JPH0748601A - High hardness and wear resistant aluminum powder alloy and method for producing the same - Google Patents

Abstract

(57) [Summary] (Correction) [Purpose] To obtain an aluminum alloy material having high strength and wear resistance that can withstand sliding without surface treatment as a sliding part, and to obtain the material with extremely high economical efficiency. I will provide a. [Structure] General formula Al-a-Si-b-T-c-X-d
-Cu-e-Mg (however, T; either one or both elements of Fe and Ni, X; Ti, Cr, V, Mo, Zr
One or more elements of, and a, b, c,
d and e are respectively in% by weight: a; 5 to 15%, b; 5-1
2%, c; 2-6%, d; 0.4-8%, e; 0.2-
It is 4% and the balance is substantially aluminum, alloy powder is cold-formed or warm-formed at 300 ° C. or lower, and the powder compact is put into a mold (mortar) whose inner surface temperature is kept at 350 ° C. to 550 ° C. Insert one or both or 3
3 seconds to 6 at a pressure of 4 to 10 t / cm ² by an upper die (upper punch) and a lower die (lower punch) held at 50 ° C to 550 ° C.
It is hot pressed and solidified to a true density ratio of 97% or more by 0 second compression.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an aluminum powder capable of producing a high-density aluminum powder alloy having excellent physical properties and mechanical properties, particularly high hardness and excellent wear resistance with high economic efficiency. The present invention relates to a method for manufacturing an alloy. The fields of application of the aluminum powder alloy of the present invention include vanes, shoes, side plates and the like of compressor parts, oil pump rotors and the like of automobile parts, and sliding parts such as rollers, gears and bearings of office equipment.

[0002]

2. Description of the Related Art Conventionally, iron-based materials have been used for compressor parts, automobile oil pumps, rollers, gears, bearings and the like. However, the weight of iron-based materials has become a problem, and in recent years, automobile-related equipment has become lighter and more efficient,
Or, it has become impossible to meet the demand for higher performance of office equipment. In particular, when it is used for a member that slides at a variable speed or a high speed, the inertial force / centrifugal force at the time of acceleration / deceleration due to sliding or rotation increases in proportion to the mass, and these forces are equal to 2% of the angular velocity of rotation. Since the size increases in proportion to the power, if the speed is increased with iron-based materials, it is necessary to make the entire equipment and device large and extremely robust, and there is a concern that the efficiency of the device itself may be impaired.

Therefore, the material of interest is a low specific gravity material, but magnesium, which is the lightest material, has a too large thermal expansion coefficient to match with peripheral members and has a low hardness, so that it is a sliding member. As it can not stand at all.
Next, addition of a large amount of silicon to a lightweight aluminum alloy in order to reduce thermal expansion and improve wear resistance was investigated by various manufacturing methods. First of all, it was examined by melting technology such as melting casting, melting rolling, continuous casting, etc., but hard alumite treatment and Ni
-Wear resistance that can withstand use as a sliding member that replaces iron-based materials without surface treatment such as P plating has not been realized.

Therefore, attempts have been made to increase the addition amount of alloying components of transition elements by improving the solidification rate in the melting and casting method, but there is a limit to the amount of fine intermetallic compounds that can be dispersed. , Fe-based, Ni-based, and F-based, which have an effect on wear resistance without deteriorating strength and toughness
The total amount of aluminide such as e-Ni that can be finely dispersed is limited to about 4.0 wt%, and if the amount of addition exceeds this limit, coarse crystallized substances or precipitates will be produced at the solidification rate of the melting and casting method. An object is generated and strength is deteriorated. As for the elements of Zr, Ti, Mo, and V, as described above, the matrix is hardened by fine precipitates by adding a small amount to further improve the wear resistance, but in the case of the melt casting method, the total addition amount is 1 wt%. If it exceeds, the strength will be reduced. It is difficult to add these elements such as Fe, Ni, Mo, Ti, Zr, and V due to problems such as segregation in the molten metal in actual operation, and even if added at the same time as Si, they are replaced by iron-based materials without surface treatment. No wear resistance is realized.

Therefore, by solidifying the rapidly solidified aluminum alloy powder as a raw material by the powder metallurgy method, it is possible to manufacture a high silicon-containing alloy and a high transition element alloy which cannot be obtained by the melting method, and wear resistance is improved. Studies have been conducted to improve the characteristics. In order to sinter such an aluminum alloy-based high alloy powder, it is possible to diffuse the metal atoms by breaking the strong non-reducible oxide film on the surface of the alloy powder and forming a metal contact part between the powders. The key point is whether or not this is possible. Conventionally, this method has been largely divided into the following two methods.

