JPH0610085A - Heat-resistant aluminum alloy powder and heat-resistant aluminum alloy - Google Patents

Abstract

(57) [Summary] [Purpose] To manufacture products with excellent room temperature strength, rigidity and creep properties. [Structure / Function] By weight%, Ni: 10 to 20%, Si:
8 to 25%, and at least Mo: 1.0 to
Heat-resistant aluminum alloy powder containing 3.0%.
When this heat-resistant aluminum alloy powder is used and made into an alloy by a sintering method, the alloy has a Young's modulus at room temperature of 100 GPa or more and is excellent in rigidity and creep characteristics.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant aluminum alloy powder and a heat-resistant aluminum alloy which have excellent high-temperature strength and high rigidity, which are useful when applied to engine parts such as connecting rods of automobiles and aircraft.

[0002]

2. Description of the Related Art Aluminum alloys have been used as structural materials for aircraft or automobiles for a long time because they are lightweight and have excellent workability. Among the conventional aluminum alloys, those having excellent heat resistance include JIS2024,
Al-Cu-Mg-based alloys such as 2018 are known.

An Al-Ni alloy containing 5% by weight or more of Ni (hereinafter simply referred to as "%") (sponsored by Japan Institute of Light Metals, A
l alloy powder metallurgy technology symposium (March 9, 1987)
(Held daily) Proposals, pages 58 and 70) are proposed. Similarly, JP-A-2-149629 and JP-A-2-14
9631, JP-A-2-149632, JP-A-2-1493
Japanese Patent No. 633 discloses "a low thermal expansion aluminum alloy excellent in wear resistance and thermal conductivity" which is made of an Al-Ni-Si-Cu-Mg-based alloy produced by a casting method and containing 8% or more of Ni. ing.

Further, Japanese Examined Patent Publication No. 2-56401 discloses Al-containing 7.7 to 15% Ni and 15 to 25% Si, and the size of Si crystal grains is 15 μm or less.
"Heat resistant and wear resistant high strength aluminum alloy powder" made of Ni-Si alloy powder is disclosed.

[0005]

The engine for automobiles is required to have a high output, and therefore engine parts such as connecting rods have a tensile strength of 200MP at 300 ° C.
It is required to be a or more and have high rigidity. From this point of view, Al-such as JIS 2024, 2018, etc.
Although the Cu-Mg alloy has excellent tensile strength at room temperature, it has a tensile strength of at most 300 MPa at a high temperature of 200 ° C.
The tensile strength is 150 MPa at a high temperature of 300 ° C., and these Al-Cu-Mg are used for engine parts such as automobiles in recent years.
System alloys cannot be applied. Also, the Al-Ni-based alloy and Al-Ni-Si-C described in the above proposal or publication.
In the u-Mg alloy, the heat resistance and the wear resistance are improved by the NiAl ₃ intermetallic compound formed in the structure, but since the product is manufactured by the casting method, the NiAl ₃ metal in the product is produced. Particle size of intercalation compound is 10
It becomes as large as μm, and at normal temperature it is at most 380 MPa, 30
It was revealed that the tensile strength decreased to 160 MPa at a high temperature of 0 ° C. For this reason, it is difficult to apply such an aluminum alloy as an engine component for automobiles in recent years.

On the other hand, with the Al-Ni-Si alloy powder described in the above publication, a product is manufactured by a sintering method. That is, an alloy raw material having a constant composition is melted and sprayed to obtain the above Al-Ni-Si alloy powder, and this Al-Ni-
A product is obtained by cold preforming, extruding, and forging Si-based alloy powder. Therefore, this Al-Ni-Si
In Ni-based alloy powder, the particle size of NiAl ₃ intermetallic compound is 4μ.
The tensile strength is 510 MPa at room temperature and 345 MPa at 250 ° C., as well as being excellent in wear resistance. However, in general, engine parts such as automobiles may not have a sufficient extrusion ratio (the cross-sectional area ratio before and after extrusion).

The present invention has been made in view of the above conventional circumstances, and an object of the present invention is to provide a heat resistant aluminum alloy powder and a heat resistant aluminum alloy capable of producing a product excellent in rigidity and creep characteristics.

[0008]

The inventor has found that an excellent heat-resistant aluminum alloy can be obtained by adding Mo to an aluminum alloy having high Ni and high Si,
The present inventors have invented the heat resistant aluminum alloy powder and the heat resistant aluminum alloy of the present invention by conducting research on such alloys.

