RU2556179C2 - Heat-resistant electroconductive alloy based on aluminium (versions) and method of production of deformed semi-finished product out of aluminium alloy - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, in particular to the deformed nanostructure alloys based on aluminium, and to the methods of their production for items working under high temperatures. Aluminium-based alloy contains the following components in wt %: copper 0.5-0.85; manganese 0.5-0.95; boron 0.02-0.15; zirconium 0.1-0.5; scandium 0.02-0.15; iron 0.01-0.3; silicon 0.01-0.15, inevitable admixtures 0-0.1, from them each 0-0.03, aluminium - rest. At that boron presents in the alloy structure in form of the nanoparticles AlB₂, AlB₁₂, borides of transient metals with average size 50 nm maximum, at that the alloy has conductivity over 54% IACS and tensile strength (σ_B) after 400 hours of heating at 250°C at least 160 MPa. According to the second option the alloy contains in wt %: copper 0.9-2.0, manganese 1.0-1.6, boron 0.02-0.15; zirconium 0.1-0.5; scandium 0.02-0.15; iron 0.01-0.3; silicon 0.01-0.15, inevitable admixtures 0-0.1, from them each 0-0.03, aluminium - rest, at that the boron presents in the alloy structure in form of the nanoparticles AlB₂, AlB₁₂, borides of transient metals with average size 50 nm maximum, at that the alloy has tensile strength after 400 hours of heating at 250°C up to 230-280 MPa. Method includes the melt preparation at temperature by 100°C above temperature of the melt liquidus, at that the alloying components are added to the melt in form of addition alloys, having fine structure with average size of the nanostructures 1500 nm maximum, crystallisation and deformation under action of the magnetic pulse field and/or low pulse current.

EFFECT: improvement of the alloy thermal resistance and conductivity.

8 cl, 2 tbl, 1 ex

Description

The invention relates to the field of metallurgy, in particular to wrought nanostructured alloys based on aluminum, copper, manganese and a method for their preparation for products operating at elevated temperatures. In particular, the alloy can be used in aviation, in astronautics, in the automotive industry, for products of electrical engineering, where combinations of sufficient and various strengths, electrical conductivity, and heat resistance are required.

Known alloys of the Al-Cu-Mn system with a high copper content ("Engineering. Encyclopedia of 40 tons. I-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, due to the use after quenching and artificial aging and high copper content.

The alloy according to the patent is known (RF patent No. 2287600, IPC С22С 21/12, publ. 20.11.2006) containing copper, manganese, zirconium and vanadium, including aluminum solid solution and secondary aluminides, characterized in that it additionally contains scandium in the following the 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 high tensile strength after 1-20 min 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, C22F 1/057, 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, electrical conductivity exceeds 53% IACS, temporary resistance (σ _in ) after 100 hours at 300 ° C exceeds 320 MPa.

The disadvantage of this alloy, in spite of many advantages, is the insufficient strength at a holding time of 400 h (250 ° C), and also the electrical conductivity is not higher than 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 electrical conductivity.

The problem is solved due to the fact that the heat-resistant conductive alloy based on aluminum, containing copper, manganese, zirconium, scandium, iron and silicon and having a structure containing aluminum solid solution and secondary aluminides of manganese, zirconium and scandium, according to the invention additionally contains boron at the following ratio of components, wt.%:

copper 0.5-0.85 manganese 0.5-0.95 boron 0.02-0.15 zirconium 0.1-0.5 scandium 0.02-0.15 iron 0.01-0.30 silicon 0.01-0.15 inevitable impurities 0-0.1, of which each 0-0.003 aluminum rest

while boron is present in the structure in the form of AlB ₂ , AlB ₁₂ nanoparticles and transition metal borides with an average size of not more than 50 nm, and the alloy has an electrical conductivity higher than 54% IACS and a tensile strength after 400 hours at 250 ° C of at least 160 MPa.

In addition, the alloy additionally contains wt.%: Cobalt 0.1-0.45, and / or nickel 0.1-0.35, and / or cadmium 0.1-0.3.

The problem is also solved due to the fact that the heat-resistant conductive alloy based on aluminum, containing copper, manganese, zirconium, scandium, iron and silicon and having a structure containing aluminum solid solution and secondary aluminides of manganese, zirconium and scandium, according to the invention additionally contains boron at the following ratio of components, wt.%:

copper 0.9-2.0 manganese 1.0-1.6 boron 0.02-0.15 zirconium 0.1-0.5 scandium 0.02-0.15 iron 0.01-0.30 silicon 0.01-0.15 inevitable impurities 0-0.1, of which each 0-0.03 aluminum rest

wherein the alloy has a tensile strength after 400 hours at 250 ° C to 230-280 MPa.

For a more stable increase in heat resistance, the alloy may additionally contain, wt.%: Cobalt 0.1-0.45, and / or nickel 0.1-0.35, and / or cadmium 0.1-0.3.

