Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C21/00—Alloys based on aluminium
• • 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
  • C22F1/04—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon

Definitions

• the invention relates to the field of metallurgy of aluminum-based materials and can be used to obtain products operating at elevated temperatures, which are subject to high requirements for electrical conductivity, thermal conductivity and high processability in pressure processing. From the material can be made products of heat exchangers of the temperature control system and products for electrical purposes, in particular cooling radiators, airborne and high-voltage wires, wires of devices of the oil and gas complex.
• the maximum working temperature of alloy products is 400 ° C. State of the art
• alloys lxxx, Zxxx, 8xxx and bxxx series are widely used in electrolytic products and heat exchange systems.
• alloys of the lxxx and 3xxx series are usually used. Alloys of these systems are characterized by high corrosion resistance, good (for alloys of lxxx series) and satisfactory thermal conductivity.
• the disadvantages of the alloys of these systems include low heat resistance, which limits their operation to a temperature of 100 ° C, due to significant softening.
• Alloys lxxx, bxxx and 8xxx series are widely used for use in electrical engineering for the manufacture of wires, tires and other products.
• these alloys provide a successful combination of strength characteristics, thermal conductivity, electrical resistivity.
• the low level of thermal resistance of these alloys (usually not exceeding 90 ° C) also does not allow them to be used for heating above 150 ° C, due to their significant softening.
• type 1419 alloys include the high sensitivity of the alloy to the content of impurities, in particular silicon, which leads to the formation of a coarse eutectic and a decrease in manufacturability when drawing thin sections of wire.
• the relatively high volume fraction of eutectic phases (compared with technical aluminum) in type 1419 alloys does not allow reaching specific electrical resistance below 32 ⁇ Ohm / mm and high thermal conductivity, which is 14% lower than technical aluminum in alloy 1419.
• Known aluminum nickel-containing material disclosed in the invention US3830635 company Southwire The material is characterized by a conductivity of 57% IACS and contains (wt.%) 0.20-1.60 nickel, 0.30-1.30 cobalt, the rest is aluminum and impurities. In a private embodiment, the material may contain 0.001-1.0% iron and magnesium. In a private embodiment, the method of producing the melt involves the introduction of additional elements (wt.%), In particular mish metal, niobium, tantalum and zirconium.
• the disadvantages of this invention include the achievement of relatively low values of electrical conductivity (at 57% IACS) and the relatively high cost of cobalt, which limits the use of this material in mass production, for example, for high-voltage wires.
• a significant increase in thermal stability at elevated temperatures without a significant increase in the resistivity of aluminum wire can be achieved by introducing small additives of transition metals, in particular scandium and zirconium.
• the alloy contains (wt.%) 0.10-0.40% iron, 0.05-0.25% silicon, 0.05-0.20% Zr, the base is aluminum and impurities.
• the alloy may contain 0.05-0.40% manganese and 0.05-0.30% chromium.
• the disadvantages of this material include insufficient thermal resistance at elevated temperatures due to the relatively low zirconium content, in addition, when the content of chromium and manganese, the material will be characterized by low values of electrical resistivity and thermal conductivity.
• the alloy contains 250-1200 ppm of scandium and the rest is an impurity. In a private embodiment, the alloy may contain up to 0.1 mass. % zirconium.
• the disadvantages of the invention should be to attribute the high final cost of the resulting product due to the content of scandium and the limited resource base for scandium. In addition, the description does not show the absolute level of strength characteristics of the obtained wire from Sc-containing aluminum alloy.
• Known aluminum alloy reflected in patent US5087301 for high-temperature applications, containing a dissolved element and a solution, where the solution and the element dissolved in it forms a matrix having a subgrain structure formed by the boundaries of subgrains and particles of dispersoids at the boundaries and within subgrains, and the size of the secondary secretions of dispersoids within the matrix is less than at the border.
