JPH05306423A - Heat resistant aluminum alloy powder and heat resistant aluminum alloy - Google Patents

Abstract

PURPOSE:To produce a product excellent in strength at high temp. as well as in strength at ordinary temp. CONSTITUTION:This product is a powder of heat resisting aluminum alloy having a composition which consists of, by weight, 10-20% Ni, 8-25% Si, and the balance Al practically free from Mg and further contains 0.6-8.0% Fe and/or 0.6-5.0% Cu and where the total content of Fe and Cu is regulated to <=10%. When this heat resisting aluminum alloy powder is used and formed into an alloy by a sintering method, the alloy having >=500MPa strength at ordinary temp. and also having, at a temp. as high as 300 deg.C, >=200MPa tensile strength and >=180MPa yield strength and excellent in strength at high temp. as well as in strength at ordinary temp. can be formed.

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 are useful when applied to engine parts such as connecting rods and the like of automobiles, aircrafts and the like and which are excellent in wear resistance and high temperature strength.

[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 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 (hereinafter simply referred to as "%") of Ni (sponsored by Japan Institute of Light Metals, A).
l alloy powder metallurgy technology symposium (March 9, 1987)
(Held daily) Proceedings, 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 having excellent 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 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.
a or more is required. From this point of view, the JIS20
Although Al-Cu-Mg-based alloys such as 24 and 2018 have excellent tensile strength at room temperature, the tensile strength is 300 MPa at a high temperature of 200 ° C and 150 MPa at a high temperature of 300 ° C. It is not possible to apply these Al-Cu-Mg based alloys to the engine parts of. Further, the Al-Ni-based alloy and Al-Ni-Si-Cu- Mg -based alloy of the proposed or publication by NiAl ₃ intermetallic compound produced during the tissue, is improved in heat resistance and abrasion resistance However, since the product is manufactured by the casting method, the particle size of the NiAl ₃ intermetallic compound in the product is as large as about 10 μm, and the tensile strength is 160 at maximum at room temperature 380 MPa and 300 ° C.
It became clear that the pressure decreased to MPa. 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.
It is m or less and is excellent in wear resistance, and also has a tensile strength of 510 MPa at room temperature and 345 MPa at 250 ° C. 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 stably producing a product excellent in wear resistance and high-temperature strength. And

[0008]

The present inventors have found that an excellent heat-resistant aluminum alloy can be obtained by blending an aluminum alloy having high Ni and high Si with at least one of Fe and Cu. I proceeded with my research. Then, it was discovered and confirmed that Mg, which is always compounded in the high Ni and high Si aluminum alloys containing at least one of Fe and Cu, has an unfavorable effect on the room temperature strength and the high temperature strength. It is an invention of an aluminum alloy powder and a heat-resistant aluminum alloy.

The heat-resistant aluminum alloy powder of the present invention is a heat-resistant aluminum alloy powder containing, by weight%, Ni: 10 to 20% and Si: 8 to 25%, and the balance Al substantially containing no Mg. And at least Fe:
0.6 to 8.0% and Cu: 0.6 to 5.0% are included, and the total amount of Fe and Cu is 10% or less.

The heat-resistant aluminum alloy powder of the present invention may further contain Zr: 0.3 to 2.0% by weight. The heat-resistant aluminum alloy powder of the present invention may further contain Ti: 1.0 to 4.0% by weight. The heat-resistant aluminum alloy of the present invention, in% by weight, contains N
A heat-resistant aluminum alloy containing i: 10 to 20%, Si: 8 to 25%, and a balance of Al, which does not substantially contain Mg, and at least Fe: 0.6 to 8.0%.
And Cu: containing 0.6 to 5.0% of 1 type, Fe and C
The total amount of u is 10% or less, the tensile strength at room temperature is 500 MPa or more, and the tensile strength at 300 ° C. is 2
It is characterized by being at least 00 MPa.