A method for producing a deformed semifinished product from an aluminum-based alloy, including the preparation of a melt at a temperature of 100 ° C higher than the liquidus temperature of the alloy, while the alloying components are introduced into the aluminum melt in the form of alloys having a fine-crystalline structure with an average nanoparticle size of not more than 1500 nm, crystallization and subsequent deformation, and crystallization and deformation are carried out under the influence of a magnetic pulse field and / or weak pulse current.

In addition, when introducing A1-B-Ti or Al-Cu-Mn (Ti) alloys into the melt, the titanium content in the melt should not exceed 0.05 wt.%.

Manganese, zirconium and cobalt slow down the decomposition of solid solution at high temperatures, slow down the process of recrystallization. Manganese and copper in the indicated concentrations cause the formation of dispersoids, which provide basic strength requirements. 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.

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. At the same time, forming stable segregations in the border regions on the defects of the crystal lattice, boron increases the ability to deform and accelerates the kinetics of aging to a certain extent.

Examples 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 a charge, aluminum (99.9%), copper (99.9%), fine-grained double ligatures: Al-Mn, Al-Zr, Al-Sc, Al-Si, Al-Fe, triple ligature Al-B- were used Ti and / or a composition for introducing boron (potassium fluoroborate, hexochloroethane, potassium fluoride). The alloy compositions are given in table 1. Round ingots were cast into a cylindrical mold. Magnetic pulse fields (MIL) or weak pulsed currents (SIT) were used to mix the melt, increase its purity (gases, impurities), affect crystallization and deformation.

The maximum deformation temperature did not exceed 400 ° C; for compositions with 0.5-0.85 wt.% Cu and 0.5-0.95 wt.% Mn, deformation was carried out at room temperature. Annealing was carried out at a temperature of 350 ° C.

Vickers hardness was measured according to GOST 2999-75 with translation into N _in and σ _in . Electrical resistivity and electrical conductivity were determined according to GOST 6132-79.

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

The proposed nanostructured wrought alloy based on aluminum has greater heat resistance and electrical conductivity.

Claims (8)

1. Heat-resistant conductive alloy based on aluminum, containing copper, manganese, zirconium, scandium, iron, silicon and having a structure containing aluminum solid solution and secondary aluminides of manganese, zirconium and scandium, characterized in that it additionally contains boron in the following ratio of components , wt.%:
copper 0.5-0.85 manganese 0.5-0.95 boron 0.02-0.15 zirconium 0.1-0.5 scandium 0.02-0.15 iron 0.01-0.30 silicon 0.01-0.15 inevitable impurities 0-0.1, of which each 0-0.003 aluminum rest
while boron is present in the structure in the form of AlB ₂ , AlB ₁₂ nanoparticles and transition metal borides with an average size of not more than 50 nm, and the alloy has an electrical conductivity higher than 54% IACS and a tensile strength after 400 hours at 250 ° C of at least 160 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. 3. A method of producing an aluminum-based alloy according to claim 1 in the form of a deformed semi-finished product, comprising preparing a melt at a temperature 100 ° C higher than the liquidus temperature of the alloy, while the alloying components are introduced into the aluminum melt in the form of alloys having a fine crystalline structure with an average nanoparticle size not more than 1500 nm, crystallization of the workpiece and its subsequent deformation, moreover, crystallization and deformation is carried out under the influence of a magnetic pulse field and / or weak pulse current. 4. The method according to p. 3, characterized in that when the alloys Al-B-Ti or Al-Cu-Mn (Ti) are introduced into the melt, the titanium content in the melt is not more than 0.05 wt.%. 5. Heat-resistant conductive alloy based on aluminum, containing copper, manganese, zirconium, scandium, iron and silicon and having a structure containing aluminum solid solution and secondary aluminides of manganese, zirconium and scandium, characterized in that it additionally contains boron in the following ratio of components , wt.%:
copper 0.9-2.0 manganese 1.0-1.6 boron 0.02-0.15 zirconium 0.1-0.5 scandium 0.02-0.15 iron 0.01-0.30 silicon 0.01-0.15 inevitable impurities 0-0.1, of which each 0-0.03 aluminum rest
wherein the alloy has a tensile strength after 400 hours at 250 ° C to 230-280 MPa. 6. The alloy according to claim 5, 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. 7. A method for producing an aluminum-based alloy according to claim 5 in the form of a deformed semi-finished product, comprising preparing a melt at a temperature 100 ° C higher than the liquidus temperature of the alloy, while the alloying components are introduced into the aluminum melt in the form of alloys having a fine crystalline structure with an average nanoparticle size not more than 1500 nm, crystallization of the workpiece and its subsequent deformation, moreover, crystallization and deformation is carried out under the influence of a magnetic pulse field and / or weak pulse current. 8. The method according to p. 7, characterized in that when the alloys Al-B-Ti or Al-Cu-Mn (Ti) are introduced into the melt, the titanium content in the melt is not more than 0.05 wt.%.