RU2243279C1 - Magnesium-based alloy and product made from the same - Google Patents

Abstract

FIELD: metallurgy, in particular high strength, corrosion resistant magnesium-based alloys for aircraft industry.

SUBSTANCE: claimed alloy contains (mass %): zinc 6,5-9.5; cadmium 0.01-1.4; zirconium 0.7-1.2; 0.01-0.6; titanium 0.004-beryllium 0.0006-0.001; and additionally bismuth 0.01-0.8 and niobium 0.01; and balance: magnesium.

EFFECT: magnesium-based alloy with low content of iron, silicium and copper impurities; as well as improved corrosion strength and mechanical properties at room and elevated temperature.

2 cl, 2 tbl, 1 ex

Description

The invention relates to the field of metallurgy, and in particular to the production of high-strength corrosion-resistant alloys based on magnesium, intended for the manufacture of flanges, drums of aircraft wheels, etc., used in aircraft.

Known alloy ZK60A company Magnesium Elektron Ltd, England, having the following chemical composition, wt.%:

Zn 4.8-6.2

Zr _min 0.45

Mg Else

(ASTM Standart Specification for Magnesium Alloy Forgings, B 91-87)

The alloy has insufficiently high mechanical properties. The disadvantage of the product made of this alloy is the tendency to segregate the structural components of the alloy in the castings and the presence of microroughs of varying degrees.

Known alloy brand ML 12 based on magnesium, the following chemical composition, wt.%:

Zn 4.0-5.0

Zr 0.6-1.1

Impurities ≤0.22

Mg Else

(GOST 2856-79. Foundry magnesium alloys. Technical requirements.)

Products from this alloy are, for example, aircraft wheels, drums, flanges, etc.

The disadvantages of the alloy are low mechanical properties. The disadvantages of products from the known alloy are relatively low mechanical properties and a limited range of products.

The closest analogue, taken as a prototype, is a casting alloy based on magnesium of the following chemical composition, wt.%:

Zn 5-7

Zr 0.6-1.1

Cd 0.1-3

Be ≤0.05

Mg Else

The alloy may additionally contain, wt.%:

Ti ≤ 0.1

CA ≤0.3

REM ≤0.5

(A.S. USSR No. 206837)

The alloy contains aluminum, iron, silicon, copper, nickel as impurities.

Products from the prototype alloy are, for example, brackets, trusses, control parts, drums, parts of devices, assemblies, etc.

The disadvantages of the prototype alloy are not high enough corrosion resistance and mechanical properties at normal and elevated temperatures.

The disadvantages of the alloy prototype are the reduced resource and reliability during their operation.

An object of the invention is the creation of an alloy based on magnesium and the product obtained from it, with increased corrosion and mechanical properties at normal and elevated temperatures, high purity by impurities of iron, silicon, copper.

The stated technical problem is achieved by the fact that the proposed alloy based on magnesium, including zinc, cadmium, zirconium, beryllium and titanium, which additionally contains bismuth and niobium in the following ratios of components, wt.%:

Zn 6.5-9.5

Cd 0.01-1.4

Zr 0.7-1.2

Bi 0.01-0.8

Nb 0.01-0.6

Ti 0.004-0.01

Be 0,0006-0,001

Mg Else

and an article made from it.

The authors found that the additional content of bismuth and niobium with the stated ratios of other components in the magnesium-based alloy ensures the complete passage of the process of modification and refinement of the alloy, thereby increasing the mechanical properties at normal and elevated temperatures and corrosion resistance.

An example implementation.

Magnesium is loaded into the crucible furnace, after its melting, alloy components are introduced into the melt. Zirconium and niobium are introduced into the alloy of magnesium-zirconium and magnesium-niobium alloys. Then, the technological operations necessary for the preparation of the alloy are performed, including the operation of introducing beryllium into the liquid alloy to reduce the oxidizability of the alloy during its melting and casting in molds. The finished liquid alloy is poured into foundry sand molds or in a chill mold. Swimming trunks and studies were carried out on three compositions of the proposed alloy and on one composition of the prototype alloy, shown in table No. 1.

The mechanical properties and corrosion resistance were studied on samples in a heat-treated state according to the T6 and T61 modes. The corrosion resistance of the samples was determined by the amount of hydrogen released when testing them in a 3% solution of sodium chloride for 48 hours.

The mechanical properties and corrosion resistance of various compositions of the proposed alloy and prototype alloy are given in table No. 2.

Analysis of the data in tables No. 1 and No. 2 shows that the proposed alloy is superior to the prototype alloy in the following characteristics:

At a temperature of 20 ° C: by tensile strength by 10-20%, by yield strength by 15-25%.

At a temperature of 150 ° C: by tensile strength by 11-20%, by yield strength by 18-38%, by corrosion resistance by 2.0-3.6 times.

The proposed alloy is non-toxic, its production does not require additional equipment, and products from it, in comparison with products from the prototype alloy, have higher reliability, long life and can be operated in all climatic conditions.

Claims (2)

1. An alloy based on magnesium containing zinc, cadmium, zirconium, beryllium and titanium, characterized in that it additionally contains bismuth and niobium in the following ratio of components, wt.%: Zn 6.5-9.5 Cd 0.01-1.4 Zr 0.7-1.2 Bi 0.01-0.8 Nb 0.01-0.6 Ti 0.004-0.01 Be 0,0006-0,001 Mg Else 2. A product of an alloy based on magnesium, characterized in that it is made of an alloy according to claim 1.