirable creep-rupture properties in a prolonged test at temperatures of 600-80 0 C. has the following composition:
• Such alloy containing 1 percent titanium has a surprisingly high creep-rupture strength. Having a life of 1,000 hours under a load of 52 kg./sq.mm. at 650 C. and a life of 10,000 hours under a load of about 40 kg./sq.mim. at 650 C., it is superior to any previously known vanadium-base alloy which contains titanium or titanium and columbium.
• the vanadium-base alloys according to the invention may be made by known metallurgical processes, e.g., in that the components of the alloy are fused together under a vacuum or in a rare gas atmosphere or by powder-metallurgical sintering processes.
• Suitable melting furnaces include, e.g., electron beam furnaces or are furnaces.
• Known processes including extruding, forging, rolling and drawing may be used to manufacture shaped parts from the alloys according to the invention.
• the vanadium-base alloys in the composition range according to the invention have advantages.
• the surprisingly high creep-rupture strength, the small neutron capture cross section, the low embrittlement which is caused by an irradiation with neutrons at temperatures of 600-B00 C., the high resistance to corrosion by liquid alkali metals and the high deformability of the alloys are decisive requirements for the use of such alloys as a material for structural elements and as a cladding material for fuel elements in nuclear reactors.
• the vanadium-base alloys in the composition range according to the invention can be used to special advantage as a material for structural elements which have a high creep-rupture strength at temperatures between 500 and l,000 C., preferably between 600 and 800 C., in conjunction with a high resistance to corrosion by liquid alkali metals, particularly sodium, a small tendency to become embrittled by the irradiation with neutrons at temperatures between 600 and 800 C. and a small neutron absorption, or any individual one of these properties.
• the alloys in the composition range according to the invention can well be formed at elevated temperatures because they have a lower resistance to deformation than alloys which contain columbium.
• Alloys in the composition range according to the present invention are used particularly as a material to make structural elements and as a cladding material for fuel elements in nuclear reactors, particularly in sodium-cooled fast breeders.
• the high resistance of the alloy according to the invention to corrosion enables the use of this alloy in chemical engineering. Owing to its high strength at elevated temperatures in conjunction with its relatively low density, the alloy is interesting as a material for aircraft and spacecraft.
• the test was carried out at a temperature of 650 C.
• Both alloys contained 600-800 p.p.m. oxygen, 400-600 p.p.m. carbon, 300-500 p.p.m. nitrogen and in the vanadium the following impurities: About 300 ppm. of each of the elements iron, nickel, chromium, about p.p.m. copper.
• the strength data indicate that the vanadium-base alloy which is free of columbium has a lower strength at the beginning of the test and that the difference is progressively reduced as the required life is increased.
• a vanadium-base alloy consisting of 0.1-2.8 percent of titanium

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Metallurgy (AREA)
• Physics & Mathematics (AREA)
• Plasma & Fusion (AREA)
• High Energy & Nuclear Physics (AREA)
• General Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Organic Chemistry (AREA)
• Manufacture And Refinement Of Metals (AREA)
• Turbine Rotor Nozzle Sealing (AREA)
• Catalysts (AREA)
• Soft Magnetic Materials (AREA)

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Cited By (3)

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• 1969
  • 1969-05-21 CH CH782769A patent/CH526636A/de not_active IP Right Cessation
  • 1969-05-22 NL NL6907885A patent/NL6907885A/xx unknown
  • 1969-05-22 AT AT489569A patent/AT285187B/de active
  • 1969-05-22 SE SE07289/69A patent/SE352903B/xx unknown
  • 1969-05-23 GB GB1234533D patent/GB1234533A/en not_active Expired
  • 1969-05-23 BE BE733595D patent/BE733595A/xx unknown
  • 1969-05-23 FR FR6916950A patent/FR2009945A1/fr not_active Withdrawn
  • 1969-05-26 US US828112A patent/US3635700A/en not_active Expired - Lifetime

Non-Patent Citations (1)

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