JPH07268529A - High strength aluminum-based alloy - Google Patents

Abstract

PURPOSE:To produce a high strength aluminum-based alloy increased in specific strength, ductility, heat resistance or the like by preparing an aluminum-based alloy constituted of specified ratios of Al, V, Fe, rare earth elements or the like and contg. quasi-crystals in the structure. CONSTITUTION:An aluminum-based alloy having a compsn. shown by the general formula Alba1QaMbXc [where Q : one or >= two kinds of elements selected from V, Mo and W, M: one or >= two kinds of elements selected from Fe, Co, Ni and Cu, X: one or >= two kinds of rare earth elements including Y or misch metals and, by atomic %, 1<=a<=7, 0.5<=b<=5, 0<c<=5 and, preferably, 3<=(a+b+c)<=7 are satisfied] and in which quasi-crystals are contained in the structure by 20 to 70% (by volume) is prepd. Thus, the aluminum-based allay excellent in ductility, heat resistance, room temp. strength, high temp. strength and hardness and high in specific strength can be obtd.

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 and c are in atomic%, 1 ≦ a ≦ 7, 0.5 ≦ b ≦ 5,0
There is provided a high-strength aluminum-based alloy having a composition represented by <c ≦ 5) and including a quasicrystal in its structure.

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 preferably has a volume ratio of 20 to 70%. 20%
If it is less than 70%, the improvement of strength, specific strength and heat resistance is insufficient, while if it exceeds 70%, the material may not be sufficiently processed due to embrittlement of the alloy. Furthermore, the quasicrystal contained in the alloy structure has a volume ratio of 5
It is more preferably 0 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 slightly different depending on the alloy composition, but 10 2 to 10 4 K / s
A predetermined quasicrystal can be formed at a cooling rate of about ec. 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]

[Action]

(1) Strength / specific strength: The amorphous aluminum alloy, which is said to have the highest strength in the past, has strength equivalent to that of Al85Ni5Y15 (tensile strength ρf = 1140MPa) with a very small amount of solute element in the present invention. Can be achieved.
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 Composition represented by Al94.5V3 Co1.5 Ce1 (atomic ratio)
Was melted in an arc melting furnace, and a ribbon (thickness: 20 μm, width 1.5 mm) was manufactured by a commonly used single roll type liquid quenching device (melt spinning device). At that time, the roll is made of copper having a diameter of 200 mm, the rotation speed is 4000 rpm, and the atmosphere is Ar of 10 −3 torr or less.

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 Composition represented by Al99-a-bVaCobCe1 (atomic ratio)
The master alloy of was melted in an arc melting furnace, and a thin strip (thickness: 20 μm, width 1.5 mm) was manufactured under the same manufacturing conditions as in Example 1. The strength of each manufactured ribbon was measured at room temperature by an Instron type tensile tester. Also,
The ductility of the alloy was examined by performing 180 ° close contact bending. The results are shown in Table 1.

[0024]

[Table 1] Composition (at%) Tensile strength 180 ° Adhesion Al V Co Ce (MPa) Bending Inventive example 1 Remaining 2 1 1 430 Possible Inventive example 2 Remaining 2 1.5 1 870 Possible Inventive example 3 Remaining 2 2 1 920 Possible Present invention example 4 Remaining 3 1 1 1020 Possible Present invention example 5 Remaining 3 1.5 1 1240 Possible Present invention example 6 Remaining 3 2 1 1190 Possible Present invention example 7 Remaining 3 2.5 1 1200 Possible Present invention example 8 Remaining 3 3 1 865 Possible Present invention example 9 Remaining 4 1 1 1150 Possible Present invention example 10 Remaining 4 1.5 1 1220 Possible Present invention example 11 Remaining 4 2 1 1080 Possible Present invention example 12 Remaining 4 2.5 1 980 Possible book Invention Example 13 Remaining 5 1 1 1040 Possible Comparative Example 1 Remaining 8 1 1 980 Impossible Comparative Example 2 Remaining 7 1 1 620 Impossible Comparative Example 3 Remaining 0 1 1 190 Possible

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 Al94.5V3 M1.5 Ce1 was melted in an arc melting furnace, and a ribbon was manufactured under the same manufacturing conditions as in Example 1. 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 prepared 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 by an extruder at an extrusion ratio of 10: 1 at a temperature of 1350 to 600 ° C. The extruded material (solidified material) obtained under the above production conditions was examined for 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). The results are shown in Table 2.