The heat-resistant aluminum alloy of the present invention has a weight%
The oxygen content may be 0.10 to 0.40% and a relatively large amount of oxygen may be contained. The heat-resistant aluminum alloy of the present invention contains Zr: 0.3 to 2.0% by weight, has a tensile strength at room temperature of 500 MPa or more, and 30%.
The tensile strength at 0 ° C. can be 200 MPa or more and the elongation can be 5% or more. The heat-resistant aluminum alloy of the present invention contains Ti: 1.0 to 4.0% by weight, has a tensile strength at room temperature of 500 MPa or more, and 30%.
The yield strength at 0 ° C can be 200 MPa or more.

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 forming 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, making intermetallic compounds such. 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 have lower hardness and are richer in toughness. Precipitation of NiAl ₃ intermetallic compound is observed in the obtained alloy by adding Ni in an amount of 5.7% or more by weight (hereinafter, simply abbreviated as%). , 30 of the resulting alloy
The tensile strength at 0 ° C. does not exceed 200 MPa and the high temperature strength is not effectively improved.

On the contrary, if Ni is added at 40% or less,
The resulting alloy produces 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 etc. will be remarkably inferior, and practical use will be difficult.

[Si: 8-25%] Fine Si in Al
It is known that A390 alloy and the like are excellent in high temperature strength and wear resistance. When a product is manufactured by a casting method, a coarse Si primary crystal is crystallized in an aluminum alloy containing 11.3% or more of Si, and such alloy attacks the mating material of the sliding portion and has a machinability. It is not preferable because the alloy itself is significantly deteriorated, and the elongation of the alloy itself is significantly reduced, which is not practical in terms of production technology (for example, cracks during processing of parts) and cracks are generated during use as parts. However, when an aluminum alloy is manufactured 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%. S
If i is blended in an amount of more than 25%, coarse Si will be added to the product even if the heat-resistant aluminum alloy powder is manufactured by the rapid solidification method.
Undesirably crystallizes out.

On the contrary, when the content of Si is less than 8%, the resulting aluminum alloy has insufficient high-temperature strength and wear resistance. [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 is 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 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 10% or less, the room temperature strength of the aluminum alloy is effectively improved.

[Cu: 0.6-5.0%] 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 when Cu content exceeds 5%, coarse crystallized substances are generated, and the high temperature strength of the aluminum alloy at 300 ° C is improved. Lower. However, if at least one of Cu and Fe is contained and the total amount of Fe and Cu is 10% or less, the room temperature strength of the aluminum alloy is effectively improved.

[Mg: Substantially Free] Generally Mg
Is known as a component that strengthens the Al matrix, similar to Cu, but the experimental results of the inventors show that the alloy containing Mg has a room temperature strength and a temperature of 300 ° C. as compared with an alloy containing no Mg. It was found that both high temperature strength and elongation were reduced.

In Japanese Patent Publication No. 63-20298, Al contains Ni and Si, and Cu and Mg.
Although there is a description as an aluminum alloy containing at least one of the above, this publication does not include an example of an aluminum alloy containing no Cu and not containing Mg. In addition, this publication describes Mg
There is no description that indicates that N has an adverse effect on room temperature strength and high temperature strength.

[Zr: 0.3-2.0%] Zr is known as an additive element for improving high temperature strength, but according to the results of the experiments conducted by the inventors, the Zr content of the aluminum alloy at room temperature and 300 ° C. is rather high. It was found to improve the elongation value. That is,
When Zr: 0.3 to 2.0% is added to the heat resistant aluminum alloy, the toughness of the alloy is effectively improved. Zr is 0.
If less than 3% is added, the effect of improving toughness is small, and if Zr is added over 2.0%, a coarse intermetallic compound (Zr
Al ₃ ) crystallizes out, which is undesirable.

[Ti: 1.0 to 4.0%] Ti is Zr
Similarly, although it is known as an additive element that improves the high temperature strength, the experimental results of the inventors show that it is 30% less than that of aluminum alloy.
It was found to improve the yield strength at 0 ° C. The compounding ratio of Ti is 1.0 to 4.0%. The composition of Ti is 1.
If it is less than 0%, the effect of improving the yield strength at high temperature is small, and if the content of Ti is more than 4.0%, the toughness of the material is lowered, which is not desirable.