• the maximum equilibrium solubility of an element in a solution (at atmospheric pressure) is less than 1 mass.
• the alloy is determined by the formula A1-X, where X is selected from the group consisting of Er, Sc, Yb, Tm and U, at least 15% of the volume fraction of the phase accounted for by a stable connection of phase A1 3 X.
• X is selected from the group consisting of Er, Sc, Yb, Tm and U, at least 15% of the volume fraction of the phase accounted for by a stable connection of phase A1 3 X.
• the alloy structure is characterized by an aluminum matrix and dispersoids of the AI 3 X phase with an Ll 2 type lattice, where X contains Sc, and at least one element of Gd and Zr, an aluminum alloy contains (wt.%): Sc 0.1 - 2.9; Gd 0.1 - 20; Zr 0.1-1.9.
• the alloy may additionally contain Mg in an amount of 1-7%.
• the objective of the invention is the creation of a new heat-resistant aluminum alloy characterized by a combination of a high level of physical and mechanical characteristics and manufacturability, in particular a high level of thermal conductivity (not lower than 220 W / (m K)), electrical conductivity (not lower than 59% IACS), mechanical properties, including preservation of strength properties after high-temperature heating up to 400 ° C, high adaptability during deformation processing, for example pressing and drawing, including thin wire up to 100 microns.
• a high level of physical and mechanical characteristics and manufacturability in particular a high level of thermal conductivity (not lower than 220 W / (m K)), electrical conductivity (not lower than 59% IACS), mechanical properties, including preservation of strength properties after high-temperature heating up to 400 ° C, high adaptability during deformation processing, for example pressing and drawing, including thin wire up to 100 microns.
• the technical result is to increase the heat resistance of the alloy while maintaining high values of thermal conductivity and electrical conductivity of the alloy due to the formation of compact particles of phases of eutectic origin and the secondary selection of the Zr-containing phase with a crystal lattice type Ll 2 .
• the cost of the alloy is reduced.
• the proposed alloy containing zirconium and at least one element selected from the group comprising iron and nickel while the structure of the alloy is an aluminum matrix, with distributed in it particles of a second-recovered phase Al 3 Zr with a crystal lattice Ll 2 and with a size of not more than 20 nm and particles of phases of eutectic origin in an amount of from 0.5 to 3.0% of the masses containing iron and / or nickel, while aluminum the matrix contains by mass no more than 1/3 of zirconium of the total zirconium content in the alloy.
• Aluminum may contain unavoidable impurities.
• the alloy contains elements in the following ratio (wt.%):
• the content of zirconium in the alloy can be 0.22-0.78% of the mass, preferably 0.22-0.3% of the mass, preferably 0.22-0.28% of the mass, preferably 0.22-0.26% mass, preferably 0.26-0.28% of the mass, preferably 0.25-0.28% of the mass, preferably 0.3-045% of the mass.
• the iron content in the alloy can be 0.20-0.8% of the mass, preferably 0.2-0.4% of the mass, preferably 0.4-0.6% of the mass, preferably 0.6-0.8% mass
• the nickel content in the alloy may be 0.005-0.4% by weight, preferably 0.005-0.01% by weight, preferably 0.01-0.11% by weight, preferably 0.11-0.22% by weight, preferably 0 , 22-0.4% of the mass.
• the aluminum matrix contains by mass no more than 1/3 of zirconium from the total content of zirconium in the alloy. In this case, it is preferable that the zirconium content in the aluminum matrix (aluminum solution) be as low as possible.
• the particle size of the secondarily isolated phase Al 3 Zr with a crystal lattice L 2 does not exceed 20 nm, preferably up to 5-10 nm.
• the structure of the conductor material should contain minimally doped aluminum solution, compact particles of eutectic phases and secondary precipitates of the Zr-containing phase with a size of up to 20 nm.
• the effect of increased heat resistance in this case is achieved from the combined positive effect of eutectic phases containing iron and / or nickel and secondary precipitates of the zirconium phase that are resistant to high temperature heating.
