JP3485961B2 - High strength aluminum base alloy - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum base alloy excellent in mechanical properties such as strength.

[0002]

2. Description of the Related Art Conventionally, for example, JP-A-1-275732.
As disclosed in the publication, an aluminum-based alloy having high strength and high heat resistance is manufactured by a rapid solidification method such as a liquid rapid cooling method. The structure of the aluminum-based alloy of the above publication obtained by the rapid solidification means is amorphous or microcrystalline, and the microcrystalline is a metal solid solution consisting of an aluminum matrix, a microcrystalline aluminum matrix phase and a stable or metastable It is composed of a complex composed of an intermetallic compound phase.

The aluminum-based alloy disclosed in JP-A-1-275732 has high strength, high heat resistance,
It is an excellent alloy that exhibits high corrosion resistance and is excellent in workability as a high-strength material, but in the high temperature range of 300 ° C or higher, its excellent properties as a rapidly solidified material deteriorate and heat resistance, especially heat resistance strength. There is room for improvement in terms of. Moreover, since the alloy of the above publication adds an element having a relatively high specific gravity, the specific strength does not become relatively large, and there is room for improvement in terms of high specific strength. Further, the alloy of the above publication has a low ductility because of a high volume ratio of the intermetallic compound, and there is room for improvement particularly in the point of elongation.

On the other hand, Al-M (M = Mn, Cr, V, M
o) -RE (Y, La, Ce, etc.)-based aluminum alloys form icosahedral quasicrystals (I phase), and their specific strength is about 1.3 times or more higher than that of Al-based amorphous alloys. It has been reported. However, it is expected that the properties such as strength, specific strength, ductility, and heat resistance will be further improved to a level sufficient for practical materials.

Further, according to Japanese Patent Publication No. 4-59380, Albal Fea Xb (X = Zn, Co, Cr, M
o, Zr, Y, Si and / or Ce, a = 7 to 15 wt
%, B = 1.5 to 10 wt%), and at least 70% has a microeutectic structure, and high temperature strength aluminum alloys are known. This microeutectic structure is composed of a substantially uniform cellular network structure of a solid solution phase containing Al and a transition metal element. This alloy has excellent high-temperature strength as compared with ordinary aluminum alloys, but the elongation at room temperature of the extruded material is less than 10%. Since the extruded material obtained by extruding a usual molten Al alloy ingot easily exceeds 10% at room temperature, the material of Japanese Patent Publication No. 4-59380 has room for improvement in ductility.

[0007]

Therefore, the present invention provides an aluminum-based alloy having a structure in which at least quasicrystals are finely dispersed in a matrix made of aluminum.
It is an object of the present invention to provide an aluminum-based alloy excellent in strength and specific strength, and more preferably in ductility, heat resistance, room temperature strength and high temperature strength and hardness, and high in specific strength.

In order to solve the above problems, the present invention provides a general formula: Albal Qa Mb Xc (provided that Q: one or more elements selected from V, Mo and W, M: Fe, C
one or more elements selected from o, Ni, Cu, one or more rare earth elements containing X: Y (yttrium), or a misch metal (Mm),
a, b, c are atomic% and 1 ≦ a ≦ 7, 0.5 ≦ b ≦ 5
0.5 ≦ c ≦ 2 ) and has a volume in the tissue.
Provided is a high-strength aluminum-based alloy characterized by containing 20 to 70% of quasicrystals.

The Q element is one or more elements selected from V, Mo and W, and these elements are indispensable for the formation of quasicrystals. It has the effects of facilitating the generation of crystals and improving the thermal stability of the alloy structure.

The M element is one or more elements selected from Fe, Co, Ni and Cu. By combining these elements with the above-mentioned Q element, quasicrystals can be easily generated and the Q element can be produced. Thermal stability is improved as well. In addition, the M element is an element having a small diffusivity with respect to Al which is the main element, has an effect of strengthening the Al matrix, and forms various intermetallic compounds with Al which is the main element or other elements to form an alloy. Contributes to improved strength and heat resistance.

