RU2138574C1 - Aluminum-based castable alloy - Google Patents

Abstract

FIELD: nonferrous metallurgy. SUBSTANCE: alloy is composed of, wt %: magnesium 6.5-7.5, silicon 0.1-0.6, manganese 0.2-0.6, titanium 0.05-0.3, iron 0.05-0.2, beryllium 0.01-0.1; one of following compounds from the group: scandium 0.01- 0.2, bismuth 0.01-0.4, silicon carbide 1.0-5.0, silicon nitride 0.1-7.0, aluminum oxide 1.0-5.0, zirconium oxide 1.0-5.0; and aluminum - the balance. Alloy can find use in manufacture of parts operated under friction and elevated impact loads. EFFECT: increased plasticity and impact resistance due to additional alloying of solid solution, disintegration of all structural constituents and receiving disperse hardener in the form of nonmetal particles. 2 tbl

Description

 The present invention relates to the field of metallurgy of aluminum-based alloys and may find application in the manufacture of products operating under friction and increased shock loads.

Known aluminum-based alloy containing the following components in wt.%:
Magnesium 6.0 - 7.0
Zirconium 0.05 - 0.20
Beryllium 0.02 - 0.10
Titanium 0.05 - 0.15
Aluminum Else
[GOST 1583. Cast aluminum alloys. Page 6]
The disadvantage of this alloy is the relatively low mechanical properties in the cast state.

The closest in technical essence and the achieved results to the proposed invention is an aluminum-based alloy containing the following components in wt.%:
Magnesium 5.5 - 6.5
Silicon 0.8 - 1.2
Manganese 0.2 - 0.4
Titanium 0.05 - 0.2
Zirconium 0.05 - 0.2
Beryllium 0.001 - 0.05
Iron Up to 0.2
Copper Up to 0.1
Zinc Up to 0.1
Aluminum Else
[ed. St. USSR N 324287, 11.23.72]
The disadvantages of this alloy are low ductility and toughness. These disadvantages are due to the fact that the presence of Mg ₅ Al ₈ , Mg ₂ Si, MnAl ₆ intermetallic phases in the alloy structure, along with an increase in strength, reduces ductility and toughness.

 The objective of the present invention is to increase the ductility while increasing the toughness by additional alloying of the aluminum solid solution, grinding all the structural components and introducing into the alloy a dispersed hardener in the form of non-metallic particles.

The problem is solved in that the proposed aluminum-based alloy contains magnesium, silicon, manganese, titanium, iron and beryllium, according to the invention additionally contains one or more elements from the group; scandium, bismuth, silicon carbide, silicon nitride, aluminum oxide and zirconium oxide in the following ratio of components in wt.%:
Magnesium 6.5 - 7.5
Silicon 0.1 - 0.6
Manganese 0.2 - 0.6
Titanium 0.05 - 0.3
Iron 0.05 - 0.2
Beryllium 0.01 - 0.1
One or more items from a group
Scandium 0.01 - 0.2
Bismuth 0.01 - 0.4
Silicon Carbide 1.0 - 5.0
Silicon Nitride 0.1 - 7.0
Alumina 1.0 - 5.0
Zirconium oxide 1.0 - 5.0
Aluminum - the rest
To test the proposed alloy were prepared compositions, the composition of which is given in table 1.

Hardening of the proposed alloy is achieved by a higher degree of alloying and microalloying of the solid solution with iron, bismuth or scandium and by introducing ceramic particles into the alloy. Bismuth with a content of up to 0.3% is dissolved in a solid solution. When the bismuth content is more than 0.3%, inclusions appear in the structure whose sizes do not exceed 1-3 microns and which act as dispersed bismuth strengtheners of more than 0.3%; inclusions appear in the structure whose sizes do not exceed 1-3 microns and which act as dispersed hardeners. In addition, the introduction of bismuth provides increased corrosion resistance under stress and improves machinability by cutting. In addition to microalloying, scandium is an effective modifier. Its introduction in combination with titanium provides a fine-crystalline structure, which in turn leads to an increase in mechanical and technological properties. Silicon carbide, silicon nitride, aluminum oxide or zirconium oxide are introduced into the alloy as a dispersed hardener (particle size 3-7 microns). The presence in the alloy structure of a large number of uniformly distributed fine particles provides an increase in the tensile strength, elastic modulus and impact strength. When iron is introduced into the alloy, a fourth phase is formed, which includes aluminum, manganese, silicon and iron, which is released during crystallization in the form of finely dispersed globular particles. Some change in the content of other elements that make up the alloy, compared with the prototype made in order to provide him with a more favorable structure. In this case, the number of Mg ₅ Al ₈ and MnAl ₆ phases decreases slightly and ductility increases.

 Table 2 shows the properties of the proposed alloy in comparison with the known alloy.

 When the content of the components is lower and higher than the protected limits, the required level of properties is not achieved. By varying the ratios of the ingredients, the desired characteristics are obtained for each particular case, depending on the technological conditions for obtaining the parts and the requirements.

Claims (1)

An aluminum-based casting alloy containing magnesium, silicon, manganese, titanium, iron and beryllium, characterized in that it further comprises one or more elements selected from the group consisting of scandium, bismuth, silicon carbide, silicon nitride, aluminum oxide, zirconium oxide in the following ratio of components, wt.%:
Magnesium - 6.5 - 7.5
Silicon - 0.1 - 0.6
Manganese - 0.2 - 0.6
Titanium - 0.05 - 0.3
Iron - 0.05 - 0.2
Beryllium - 0.01 - 0.1
One or more items selected from the group containing
Scandium - 0.01 - 0.2
Bismuth - 0.01 - 0.4
Silicon Carbide - 1.0 - 5.0
Silicon Nitride - 0.1 - 7.0
Alumina - 1.0 - 5.0
Zirconium oxide - 1.0 - 5.0
Aluminum - Else

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