• a high level of thermal conductivity and electrical conductivity is determined by the minimum content of alloying components in the aluminum solution.
• Iron in an amount of 0.20-0.8% of the mass is necessary to increase the overall level of mechanical properties of technical aluminum without significantly reducing the electrical resistivity. When the iron content is higher than the declared effect of this element will have a significant negative effect on the electrical resistivity of the alloy by reducing the volume fraction of the aluminum solution. The minimum content corresponds to the achievement of the minimum level of strength characteristics.
• Zirconium in an amount of 0.22-0.70% of the mass is necessary for the formation of secondary precipitates of the metastable phase Al 3 (Zr) with a crystal lattice L l 2 . In general, zirconium is redistributed between the aluminum solution and the secondary precipitates of the metastable phase Al 3 (Zr) Ll 2 .
• the high content of zirconium in the aluminum solution leads to a decrease in thermal conductivity and an increase in electrical resistance.
• zirconium concentrations in the alloy below 0.22%, the amount of secondary precipitates of the metastable Al 3 (Zr) phase with the Ll 2 type lattice will not be sufficient to achieve the specified strength characteristics and heat resistance, and with large quantities it will be necessary to increase the casting temperature above 800 ° C, otherwise In this case, a phase with a lattice of the D0 23 type can be formed in the structure of primary crystals.
• Nickel in the amount of 0.005-0.4% of the mass is necessary to increase the overall level of mechanical properties of technical aluminum without significantly reducing the electrical resistivity due to slightly dissolving in the aluminum solution.
• a structure with a favorable morphology of eutectic phases in particular, Al 3 Ni and / or Al 9 FeNi phases, will be obtained.
• Such a structure with a favorable morphology of the nickel and / or iron-nickel phase will provide high processability during deformation processing (rolling, pressing, drawing and others).
• its effect will be insufficient to ensure the required structure, and an increase above the upper limit will not have a significant effect on the improvement of manufacturability during pressure treatment.
• alloy compositions were prepared under laboratory conditions (Table 1). Alloys were prepared in a resistance furnace in graphite crucibles made of aluminum (99.95), and alloys ⁇ 1-20 ⁇ , Al-10Fe, Al-15Zr. The alloys were obtained in the form of flat ingots with a cross section of 200x40 mm, then the ingots were rolled into sheets 2 mm thick at room temperature using an intermediate heat treatment with a maximum heating temperature of 460 ° C, which decays the aluminum matrix to form secondary particles of the Al 3 Zr Ll phase 2 .
• the structural parameters, in particular, the presence of primary crystals of the zirconium phase, were evaluated by a metallographic method.
• the particle size of the secondary precipitates was estimated using the method of transmission electron metallography (TEM).
• TEM transmission electron metallography
• the zirconium content in the aluminum matrix was estimated by the calculation and experimental method using the Thermocalc program (TTAL5 database) and the electrical resistivity values, taking into account that the values primarily depend on the content of alloying elements in the aluminum matrix.
• compositions 2-6) provide the required parameters of the structure, the values of electrical conductivity and heat resistance.
• the alloy of composition 1 does not satisfy in terms of heat resistance (due to a drop in ⁇ values of more than 10%), which is associated with the relatively low mass fraction of particles of crystallization origin containing iron and nickel (Q K m ) and insufficient zirconium content in the alloy.
• Q K m iron and nickel
• the aluminum alloy matrix contained a variable mass concentration of zirconium.
• the rest of the zirconium was present as secondary precipitates of the Al 3 Zr Ll 2 phase.
• a variable zirconium concentration was achieved by varying the annealing temperature of the sheets in the range of 350 and 460 ° C, and for “1” (100% Zr) in the aluminum solution, the molten state values corresponded.

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• 2016
  • 2016-07-01 RU RU2017112928A patent/RU2659546C1/ru active
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