RU2573463C1 - Aluminium-based heat-resistant electroconductive alloy - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: aluminium-based alloy contains the following in wt %: copper 0.5-2.0; manganese 0.3-1.6; zirconium 0.1-0.5; boron 0.02-0.15; silver 0.01-0.5; scandium 0.02-0.15; iron 0.01-0.3; silicon 0.01-0.35, inevitable admixtures up to 0.1, from them each up to 0.03, aluminium - rest. The alloy has structure containing the aluminium solid solution and nanoparticles of secondary zirconium and scandium aluminides, and boron presents in the alloy structure in form of nanoparticles AlB₂, AlB₁₂ with average size 50 nm maximum. The alloy has tensile strength (σ_h) after holding at 250°C for 400 hours is at least 170 MPa, and electrical conductivity is at least 55% IACS.

EFFECT: increased heat resistance.

2 cl, 2 tbl

Description

The invention relates to the field of metallurgy, in particular to wrought nanostructured alloys based on aluminum, copper, manganese, zirconium, scandium, iron, silicon and methods for their manufacture for products operating at elevated temperatures. In particular, the alloy can be used in aviation, astronautics, and automotive for electrical products, where combinations of sufficient increased strength, heat resistance, and electrical conductivity are required.

Known alloys of the Al-Cu-Mn system with a high copper content (Engineering. Encyclopedia of 40 tons. II-3. Non-ferrous metals and alloys. M: Engineering, 2001, S. 144-156). These are alloys D20, 1201, D21, 01205 with 5.8-7.0 wt. % copper. They have an electrical conductivity of not higher than 30-35% IACS.

Known alloy patent RF №2287600, IPC C22C 21/12 publ. November 20, 2006, containing copper, manganese, zirconium and vanadium, including aluminum solid solution and secondary aluminides, characterized in that it additionally contains scandium in the following ratio of components, wt. %: copper 1.2-2.4; manganese 1.2-2.2; zirconium 0.5-0.6; vanadium 0.01-0.15; scandium 0.01-0.2; aluminum is the rest. After 100 hours of exposure, the alloy has a tensile strength at 350 ° C above 30 MPa. With a relatively high tensile strength after 1–20 min of annealing at 200–410 ° C equal to 300 MPa, the alloy has low electrical conductivity — below 48% IACS.

Closest to the claimed object is an alloy based on aluminum, RF patent No. 2446222, IPC C22C 21/14, publ. 03/27/2012, containing components in the following ratio, wt. %: copper 0.9-1.9; manganese 1.0-1.8; zirconium 0.2-0.64; scandium 0.01-0.12; iron 0.15-0.5; silicon 0.05-0.15; aluminum - the rest; nanoparticles of the Al ₃ (Zr, Sc) phase with an average size of not more than 20 nm, the electrical conductivity exceeds 53% IACS, the temporary resistance σ _in after 100 hours at 300 ° C exceeds 320 MPa.

The disadvantage of this alloy, despite many advantages, is the lack of strength at a temperature of 250 ° C and exposure for 400 hours and electrical conductivity (53% IACS).

The basis of the invention is the task of creating a new nanostructured deformable alloy based on aluminum, which has greater heat resistance and / or electrical conductivity compared to the prototype alloy for various semi-finished products and products.

The problem is solved due to the fact that a heat-resistant conductive alloy based on aluminum, containing copper, manganese, zirconium, scandium, iron and silicon, with a structure containing aluminum solid solution and nanoparticles of secondary zirconium and scandium aluminides Al ₃ (Zr, Sc), characterized in that it additionally contains silver and boron in the following ratio of components, wt. %:

copper 0.5-2.0 manganese 0.3-1.6 boron 0.02-0.15 zirconium 0.1-0.5 silver 0.1-0.5 scandium 0.02-0.15 iron 0.01-0.30 silicon 0.1-0.35 inevitable impurities 0-0.01, of which each 0-0.03 aluminum rest,

moreover, boron is present in the structure in the form of AlB ₂ , AlB ₁₂ nanoparticles with an average size of not more than 50 nm, while the alloy has an electrical conductivity of at least 55% IACS and a tensile strength after 400 hours at 250 ° C of at least 170 MPa. The alloy may further comprise, by weight. %: cobalt 0.1-0.45, and / or nickel 0.1-0.35, and / or cadmium 0.1-0.3, and / or REM 0.001-0.1, and / or germanium 0 05-0.3.

