Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
  • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
  • C22F1/16—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of other metals or alloys based thereon
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K20/00—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating
  • B23K20/22—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating taking account of the properties of the materials to be welded
  • B23K20/233—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating taking account of the properties of the materials to be welded without ferrous layer
  • B23K20/2333—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating taking account of the properties of the materials to be welded without ferrous layer one layer being aluminium, magnesium or beryllium
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
  • B23K35/001—Interlayers, transition pieces for metallurgical bonding of workpieces
  • B23K35/002—Interlayers, transition pieces for metallurgical bonding of workpieces at least one of the workpieces being of light metal
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B15/00—Layered products comprising a layer of metal
  • B32B15/01—Layered products comprising a layer of metal all layers being exclusively metallic
• • 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

Definitions

• Beryllium has not gained full acceptance because of its sensitivity towards notching and such after effects as loss of ductility, propagation of cracks and the like. It is also faced by the problem of inter-crystalline corrosion, high susceptibility to diffusion of other metals and gases, and toxicity of dusts released by the beryllium during processing.
• An important concept of this invention resides in the coating of the beryllium part with at least one layer of at least one plastic metal, such as aluminum, alloys of aluminum, magnesium, zinc and antimony.
• the beryllium can be coated with one or several layers of one or a number of the plastic metals by mechanical transformation in a temperature range which is compatible with the ductility of the beryllium and in which the inter-metallic diffusion can be controlled.
• the desired metal coating can be achieved by such mechanical transformation as flattening, rolling, drawing, spinning and hammering, with the coating being formed at a temperature below 620" C. and preferably at a temperature within the range of 300-400 C.
• the beryllium it is possible to plate the beryllium to provide a coating of aluminum or an alloy of aluminum or of magnesium, zinc or antimony. It is also possible to apply the coating material in a multi-layered sandwich. Aluminum is preferred as the coating metal because it does not form brittle compounds with beryllium.
• the temperature range which can be used is much wider.
• the lower limit is more or less dictated by the ductility of the beryllium which permits the transformation sought to be achieved. it is influenced also by the purity and the structure of the material handled such that it becomes possible to achieve transformation at room temperature.
• the upper limit corresponds to the melting point or the temperature of irreversible transformation of the plating metal. It is also influenced by the melting point temperature of the eutectic that is formed between the base metal and the plating metal.
• the upper limit is a temperature within the range of 600-620 C for pure aluminum, 550 aluminum, 380400 antimony.
• the starting material will comprise a sheet of beryllium prepared from a cast ingot by hot transformation in an inert atmosphere, such as by spinning or forging, followed by transformation at a lower temperature, without surface protection, to achieve a reduction by cold working of 50l00%.
• the first transformation breaks the coarse structure of the ingot and the second improves the surface characteristics and provides additional refining.
• the beryllium sheet can 'be subjected to various types of mechanical or thermal processing, such as planing or sanding.
• the laminated surface is of a rather good quality so that deep surface treatment will not be required.
• the intermediate product is cut to the desired dimensions and is pickled in a bath of HNO +H F for removal of the layer of oxide and other surface impurities. It is then introduced into a jacket in the form of a sheet of aluminum which is folded about the product in which the aluminum sheet has previously been degreased and brushed.
• the combination is preheated in an electric furnace having a temperature within the range of 400-600 C. and preferably about 600 C. with the heat arising from the bottom of the furnace.
• the preheating temperature is at least equal to the transformation temperature with the differences being accounted for by the temperature of the tools and the time for handling.
• the sandwich of beryllium and aluminum is removed from the furnace and is rapidly transferred to between heated rollers of a rolling mill.
• the speed of rolling is 10-20 meters per minute with a reduction of 10-15% being taken with each pass followed by reheating to 600 C. for 5 minutes.
• a reduction of at least 50% in cross-section is desired to achieve a good plating operation but a reduction as high as can be employed. Very thorough cold working can be achieved if the beryllium is first annealed but this is not essential to obtain good plating.
• the assembly is slowly cooled, preferably while enclosed in an inorganic insulator to minimize the rate of cooling. Thereafter, the product can be cut and machined without the necessity to take other precautions except for the use of sufiicient exhaust for the removal of chips which might fall from the product. The chipping off of sharp edges occurs only to a small extent.
• Thermal treatments may be employed to overcome the stresses introduced and to improve the plasticity of the C. for most of the alloys of C. for zinc and 580-600 C. for
• the plated metal is heated to a temperature which varies somewhat in proportion to time such as 550 C. for 500 hours, 575 C. for 200 hours, or 600 C. for 100 hours. These treatments, which should be carefully controlled, will tend to widen or expand the beryllium-diffusion layer by a substantial amount.
• Example 1 Two layers of 99.5% aluminum are provided on the opposite sides of a sheet of cast beryllium to provide a composite thickness of 4 mm., 80% of which is the cast beryllium sheet.
• the composite is hardened by hammering or forging to effect a 50% reduction in cross-section after which the composite is given a first anneal at 500 C.
• the annealed sheet is again forged to effect a reduction in thickness of 140% whereby the final thickness of the composite sheet is reduced to 1.15 mm.
• the first anneal is intended to restore the ductility, as measured by a 40 bend on a punch having a 5 mm. radius, before proceeding with the further reduction step.
• the processed sheet can be employed in the state resulting from the final working or it can be annealed at a temperature of about 600 C.
• Example 2 A composite sheet is formed of two sheets of cast beryllium interleaved between three layers of aluminum to give a total thickness of 3 mm.
• the applications will be governed by the characteristics obtained in the product, such as its mechanical, physical and chemical characteristics.
• the physical and chemical characteristics, which are innate in the surfaces of the plated beryllium, are governed also by the assembly possibilities of such products. The following is typical of the possibilities:
• brazing metal such as an alloy of aluminum with silicon or with zinc
• beryllium is intended to include beryllium and alloys of beryllium.
• the metallurgical process for the improvement of the mechanical and physical properties of beryllium products comprising mechanically plating the beryllium with at least one layer of a plastic metal selected from the group consisting of aluminum, magnesium, zinc and antimony at a temperature below 620 C. while mechanically working to effect a reduction in cross-section of at least 50%.
• a product produced by the method of claim 1 having a core of beryllium with at least two layers of a metal selected from the group consisting of aluminum, alloys of aluminum, magnesium, zinc and antimony.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Physics & Mathematics (AREA)
• Materials Engineering (AREA)
• Thermal Sciences (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Coating With Molten Metal (AREA)
• Laminated Bodies (AREA)
• Electroplating Methods And Accessories (AREA)
• Pressure Welding/Diffusion-Bonding (AREA)
• Manufacture And Refinement Of Metals (AREA)
• Forging (AREA)

Applications Claiming Priority (1)

Publications (1)

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Family Applications (1)

Country Status (6)

Cited By (1)

Citations (10)

• 1965
  • 1965-10-14 FR FR34967A patent/FR1472070A/fr not_active Expired
• 1966
  • 1966-10-10 LU LU52140D patent/LU52140A1/xx unknown
  • 1966-10-13 CH CH1477966A patent/CH467871A/fr unknown
  • 1966-10-13 GB GB45831/66A patent/GB1148766A/en not_active Expired
  • 1966-10-13 DE DE19661577076 patent/DE1577076A1/de active Pending
  • 1966-10-13 US US586360A patent/US3434319A/en not_active Expired - Lifetime

Patent Citations (10)

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