Superplastic aluminium-based alloy

FIELD: metallurgy.

SUBSTANCE: alloy contains, wt %: 3.5-4.5 zinc, 3.5-4.5 magnesium, 0.6-1.0 copper, 2.0-3.0 nickel, 0.25-0.3 zirconium, aluminium - balance, at the same time after strengthening thermal treatment the alloy has yield point of 570 MPa, strength limit of 600 MPa, hardness of 160 HY, and after deformation at 440-480°C with speed of 0.001-0.01 1/s the alloy has elongation of more than 500%.

EFFECT: production of alloy with equiaxial homogeneous fine-grain structure.

4 ex

 

The invention relates to the field of metallurgy, namely the development of new alloys and obtaining from them superplastic strain sheet blanks by heat treatment and pressure treatment. The invention is a new aluminum alloy that is designed for producing superplastic sheets.

One of the necessary factors to achieve superplasticity is mikrotalasna structure of alloys with a grain size less than 10 microns (Bio, Vchorniy "Superplasticity of alloys with ultrapack grain, 1981).

Among the existing methods (technologies) in the industry known methods for producing sheets of various alloys with microkernel structure using thermo-mechanical processing and subsequent recrystallization.

The formation microkernel structure by recrystallization in two ways. First, due to recrystallization during heating of the sheet to a temperature superplastic deformation, secondly, in the case of braking static recrystallization, microsetella structure can be formed in the process of superplastic deformation due to continuous dynamic recrystallization. This material belongs to the second type. To provide the braking effect of static recrystallization in the presence at a temperature of surplu the static deformation of the dispersed particle size of less than 100 nm. Such particles in aluminum alloys form a transitional metals, scandium and zirconium. A well-known alloy for superplastic sheet forming Supral 100. This alloy has the composition Al-(5-6)%Cu-(0.4 to 0.6)%Zr. The technology of its receipt based on the high cooling rate during crystallization, providing a high content of zirconium in solid solution and the subsequent allocation when thermal deformation processing of dispersed particles aluminide Zirconia stabilizing grain structure and constraining the recrystallization. In the process of superplastic deformation alloy recrystallizes formed mikrotalasna structure that provides high performance superplasticity. However, the alloy according to the level of mechanical properties among the aluminum is srednepozny.

The most similar composition, are the following alloys AA or AA. However, these alloys contain large amounts of zinc (from 4.3 to 5.5%, but fewer magnesium (2,6-3,7)% and does not contain Nickel in the platings. Known Nickel-containing alloy system Al-Zn-Mg-Cu-Ni (USA Patent 6,585,932), however, described in the patent, the alloy contains about 2% magnesium 6% zinc, i.e. zinc and magnesium in a different quantity and value.

Methods of obtaining superplastic state for high-strength alloys (AA 7000 series) are described in patents US 4.486.244 from 4.12.1984, 4.618.382 from 21.10.1986, 4.867.805 from 19.09.1989, 5.490.88 from 13.02.1996 and 5.772.804 30.06.1998, 5.122.196 from 16.06.1992, 06-010087 from 18.01.1994.

However, the alloys have a grain size of about 8-10 microns and superplastic only in the velocity range 10-5-10-3with-1.

The closest to this technology for producing superplastic sheets of alloys A series described in the patent US 4.486.244 from 4.12.1984. However, the described method eliminates the necessity of application of operations heterogenization (intermediate quenching and subsequent annealing at 400°C), does not require high-speed heating to temperatures of superplastic deformation, the use of large or heavy plastic deformation.

The technical purpose of this invention to provide a sheet of high strength aluminum alloy with a homogeneous fine-grained structure, which is formed only in the process of superplastic deformation, and a uniform distribution of dispersed particles of intermetallic compounds, details of which can be obtained by the method of superplastic forming.

High-strength alloys developed on the basis of the system Al-Zn-Mg-Cu alloys AA series (USA) or alloys of type B95 (RF)). This alloy has the following chemical composition (3.5 to 4.5)% Mg-(3,5-4,5)% Zn-(0,6-1,0)% Cu-(2-3)% Ni-(0,25-0,30)% Zr. Zinc and magnesium are contained in approximately equal concentrations. The specified content of alloying elements allows to achieve a given set of properties: mechanical properties (pre who ate fluidity, tensile strength) after processing mode hardening and aging and high levels of superplastic.

To solve this problem is proposed, the following technology; the melt temperature of 800°C is poured into a water-cooled mold (cooling rate of not less than 15 K/s). Follows two-step homogenization annealing (440°C, 3-6 hours and 500°C, 3-4 hours). The temperature of the second stage above the temperature of the nonequilibrium solidus 485°C. Hot rolling is carried out at a temperature of 430°C, with a total reduction of 70%. Followed by cold rolling with a reduction of 70%.