One is a method of mixing a sintering aid,
This is a powder having an alloying component that generates a eutectic liquid phase at a temperature lower than the melting point of aluminum or an aluminum alloy composition is added and mixed as a sintering aid to a raw material, and compression molded,
Furthermore, the eutectic liquid phase is generated from the metal contact portion between the sintering aid formed in the compact and the aluminum powder or aluminum alloy powder during the temperature rising process of the sintering process, and the metal contact portion is enlarged and baked. It is a method of advancing the conclusion.

As a method for producing such a sintered alloy containing 10% by weight or more of alloying elements, Japanese Patent Publication No.
No. 209 is a eutectic liquid phase Al-11.7 wt% Si
Manufacture of a sintered body containing Si in a total amount of 20 to 50% by mixing Al-Si binary alloy powder having a composition in the vicinity with metallic Si powder as a sintering aid and alloy component powder as required. Law, and in Japanese Examined Patent Publication No. 59-37339, Al-10
A method for producing a high Si-containing sintered body has been proposed in which Cu, Mg, and Si components are added as a single composition powder or an alloy composition powder to a Si powder of up to 35% by weight. Is not a level that can be used for its intended purpose.

The other method of applying plastic working is a method recently developed as a new powder metallurgical technique, and is a physical method of joining powders by plastic deformation. By subjecting the powder to strong plastic working, the powder is plastically deformed, the oxide film on the surface of the powder is broken and divided, and adjacent powder particles are connected to form a metal contact portion. This method does not require a sintering aid because it breaks the oxide film by a physical method. As the plastic working method, a hot pressing method, a powder forging method, a powder extrusion method, a powder rolling method and the like are used. In addition, since the plastic working method can perform the plastic working in a relatively low temperature range, it is possible to obtain a high-density alloy that retains the effect of rapid solidification to some extent. JP-A-60-121203
No. 1 proposes a method of extruding aluminum alloy powder at a temperature of 250 to 550 ° C. and an extrusion ratio of 4: 1 to 15: 1. Since the aluminum alloy powder is extruded by a strong shearing force, the oxide film on the powder surface is broken and the metal inside the adjacent powder particles is bonded.

Further, Japanese Unexamined Patent Publication No. 61-136602 proposes a method of hot pressing aluminum alloy powder and hot pressing, and Japanese Unexamined Patent Publication No. 62-224602 proposes a manufacturing method by sintering forging. . However, even in these cases, the hardness of the obtained alloy is limited to about 200 to 250 MHv, and in terms of wear resistance, it is not a material that can be replaced with an iron-based material without surface treatment. Further, in the production by these powder metallurgy methods, expensive heating equipment is required in the heating step before the sintering step and the plastic working step, and a large amount of energy is required for heating.

In addition, abrasion resistance is improved by forming a composite material in which particles and fibers such as ceramics are dispersed by a conventional melt casting method or a powder metallurgy method as disclosed in JP-A-60-50138. Attempts have also been made, but the hardness of the matrix portion is 200 MHv or less, and adhesion wear occurs in the matrix portion during sliding, which is not practical.
Therefore, except for sliding materials that have a very small load, when aluminum alloy is used as the sliding material, one side must be surface-treated, for example, Ni-P plating or CrN coating,
Iron spraying is applied. These treatment methods are not only expensive, but also require that the surface portion be subjected to finishing processing such as polishing again. Needless to say, if the surface treatment layer is lost during use, the material will immediately lose reliability.

Therefore, the inventor of the present invention filed on May 21, 1993, "Highly Hard Wear-Resistant Aluminum Powder Alloy and Method for Producing the Same", contains rapidly solidified aluminum alloy powder in a mold maintained at a predetermined temperature. We proposed a method to directly solidify powder and to compact and solidify the powder by instantly raising the temperature by heat conduction from the mold and compressing it. As a result, Young's modulus is 100 GPa or more and Vickers hardness is 350M.
We have developed a high hardness and wear resistant aluminum powder alloy that is Hv or higher. However, depending on friction sliding conditions, sample shape, and the like, a high load may act during sliding, such as a vane for a compressor, and high strength characteristics, particularly bending strength are required. Specifically, a bending strength exceeding 600 MPa may be required, but it has been difficult to achieve a bending strength exceeding 600 MPa with the wear-resistant aluminum alloy member obtained by the manufacturing method of the above patent. .