The X element is one or more kinds of rare earth elements containing Y (yttrium) or misch metal (Mm), and these elements are Q-generated by a quasicrystal.
It is effective in expanding the low solute concentration of the added Q and M transition metals in the M composition region, and improves the effect of refining the phase by cooling from a high temperature state such as a molten metal. In addition, due to the refinement effect, the ductility is improved together with the strength. As the X element, Ce and La, which are light rare earths, are particularly preferable for increasing the specific strength. The amount of rare earth element is c = 0.5 to 2 at%,
In particular, 1 to 1.5 at% is preferable.

In the above general formula, a is 1 to 7a in atomic%.
t%, b 0.5 to 5 at%, c 0 (0 is not included)
The reason for limiting each to 5 at% is that the strength is higher than that of a conventional (commercially available) high-strength aluminum alloy even at room temperature and a high temperature of 300 ° C. or higher within the range. Particularly preferred is the range of 3 ≦ (a + b + c) ≦ 7.

The above quasicrystal is an icosahedral quasicrystal phase (ic
osahedral, I phase) or regular decagonal quasicrystal (decagonal,
D phase) or these approximate crystal phases. Approximate crystals are icosahedral phase (I phase) and regular decagon (D phase)
Is a crystal having a regular array.

Further, its structure is composed of a phase made of any of amorphous, aluminum crystal, and supersaturated solid solution of aluminum crystal in addition to quasicrystal, and the latter may be a complex (mixed phase) thereof. Further, in some cases, these structures may contain various intermetallic compounds produced by aluminum and other elements and / or intermetallic compounds produced by other elements. In particular, the presence of the intermetallic compound is effective in strengthening the matrix and controlling the crystal grains. Further, in the present invention, the structure of the alloy is such that fine quasicrystalline particles are uniformly dispersed in the amorphous phase, the aluminum phase, and the supersaturated solid solution phase of aluminum.

In the above, the quasicrystal contained in the alloy structure is 20 to 70% by volume . When it is less than 20%, the strength, specific strength and heat resistance are insufficiently improved, while when it exceeds 70%, the material may not be sufficiently processed due to embrittlement of the alloy. . Further, it is preferable that the quasicrystal contained in the alloy structure has a volume ratio of 50 to 70% .

In the aluminum-based alloy of the present invention, the molten metal of the alloy having the above composition is formed by the single roll method, the twin roll method,
It can be directly obtained as a ribbon, a powder, etc. by a spinning liquid spinning method, various atomizing methods, a liquid quenching method such as a spray method, a sputtering method, a mechanical alloying method, a mechanical gliding method and the like. In the case of these methods, it is 10 ² to 10 ⁴ K / se although it depends on the alloy composition.
A predetermined quasicrystal can be formed at a cooling rate of about c. The rapidly solidified material described above can be used for parts having predetermined dimensions and thickness by a method such as powder compaction, adhesion, brazing and the like. Further, it can be used for various parts by extruding powder to have a predetermined size.

The aluminum-based alloy of the present invention is obtained by the above-mentioned manufacturing method to obtain a rapidly solidified material having a solid solution structure at least partially, and heat-treating the material, or a rapidly solidified material having a solid solution structure at least partially. For example, a quasicrystal can be precipitated from a solid solution by assembling ribbons, powders, etc. and subjecting them to thermal processing such as compaction and extrusion. The temperature at this time is preferably 360 to 600 ° C. It is preferable that quasicrystals are crystallized as primary crystals by this rapid solidification in terms of strength improvement.

The average particle size of the quasicrystals and the various intermetallic compounds optionally present is preferably from 10 to 1000 nm. This is because when the average particle size is less than 10 nm, it is difficult to contribute to the strength of the alloy, and when it is present in the structure more than necessary, there is a risk of embrittlement of the alloy. This is because if it becomes too large, it becomes impossible to maintain the strength, and there is a high possibility that it will not function as a reinforcing element. The average interparticle distance between the quasicrystal and the intermetallic compound is 10
It is preferably ˜500 nm. When the average inter-particle distance is less than 10 nm, the obtained alloy has high strength and hardness but is insufficient in ductility, and when it exceeds 500 nm, the strength is sharply reduced, and high strength alloy may not be obtained. Is caused. Therefore, with the composition represented by the above general formula, Young's modulus, high temperature, room temperature strength, ductility, fatigue strength and the like can be further improved.

