RU2233345C1 - Aluminium-base structural, deformable, thermally non-strengthening alloy - Google Patents

Abstract

FIELD: alloy metallurgy.

SUBSTANCE: invention relates to deformable thermally non-strengthening alloys designated for using as deformed semi-finished product as the structural material. Invention proposes alloy comprising the following components, wt.-%: magnesium, 5.0-5.6; titanium, 0.01-0.03; beryllium, 0.0002-0.005; zirconium, 0.05-0.12; scandium, 0.16-0.26; cerium, 0.0002-0.0009; manganese, 0.15-0.5, and group of elements including iron and silicon, 0.05-0.12; aluminum, the balance. The ratio of the content of iron to the content of silicon must 1 or above. Invention provides the development of alloy eliciting higher indices of static strength, failure viscosity and cyclic crack resistance as compared with the known alloy.

EFFECT: improved and enhanced properties of alloy.

2 tbl, 1 ex

Description

The present invention relates to the metallurgy of alloys, in particular deformable thermally unstrengthened alloys intended for use in the form of deformed semi-finished products as a structural material.

Known in metallurgy are structural deformable thermally unstrengthened alloys based on aluminum (see GOST 4784-74), in particular, AMg6 alloy of the following chemical composition, wt.%:

Magnesium 5.8-6.8

Manganese 0.5-0.8

Titanium 0.02-0.1

Beryllium 0.0002-0.005

Aluminum Else

However, the existing alloy has low strength characteristics, in particular, a low yield strength of deformed semi-finished products in annealed and hot-deformed conditions.

Known deformable thermally unstrengthened alloy based on aluminum, intended for use in the form of deformed semi-finished products as a structural material (see patent RU No. 2085607, Mcl C 22 C 21/06 - prototype), the following chemical composition, wt.%:

Magnesium 3.9-4.9

Titanium 0.01-0.1

Beryllium 0.0001-0.005

Zirconium 0.05-0.15

Scandium 0.20-0.50

Cerium 0.001-0.004

Aluminum Else

The known alloy has insufficiently high characteristics of static strength, fracture toughness and cyclic crack resistance with high processability in metallurgical production, high corrosion resistance, good weldability and high performance at cryogenic temperatures.

A structural deformable thermally non-hardenable aluminum-based alloy is proposed, containing magnesium, titanium, beryllium, zirconium, scandium and cerium, which additionally contains manganese and a group of elements including iron and silicon, and the components are taken in the following ratio, wt.%:

Magnesium 5.0-5.6

Titanium 0.01-0.03

Beryllium 0.0002-0.005

Zirconium 0.05-0.12

Scandium 0.16-0.26

Cerium 0,0002-0,0009

Manganese 0.15-0.5

A group of elements including

iron and silicon 0.05-0.12

Aluminum Else

however, the ratio of iron to silicon should be equal to or greater than unity.

The proposed alloy differs from the known one in that it additionally contains manganese and a group of elements, including iron and silicon, in the following ratio of components, wt.%:

Magnesium 5.0-5.6

Titanium 0.01-0.03

Beryllium 0.0002-0.005

Zirconium 0.05-0.12

Scandium 0.16-0.26

Cerium 0,0002-0,0009

Manganese 0.15-0.5

A group of elements including

iron and silicon 0.05-0.12

Aluminum Else

however, the ratio of iron to silicon should be equal to or greater than unity.

The technical result is an increase in the characteristics of the static and dynamic strength of the alloy, which allows to increase the resource, reliability and weight return characteristics of structures operating under static and dynamic loads, in particular aircraft structures, including those operating on cryogenic fuel.

With the proposed content and ratio of components in the proposed alloy due to the secondary emissions of finely dispersed intermetallic compounds containing aluminum, scandium, zirconium and other transition metals included in the alloy, a high level of static strength is ensured. At the same time, a sufficiently plastic matrix, which is mainly a solid solution of magnesium and manganese in aluminum, due to the high plasticity margin, provides high resistance of the alloy to crack development under static and cyclic loading. The regulated value of the ratio of the iron content to the silicon content at their sufficiently low total content optimizes the morphology of the primary intermetallic compounds of crystallization origin, containing mainly aluminum, iron and silicon, which contribute to some increase in the static strength of the alloy while maintaining ductility.

Example.

Using a mixture of aluminum of grade A99, magnesium Mg90, double alloys aluminum – titanium, aluminum – beryllium, aluminum – zirconium, aluminum – scandium, aluminum – cerium, aluminum – manganese, aluminum – iron and silumin in an electric furnace, the melt was prepared using the semi-continuous method flat ingots with a section of 165 × 550 mm were cast from the alloy of the proposed composition with a minimum (composition 1), optimal (composition 2), maximum (composition 3) content of components, transcendent content of components (compositions 4, 5), as well as from known (composition 6) alloy (tab. 1).

In the manufacture of an alloy under industrial conditions of metallurgical production, it is possible to use waste from standard aluminum-magnesium alloys as charge materials.

The ingots were homogenized, machined to a thickness of 140 mm, after which they were rolled to a thickness of 7 mm in a hot rolling mill at 400 ° C, and then to a thickness of 2 mm in a cold rolling mill. The obtained cold-rolled sheets were annealed in an air circulating electric furnace. The annealed sheets served as test material. The tests were carried out at room temperature.

In the direction across the rolling, standard flat samples were cut out and mechanical properties under static tension were determined: tensile strength σ _B , yield strength σ _0.2 , elongation δ.

на поперечных образцах шириной В=200 мм.Tests for fracture toughness (static fracture toughness) were carried out on a MTS-100 servo-hydraulic testing machine. The critical value of the conditional stress intensity factor was determined

on transverse samples with a width of B = 200 mm.

Tests for cyclic crack resistance were carried out on a PSA-10 servo-hydraulic machine. Transverse specimen loading

.a width of B = 200 mm was carried out by a sinusoidal cycle with a frequency of f = 10 Hz, the asymmetry of the cycle R = 0.1. We determined the growth rate of the fatigue crack (SRTU), dа / dN, with the magnitude of the amplitude of the stress intensity factor ΔK = 31.2

.

The test results are given in table. 2.

As can be seen from the table. 2, the proposed alloy has higher characteristics of static strength, fracture toughness and cyclic crack resistance in comparison with the known. The use of the proposed alloy as a structural material will reduce the weight of structures by 10-15%, increase their reliability and durability, which is especially important for aircraft construction. Good weldability and high corrosion resistance of the proposed alloy, characteristic of thermally unstrengthened aluminum-based alloys, will allow it to be used to create new types of aircraft using welding as the main type of joints. The proposed alloy can be used in welded structures both as a base metal and as a filler material in fusion welding.

Claims (1)

Structural deformable thermally non-hardening aluminum-based alloy containing magnesium, titanium, beryllium, zirconium, scandium and cerium, characterized in that it additionally contains manganese and a group of elements including iron and silicon, and the components are taken in the following ratio, wt.%: Magnesium 5.0-5.6 Titanium 0.01-0.03 Beryllium 0.0002-0.005 Zirconium 0.05-0.12 Scandium 0.16-0.26 Cerium 0,0002-0,0009 Manganese 0.15-0.5 A group of elements including iron and silicon 0.05-0.12 Aluminum Else however, the ratio of iron to silicon should be equal to or greater than unity.

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