RU2230814C1 - Magnesium-based alloy and product manufactured therefrom - Google Patents

Abstract

FIELD: nonferrous metallurgy.

SUBSTANCE: invention relates to preparation of high-strength, high-purity magnesium-based alloys for use in manufacturing casings, instrument panels, brackets, drums, and other equipment finding use in aircraft engineering. Alloy of invention contains, wt %: zinc 6.8-9.0, zirconium 0.7-1.0, cadmium 0.01-1.0, and additionally niobium 0.01-0.2, titanium 0.0025-0.005, rare-earth metals 0.02-0.6, impurities no more than 0.05. and magnesium - the balance.

EFFECT: improved mechanical strength and increased corrosion resistance.

2 cl, 2 tbl

Description

The invention relates to the field of metallurgy of non-ferrous alloys, and in particular to the production of high-strength, high-purity magnesium-based alloys intended for the manufacture of housings, instrument frames, brackets, drums, flanges and other parts 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 Standard 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 segregation in castings and the formation of microroughs of varying degrees.

Known alloy based on magnesium, having the following chemical composition, wt.%:

Zn 1.8-2.5

Zr 0.7-1.0

Nd 0.8-1.2

Ti 0.1-0.2

Mg Else

(A.S. USSR No. 16788810).

The alloy is intended for the manufacture of sports equipment, such as sports onions.

The disadvantages of the alloy are low corrosion resistance and unstable mechanical properties in massive semi-finished products.

The disadvantage of products from the known alloy is the difference in mechanical properties over the thickness of the section in the manufacture of massive casting, which does not allow the use of alloy in aircraft.

The closest analogue, taken as a prototype, is an alloy based on magnesium ML8 of the following chemical composition, wt.%:

Zn 5.5-6.6

Zr 0.7-1.1

Cd 0.2-0.8

Impurities ≤0.22

Mg Else

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

Products from this alloy are, for example, housings, brackets, flanges used in aerospace engineering.

The disadvantages of the prototype alloy are low strength characteristics, high content of harmful impurities and low corrosion resistance. These shortcomings do not allow the use of the ML8 alloy as highly loaded parts of aviation equipment operating in all climatic conditions.

In addition, the disadvantage of the alloy of the prototype is the tendency to the formation of crystallization cracks during casting.

An object of the invention is the creation of an alloy based on magnesium and products obtained from it, with increased strength and corrosion characteristics, high purity by impurities: iron, silicon, copper.

The technical task is achieved by the fact that the proposed alloy based on magnesium, including zinc, zirconium, cadmium and impurities, which additionally contains niobium, titanium and rare earth metals REM, with the following ratio of components, wt.%:

Zn 6.8-9.0

Zr 0.7-1.0

Cd 0.01-1.0

Nb 0.01-0.2

Ti 0.0025-0.005

REM 0.02-0.6

impurities Not more than 0.05

Mg Else

and an article made from it.

When niobium, titanium, and rare-earth metals are introduced into a magnesium-based alloy with a ratio of other components within the claimed limits, the mechanical properties and corrosion resistance of the alloy increase, which allows it to be used for work in all climatic conditions.

The effect of reducing the content of impurities and increasing the corrosion resistance of the alloy is achieved due to the refining action of titanium and niobium, which, interacting with impurities (iron, silicon, copper, nickel), form numerous compounds in the melt that precipitate in the form of a precipitate at temperatures exceeding the solidification temperature of the alloy .

Implementation example

Magnesium is loaded into the crucible furnace, after its melting, alloy components are introduced into the melt. Niobium is introduced into the alloy from the ligature of magnesium — niobium or from the ligature of magnesium — niobium — REM. Next, the technological operations necessary in the process of its preparation are carried out. The finished liquid alloy is poured into sand forms or into a chill mold. The chemical composition of the proposed alloy and prototype alloy are presented in table 1.

The mechanical properties of the samples were investigated in a heat-treated state according to the T6 and T61 modes. Corrosion resistance was determined in the molten state in a 3% NaCl solution by the amount of hydrogen released. Comparative properties of the proposed alloy and prototype alloy are presented in table 2.

The analysis of tables 1 and 2 shows that the mechanical properties of the proposed alloy compared to the prototype alloy above:

by tensile strength by 20-25%;

yield strength by 30-35%;

relative elongation of 1.5-2.5 times;

purity (total content of harmful impurities) 4 times;

the corrosion resistance in a 3% NaCl solution is 2.0 times.

Thus, the use of the proposed magnesium-based alloy will allow to obtain products with improved mechanical properties and corrosion resistance, capable of working in all climatic conditions.

Products from the proposed alloy have high reliability and resource.

Claims (2)

1. Magnesium-based alloy containing zinc, zirconium, cadmium and impurities, characterized in that it additionally contains niobium, titanium and rare earth metals (REM) in the following ratio, wt.%: Zn 6.8-9.0 Zr 0.7-1.0 Cd 0.01-1.0 Nb 0.01-0.2 Ti 0.0025-0.005 REM 0.02-0.6 Impurities Not more than 0.05 Mg Else 2. A product of an alloy based on magnesium, characterized in that it is made of an alloy according to claim 1.