RU2355802C1 - Alloy on the basis of magnesium and product made of it - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, particularly receiving of high-strength alloys on the basis of magnesium, provided for manufacturing of ironworks, blackets, wheel hubs and other details used in aeronautical engineering. It is provided alloy on the basis of magnesium of the following chemical composition, in wt %: zinc 8.0-8.5; zirconium 0.7-0.9; cadmium 0.1-0.2; silver 2.5-3.0; boron 0.10-0.15; magnesium - the rest.

EFFECT: invention is directed for increasing of ultimate stress limit and yield point, and also manufacturability of alloy and its casting characteristics, what provides receiving of ingots of high complexity.

2 cl, 2 tbl, 1 ex

Description

The invention relates to the field of metallurgy, and in particular to the production of high-strength magnesium-based alloys intended for the manufacture of instrument housings, brackets, wheel drums and other parts used in aircraft.

Known alloy brand ML8 based on magnesium of the following chemical composition, wt. %:

Zinc 5.5-6.6 Zirconium 0.7-1.1 Cadmium 0.2-0.8 Impurities ≤0.2 Magnesium rest

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

Mechanical properties of the alloy after heat treatment: tensile strength 264 MPa, yield strength 166.5 MPa, elongation 4%. Products from this alloy are, for example, aircraft wheels and their components.

The disadvantages of the alloy and products made from it are low mechanical properties, a tendency to heat resistance, a tendency to cracks in castings during casting and a limited range of products.

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

Zinc up to 1.3 Zirconium 0.2-0.7 Neodymium 2.0-4.5 REM (with atomic number 62-71) 0.2-0.7 Magnesium rest

(Application No. WO 2005035811).

The mechanical properties of this alloy after heat treatment are: tensile strength 270-300 MPa, elongation 4-7%.

The disadvantages of the alloy are low mechanical properties, the high cost of the alloy due to the high content of neodymium and other rare earth metals.

The disadvantages of products from this alloy is the increased complexity in the production.

The closest analogue taken as a prototype is an alloy grade ML18 of the following chemical composition, wt.%:

Zinc 7.0-8.0 Zirconium 0.7-1.1 Cadmium 0.4-1.0 Silver 1.0-1.6 Magnesium rest

(Reference "Magnesium alloys", volume 1. M .: "Metallurgy", 1978, p. 70).

The disadvantage of the prototype alloy is not a sufficiently high yield strength, insufficiently high casting properties, as well as a relatively high content of toxic cadmium.

The disadvantages of the alloy products of the prototype are the tendency to form hot cracks, the inability to obtain castings of high complexity, increased toxicity in the process of their production and pollution with toxic environmental substances.

The technical task of the invention is the creation of an alloy based on magnesium and products obtained from it, with high mechanical and casting properties, reduced toxicity during its smelting and machining.

The technical task is achieved by the fact that the proposed alloy based on magnesium, including zinc, zirconium, cadmium, silver, which additionally contains boron in the following ratio of components, wt.%:

Zinc 8.0-8.5 Zirconium 0.7-0.9 Cadmium 0.1-0.2 Silver 2.5-3.0 Boron 0.1-0.15 Magnesium rest

The authors found that the additional content of boron at the stated ratios of other components in the magnesium-based alloy provides an increase in mechanical and casting properties and a decrease in toxicity during the melting of the alloy and operation of parts from it.

An example implementation.

Magnesium was loaded into the crucible furnace; after its melting, alloy components were introduced into the melt. Zirconium was introduced into the liquid alloy from the magnesium-zirconium alloy, boron from boric anhydride. Then, the technological operations required in the alloy preparation process were performed. The finished liquid alloy was poured into foundry sand molds or in a chill mold. The studies were carried out on three compositions of the proposed alloy and on one composition of the prototype alloy specified in table 1.

Table 1
The chemical composition of magnesium alloys Alloy composition Chemical composition, wt.% Zn Zr Cd Ag AT Mg one 8.0 0.7 0.1 2.5 0.1 ost 2 8.2 0.8 0.15 2.8 0.12 ost 3 8.5 0.9 0.2 3.0 0.15 ost prototype 7.5 0.85 0.70 1.4 - ost

Table 2 presents the mechanical properties of the proposed alloy and prototype alloy.

table 2
Mechanical properties of alloys Alloy composition Type of heat treatment Tensile strength, MPa Yield Strength, MPa Relative extension, % 20 ° C 150 ° C one T6 342.0 290.0 190.0 4,5 2 T6 345.0 297.0 200,0 4.2 3 T6 347.0 310.0 195.0 4.0 Prototype T6 335.0 245.0 160,0 5,0

As can be seen from table 2, the proposed alloy in comparison with the prototype alloy has higher mechanical properties: tensile strength increases by 10%, yield strength at a temperature of 20 ° C and 150 ° C - by 20%.

In addition, studies have shown that the proposed alloy has a lower tendency to form hot cracks during casting, the heat resistance along the ring width of the proposed alloy is 25 mm, and that of the prototype alloy is 30 mm.

Thus, the use of the proposed alloy in loaded aviation products helps to increase their reliability and service life, and also allows to obtain products of high complexity.

Claims (2)

1. Magnesium-based alloy containing zinc, zirconium, cadmium, silver, characterized in that it additionally contains boron in the following ratio of components, wt.%:
Zinc 8.0-8.5 Zirconium 0.7-0.9 Cadmium 0.1-0.2 Silver 2.5-3.0 Boron 0.10-0.15 Magnesium Rest 2. The product of an alloy based on magnesium, characterized in that it is made of an alloy according to claim 1.