[0012]

The present invention has a wear resistance comparable to that of an iron-based material capable of withstanding sliding without surface treatment for the purpose of wear prevention, and has a high level of use for the intended use field. The production of an aluminum powder alloy material having transverse rupture strength is to be realized at an extremely high economical efficiency as compared with the conventional powder metallurgy production method.

[0013]

As a result of various experiments and studies, the present inventors have developed a method for manufacturing a sliding member made of an aluminum alloy having excellent wear resistance. The contents of the configuration will be described below. (1) A high hardness wear-resistant aluminum powder alloy having a Young's modulus of 100 GPa or more, a Vickers hardness of 350 MHv or more, and a transverse rupture strength of 650 MPa or more. (2) General formula Al-a-Si-b-Tc-Xd-Cu
-E.Mg (however, T: either one or both of Fe and Ni elements, X: one or more elements of Ti, Cr, V, Mo, Zr, and a, b, c , D, e
Are in weight%, respectively; a; 5 to 15%, b; 5 to 12%,
c; 2 to 6%, d; 0.4 to 8%, e; 0.2 to 4% with the balance being substantially aluminum and inevitable impurities). ) High hardness and wear resistance aluminum powder alloy. (3) An aluminum alloy having the above composition, wherein the Si component is a Si crystal having a grain size of 1 μm or less, and the T component is Al and A having a longest diameter portion of 3 μm or less.
1-Fe, Al-Ni, Al-Fe-Ni based intermetallic compound, wherein the X component has a particle size of 1 μm or less, and these components are uniformly dispersed in the matrix in the above-mentioned form. The high-hardness wear-resistant aluminum powder alloy according to (2) above, which is characterized by the above. (4) In the aluminum powder alloy having the composition described in (2) above, at least one kind of hard particles selected from carbides, oxides, and nitrides having a maximum particle size of 20 μm and an average particle size of 10 μm or less, The high-hardness wear-resistant aluminum powder alloy according to (2) or (3) above, which is uniformly dispersed in the base material in an amount of 2 to 40% by volume.

(5) Further, the rapidly solidified aluminum alloy powder as the raw material powder or the mechanically pulverized and reaggregated aluminum alloy powder is cold-formed or warm-formed at 300 ° C. or less, and the powder compact is heated to the inner surface temperature. 350 ° C-550
Inserted in a mold (mill) held at ℃, and press either one or both at 350 ℃ ~ 550 ℃ upper mold (upper punch) and lower mold (lower punch) pressure 4 ~ 10t / c
A true density ratio of 97 is obtained by pressurizing and compressing at m ² for 3 seconds to 60 seconds.
% Hot forming and solidifying, the method for producing a high-hardness wear-resistant aluminum powder alloy according to the above (1). (6) After the powder is solidified by pressing and compression, the powder solidified body is 30
The method for producing a high-hardness wear-resistant aluminum powder alloy according to the above item (5), which comprises heating to 0 to 500 ° C. for 0.5 to 4 hours or further cooling with water and then aging treatment at 200 ° C. or less. (7) The rapidly solidified aluminum alloy powder or the mechanically pulverized and re-agglomerated aluminum alloy powder as the raw material has the general formula A
la-Si-b-Tc-Xd-Cu-e-Mg
(However, T: either one or both elements of Fe and Ni, X: one or more elements of Ti, Cr, V, Mo, Zr, and a, b, c, d, e 5% to 15%, b; 5 to 12%, and c; 2 to 6 in% by weight, respectively.
%, D; 0.4 to 8%, e; 0.2 to 4%, the balance being substantially aluminum and unavoidable impurities) (5) (6) above A method for producing the high hardness wear-resistant aluminum powder alloy described. (8) The above-mentioned (5) to (7), wherein the solidification rate of the rapidly solidified aluminum alloy powder as the raw material powder is 10 ³ ° C / sec or more and does not exceed 10 ⁶ ° C / sec. For producing a high hardness and wear resistant aluminum powder alloy. (9) The rapidly solidified aluminum alloy powder, which is a raw material powder, is a powder produced by a spraying method and has a maximum particle size of 150 μm or less and an average particle size of 50 μm or less. The method for producing a high hardness and wear resistant aluminum powder alloy according to the item 8). (10) The rapidly solidified aluminum alloy powder or the mechanical reaggregation-treated aluminum alloy powder, which is the raw material powder, has a fluidity of 60 seconds / 50 g or less at the orifice 4 mmφ as it is or by mechanical granulation processing or mixing processing. The method for producing a high-hardness wear-resistant aluminum powder alloy according to the above (5) to (9), characterized in that (11) The rapidly solidified aluminum alloy powder or mechanically ground reaggregated aluminum-based composite powder, which is the raw material powder, is
Before powdering in cold forming or warm forming described in item (5) 3
Above (5) characterized by being heated below 00 ° C
A method for producing a high hardness wear-resistant aluminum powder alloy according to any one of (1) to (10). (12) In the rapidly solidified aluminum alloy powder or mechanically pulverized reaggregated aluminum-based composite powder having the composition according to (7), after adding and mixing the hard particles according to (4), mechanical pulverization The above (7) to (11) characterized by using a rapidly solidified aluminum alloy powder or mechanically ground reaggregated aluminum-based composite powder in which these particles are uniformly dispersed in the matrix by a combination of mixing and reaggregation methods
A method for producing a high-hardness wear-resistant aluminum powder alloy according to the item. (13) In the molten aluminum alloy having the composition according to the item (7), the hard particles according to the item (4) are added, and these particles are uniformly dispersed in the molten metal by a melting casting method or an induction melting method. After that, characterized by using the rapidly solidified aluminum alloy powder or mechanically pulverized reaggregated aluminum-based composite powder produced by the spraying method (7) to
The method for producing a high hardness wear-resistant aluminum powder alloy according to the item (11). The above mechanical pulverization / mixing / re-aggregation method specifically means a mixing / pulverization means including a mechanical alloying method, a mechanical grinding method, and a granulation method.