In this case, boron forms stable segregation in the border regions on defects of the crystal lattice, increasing the ability of the alloy to deform, changing the kinetics of aging. For a more stable increase in heat resistance, the alloy may additionally contain the above contents: cobalt and / or nickel and / or cadmium, and / or REM, and / or germanium.

The alloy can be prepared in the form of various cast and deformed semi-finished products (sheets, tires, stamping, wire for on-board wires and other applications), the manufacturing technology of which includes the preparation of the melt at a temperature exceeding the liquidus temperature by 100 ° C. The components are introduced into the melt in the form fine crystalline ligatures with an average nanoparticle size of not more than 1300 nm. When using Al-B-Ti or Al-Cu-Mn (Ti) ligatures, the titanium content in the melt is maintained no more than 0.03 wt. %

In addition, the crystallization of the cast billet and its deformation is carried out under the influence of a magnetic pulse field and / or weak pulse current to ensure the required nanoparticle size and heat resistance.

To ensure a cast structure closer to the deformable one, high temperatures of 900-800 ° C are maintained during crystallization.

Manganese, zirconium and cobalt slow down the decomposition of solid solution at high temperatures and slow down the recrystallization process. Manganese and copper in these concentrations cause the formation of dispersoids, providing basic requirements for strength and thermal conductivity. Their increase reduces the conductivity. Zirconium and scandium contribute to the formation of nanoparticles and contribute to the achievement of the required strength at elevated temperatures. An increase in their content decreases electrical conductivity. Small manganese concentrations increase long-term strength at temperatures of 250-300 ° C.

Iron and silicon also reduce electrical conductivity, but in the form of joint compounds with eutectic type manganese Al (Fe, Mn) Si contribute to the formation of a structure that increases the strength of the alloy.

Boron in the form of nanoparticles with aluminum and in the form of borides with transition metals increases the electrical conductivity of the alloy.

Examples of the implementation of the claimed material.

Alloys were prepared in an electric resistance furnace in alundum crucibles at a melt temperature of 100 ° C above the liquidus line. As the charge used aluminum (99.9%), copper (99.9%) and fine-grained ligatures: double Al-Mn, Al-Zn, Al-Sc, Al-Si, Al-Fe, triple ligatures Al-B- Ti and / or Al-Cu-Mn (Ti). The alloy compositions are given in table 1. Round ingots were cast into a cylindrical mold. Magnetic pulse fields (MIL) were used to mix the melt, weak current pulses during crystallization.

Then, the samples were annealed at 450 ° C ± 10 ° for 4 hours and precipitated to 60-70%), Brinell hardness and electrical conductivity were measured.

Brinell hardness was measured according to GOST 9012-59 with a transfer to tensile strength. Electrical conductivity was measured according to GOST 27333-87 by the eddy current method.

As can be seen from the analysis of tables 1 and 2, compositions No. 1 and No. 2 have a higher electrical conductivity, and compositions 3 and 4 have a higher tensile strength after holding for 400 hours. at 250 ° C compared with the prototype (US Pat. No. 2446222).

The proposed nanostructured wrought alloy based on aluminum has greater heat resistance or electrical conductivity compared to the prototype and contains an option with higher electrical conductivity with relatively low heat resistance and higher heat resistance along with lower electrical conductivity compared to the prototype.

Claims (2)

1. Heat-resistant electrically conductive aluminum-based alloy containing copper, manganese, zirconium, scandium, iron and silicon, with a structure comprising an aluminum solid solution and nano aluminides secondary zirconium and scandium Al ₃ (Zr, Sc), characterized in that it additionally contains silver and boron in the following ratio of components, wt. %:
copper 0.5-2.0 manganese 0.3-1.6 boron 0.02-0.15 zirconium 0.1-0.5 silver 0.01-0.5 scandium 0.02-0.15 iron 0.01-0.30 silicon 0.1-0.35 inevitable impurities to 0.1, of which each to 0.03 aluminum rest,
wherein the boron is present in the structure in the form of nanoparticles AlB _2, AlB ₁₂ having an average size of not more than 50 nm, the alloy has an electrical conductivity not less than 55% IACS and a tensile strength after 400 hours at 250 ° C of not less than 170 MPa. 2. The alloy according to claim 1, characterized in that it further comprises wt. %: cobalt 0.1-0.45, and / or nickel 0.1-0.35, and / or cadmium 0.1-0.3, and / or REM 0.001-0.1, and / or germanium 0 05-0.3.