Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
  • H01B1/02—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of metals or alloys
  • H01B1/026—Alloys based on copper
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C9/00—Alloys based on copper

Definitions

• the present invention relates to alloys and, more particularly, to copper base alloys having a unique combination of properties and characteristics.
• the art has endeavored to produce high conductivity materials having improved mechanical properties and characteristics at both room and elevated temperatures.
• the materials having high electrical and thermal conductivity contain copper.
• alloying ingredients added to strengthen or harden copper or its alloys ordinarily cause a detrimental decrease in conductivity.
• increasing quantities of alloying ingredients tend to increase strength, they also tend to worsen the electrical and thermal conductivity.
• An arsenic addition, e.g., 0.1% to 0.5%, to the copperzirconium alloy system provided the art with an alloy having improved room temperature properties and characteristics which were attained without disadvantageously affecting the other useful properties and characteristics.
• a hafnium addition, e.g., 0.1% to 1.2%, to the copper-zirconium system proved to be an advance in a still different direction.
• the hafnium-containing alloys have better mechanical properties and characteristics at 400 C. than do either the copper-zirconium or coper-zirconium-arsenic alloys.
• Another object of this invention is to provide novel copper alloys having improved age-hardening characteristics.
• the invention also contemplates new, high conductivity copper alloys having good elevated temperature properties and/or characteristics.
• Still another object contemplated by this invention is the provision of electrical and electronic components having useful strengths at elevated temperatures.
• One of the other objects of this invention contemplates the provision of copper alloys having a unique combination of ingredients in special proportions, which alloys are characterized by markedly improved elevated temperature properties and/ or characteristics.
• a further object of the present invention is to provide a special process for hardening copper-base alloys without materially diminishing other valuable properties and/ or characteristics of such alloys.
• a still further object is the provision of a novel process for making the copper-base alloys of this invention.
• the present invention contemplates the production of unique copper-zirconium alloys having high electrical and thermal conductivity together with unexpectedly good strengths and hardnesses at temperatures in excess of 500 C., e.g., 600 C.
• the copper alloys of this invention contain, in weight percentages, 0.005% to 0.1% vanadium and 0.003% to 1%, e.g., 0.01% to 0.3%, zirconium.
• a relatively small amount of hafnium is commonly associated with zirconium in the forms in which zirconium is commercially available.
• zirconium is available as an alloy sponge nominally consisting of, by Weight, up to 4% hafnium, e.g., 0.5 with the balance essentially zirconium.
• the alloys of this invention can also contain such hafnium introduced into them with the zirconium, and any such hafnium up to 20% of the zirconium is deemed to be zirconium for the purposes of this invention.
• the alloys of this invention also contain copper which makes up the balance of the alloys aside from the usual impurities and residual deoxidizers.
• the copper employed in this invention be of high purity and be substantially oxygen-free.
• any chemically deoxidized copper such as phosphorus or lithium-deoxidized copper is generally satisfactory for use in making the alloy, it is advantageous to use copper which is substantially oxygen-free without requiring treatment with any of the conventional deoxidants.
• Cathode copper is accordingly particularly suitable as is copper which has been produced in a reducing atmosphere such as OFHC brand copper (which is 99.99% pure), copper prepared in an inert atmosphere, under a charcoal cover, or in a vacuum.
• alloys of this invention containing the aforementioned ingredients (copper, zirconium and vanadium) in the aforementioned proportioned amounts are charac terized by a high recrystallization temperature and re sistance to grain growth at elevated temperatures.
• incipient grain growth occurs between about 550 C. and 600 C.
• the alloys according to this invention contain copper, zirconium and vanadium in specially related and controlled amounts and each of these elements in combination with each of the other two ingredients plays an important role in controlling the prop erties and/or characteristics of the alloys.
• the zirconium content is in the range of 0.003% to 1%, e.g., 0.01% to 0.3%, by weight of the alloy.
• the inclusion of zirconium in the amounts specified in the copper alloys of this invention contributes significantly to the tensile strength when appropriate amounts of vanadium are copresent, Accordingly, if too little zirconium is present (less than 0.003% the strength of the alloy detrimentally decreases.
• zirconium is present since its contribution to the strength of the alloy is greatly enhanced.
• Zirconium appears to have at least one other important function, i.e., it appears that zirconium affords some assistance in increasing the solubility of vanadium in the copper alloys of this invention.
• the maximum amounts of zirconium must also be controlled in order to attain a better combination of properties and characteristics such as workability, strength, conductivity, etc.
• the amount of zirconium present should not exceed about 1% and, where maximum conductivity is an important design factor, the amount present should be less than about 0.3% and, advantageously, less than about 0.15%.
• Vanadium should be present in amounts of 0.005% to 0.1%, e.g., 0.01% to 0.1%, by weight of the alloy, since it has a synergistic effect with zirconium and copper in producing high conductivity alloys having excellent elevated temperature strengths and hardnesses. If less than 0.005% is present, there is little or no perceptible improvement in the elevated temperature properties of the copper-zirconium alloys. If more than 0.1% vanadium is present, inclusions (which may possibly be vanadium carbide or some copper-zirconium-vanadium complex) are formed which substantially impair the workability of the alloy.
• the upper portion of the vanadium range is 0.05% since only minimal improvement can be expected with further vanadium additions.
• the vanadium added is at least 99.5% pure with the remainder predominately iron.
• a ferro-vanadium alloy nominally containing 90% vanadium and iron may be used in producing the alloys of this invention adapted to be used in less stringent applications.