For sheets of the alloy obtained by the above technology, defined mode aging 110°C, 6 h +140°C, 12 hours, providing maximum strength characteristics at room temperature yield strength of 570 MPa, the tensile strength of 600 MPa, the hardness of 160 HV.

As a result of annealing, cold-formed sheet to a temperature superplastic forming is formed partially recrystallized structure. The alloy is fully recrystallized only during superplastic deformation. Equiaxial mikrotalasna structure is formed by a uniform distribution of particles of intermetallic compounds of Nickel and zirconium-containing phases. The uniform distribution of the particles is achieved through the study of patterns in the process pressure.

Note the R 1:

Alloy 1

The alloy composition of 4% Mg - 4% Zn and 0.8% Cu - 3% Ni - 0,28% Zr was processed as follows.

Technology 1

1. For the preparation of alloy used aluminum brand A99 motorway, magnesium Mg, zinc S and ligatures, such as "Al - 53.5 wt.% Cu", "Al - 20 wt.% Ni and Al - 3.5 wt.% Zr".

2. Smelting is conducted in gravito-fireclay crucibles with sequential introduction of molten aluminum alloys, Al-3.5% of Zr; Al - 20% Ni"; "Al - 53.5 wt.% Cu and magnesium in pure form. Before the introduction of the magnesium melt is brought to a temperature of 780°C for more rapid dissolution and smaller losses on fumes during subsequent heating to 800°C. For a more complete homogenization of the melt before casting maintained it for 10-15 minutes at 800°C. If you don't provide the specified overheating of the melt, the crystallization allocated primary zirconium aluminides, which in consequence reduces the characteristics of superplastic material.

3. Casting the melt was carried out on the installation of semi-continuous casting with cooling rates not less than 15 K/S. Lower cooling rates can lead to depletion of aluminum solid solution with Zirconia due to the release of primary crystals.

4. The homogenization annealing ingots were carried out in 2 stages - at 440°C for 3 hours and at 500°C for 3 hours. The second stage of homogenization temperatures above nonequilibrium solidus. In this mode homogenizate ingots passes completely. After homogenizing the ingot should be treated to remove surface defects and cut shrink the sink. The solidus temperature homogenized alloy is 506°C.

5. Hot rolling was carried out at 420±10°C, with a total reduction of 70%.

6. Cold rolling was conducted with a total reduction of 70%.

Next was evaluated mechanical properties and characteristics of superplastic sheets.

To determine the mechanical properties of the samples were subjected to quenching with temperature 480°C, 20 minutes exposure and aging on mode 110°C, 6 h +140°C, 12 hours. The yield amounted to 570 MPa, the tensile strength of 600 MPa, an elongation of 5%.

A technological regime provided forming part of precrystallization patterns before sverkhplasticheskoi deformation at temperatures up to 480°C. In the process of superplastic deformation structure completely recrystallized, after 600% strain at a rate of 2×10-3with-1the average grain size in the alloy was 4.5 μm.

The maximum elongation before breaking, obtained at temperatures of 440-480°C and a maximum strain rate of 1×10-2c-1amounted to 650%, at speed (5×10-3c-1) - 750%, and at (2×10-3c-1) - amounted to 690%.

Example 2

Alloy 2

The alloy composition of 3.5% Mg to 4.0% Zn and 0.8% Cu - 3% Ni - 0,30% Zr was processed according to the technology 1, described is the example 1.

The maximum elongation before breaking, obtained at temperatures of 440-480°C and a maximum strain rate of 1×10-2c-1amounted to 470%, and at speed (2×10-3with-1) - amounted to 550%.

Example 3

Alloy 3

The alloy composition of 4.5% Mg, and 3.5% Zn and 0.8% Cu - 3% Ni - 0,30% Zr was processed according to the technology 1 described in example 1.

The maximum elongation before breaking, obtained at temperatures of 440-480°C and strain rate of 1×10-2c-1amounted to 300%, and at speed (2×10-3c-1) amounted to 580%.

Example 4

Alloy 4

The alloy composition of 4.0% Mg to 4.0% Zn and 0.8% Cu - 2% Ni - 0,30% Zr was processed according to the technology 1 described in example 1.

The maximum elongation before breaking, obtained at temperatures of 440-480°C and strain rate of 1×10-2c-1amounted to 400%, and at speed (2×10-3c-1) 440%.