[O: 0.05 to 0.40%] Generally, oxygen is considered to impair the strength and elongation of the heat-resistant aluminum alloy, but according to the experimental results of the present inventors, oxygen is less than 0.40%. It has been found that the above properties of the heat-resistant aluminum alloy of the present invention are not substantially affected if the content is within the range. If the atomized powder is produced in a non-oxidizing atmosphere, the oxygen content can be less than 0.05% even in the case of sealing and extruding in an oxidizing atmosphere. Further, setting the content of oxygen to less than 0.10% 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, and the manufacturing process can be simplified.

[0023]

EXAMPLES Examples of the present invention will be described below with reference to Tables 1 and 2 and FIG. 1 together with comparative examples.

[0024]

[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 14 and Comparative Examples 1 to 7 were obtained. Pure A of these heat-resistant aluminum alloy powders
1 tube with a bottom and loaded under vacuum condition with a surface pressure of 3 to
Cold preforming was carried out at n / cm ² to produce a preform of φ30 × L80. 450 ° C of these preforms
For 30 minutes, and hot extrusion was performed at a relatively large extrusion ratio of "10" to obtain a rod-shaped aluminum alloy having a diameter of 10 mm.

[Evaluation 1] With respect to each of the above aluminum alloys, strength characteristics were measured at room temperature, 150 ° C. and 300 ° C. The measured tensile strength, yield strength and elongation are also shown in Table 1. From Table 1, the aluminum alloys of Examples 1 to 14 all have a tensile strength of 5 at room temperature (RT).
It can be seen that it is excellent, exceeding 00 MPa. Moreover, the aluminum alloys of Examples 1 to 14 were each 300 ° C.
It can be seen that the tensile strength in Example 2 exceeds 200 MPa and is excellent.

On the other hand, Comparative Examples 1 to 1 containing no Cu or Fe
It can be seen that each of the aluminum alloys of No. 5 has a tensile strength at room temperature of less than 500 MPa and is inferior to those of Examples 1 to 14. When the aluminum alloy of Example 3 containing no Mg and the aluminum alloy of Comparative Example 6 containing Mg are compared, room temperature strength and high temperature strength at 300 ° C. are reduced by about 10 to 120 MPa by containing Mg. I understand. Further, Examples 12, 13, 14
And that the yield strength at 300 ° C. is excellent and the heat resistance is excellent even when the addition amounts of Ni, Fe, and Cu are changed. Furthermore, it can be seen that the aluminum alloys of Examples 8 and 9 containing Zr have particularly excellent elongation values at 300 ° C. Further, it is found that the aluminum alloys of Examples 10 and 11 containing Ti have particularly excellent yield strength at 300 ° C.

[Evaluation 2] The rigidity of each of the aluminum alloys of Examples 1 to 14 was measured. Example 1
Young's modulus of each of 14 aluminum alloys is 110 to 130
While it is GPa, it is a standard aluminum alloy (JI
The Young's modulus of the cast body of S1060 to 2040, A390, etc.) is as low as 70 to 90 GPa, and it can be seen that the aluminum alloys of Examples 1 to 14 also have significantly excellent rigidity.

[Evaluation 3] The coefficient of thermal expansion of each of the aluminum alloys of Examples 1 to 14 was measured. The coefficient of thermal expansion of each aluminum alloy of Examples 1 to 14 is 12 to 15.
× 10 ^-6 / ° C, which is a standard aluminum alloy (JIS
(1060 to 2040, A390, etc.) has a low coefficient of thermal expansion as compared to 19 to 22 × 10 ⁻⁶ / ° C., and the aluminum alloys of Examples 1 to 14 are also excellent in thermal expansion characteristics. You can see that