The heat-resistant aluminum alloy powder of the present invention is a heat-resistant aluminum alloy powder containing 10 to 20% by weight of Ni and 8 to 25% of Si, and at least Mo: 1.0 to 3. It is characterized by containing 0%. The heat-resistant aluminum alloy powder of the present invention has a weight percentage of at least Fe: 0.6 to 8.0% and C.
u: 0.6-5.0% is included, and the total amount of Fe and Cu can be 8.0% or less. Further, the heat resistant aluminum alloy powder of the present invention is, by weight%, at least Zr: 0.3 to 3.0% and Ti: 1.0 to 4.
0% of one can be included.

The heat-resistant aluminum alloy of the present invention has a weight percentage of
And a heat-resistant aluminum alloy containing Ni: 10 to 20% and Si: 8 to 25%, further comprising at least M
o: Including 1.0 to 3.0%, Young's modulus at room temperature is 10
It is characterized by being 0 GPa or more. The heat-resistant aluminum alloy of the present invention may contain a relatively large amount of oxygen, such as an oxygen content of 0.05 to 0.40% by weight.

The heat-resistant aluminum alloy of the present invention has a weight percentage.
And at least Fe: 0.6 to 8.0% and C
u: 0.6 to 5.0% of one kind is contained, the total amount of Fe and Cu is 8.0% or less, and the Young's modulus at room temperature can be 105 GPa or more. The heat-resistant aluminum alloy of the present invention is, by weight%, further at least Zr: 0.3 to 3.0% and Ti: 1.0 to 4.0%.
And the Young's modulus at room temperature can be 108 GPa or more. Further, the heat resistant aluminum alloy of the present invention can have a total amount of Fe, Ti, Ni and Zr of 14.5% or more by weight% and a Young's modulus of 110 GPa or more at room temperature.

This heat-resistant aluminum alloy powder can be manufactured by melting and spraying alloy raw materials having a constant composition. Further, the heat-resistant aluminum alloy of the present invention can be produced by using the heat-resistant aluminum alloy powder of the present invention and making it an alloy material by a sintering method. That is, the heat-resistant aluminum alloy powder of the present invention is put in a case, and cold preforming and extrusion forging are performed in this state.

The blending ratio and action of the elements constituting the heat resistant aluminum alloy powder and the heat resistant aluminum alloy of the present invention will be described below. [Ni: 10 to 20%] Ni together with Al is NiA
l _3, NiAl, making Ni ₃ Al, intermetallic compounds and the like. These intermetallic compounds are stable even at high temperatures and contribute to the wear resistance and high temperature strength of the alloy. In particular, NiAl ₃ intermetallic compounds include other NiAl intermetallic compounds, Ni ₃ Al,
Compared to intermetallic compounds, etc., it has lower hardness and is rich in toughness.

In weight% (hereinafter, simply abbreviated as%), Ni
Addition of 5.7% or more, precipitation of NiAl ₃ intermetallic compound is observed in the obtained alloy, but Ni is 1
If the content is less than 0%, the tensile strength of the obtained alloy at 300 ° C. will not be 200 MPa or more, and the high temperature strength will not be effectively improved. On the contrary, if Ni is 40% or less,
The resulting alloy makes a NiAl ₃ intermetallic compound, but Ni
If it exceeds 20%, the alloy becomes brittle and the elongation value at room temperature becomes extremely small. Therefore, Ni is 20%
If it is added in excess, the high temperature strength and wear resistance of the product will be excellent, but the machinability will be remarkably inferior, and practical use will be difficult. [Si: 8-25%] The alloy in which fine Si is dispersed in Al is excellent in high temperature strength and wear resistance.
Known for alloys and the like.

When the product is manufactured by the casting method, S
Coarse Si for aluminum alloys containing 11.3% or more of i
The primary crystals crystallize, and such alloys attack the mating material of the sliding part, the machinability deteriorates significantly, the elongation of the alloy itself decreases significantly, and the production technology (for example, cracks during parts processing) Etc.) is not practical, and cracks may occur during use as parts, which is not preferable. However, when producing an aluminum alloy by the rapid solidification powder metallurgy method, an aluminum alloy in which fine Si is crystallized can be obtained even if Si is mixed up to 25%. When Si is blended in an amount of more than 25%, coarse Si crystallizes in the product even when the heat-resistant aluminum alloy powder is produced by the rapid solidification method, which is not preferable.