As an aluminum alloy material having wear resistance comparable to an iron-based material capable of withstanding sliding without surface treatment for the purpose of wear prevention for the intended use field, adhesion wear during sliding In order to prevent this, it is necessary for the matrix to have the same hardness as that of the iron-based material or surface-treated coating. In order to obtain such high hardness, it is necessary to use powder having high hardness as a raw material. There are the following two means to realize a hardness of 350 MHv or more with Vickers hardness using aluminum as a matrix. One is a rapid solidification method and the other is a mechanical pulverization and agglomeration method. These improve the hardness by finely dispersing thermally metastable or non-equilibrium precipitates or crystallized substances in the powder for dispersion strengthening, or by solid solution strengthening the alloy components by supersaturation. Is the way.

On the other hand, in order to produce a rapidly solidified aluminum powder alloy member having high strength characteristics by a powder metallurgy process, the oxide film on the powder surface is destroyed to expose a new surface, and a strong bond between the powder particles is formed. To make it happen. For that purpose, it is effective to raise the temperature of the powder to a temperature range in which it can be plastically deformed as much as possible without damaging the rapidly solidified structure and to divide / break the oxide film by pressurization / compression. It is desirable that the powders are as close to each other as possible in a state where the powders are heated and heated.
Therefore, when heating the rapidly solidified aluminum alloy powder, the bulk state obtained by temporarily molding the powder is superior to the state of the powder in thermal conductivity, which is advantageous for raising the temperature in a short time.

That is, according to the present invention, the powder molded body inserted only by heat transfer from the heated mold is instantly heated to a temperature range where plastic deformation is possible and solidified by pressurization and compression.
Solidified into a near net shape in the warm forming process with minimal loss of metastable / non-equilibrium structural characteristics obtained by rapid solidification and mechanical pulverization / re-agglomeration with minimal consumption of heat energy. The feature is that they found something to do. As a result, a high hardness aluminum alloy material having a thermal expansion coefficient close to that of an iron-based material is realized, and a sliding member having extremely excellent wear resistance is obtained.

In the present invention, the composition of the aluminum powder alloy,
Precipitates in the matrix, alloy powder properties and manufacturing conditions are limited. The meaning of these limitations is explained below.

1. Aluminum powder alloy composition, precipitates in the matrix, alloy powder characteristics

(1) Composition of aluminum powder alloy / precipitate in the base material, the rapidly solidified aluminum alloy powder or the mechanically pulverized and reaggregated aluminum alloy powder used here has the general formula Al
-A-Si-b-T-c-Xd-Cu-e-Mg (however, T; either one or both of Fe and Ni elements,
X: one or more elements of Ti, Cr, V, Mo, and Zr, and a, b, c, d, and e are each weight% a: 5 to 15%, b; 5 to 12 %, C; 2-6%,
The composition is such that d: 0.4 to 8%, e: 0.2 to 4%, and the balance is substantially aluminum and unavoidable impurities).