Therefore, according to the evaluations 1 to 3, Examples 1 to 1
The aluminum alloy produced by sintering the heat-resistant aluminum alloy powder of No. 14 is lightweight, and is excellent in wear resistance, rigidity, thermal expansion characteristics and tensile strength at room temperature, and has a tensile strength at a high temperature of 300 ° C. Is 200 MPa or more and the yield strength is 180 MPa or more.
Moreover, since the heat-resistant aluminum alloy powders of Examples 8 to 9 also contain a predetermined amount of an additive element of Zr, they have the above-mentioned characteristics and have an elongation value at room temperature of 0.5% or more and 300 ° C.
It can be seen that the elongation value at 5.0% or more has a high elongation. Moreover, since the heat-resistant aluminum alloy powders of Examples 10 to 11 also contain a predetermined amount of Ti, they have the above-mentioned properties and the yield strength at 300 ° C. is 200 MPa or more.

[Evaluation 4] Similar to the above Examples 1 to 14, the aluminum alloy composition was Al-15Ni-15Si.
Aluminum alloy consisting of -3Cu powder (Example 1
5: the same composition as in Example 3), an aluminum alloy having an aluminum alloy composition of Al-10Ni-8Si-3Fe-2Ti (Example 16), and an aluminum alloy composition of Al-12Ni-8Si-3Fe-1Zr. And an aluminum alloy (Example 17) made of the above powder.

Further, an aluminum alloy cast body made of A390 by a casting method (Comparative Example 10) and JIS2024
And an MMC cast body (Comparative Example 11) in which 20% of SiC whiskers were dispersed in an aluminum alloy based on. Further, similarly to the above, an aluminum alloy (Comparative Example 12) obtained by adding 30% of Si particles to an aluminum alloy powder based on JIS2024 was manufactured.

Regarding the aluminum alloys or castings of Examples 15, 16 and 17 and Comparative Examples 10 to 12,
The following conditions (A) and (B) were measured using an Ogoshi-type wear scar tester.
Wear scar area (mm ² ) and specific wear amount (×
A wear test was conducted to obtain 10 ⁻⁶ mm ³ / kg · mm). The results are shown in Figure 1. Condition (A) ... Speed: 0.31 m / s, load: 6.3 k
g, distance: 100 m Condition (B) ... Speed: 0.91 m / s, load: 12.6 k
g, distance: 100 m As the mating material, Fe-0.8C-5Mo-2.
An Fe-based sintered material made of 5Co was adopted.

As shown in FIG. 1, Examples 15, 16 and 1
It can be seen that the aluminum alloy of No. 7 has smaller wear scar area and specific wear amount than any of the cast bodies or aluminum alloys of Comparative Examples 10 to 12, and is excellent in wear resistance. [Evaluation 5] An 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 2 and 3 show the aluminum alloy composition and the oxygen content (%) in the aluminum alloy as Examples 18 and 19, respectively.

Aluminum alloy powder sprayed with nitrogen using nitrogen as a spraying medium in the air was sieved with -100 mesh, and then cold isostatic pressing (CIP) was performed. Was extruded by heating. Table 2 shows the aluminum alloy composition and the amount of oxygen (%) in the aluminum alloy as Examples 20 and 21. As a comparative example, an aluminum powder sprayed with nitrogen in a nitrogen atmosphere-
After sieving with 100 mesh, it is placed in a pure aluminum can with a bottom, vacuumed and degassed, then sealed, and hot isostatic pressing (HI
After P), heat extrusion was performed. Comparative Example 13,
Table 2 shows the aluminum alloy composition as 14 and the oxygen content (%) in the aluminum alloy.

[0036]

[Table 2]

Generally, oxygen is considered to hinder the strength, elongation, etc. of the heat-resistant aluminum alloy.
The aluminum alloy of 9 has the same wear resistance, rigidity, and heat resistance as those of the aluminum alloys of Examples 1 to 14 without requiring the canning operation and the vacuum degassing operation unlike the aluminum alloys of Comparative Examples 13 and 14. An aluminum alloy having expansion characteristics, room temperature strength and high temperature strength could be manufactured. Therefore, Table 2
From the above, it can be seen that if the oxygen content is in the range of less than 0.40%, 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 at 40%, so that the manufacturing process of the aluminum alloy can be simplified and the manufacturing cost can be reduced.

