JPS60200945A - High elasticity aluminum alloy and its manufacture - Google Patents

Abstract

PURPOSE:To obtain an Al alloy having a high modulus of elasticity by powdering an Al alloy contg. specified amounts of Si, Fe, Mg and Cu and by subjecting the resulting powder to hot plastic forming. CONSTITUTION:Powder of <=40 mesh particle size is formed from a molten Al alloy consisting of, by weight, 7.0-17.0% Si, <=12% Fe, <=2% Mg, <=6.5% Cu and the balance essentially Al by spraying. The molten Al alloy may be powdered by rapid solidification at >=10<2>K/S. The resulting Al alloy powder is subjected to hot plastic working such as hot extrusion or hot forging to obtain an Al alloy. Since this Al alloy contains Si at a concn. close to the concn. at the eutectic point, it has superior tensile strength and hardness as well as a high modulus of elasticity, so the alloy can be widely used as a material for an airplane, an automobile, precision machine parts, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field The present invention relates to improving the properties of aluminum alloys, particularly the modulus of elasticity.

(b) Technical background Aluminum alloys are lighter in specific gravity than iron-based alloys and have excellent corrosion resistance.In addition, they can be easily plastically worked at low temperatures, making them a useful metal material for making equipment lighter and more energy efficient. It is.

However, aluminum itself is a metal that inherently has low strength, poor heat resistance, and poor wear resistance, so it is not suitable for use as a structural material for mechanical parts or structures that require strength, heat resistance, and wear resistance. However, through the development of various alloying and heat treatment methods, high-performance aluminum materials have been developed, and their application to a wide range of applications is being considered.

High-strength aluminum base interest rate is 7000 series, 2
The 000 series alloy is well known, but recently in the United States, 7090 alloy and 7091 alloy, which have even higher strength, have been developed.

In the United States, high-strength aluminum alloys are mainly used for aircraft, but the characteristics required of aluminum alloys for aircraft are high elasticity and high strength, each with a
kg/mrl, preferably 60 kq/mrl or more. However, some of the aluminum alloys currently on the market have a high tensile strength of around 60 kg/mt/r, but the modulus of elasticity is less than 8001 d, less than half that of iron-based materials, and these also sacrifice corrosion resistance considerably. It is said that For this reason, in order to obtain a high modulus of elasticity, attempts have been made to combine carbon, ceramic fibers, particles, and add Li, but these efforts have not yet reached the stage of practical use.

e→Disclosure of the Invention The present invention was made to improve the properties of aluminum alloy, and contains SI element and Fe in the aluminum base material.
Strength by adding elements, Cu element, and Mg element,
In the process of improving wear resistance and heat resistance, it was discovered that an alloy containing a Si concentration near the eutectic point has a high elastic modulus.

Si element is important as an additive element for the aluminum alloy of the present invention, and the concentration of this Si element is 7.0% by weight to 1% by weight.
It is 7.0% by weight.

In the AI-old thread alloy phase diagram, 11.7%Si is the eutectic point1, but the Si concentration of this alloy is ±5 including this eutectic point.
It is within %. In this alloy system, the amount of Si is 15%
In the case of 7 modulus, the elastic modulus tends to be lower than that of 12Si, and in order to obtain a high elastic modulus, the closer the concentration of Si element is to the vicinity of the eutectic temperature, the better.

The Fe element tends to exhibit a higher elastic modulus as the amount added increases, but when the Fe element exceeds 12% by weight, the hot plastic workability (hot forgeability, hot rollability, hot extrudability) deteriorates. The Fe element content is set to 12% by weight or less, since it deteriorates significantly.

The Mg and Cu elements are intended to strengthen the 71-trix by precipitation, and are set at 2% by weight or less and 65% by weight or less, respectively.

If the amount of Mg added is too large, processability will deteriorate, so the amount of Mg added should be 2% or less. Moreover, addition of a large amount of Cu not only does not show a significant improvement in strength, but also adds Cu to induce the generation of micro defects.
The amount of addition is preferably 65% by weight or less.

It is very difficult to manufacture aluminum alloys containing large amounts of Si and Fe elements, such as the present alloy system, by conventional casting methods. The reason for this is that the solid solubility of Si and Fc elements in Aβ is small, and when a large amount of Si and Fe elements are added to the AI matrix, coarse and strong primary crystals of 81 and FC occur, which increases the strength of the alloy. This is because it will cause significant damage.

Although there are methods for making the primary crystals of Si and Fe finer, such as adding a small amount of P, etc., it is very effective to increase the solidification rate during solidification of the molten metal. For this purpose A1
Adding molten alloy to water, gas, or 102/S
Solidify at two solidification speeds to form an alloy. Sprayed powder of 40 mesh or less has a solidification rate of 102 to 78 or more, but 1
02I (10μ7n for alloys solidified at a speed of 78 or more
The above precipitates are no longer seen, and a horizontally uniform structure is formed.

When the powder produced in this way is made into an alloy material by hot plastic processing (hot extrusion, hot forging), the true density ratio is approximately 1.
It is possible to obtain an alloy material having a uniform structure of 0.00%.

The A1 alloy material thus obtained has significantly improved strength, heat resistance, and wear resistance compared to the conventional A4 alloy.

Example Aβ-8i Fe-C obtained by air atomization
Using an alloy powder of 100 meshes or less of u Mg yarn, an extruded steel was produced, and the characteristics of the alloy phase were investigated.

Extrusion was carried out by heating the alloy powder molded into a can at 470°C for about 2 hours at an extrusion ratio of 7:1.

fi, 1-8i -Fe Cu produced as above
-Characteristics of Mg-based alloys by rate are shown in Table 1. As a comparative example, the characteristics of 2014.7'075 strong aluminum alloy produced by casting method are also shown.

The elastic modulus was measured by the gauge method and the ultrasonic method, and both showed good agreement.

Table 1 Characteristics of aluminum alloy material Aj7-3i-Fe based alloy contains 45% by weight of Cu and 1% by weight of Mg.

As can be seen from the table, 12% by weight of S, which is close to the eutectic concentration,
The alloy containing l has a concentration far from the eutectic concentration of 7% by weight.
, 155% by weight alloy shows a higher elastic modulus.

At the same time, the material showed high values for tensile strength and hardness, and also had good wear resistance and heat resistance, small thermal expansion, and good plastic workability.

As shown above, AI containing the S1 element at a eutectic concentration
-'Si -Fe-Cu-Mg alloy has good mechanical properties, thermal properties, and plastic workability.
It is thought that the A4 alloy can be applied to a wider range of applications, such as A-, =I materials for automobiles, Aiwa for precision machinery parts, etc.

Claims (1)

[Claims] (+l 7. O-type plate containing % to 17.0% by weight of Si element and 12% by weight or less of Fe element, and 2% by weight or less of Mg element and 6.5% by weight or less Contains Cu element with the remainder being substantially Al, and has an elastic modulus of 8000 kg/m
A high modulus aluminum alloy characterized by having a modulus of d or more. +2] Contains 7.0% to 170% by weight of elemental elements and 12% by weight or less of Fe element, and 2% by weight or less of Mg
It is an aluminum alloy containing 65% by weight or less of the Cu element and the remainder substantially consisting of Al, and is a powder with a particle size of 40 mesh or less produced from molten metal by a spraying method,
1. A method for producing a highly elastic aluminum alloy, characterized in that powder obtained by rapid solidification at a 102 to 78 or higher temperature is formed by a hot plastic working method.