[0030]

[Table 2] 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 ) 14 Residual V = 1.0 Co = 3.0 Ce = 1.0 288 720 19.5 310 15 Remaining V = 1.5 Fe = 3.0 Y = 1.0 290 830 15.5 335 16 Remaining V = 3.0 Co = 1.5 Ce = 1.0 340 1030 18.0 350 17 Remaining V = 3.0 Fe = 1.5 Mm = 1.0 338 950 16.0 340 18 Remaining V = 3.0 Co ＝ 1.0 Ce ＝ 1.0 275 720 18.2 280 Cu ＝ 1.0 19 Remaining V ＝ 4.0 Co ＝ 1.5 Ce ＝ 1.0 294 880 17.6 305 20 Remaining V ＝ 5.0 Cu ＝ 1.0 Y ＝ 1.0 308 960 13.9 310 21 Remaining Mo ＝ 2.5 Ni ＝ 1.5 La ＝ 1.0 292 980 16.3 305 22 Residual Mo ＝ 3.0 Co ＝ 1.5 Ce ＝ 1.0 330 1020 17.5 335 23 Residual Mo ＝ 3.0 Ni ＝ 1.0 Y ＝ 1.0 285 910 16.5 315 Cu ＝ 0.5 24 Residual Mo ＝ 4.0 Fe ＝ 1.0 Mm = 1.5 299 890 13.8 325 25 Remaining Mo = 4.0 Ni = 1.0 Y = 1.0 291 880 14.6 320 26 Remaining Mo = 4.0 Co = 1.0 Ce = 1.0 318 960 13.0 310 Ni = 1.0 27 Remaining Mo = 5.0 Co = 1.0 Mm = 1.0 330 980 12.5 320 28 Remaining Mo ＝ 6.0 Fe ＝ 0.5 Y ＝ 0.5 293 950 12.3 315 29 Remaining W ＝ 1.0 Co ＝ 3.0 Mm ＝ 1.0 301 920 13 .3 315 30 Remaining W = 2.0 Fe = 3.0 Mn = 1.0 325 940 12.9 330 31 Remaining W = 3.0 Co = 1.5 Ce = 1.0 330 1010 11.9 320 32 Remaining V = 1.5 Co = 1.5 Y = 1.0 315 990 15.8 320 Mo = 1.5

[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.

Front Page Continuation (71) Applicant 000004075 Yamaha Corporation 10-1 Nakazawa-cho, Hamamatsu City, Shizuoka Prefecture (72) Inventor Ken Masumoto 3-8-22 Uesugi, Aoba-ku, Sendai City, Miyagi Prefecture (72) Inventor Akihisa Inoue 11-806 (72) Kawauchi House, Aoba-ku, Aoba-ku, Sendai City, Miyagi Prefecture Inventor Hisamu Kimura 44 Fujiwara Bridge, Arahama, Watari Town, Watari-gun, Miyagi Prefecture (72) Kenichiro Sasamori 56-1, Kakuda Town, Kakuda City, Kakuda City, Miyagi Prefecture ( 72) Inventor Yoshiyuki Shinohara, 1-9-9 Yaesu, Chuo-ku, Tokyo Within Imperial Piston Ring Co., Ltd.

Claims (9)

[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 <c ≦ 5),
A high-strength aluminum-based alloy characterized by containing quasicrystals in its 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), a regular decagonal (D phase), or an approximate crystal phase thereof, the high-strength aluminum-based alloy according to claim 1. 4. The quasicrystal contained in the tissue has a volume ratio of 20.
The high-strength aluminum-based alloy according to any one of claims 1 to 3, wherein the high-strength aluminum-based alloy is 70% to 70%. 5. The high-strength aluminum-based alloy according to any one of claims 1 to 4, wherein the structure thereof comprises a quasicrystal and a phase composed of any one of amorphous, aluminum, and a supersaturated solid solution of aluminum. 6. The high-strength aluminum-based alloy according to claim 5, wherein the structure further contains an intermetallic compound of aluminum and another element and / or an intermetallic compound produced by the other elements. . 7. The high-strength aluminum-based alloy according to any one of claims 1 to 6, which is a rapidly solidified material. 8. The method according to claim 1, wherein the rapidly solidified material is heat treated.
The high-strength aluminum-based alloy as described in any one of 1 above. 9. The method according to claim 1, wherein the rapidly solidified powder is extruded.
The high-strength aluminum-based alloy as described in any one of 1 above.