[0039]

As described in detail above, the heat-resistant aluminum alloy of the present invention contains a predetermined amount of Ni, Si, Fe, Cu and does not contain Mg, and thus is lightweight and
It has excellent wear resistance and tensile strength at room temperature, and has excellent high-temperature strength of 200 MPa or more and yield strength of 180 MPa or more at a high temperature of 300 ° C.

On the other hand, in the heat resistant aluminum alloy of the present invention,
If a predetermined amount of additional elements of Zr and Ti are blended, it has the above-mentioned characteristics and an elongation value at room temperature of 0.4% or more, 3 or more.
An aluminum alloy having a toughness with an elongation value at 00 ° C of 2.5% or more. Further, the heat resistant aluminum alloy of the present invention maintains high room temperature strength and high temperature strength even if it contains a relatively large amount of oxygen. Therefore, the heat-resistant aluminum alloy of the present invention can be easily manufactured and the manufacturing cost can be reduced.

Therefore, even if engine parts such as automobiles are manufactured with the heat resistant aluminum alloy of the present invention, the aluminum alloy is lightweight and has stable wear resistance, rigidity, thermal expansion characteristics, room temperature strength and high temperature. Since it can exhibit strength, it becomes an engine component that can reliably meet the recent demand for higher output. In addition, in the heat-resistant aluminum alloy of the present invention, even if Fe is contained in a relatively large amount, excellent wear resistance, rigidity, thermal expansion characteristics, normal 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 manufactured.

[Brief description of drawings]

FIG. 1 is a graph showing a wear scar area and a specific wear amount of an example of an abrasion test result in Evaluation 4 and a comparative example.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ibashi ▲ Kuni ▼ hiko 1 Toyota-cho, Toyota-shi, Aichi Toyota Motor Co., Ltd. (72) Inventor Yasuhiro Yamada 1-cho, Toyota-shi, Aichi Toyota Motor Corporation Stock In-house (72) Inventor Jun Kusunii 3-6-8, Kutaro-cho, Chuo-ku, Osaka Toyo Aluminum Co., Ltd. (72) In-house Ake Tanaka 3-6-8, Kutaro-cho, Chuo-ku, Osaka Toyo Aluminum Within the corporation

Claims (7)

[Claims] 1. By weight%, Ni: 10 to 20%, Si: 8
A heat-resistant aluminum alloy powder containing ˜25% and the balance Al substantially free of Mg, further comprising at least Fe: 0.6-8.0% and Cu:
A heat-resistant aluminum alloy powder, which contains one of 0.6 to 5.0% and has a total amount of Fe and Cu of 10% or less. 2. In% by weight, further Zr: 0.3-2.0%
The heat-resistant aluminum alloy powder according to claim 1, containing. 3. In% by weight, further Ti: 1.0 to 4.0%.
The heat-resistant aluminum alloy powder according to claim 1, containing. 4. By weight%, Ni: 10 to 20%, Si: 8
A heat-resistant aluminum alloy containing ˜25% and the balance Al substantially free of Mg, further comprising at least Fe: 0.6-8.0% and Cu:
0.6 to 5.0% of 1 type, the total amount of Fe and Cu is 10% or less, and the tensile strength at room temperature is 500M.
Tensile strength at 200 ° C or higher and 200 MPa
The heat-resistant aluminum alloy characterized by the above. 5. Oxygen content is 0.05 to 0.4 in% by weight.
The heat resistant aluminum alloy according to claim 4, which is 0%. 6. In% by weight, further Zr: 0.3-2.0%
The tensile strength at room temperature is 500 MPa or more, the tensile strength at 300 ° C. is 200 MPa or more, and the elongation is 5%.
The heat-resistant aluminum alloy according to claim 4, which is the above. 7. By weight%, further Ti: 1.0 to 4.0%.
The heat-resistant aluminum alloy according to claim 4, which has a tensile strength at room temperature of 500 MPa or more and a yield strength at 300 ° C. of 200 MPa or more.