The aluminum-based alloy of the present invention has an alloy structure (proportion of quasicrystals and other types of phases) by selecting appropriate manufacturing conditions, particularly cooling rate and heat treatment conditions;
It is possible to control the particle size of each phase such as a quasicrystal, the dispersion state, and the like, and it is possible to obtain a material suitable for various application properties (for example, strength, hardness, ductility, heat resistance, etc.). Further, as described above, by controlling the average particle size of the quasicrystal or various intermetallic compounds in the range of 10 to 1000 nm and controlling the average interparticle distance in the range of 10 to 500 nm, excellent superplastic working is achieved. The property as a material can also be given. In the alloy of the present invention, it is preferable for quenching to crystallize a quasicrystal as a primary crystal to improve strength.

[0020]

[Operation] (1) Strength / specific strength: Amorphous aluminum alloy which is said to have the highest strength in the past is Al ₈₅ Ni ₅ Y
_{In the} present invention, a strength equivalent to ₁₅ (tensile strength ρ f = 1140 MPa) can be achieved with a very small amount of solute element. Further, in the present invention, the same degree of strength can be achieved with a smaller amount of solute element as compared with the conventional quasicrystalline aluminum alloy. (2) Ductility: The alloy of the present invention has extremely excellent ductility despite its extremely high strength, and has the best properties in comparison with those obtained by processing a conventional ingot. (2) Heat resistance: The material of the present invention has advantages such as little change in characteristics due to heating during hot working and little difference in strength between room temperature and high temperature.

[0021]

EXAMPLES The present invention will be specifically described below based on examples. Example ₁ A mother alloy having a composition (atomic ratio) represented by Al _94.5 V ₃ Co _1.5 Ce ₁ was melted in an arc melting furnace, and a ribbon was formed by a commonly used single roll type liquid quenching device (melt spinning device). Thickness: 20 μm, width 1.5 m
m) was produced. The roll at that time was made of copper with a diameter of 200 mm, the rotation speed was 4000 rpm, and the atmosphere was 10 ⁻³ torr.
The following is Ar.

As a result of TEM observation and electron beam diffraction of the produced ribbon after electrolytic polishing, it was found to be a mixed phase alloy composed of a quasicrystalline I phase and an aluminum crystalline phase. FIG. 1 showing the results shows that the I phase has a diameter of about 30 nm and is uniformly dispersed in the aluminum phase (white tissue portion) matrix. Phase I has a volume ratio of 68%,
It was found to be the main phase in the alloy structure.

Example 2 A mother alloy having a composition (atomic ratio) represented by Al _99-ab V _a Co _b Ce ₁ was melted in an arc melting furnace, and a ribbon (thickness) was formed under the same manufacturing conditions as in Example 1. : 20 μm, width 1.5 mm) was manufactured. The strength of each manufactured ribbon was measured at room temperature by an Instron type tensile tester. Also, 1
The ductility of the alloy was investigated by performing 80 ° contact bending. The results are shown in Table 1.

[0024]

[Table 1]

According to Table 1, it was found that the alloys of Examples 1 to 13 of the present invention were alloys having excellent strength and excellent ductility (viscosity). Comparative Example 1 has high strength, but V, C
This is an example in which the ductility is low because the total amount of o and Ce is large. As a result of TEM observation and electron diffraction of the alloy structure, almost the same results as in Example 1 were obtained. On the other hand, Comparative Example 1 has a large amount of V, and Comparative Example 2 is an example having low strength and ductility because V is not added.

