RU2416658C1 - Deformed, not thermally hardenable alloy on base of aluminium - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: here is disclosed deformed, not thermally hardenable alloy on base of aluminium used in form of deformed semi-finished products as structure material, mainly, for current conducting elements of constructions in airspace engineering, ship building, cryogenic machine engineering and other branches of industry. The alloy contains wt %: magnesium 0.55-0.85, scandium 0.2-0.4, hafnium 0.02-0.05, yttrium 0.0001-0.005, aluminium - the rest.

EFFECT: increased strength, electro- and heat conductivity of alloy.

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Description

The present invention relates to the field of metallurgy, in particular to deformable thermally non-hardening alloys intended for use in the form of deformed semi-finished products as a structural material mainly for conductive and heat-conducting structural elements in aerospace engineering, shipbuilding, cryogenic engineering and other industries.

Known deformable thermally unstrengthened alloy based on aluminum, used as a heat-conducting material, the following chemical composition (wt.%):

Manganese 1.0-1.6 Aluminum rest

(see Industrial aluminum alloys. Reference ed. / Alieva S.G., Altman MB, Ambartsumyan S.M. et al. , p.29).

However, the existing alloy has low strength properties.

Known deformable thermally unstrengthened alloy based on aluminum, used as a heat-conducting material, the following chemical composition (wt.%):

Magnesium 1.8-2.8 Manganese 0.2-0.6 Aluminum rest

(see Industrial aluminum alloys. Reference ed. / Alieva S.G., Altman MB, Ambartsumyan S.M. et al. 2nd ed., revised and enlarged. - M.: Metallurgy, 1984 , p. 44), prototype.

A disadvantage of the known alloy is low strength, low electrical conductivity and low thermal conductivity and, as a result, the increased weight of structural elements and reduced characteristics of the weight return of the entire structure.

A deformable thermally non-hardenable aluminum-based alloy is proposed, containing magnesium, which additionally contains scandium, hafnium and yttrium in the following ratio of components (wt.%):

Magnesium 0.55-0.85 Scandium 0.2-0.4 Hafnium 0.02-0.05 Yttrium 0.0001-0.005 Aluminum rest.

The proposed alloy differs from the prototype in that it additionally contains scandium, hafnium and yttrium and the components are taken in the following ratio (wt.%):

Magnesium 0.55-0.85 Scandium 0.2-0.4 Hafnium 0.02-0.05 Yttrium 0.0001-0.005 Aluminum rest.

The technical result is an increase in the strength, electrical conductivity and thermal conductivity of the alloy, which will reduce the weight and dimensions of structural elements and, accordingly, increase the characteristics of the weight return of the structure as a whole.

With the proposed content and ratio of components in the proposed alloy with unavoidable technological heating (heating under deformation, annealing), secondary finely dispersed intermetallic compounds containing aluminum, scandium and other transition metals that are part of the alloy that strengthen the alloy are precipitated, with maximum hardening being achieved when heated to a temperature of 288 ° C and holding at this temperature, the alloy matrix, which is mainly a low concentration solid solution, is rot in aluminum, provides the necessary level of electrical and thermal conductivity.

Example

Received the proposed alloy from a mixture consisting of aluminum A99, magnesium MG95, yttrium and double ligatures aluminum-scandium and aluminum-hafnium. The alloy was prepared in an electric crucible melting furnace and flat ingots 16 × 160 × 200 mm in size were cast. The chemical composition of the alloy is given in table 1.

The ingots were machined to a thickness of 14 mm, after which they were heated to 288 ° C and hot rolled to a thickness of 6 mm, then cold to a thickness of 3 mm. The cold-rolled preforms were annealed at 288 ° С for 8 h. The annealed sheets thus obtained with a thickness of 3 mm were straightened on a roller straightening machine, and then they were tested at room temperature with the determination of yield strength, electrical conductivity γ, and thermal conductivity λ. We also tested the sheets of the prototype alloy made in the same way, the chemical composition of which is shown in table 1.

The test results are shown in table 2.

Table 1 Alloy Chemical composition, wt.% Magnesium Manganese Scandium Hafnium Yttrium Aluminum Proposed 0.6 - 0.22 0,027 0.0025 Rest Prototype 2.5 0.3 - - - Rest

table 2 Alloy Strength, electrical and thermal conductivity of annealed sheets Yield Strength, σ _0.2 , MPa Electrical conductivity, γ, MSm / m Thermal conductivity, λ, W / mK Proposed 255 thirty 188 Prototype 184 19.6 151

Thus, the proposed alloy has a 1.3 times higher yield strength, 1.5 times higher electrical conductivity and 1.25 times higher thermal conductivity, which will allow 1.2-1.3 times lower weight and dimensions of conductive and heat-conducting structural elements and, accordingly, to increase the characteristics of the weight return of the structure as a whole, which is fundamentally important for aerospace engineering, shipbuilding and other industries.

Claims (1)

Wrought thermally unreinforced aluminum-based alloy containing magnesium, characterized in that it additionally contains scandium, hafnium and yttrium in the following ratio, wt.%:
Magnesium 0.55-0.85 Scandium 0.2-0.4 Hafnium 0.02-0.05 Yttrium 0.0001-0.005 Aluminum Rest