• the alloys contain, in weight percentages, 0.01% to 0.15% zirconium, 0.01% to 0.05% vanadium and the balance, apart from less than 0.001% of impurities and residual deoxidizers, initially oxygen-free copper.
• Such alloys have a superior combination of physical, mechanical and/or metallurgical properties and/or characteristics.
• UTS ultimate tensile strengths
• YS 0.1% offset yield strength
• the 90% cold-worked alloys after subjecting to a working and heat-treating process, including an ageing treatment at 600 C., which process is more fully described hereinafter, the 90% cold-worked alloys have a room-temperature UTS of at least 48,000 p.s.i. and a conductivity in relation to the International Annealed Copper Standard (IACS) of at least 92%.
• IACS International Annealed Copper Standard
• Alloys within the broad and advantageous ranges are age-hardenable whenever they are first subjected to coldworking.
• the alloys are cold-worked at least 40%, i.e., at least 50%, to obtain greater age-hardening response.
• the alloys so prepared have a strain-lattice structure which apparently contributes to the useful elevated temperature properties and characteristics of the alloys.
• the ageing temperatures lie between 350 C. and 650 C.
• the ageing time is about 30 minutes to 3 hours and, advantageously, one hour. Better results are achieved when the age-hardening heat treatment is conducted at temperatures between 450 C. and 600 C and, more advantageously, between 500 C. and 600 C. and held at that temperature for one hour.
• the alloys of this invention When heat-treated in this manner, the alloys of this invention have conductivities as high as 94% IACS at room temperature and strengths (UTS) as high as 27,000 p.s.i. when tested at the high temperature of 600 C. after holding at that temperature for about one hour.
• This novel process comprises melting high-purity copper and then adding vanadium to the melt (before adding zirconium) at a temperature between 1450 C, and 1600 C. If, on the other hand, zirconium is added prior to, or at the same time as, vanadium, there are considerable losses. Accordingly, when zirconium is added prior to the vanadium, zirconium losses may be as high as 40%. In contradistinction thereto, when vanadium is added prior to zirconium under appropriate conditions, there are substantially no losses.
• the melt is held at that temperature for at least 5 minutes but preferably not more than 30 minutes, e.g., 10 minutes, in order to minimize vanadium losses.
• zirconium which is advantageously in the form of zirconium sponge although other forms may be used such.as a copper-zirconium addition alloy nominally containing 30% zirconium
• the temperature of the melt is reduced to between 1200" C. and 1325 C.
• the melt is thereby established, i.e., all losses of alloying ingredients are accounted for, and the established melt contains, by weight, 0.003% to 1% zirconium, 0.005% to 0.1% vanadium and the balance copper.
• the established melt contains, by weight, 0.01% to 0.15% zirconium, 0.01% to 0.05 vanadium and the balance being essentially copper.
• the temperature is then raised to approximately 1350 to 1400 C, and held thereat for about 5 minutes to 30 minutes before casting at a temperature between l250 and 1350 C. in order to insure substantially complete alloying without unnecessary losses.
• Castings produced in accordance with the aforedescribed process are sound and have good surfaces.
• the castings were hot-rolled to 0.25" diameter rods at 950 C. and then solution annealed at 1000 C. for one hour under charcoal.
• the solution annealing temperatures can be varied between 900 C. and 1000 C. and the time at temperature can be varied between 20 minutes and 2 hours.
• the solution-annealed 0.25"-rods were then quenched in water. After quenching, the rods were cold-Worked 90% to 0.079" diameter rods and mechanically tested to rupture at room temperature. The results of these tests are set forth in Table II.
• alloys of this invention have useful mechanical properties and/or characteristics in the unaged but cold-worked condition.
• alloys 1, 2, 3, 6 and 7 were aged at various temperatures for one hour under charcoal, water quenched and then tested. The results of these tests are set forth in Table III.
• the alloys of the present invention by virtue of their excellent properties and/or characteristics at temperatures up to 600 C. in conjunction with conductivities up to 94% IACS, find use in a variety of important applications.
• the wrought alloys can be used in electric and electronic structural applications e.g., for the manufacture of klystron tubes, requiring retention of C.
• the structural component has to be brazed or otherwise joined to another structural component using a joining method or alloy that causes a weakness in the overall system.
• the alloys of the present invention can be used in structural applications where high thermal conductivity in combination with good strength at temperatures up to 600 C. is an important design factor.
• One important application of this type is using the alloy in rocket nozzles.
• the alloys contemplated herein are also commercially attractive since they contain relatively small amounts of alloying ingredients, e.g., as low as 0.01 weight percent total or even less.
• a copper base alloy having high conductivity in combination with excellent strengths at temperatures up to 600 C. which alloy contains, by weight, 0.003% to 1% zirconium, 0.005% to 0.1% vanadium and the balance, aside from impurities and residual deoxidizers, substantially all copper.
• a copper base alloy having high conductivity in combination with excellent strengths at temperatures up to 600 C. which alloy contains, by weight, 0.01% to 0.3% zirconium, 0.01% to 0.1% vanadium and the balance, aside from impurities and residual deoxidizers in amounts of less than 0.001%, substantially all copper.
• a ternary copper base alloy containing, by weight, 0.01% to 0.15% zirconium, 0.01% to 0.05% vanadium and the balance high-purity copper.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Conductive Materials (AREA)

Priority Applications (6)

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Cited By (4)

Citations (1)

• 1965
  • 1965-02-12 US US432383A patent/US3330653A/en not_active Expired - Lifetime
  • 1965-10-26 GB GB45233/65A patent/GB1119783A/en not_active Expired
  • 1965-11-23 DE DE19651483180 patent/DE1483180A1/de active Pending
  • 1965-12-21 FR FR43185A patent/FR1461090A/fr not_active Expired
  • 1965-12-27 BE BE674361D patent/BE674361A/xx unknown
• 1966
  • 1966-02-11 NL NL6601773A patent/NL6601773A/xx unknown

Patent Citations (1)

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