Superplastic aluminum alloy containing zinc, magnesium, copper, Nickel and zirconium, characterized in that it contains components in the following ratios, wt%:

zinc3.5 to 4.5
magnesium3.5 to 4.5
copper0,6-1,0
Nickel2,0-3,0
zirconium of 0.25-0.3
aluminumthe rest,

after hardening of the alloy has a yield strength of 570 MPa, the tensile strength of 600 MPa, the hardness of 160 HV and after deformation at a temperature of 440-480°C with a speed of 0.001 to 0.01 1/s alloy has an elongation of more than 500%.



 

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8 cl, 2 dwg, 10 tbl, 4 ex

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2 cl, 5 tbl

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1 tbl, 1 ex

FIELD: metallurgy.

SUBSTANCE: plate of 10 mm thickness or larger from aluminium alloy features higher durability. Note here that said aluminium alloy has the following chemical composition with the following components, in wt %: Mg 4.0-6.0, Mn 0.2-1.4, Zn not over 0.9, Zr < 0.3, Cr < 0.3, Sc < 0.5, Ti < 0.3, Fe < 0.5, Si < 0.45, Ag < 0.4, Cu < 0.25, other elements and unavoidable impurities of each aforesaid element - <0.05, sum - <0.20, aluminium making the rest. Plate features elongation in L direction exceeding 10% and tensile strength making, t least, 330 MPa. Proposed plate is produced by casting, preheating and/or homogenising, hot rolling, first cold forming, annealing at less than 350°C, and second cold forming.

EFFECT: higher resistance to kinetic projectiles, better formability.

27 cl, 3 dwg, 2 tbl, 2 ex

FIELD: metallurgy.

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EFFECT: deformed billets with high mechanical strength while maintaining flexibility.

1 tbl, 1 ex

FIELD: metallurgy.

SUBSTANCE: there is received constructional material from alloy on the basis of aluminium, containing components at following ratios, wt %: magnesium 10.50-15.50, manganese 0.05-0.10, zirconium 0.01-0.15, titanium 0.09-0.15, silicon and iron not more than 0.08, aluminium is the rest. Crystallisation of melt is implemented in rotary crystalliser at gravitation coefficient, equal to 180-250, during time of melt existence, equal to 12-15 s/kg, and cooling rate not higher than 5°C/s. Ingot is thermal treated and rolled. At first it is heated during 2-4 hours at temperature 340-380°C, then at that temperature is implemented its hot rolling up to thickness 4-8 mm at a degree of deformation in each cycle up to 30% and final temperature of semi-finished rolled products in the range 310-330°C. Then it is implemented cold rolling of semi-finished rolled products at a degree of deformation in each cycle up to 50% with intermediate softening during 0.5-2.0 hours at tempearture 310-390°C up to required thickness 0.5-2.0 mm and it is implemented finish annealing of rolling during 5-40 minutes at temperature 400-450°C.

EFFECT: increased durability, plasticity and manufacturability of rolling.

2 dwg, 2 cl

FIELD: metallurgy industry.

SUBSTANCE: invention refers to metallurgy, and namely to methods of producing superductile plates from aluminium alloys of aluminium-magnesium-lithium system, and can be used for superductile moulding of complex-shaped parts, as well as structural material when producing extruded sections. From an ingot there made is a half-finished article in the form of a cylinder. Hardening is carried out at 460±10°C during 0.5 hour. After that the half-finished article is extruded in intersecting channels with diameter corresponding to diameter of half-finished article deformed with a shear at the temperature of 300-400°C with accumulated deformation degree e=10. Rolling is carried out at the temperature of 330-370°C.

EFFECT: producing plates with high homogeneity of mechanical properties and improved superductility indices at low temperatures and high metal flow rates.

1 tbl, 1 ex

FIELD: metallurgy.

SUBSTANCE: said utility invention relates to Al-Zn-Mg alloys, namely, to alloys for welded structures, such as structures used in marine construction, during manufacture of car and industrial vehicle bodies, and stationary or movable tanks. The method involves manufacture of a plate using semi-continuous casting. The plate is made of an alloy containing, % weight: Mg 0.5-2.0, Mn < 1.0, Zn 3.0-9.0, Si < 0.50, Fe < 0.50, Cu < 0.50, Ti < 0.15, Zr < 0.20, Cr < 0.50, aluminium with its inevitable impurities being the remaining, Zn/Mg > 1.7. After that, the plate is subjected to homogenisation and/or reheating at a temperature T1 selected so that 500°C ≤T1≤(Ts-20°C) where Ts is the alloy burning temperature. The first hot rolling stage includes one or several rolling passes on a hot-rolling mill, the input temperature T2 is selected so that (T1-60°C)≤T2≤ (T1-5°C), and the rolling process is performed in such a way that the output final temperature T3 would be so that (T1-150°C)≤T3≤(T1-30°C) and T3 < T2. The strip produced at the said first hot rolling stage is rapidly cooled to the temperature T4. The second stage of hot rolling of the said strip is performed at the input temperature T5 selected so that T5≤T4 and 200°C≤T5≤300°C. The rolling process is performed in such a way that the coiling temperature T6 would be so that (T5-150°C)≤T6≤(T5-20°C).

