JPH05117797A - Heat and creep resistant aluminum alloy excellent in toughness - Google Patents

Abstract

PURPOSE:To provide an Al alloy having excellent strength and creep resistance at high temp. and also having excellent toughness at ordinary temp., by powder metallurgical processing. CONSTITUTION:This Al alloy consists of 5-<10% Si, 2-7% Fe, 1-5% Ni, 0.5-<2% Mo, 0.3-<2% Zr (Mo+Zr<2%) and the balance essentially Al.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum alloy excellent in toughness, heat resistance and creep resistance. In this specification, "%" means
Means "wt%".

[0002]

2. Description of the Related Art Aluminum alloys (hereinafter referred to as Al alloys) manufactured by powder metallurgy (hereinafter referred to as PM method) are compared with Al alloys manufactured by ingot metallurgy (hereinafter referred to as IM method). Since more additive elements can be more uniformly dispersed in the Al matrix, it has excellent heat resistance and wear resistance which cannot be obtained by the IM method.

When manufacturing an Al product by the PM method,
Usually, using powder, flakes or ribbon-shaped material produced by rapid solidification, first hot extrusion molding,
Next, various molded products are obtained by using the obtained molded billet. According to this method, the oxide film on the surface of each powder, flake or ribbon is broken by the shearing force at the time of hot extrusion, and a bond between the exposed Al surfaces is obtained. The powder rolling method and the powder forging method also cause the destruction of the oxide film, but the shearing force and the amount of deformation applied to the individual powders are not so large as during extrusion, so the bond is as strong as when extruding. Don't

The inventor of the present invention first found that Fe and C were added to the Al--Si system.
When an alloy to which a transition metal element such as r is added is used, a sufficiently strong molded body can be obtained even at a relatively low extrusion ratio of 10 or less, and even at an extremely low extrusion ratio of 2 to 5. I found out that
3-115625). However, as a result of subsequent research, some of the Al alloy composition ranges disclosed in Japanese Patent Application No. 63-115625 do not sufficiently satisfy the performance as members requiring particularly severe heat resistance and creep resistance. It has been found. It was also found that there are alloys having a composition range that is excellent in strength and creep resistance at high temperatures and has insufficient toughness at room temperature.

[0005]

As a result of further research in view of the current state of the art as described above, the present inventor has found that an Al alloy having a new composition has a high heat resistance and a high resistance at a high temperature of about 300 ° C., for example. It was found that the creep property is also extremely excellent and the toughness at room temperature is also excellent.

[0006] That is, the present invention provides the following Al alloys: 1 (a) Si 5% or more and less than 10%, (b) Fe2
~ 7%, (C) Ni 1-5%, (D) Mo 0.5% or more and less than 2% and (e) Zr 0.3% or more to less than 2% (however, the total amount of Mo and Zr is less than 2%. 1) and a heat-resistant and creep-resistant aluminum alloy having excellent toughness, the balance being substantially Al, and 2) the first alloy further containing at least one of Cu 0.3 to 6% and Mg 0.3 to 5%. The heat-resistant and creep-resistant aluminum alloy according to the item. "

The Al alloy powder used in the present invention is
(A) Si 5% or more and less than 10%, (b) Fe2 to 7
%, (C) Ni 1 to 5%, (d) Mo 0.5% or more and less than 2% and (e) Zr 0.3% or more to less than 2% (however, the total amount of Mo and Zr is less than 2%). Is required to be included. An Al alloy containing Si in an amount of less than 5 to 10% in this composition range allows the individual powders to be firmly bonded to each other even at a low extrusion ratio. Regardless, it shows almost constant strength and elongation. Even when the content of Si is 10 to 30%,
Although the same effect can be obtained, since the volume content of Si particles in the Al matrix is high, the toughness at room temperature is lowered. Fe and Ni are components that improve the heat resistance and strength of Al. Fe2 to 7% and Ni1
Alloys containing ~ 5% exhibit well-balanced properties in heat resistance, strength and toughness. If the content is more than the above lower limit, the heat resistance and strength are not sufficiently improved, while if it exceeds the upper limit, the heat resistance and strength are improved, but the toughness is reduced. . Mo and Zr are components that improve the heat resistance, creep resistance and strength of Al. When these contents are below the above lower limits, these properties are not sufficiently improved, whereas when they are above the upper limits (total amount is less than 2%), the toughness is also high. Is reduced.