On the other hand, when the content of Si is less than 8%, the resulting aluminum alloy has insufficient high-temperature strength and wear resistance. [Mo: 1.0 to 3.0%] Mo is known as an element that improves heat resistance, but according to the experimental results of the inventors,
It was found that it contributes significantly to the improvement of the rigidity and the creep strength of the aluminum alloy. That is, when Mo: 1.0 to 3.0% is blended with the heat resistant aluminum alloy, the rigidity of the alloy is effectively improved. If Mo is added less than 1.0%, the effect of improving the rigidity is small, and if Mo is added more than 3.0%, the high temperature strength decreases. [Fe: 0.6 to 8.0%] In general, addition of Fe is not preferable, and even if it is contained, it is desirable that the content of Fe be 0.5% or less. It was found that the normal temperature strength and the high temperature strength of 300 ° C. of the obtained aluminum alloy are improved by blending.
When the content of Fe is less than 0.6%, the effect of improving the room temperature strength and the high temperature strength of 300 ° C. of the aluminum alloy is small, and
If the content of e exceeds 8%, the aluminum alloy becomes brittle. However, at least one kind of Fe and Cu described later is contained, and if the total amount of Fe and Cu is 8% or less, the room temperature strength of the aluminum alloy is effectively improved. [Cu: 0.6 to 5.0%] Cu imparts age hardening to the heat resistant aluminum alloy and strengthens the Al matrix. A Cu content of 0.6% or more has the effect of improving the room-temperature strength of the aluminum alloy, and a Cu content of more than 5% produces coarse crystallized substances, resulting in 300% of the aluminum alloy.
Decreases high temperature strength at ° C. However, Cu and Fe described above
Means that at least one kind is contained, and if the total amount of Fe and Cu is 8% or less, the room temperature strength of the aluminum alloy is effectively improved. [Zr: 0.3-3.0%] Zr is known as an additive element that improves high-temperature strength, but the experimental results of the present inventors show that the elongation value of an aluminum alloy at room temperature and 300 ° C. It turned out to improve. That is, when the heat resistant aluminum alloy is blended with Zr: 0.3 to 3.0%, the toughness of the alloy is effectively improved. If Zr is less than 0.3%, the effect of improving toughness is small, and if Zr is more than 3.0%, a coarse intermetallic compound (ZrAl ₃ ) is crystallized, which is not desirable. [Ti: 1.0 to 4.0%] Ti is known as an additive element that improves the high temperature strength like Zr, but the experimental results of the inventors show that the yield strength of an aluminum alloy at 300 ° C is It turned out to improve. The compounding ratio of Ti is 1.0 to 4.0%. If the Ti content is less than 1.0%, the effect of improving the yield strength at high temperatures is small, and if the Ti content is more than 4.0%, the toughness of the material decreases, which is not desirable. [O: 0.05 to 0.40%] Generally, oxygen is considered to hinder the strength and elongation of the heat-resistant aluminum alloy. However, according to the experimental results of the present inventors, oxygen is less than 0.40%. It has been found that, if contained, the above-mentioned properties of the heat resistant aluminum alloy of the present invention are not substantially affected. If the atomized powder is produced in a non-oxidizing atmosphere, the content of oxygen can be less than 0.05% even in the case where the atomized powder is sealed and extruded in an oxidizing atmosphere. Also,
Setting the content of oxygen to less than 0.05% requires strict process control and the like in the production stage of the heat resistant aluminum alloy of the present invention. Since the heat-resistant aluminum alloy of the present invention can contain a relatively large amount of oxygen of 0.40%, the heat-resistant aluminum alloy of the present invention can be easily manufactured,
The manufacturing process can be simplified.

[0017]

EXAMPLES Examples of the present invention will be described below with reference to Tables 1 to 3 and FIG. 1 together with comparative examples.