EFFECT: enhancement of balance between mechanical properties and corrosion resistance of base metal and welded joint using simplest and most reliable method.

34 cl, 8 dwg, 20 tbl, 10 ex

FIELD: foundry and rolling processes.

SUBSTANCE: structural material contains following components, wt %: magnesium 9.0-11.0, zirconium 0.15-0.2, cobalt 0.01-0.001, beryllium 0.001-0.02, boron 0.005-0.007, aluminum - the balance. Crystallization of melt is carried out in rotary crystallizer at gravitation coefficient 220-250 and melt lifetime 12-15 sec/kg. Ingot is first heated for 2-4 h at 340-380° C and then subjected to hot rolling at that temperature until thickness 4-8 mm is attained at deformation rate up to 30% in each cycle and final rolling temperature 310-330° C. Thereafter, cold rolling is effected with deformation rate up to 50% in each cycle and intermediate annealings for 0.5-2.0 h at 310-390° C until required thickness 0.5-2.0 mm is attained followed by final annealing of rolled metal for 5-40 min at 400-450° C.

EFFECT: increased strength, plasticity, and processability of aluminum-based alloy with 9-11% magnesium.

2 cl, 2 dwg, 1 tbl

FIELD: nonferrous metallurgy.

SUBSTANCE: invention is intended for use in metallurgy, mechanical engineering, and aircraft industry, in particular for manufacturing honeycomb structures. Alloy is composed of, wt %: magnesium 8-10, manganese 0.1-0.15, zirconium 0.15-0.2, cobalt 0.05-0.2, boron 0.005-0.007, beryllium 0.001-0.02, iron 0.15-0.2, silicon 0.15-0.2, titanium 0.1-0.2, aluminum - the balance. Ingot for manufacturing structural foil is obtained by semicontinuous casting in rotary crystallizer at volumetric cooling 4-20°C/sec. Structural foil manufacturing process comprises homogenization, hot rolling, annealing, cold rolling followed by annealing in air atmosphere, second cold rolling followed by annealing, and final cold rolling.

EFFECT: increased strength of alloy at ambient and elevated temperatures and improved processability un rolling stage.

3 cl, 3 tbl

FIELD: metallurgy of aluminum base alloys such as Al-Mg-Li-Cu system alloys used as constructional materials in aircraft making and spatial technology, transport machine engineering for making facing and inner reinforcing structures.

SUBSTANCE: alloy contains next ingredients, mass %: lithium, 1.5 - 1.9; magnesium, 1.2 - 3.5; copper, 1.4 - 1.8; zinc, 0.01 -1.2; manganese, 0,01 - 0.8; titanium, 0.01 -0.25; silicon, 0.005- 0.8; cerium, 0.005 -0.4; at least one element selected from group including scandium, 0.01 - 0.3; zirconium, 0.003 - 0,15; beryllium, 0.001 - 0.2; aluminum, the balance. Method for heat treatment of alloy comprises steps of quenching, straightening and artificial aging according to three-step mode. Quenching is performed from temperature 510 - 535°C. First step of artificial aging is realized at temperature 95 - 120°C. In concrete variants of invention second step of aging is realized at temperature 130 -180°C for 3 - 25 hours. Third step of artificial aging is realized at temperature 95 - 120°C for time period 15 h and more. Invention provides enhanced strength and thermal stability of alloy after heating at 85°C for 100 h while keeping high viscosity of rupture and technological plasticity of alloy at making thin sheets by coil rolling.

EFFECT: improved strength and thermal stability of alloy.

3 cl, 4 tbl, 1 ex

FIELD: metallurgy.

SUBSTANCE: alloy contains the following, wt %: silicon 6.6-7.4, magnesium 0.31-0.45, copper 0.18-0.32, manganese 0.15-0.45, iron 0.15-0.4, aluminium is the rest, at that, the alloy has liquidus temperature within 608 to 620°C; temperature of balanced solidus of not less than 552°C and structure after heat treatment as per mode T66, which contains the amount of inclusions of silicon phase within 6.4 to 7.5 vol. %; iron in the alloy structure is completely bound to skeletal inclusions of phase Al15(Fe,Mn)3Si2, and magnesium is completely bound to secondary extractions of phase Al15Cu2Mg8Si6.

EFFECT: creation of alloy for obtaining high-duty shaped castings and having high technological and operating characteristics.

2 cl, 2 tbl, 2 ex, 2 dwg

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