Cu and Mg are, in comparison with the above elements,
Due to the large amount of solid solution in the Al matrix and the precipitation of the metastable phase, room temperature to 300 ° C, especially room temperature to
The strength of the Al alloy of the present invention in the temperature range of 200 ° C. is 10 to 2
Improve about 0%. Cu and Mg content is 0.3%
If it is less than the above, the effect of addition is small. On the other hand, when the amount of Cu exceeds 6%, the alloy strength is not further improved. It can be said that this is a natural result even considering that the maximum solid solubility limit of Cu in Al is 5.65%. Further, if the amount of addition of Mg in the Al alloy exceeds 5%, the toughness at room temperature will deteriorate.

[0009] Generally, in any alloy,
The alloy components are related to one another and affect the properties of the alloy. Therefore, in the above description, the reasons for defining the content of each alloy component have been individually simplified, but such description does not always completely explain the relationship between the alloy components and the characteristics of the Al alloy of the present invention. Not to mention that.

[0010]

In the Al alloy of the present invention having a specific composition,
With a low extrusion ratio of 10 or less, and an extremely low extrusion ratio of 2 to 5, a strong bond can be obtained. In addition, the Al alloy of the present invention is also extremely excellent in heat resistance and creep resistance, and moreover, the strength in the temperature range from room temperature to 300 ° C. is improved by about 10 to 20% without impairing these properties. Becomes Further, since the Al alloy of the present invention is excellent in toughness, the post-processability such as hot forgeability of the obtained extruded molded product is good, and it is extremely excellent in practicality as a material for machine parts and the like. Therefore, according to the present invention, an Al alloy is used for compressor parts,
It is expected to be applied to turbine impellers and automobile engine parts (for example, valve systems and connecting rods).

[0011]

EXAMPLES Examples and comparative examples will be shown below to further clarify the characteristics of the present invention.

Example 1 Al alloy No. 1 having the composition shown in Table 1 was used. 1-1
4 was pulverized by an air atomizing method and classified to -100 mesh. In Table 1, the amount of each component is
"%" Is shown and the balance is essentially Al. Also, Al
Alloy No. 1 to 6 and No. Nos. 12 to 14 are the products of the present invention, and No. 7 to 11 are comparative example products.

[0011]

The obtained Al alloy powder was cold preformed into a billet having a diameter of 30 mm and a height of 80 mm, and then 450 ° C.
In, the extrusion ratio = 3 was extruded. Tensile test pieces and creep test pieces were produced from the obtained extruded rods, and the tensile strength and elongation at room temperature, the tensile strength at 300 ° C. and the creep test at 300 ° C. (when a stress of 8 kg / mm ² was applied) The time to break was measured). The results are shown in Table 2.

[0013]

As is clear from the results shown in Table 2, the A1 alloy No. 1 of the present invention was used. Nos. 1 to 6 have high strength at room temperature and elongation of 2% or more, and exhibit high tensile strength and excellent creep resistance even at 300 ° C. In addition, the Al alloy No. In Nos. 12 to 14, the strength at room temperature is greatly improved. On the other hand, the Al alloy No. having a composition outside the present invention. In Nos. 7 to 11, the balance of various characteristics is lost. That is, alloy No. In Nos. 8 and 9, the creep rupture time at 300 ° C. is long, but the elongation at room temperature is low. On the other hand, alloy No. In Nos. 7, 10 and 11, although the elongation at room temperature was high, the creep rupture time was extremely short.

Claims (2)

[Claims] (A) Si 5% or more and less than 10%,
(B) Fe 2 to 7%, (c) Ni 1 to 5%, (d) Mo
Toughness containing 0.5% or more and less than 2% and (e) Zr 0.3% or more to less than 2% (however, the total amount of Mo and Zr is less than 2%), and the balance substantially consisting of Al. Excellent heat and creep resistance aluminum alloy. 2. Further, Cu0.3-6% and Mg0.3
The heat-resistant and creep-resistant aluminum alloy according to claim 1, containing at least one of -5%. [0001]