[0018]

[Table 1]

The molten metal having the composition shown in Table 1 was pulverized by an atomizing method and then classified by a 100-mesh sieve,
Heat resistant aluminum alloy powders of Examples 1 to 8 and Comparative Examples 1 to 6 were obtained. Pure heat resistant aluminum alloy powder
Loaded in a tube with a bottom, and the surface pressure is 3 tons under vacuum conditions.
/ Cm ² and cold preforming to produce a preform of φ30 × L80. These preforms were heated at 450 ° C. for 30 minutes and hot extruded at a relatively large extrusion ratio “10” to obtain a rod-shaped aluminum alloy having a diameter of 10 mm. [Evaluation 1] The strength characteristics of each of the above aluminum alloys were measured. The measured tensile strength, yield strength and Young's modulus are also shown in Table 1.

From Table 1, it can be seen that the aluminum alloys of Examples 1 to 8 each have a Young's modulus exceeding 120 GPa and are excellent. In addition, the aluminum alloys of Examples 1 to 8 each have a tensile strength of 50 at room temperature (RT).
It can be seen that it exceeds 0 MPa and is excellent. Furthermore, it can be seen that the aluminum alloys of Examples 1 to 8 all have excellent tensile strength at 300 ° C. of more than 220 MPa.

On the other hand, comparing the aluminum alloys of Examples 1 and 3 containing Mo with the aluminum alloys of Comparative Examples 1 and 3 not containing Mo, the Young's modulus is improved by about 4 to 14 GPa by containing Mo. I understand. Furthermore, in the aluminum alloys of Examples 4 and 5 containing Zr,
It can be seen that the elongation value at 300 ° C. is 8% or more, which is particularly excellent.

Further, it is understood that the aluminum alloys of Examples 7 and 8 containing Ti have a yield strength at 300 ° C. of more than 200 MPa and are particularly excellent. [Evaluation 2] A creep test was performed on the aluminum alloy of Example 4 and the aluminum alloys of Comparative Examples 3, 5, and 6. The test was performed by measuring the time to fracture when a load of 97 MPa was applied at 300 ° C. The measurement results are shown in Table 2.

[0023]

[Table 2]

As shown in Table 2, the aluminum alloys of Comparative Examples 3, 5 and 6 broke in 4.7 to 29.3 hours, whereas the aluminum alloy of Example 4 had a breaking rate of 90.8 to 1
It broke at 12.8 hours. Therefore, it can be seen that the aluminum alloy of Example 4 can exhibit particularly excellent creep characteristics. [Evaluation 3] The coefficient of thermal expansion of each of the aluminum alloys of Examples 1 to 8 was measured.

The coefficient of thermal expansion of each aluminum alloy of Examples 1 to 8 is 12 to 16 × 10 ⁻⁶ / ° C., and a conventional aluminum alloy (JIS 1060 to 2040, A390, etc.) is used.
The coefficient of thermal expansion of the cast product is lower than that of 19 to 22 × 10 ⁻⁶ / ° C. FIG. 1 shows the relationship between the coefficient of thermal expansion and the Si content in JIS1060 and Example 1. This shows that the aluminum alloys of Examples 1 to 8 are also excellent in thermal expansion characteristics. [Evaluation 4] Aluminum alloy powder atomized in the air was sieved with -100 mesh, and then cold isostatic pressing (CI
P), and heat extrusion in the atmosphere was performed with this green compact. Tables 3 show these Examples 9 and 10.

Further, aluminum alloy powder sprayed with nitrogen using nitrogen as a spray medium in the air is sieved with -100 mesh, and then cold isostatic pressing (CIP) is performed. Was extruded by heating. Table 3 shows these Examples 11 and 12. As a comparative example, aluminum powder sprayed with nitrogen in a nitrogen atmosphere was sieved with -100 mesh, charged into a pure aluminum can with a bottom, vacuumed / degassed, sealed, and hot isostatically molded ( After HIP), heat extrusion was performed. Table 3 shows these Comparative Examples 7 and 8.

[0027]

[Table 3]

Generally, oxygen is considered to hinder the strength, elongation, etc. of the heat resistant aluminum alloy.
The aluminum alloy of No. 1 has the same rigidity, thermal expansion characteristics, and room temperature strength as those of the aluminum alloys of Examples 1 to 8 without requiring the canning operation and the vacuum degassing operation unlike the aluminum alloys of Comparative Examples 7 and 8. And an aluminum alloy with high temperature strength could be produced. Therefore, from Table 3, oxygen is 0.4
It can be seen that if the content is less than 0%, the above properties of the heat resistant aluminum alloy have substantially no effect.