Note that V = 2, 3, 4, 5, 7 at% of 5
With the addition amount of one level, the strength is highest at V = 3 to 4% (Invention Example 9). Co is Co = 1.
The strength is highest in the range of 5 to 2.5 at%, but when V is as high as 4 at%, the strength is reduced at Co = 2.5 at (Invention Example 12). Therefore, when the amount of V and Co added in the above range, the tensile strength is 1000MP.
High strength of a or more is obtained, and rare earth is Ce = 1 at%
Since it is low, it is preferable in terms of specific strength.

Example 3 A mother alloy having a composition (atomic ratio) represented by Al _94.5 V ₃ M _1.5 Ce ₁ was melted in an arc melting furnace, and a ribbon was manufactured under the same manufacturing conditions as in Example 1 below. The hardness Hv (DPN) of each manufactured ribbon was measured by a Vickers micro hardness meter (load: 20 g), and the strength σf (MPa) at room temperature was measured by an Instron type tensile tester. The result is shown in FIG.

It can be seen from FIG. 2 that the alloy of the present invention has excellent strength and hardness. In particular, Co among M elements has a large effect of improving strength. The structure of the alloy was almost the same as in Example 1 as a result of TEM observation and electron diffraction.

Example 4 Aluminum-based alloy powders having the compositions shown in Tables 2 and 3 were produced by gas atomization. After filling the produced aluminum-based alloy powder into a metal capsule, degassing was performed to produce a billet for extrusion. This billet was extruded with an extruder at an extrusion ratio of 10: 1 to 3
Extrusion was carried out at a temperature of 50 to 600 ° C. Mechanical properties at room temperature (hardness, strength, elongation) at room temperature and mechanical properties at high temperature (strength after holding at 300 ° C. for 1 hour) of the extruded material (solidified material) obtained under the above production conditions
And the results are shown in Table 2.

[0030]

[Table 2]

[0031]

[Table 3] Composition (at%) Tensile strength Elongation Tensile strength Main room temperature Room temperature 300 ° C Bright example Al Q M X ( Hv ) σf (MPa ) % σf (MPa ) 33 Residual Mo = 2.0 Ni = 1.0 Mm = 1.0 289 920 14.8 315 W = 1.0 Cu = 0.5

From the results shown in Tables 2 and 3, the extruded alloy of the present invention has excellent hardness and strength at room temperature,
It has high elongation of more than 0% and high temperature (300
(° C.) It is understood that it has excellent properties in strength under the environment. Further, it was found that when an extruded material is produced, it has excellent workability and is heated to a very high temperature of 350 to 600 ° C., but the change in characteristics due to heating is less than that of a material in a rapidly solidified state.

Further, a test piece for TEM observation was cut out from the extruded material obtained under the above manufacturing conditions, and the structure of the alloy and the grain size of each phase were observed. As a result of TEM observation, the quasicrystal was an icosahedral phase (I phase) alone or a mixed phase of an icosahedral phase and a regular decagonal phase (D phase). Also, an approximate crystal phase was present depending on the alloy type. The quasicrystal in the structure has a volume ratio of 20 to 70.
%Met.

Further, the alloy structure is a mixed phase of aluminum or a supersaturated solid solution phase of aluminum and a quasicrystalline phase, and various intermetallic compound phases are mixed with this depending on the type of alloy. In the composition in which the intermetallic compound was deposited, the intermetallic compound was uniformly and finely dispersed in the alloy structure. Furthermore, the average particle size of the quasicrystalline phase and the intermetallic compound phase is 10 to 10
The average interparticle distance is 10 to 50
It was 0 nm. In this example, the particle size of each phase varied within the above range was found to be related to the degassing conditions including the powder compacting condition during degassing and the extrusion temperature.

In Examples 1, 2 and 3 described above, the amorphous phase is mixed in the structure of the alloy by increasing the rotation speed of the roll and increasing the cooling rate during the production of the ribbon. be able to. Further, under the manufacturing conditions shown in Examples 1, 2 and 3, first, a structure similar to that of the example is formed, and this is heated to obtain an alloy in which an intermetallic compound is precipitated. Further, by controlling the production conditions as described above, the average particle size of each phase can also be controlled. The alloy thus obtained is an alloy excellent in mechanical properties as in the examples.

[0036]

INDUSTRIAL APPLICABILITY As described above, the alloy of the present invention has excellent hardness and strength at room temperature and high temperature, excellent heat resistance, and high strength and small specific gravity due to the small amount of rare earth element added. Therefore, it is also useful as a high specific strength material.

Further, since the alloy of the present invention is a ductile material having a high elongation, it can be easily processed in various ways and fatigue fracture hardly occurs.

Further, due to having excellent heat resistance, it is possible to maintain the excellent characteristics produced by the rapid solidification method and the characteristics produced by the heat treatment or the thermal processing even if the thermal influence during the processing is exerted. It is a thing.

Therefore, the aluminum-based alloy of the present invention has characteristics not found in any conventional amorphous material, microcrystalline material, melt-extruded material, and the like, and the amount of solute elements is relatively small and low. Since it is inexpensive and easy to process, it is expected that the weight of various parts will be further reduced.

[Brief description of drawings]

FIG. 1 is a TEM observation of the alloy in Example 1 (105).
2 is a photograph showing a metallographic structure based on electron diffraction results.

FIG. 2 is a graph showing the strength test results of alloys in Example 3.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ken Masumoto 3-8-22 Uesugi, Aoba-ku, Sendai-shi, Miyagi (72) Inventor Akihisa Inoue Kawauchi Muzenchi, Kawauchi, Sendai-shi, Miyagi 11-806 ( 72) Inventor Hisami Kimura 44 Fujihirabashi, Arahama, Watari-cho, Watari-gun, Miyagi Prefecture (72) Kenichiro Sasamori 56-1 Tamachi, Kakuda-ji, Kakuda-shi, Miyagi (72) Inventor Yoshiyuki Shinohara 1-9, Yaesu, Chuo-ku, Tokyo 9 Teikoku Piston Ring Co., Ltd. (72) Inventor Katsuhiko Onoue 10-1 Nakazawa-cho, Hamamatsu-shi, Shizuoka Prefecture Yamaha Corporation (56) Reference JP-A-6-41702 (JP, A) JP-A-4 -41654 (JP, A) JP-A-1-127641 (JP, A) JP-A-5-125474 (JP, A) JP-A-3-501392 (JP, A) (58) Fields investigated (Int.Cl) . ⁷ , DB name) C22C 21/00-21 / 18,45 / 08

Claims (8)

(57) [Claims] 1. A general formula: Albal Qa Mb Xc (however,
Q: One or more elements selected from V, Mo, W, M: One or more elements selected from Fe, Co, Ni, Cu, One or two elements containing X: Y (yttrium) The above rare earth element or misch metal (Mm), where a, b and c are 1% a ≦ 7 in atomic%.
0.5 ≤ b ≤ 5, 0.5 ≤ c ≤ 2 ), and a high-strength aluminum-based alloy containing 20 to 70% by volume of quasicrystal in the structure. 2. The high-strength aluminum-based alloy according to claim 1, wherein the composition is 3 ≦ (a + b + c) ≦ 7. 3. A quasicrystal is an icosahedral phase (icosahedral, I).
Phase), regular decagon (decagonal, D-phase) or a high strength aluminum based alloy according to claim 1 or 2, wherein any of these approximations crystalline phase. 4. The high-strength aluminum-based alloy according to any one of claims 1 to 3, wherein the structure thereof comprises a quasicrystal and a phase composed of any of amorphous, aluminum crystal , and a supersaturated solid solution of aluminum. . 5. The high-strength aluminum-based alloy according to claim 4, wherein the structure further contains an intermetallic compound of aluminum and another element and / or an intermetallic compound produced by the other elements. . 6. The high-strength aluminum-based alloy according to any one of claims 1 to 5, which is a rapidly solidified material. 7. The method according to claim 1, wherein the rapidly solidified material is heat treated.
The high-strength aluminum-based alloy according to any one of items 1 to 10 . 8. The method according to claim 1, wherein the rapidly solidified powder is extruded.
The high-strength aluminum-based alloy according to any one of items 1 to 10 .