Therefore, the oxygen content is 0.05 to 0.
It can be seen that a heat-resistant aluminum alloy having similar characteristics can be obtained even with 40%, so that the manufacturing process of the aluminum alloy can be simplified and the manufacturing cost can be reduced.

[0030]

As described in detail above, since the heat-resistant aluminum alloy of the present invention contains a predetermined amount of Ni, Si, Mo, it has excellent tensile strength at room temperature and high temperature, and Excellent rigidity and creep properties. On the other hand, in the heat resistant aluminum alloy of the present invention, a predetermined amount of Fe,
When the additive elements of Cu and Cr are blended, an aluminum alloy having the above-mentioned properties and having excellent tensile strength of 200 MPa or more and high temperature strength is obtained.

Further, the heat-resistant aluminum alloy of the present invention,
If a predetermined amount of Zr additive element is blended, it has the above-mentioned characteristics, and the elongation value at room temperature is 0.4% or more and 300 ° C.
The aluminum alloy has an elongation value of 2.5% or more and a toughness. Furthermore, when the heat-resistant aluminum alloy of the present invention is mixed with a predetermined amount of an additive element of Ti, it has the above-mentioned characteristics and has a yield strength of 2 at a high temperature of 300 ° C.
It becomes an aluminum alloy of 00 MPa or more.

The heat resistant aluminum alloy of the present invention is
Even if it contains a relatively large amount of oxygen, high room temperature strength and high temperature strength are maintained. Therefore, the heat-resistant aluminum alloy of the present invention can be easily manufactured and the manufacturing cost can be reduced. Therefore, even if an engine component such as an automobile is manufactured with the heat resistant aluminum alloy of the present invention, the aluminum alloy is lightweight and can exhibit rigidity, thermal expansion characteristics, room temperature strength and high temperature strength. The engine component can surely meet the recent demand for higher output.

In addition, the heat-resistant aluminum alloy of the present invention has excellent wear resistance, even if it contains a relatively large amount of Fe.
Since the rigidity, thermal expansion characteristics, room temperature strength and high temperature strength can be stably exhibited, even when the aluminum-based member and the iron-based member are mixed and recovered after disposal, the heat-resistant aluminum alloy of the present invention can be easily obtained. Can be manufactured.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the coefficient of thermal expansion and the Si content in Examples and the like in Evaluation 3.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hirohisa Miura 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Co., Ltd. (72) Inventor Yasuhiro Yamada 1, Toyota Town, Aichi Prefecture, Toyota Motor Co., Ltd. ( 72) Inventor Shoei Tanaka 3-6-8, Kutaro-cho, Chuo-ku, Osaka Midosuji Daiwa Building Toyo Aluminum Stock Association In-house

Claims (8)

[Claims] 1. By weight%, Ni: 10 to 20%, Si: 8
A heat-resistant aluminum alloy powder containing .about.25%, further containing at least Mo: 1.0-3.0%. 2. In weight%, at least Fe: 0.6
~ 8.0% and Cu: 0.6-5.0%, including 1 type,
The heat resistant aluminum alloy powder according to claim 1, wherein the total amount of Fe and Cu is 8.0% or less. 3. In% by weight, at least Zr: 0.3
-3.0% and Ti: 1.0-4.0% of 1 type, The heat resistant aluminum alloy powder of Claim 1 or 2. 4. By weight%, Ni: 10 to 20%, Si: 8
A heat-resistant aluminum alloy containing 25 to 25% of Mo, further containing at least Mo: 1.0 to 3.0%, and having a Young's modulus of 100 GPa or more at room temperature. 5. Oxygen content is 0.05-0.4 by weight.
The heat resistant aluminum alloy according to claim 4, which is 0%. 6. In weight%, at least Fe: 0.6
~ 8.0% and Cu: 0.6-5.0%, including 1 type,
While the total amount of Fe and Cu is 8.0% or less,
The heat resistant aluminum alloy according to claim 4 or 5, which has a Young's modulus of 105 GPa or more at room temperature. 7. In weight%, at least Zr: 0.3
.About.3.0% and Ti: 1.0 to 4.0%.
The Young's modulus at room temperature is 108 GPa or more,
The heat-resistant aluminum alloy according to 5 or 6. 8. The weight percent total amount of Fe, Ti, Ni and Zr is 14.5% or more, and the Young's modulus at room temperature is 110 GPa or more, according to claim 4, 5, 6 or 7. Heat resistant aluminum alloy.