[Addition of Si] Since Si is a kind of hard particles, it has an effect of improving wear resistance and rigidity of the solidified body by being finely and uniformly dispersed in the base material. If the amount added is less than 5% by weight, no sufficient effect can be obtained. From the viewpoint of the strength and toughness of the solidified body, it is desirable that the grain size of the primary crystal Si dispersed is 1 μm or less, but if it is added in excess of 15% by weight, the strength and toughness of the solidified body due to the coarsening of the Si crystal will be improved. Induce a decline. Therefore, Si
The addition amount is preferably 5 to 15% by weight.

[Addition of Fe and Ni] Fe and Ni have the effect of improving the heat resistance and rigidity of the powder solidified body by forming a metastable phase / non-equilibrium phase with fine aluminum. In other words, by improving the heat resistance, seizure with the mating material during sliding is greatly suppressed, so Fe and Ni
Is required to be added. For that purpose, it is desirable that the addition amount of one or both of Fe and Ni is 5 to 12% by weight. If the addition amount is less than 5% by weight, sufficient heat resistance and rigidity cannot be obtained, and the seizure resistance of the powder solidified product deteriorates. Also, the strength of the solidified body
Al-Fe based, Al-Ni based, dispersed from the viewpoint of toughness,
The size of the intermetallic compound such as Al-Fe-Ni system is 3 μm
Hereafter, it is preferably 1 μm or less, and it is necessary that it has a spherical shape. However, when it is added in an amount of more than 12% by weight, the above intermetallic compound becomes acicular and coarse, and thus a solidified body is formed. However, there arises a problem that the strength and toughness of the steel deteriorate.

[Addition of Ti, Cr, V, Mo, Zr] Since these refractory metal elements are thermally stable and hard, the grain size in the matrix is 1 μm, preferably 0.5.
The uniform dispersion of less than or equal to μm has the effect of improving the heat resistance and hardness of the solidified body. To do that, Ti,
It is desirable to add 2 to 6% by weight of one or more elements selected from Cr, V, Mo and Zr. If the addition amount is less than 2% by weight, the above effect cannot be sufficiently obtained. Further, if it is added in an amount of more than 6% by weight, the temperature for spraying becomes high as well as the problem that the strength of the powder solidified body is reduced due to embrittlement, which causes an economical problem due to an increase in power consumption during melting.

[Addition of Mg] In the present invention, the addition of Mg is important. Mg has a function of reducing when the oxide film formed on the powder surface at the time of spraying is solidified, and expands the metal contact portion to accelerate the sintering phenomenon. If the added amount of Mg is less than 0.2% by weight, the above effect becomes insufficient. On the other hand, if it exceeds 4% by weight, it tends to be affected by the temperature, and the heat resistance and hardness of the base material are deteriorated. Therefore, the desirable Mg content is 0.2 to 4% by weight.

[Addition of Cu] In the present invention, Cu improves the corrosion resistance of the powder solidified body and coexists with Mg at a temperature of 300 to 500 ° C. for 0.5 to 4 hours for solution treatment, and at 200 ° C. or less. The mechanical properties can be improved as necessary by performing the aging treatment of. C
If the amount of u added is less than 0.4% by weight, the above-mentioned effects will be insufficient. On the other hand, if it exceeds 8% by weight, it is likely to be affected by the temperature in the use environment, and the heat resistance and hardness of the base material are deteriorated. Therefore, the desirable Cu content is 0.4 to 8
% By weight.

(2) Quenching degree of spray powder (solidification rate) In the present invention, the solidification rate of the molten aluminum alloy during the production of the spray powder is important. By the rapid solidification, the metastable phase and fine precipitates / crystallized substances as described above are formed in the raw material powder, or a supersaturated solid solution is formed. If the solidification rate is less than 10 ³ ° C / sec, the powder solidified body becomes brittle due to the coarsening of the precipitation phase, resulting in a significant decrease in strength, and the effects described above become insufficient, resulting in excellent wear resistance. Since it becomes difficult to produce a sliding member made of a high hardness aluminum alloy having properties, it is essential that the solidification rate is 10 ³ ° C / sec or more. However, it is desirable that the solidification rate of the sprayed powder does not exceed 10 ⁶ ° C / second because of the economical problem that it is difficult to spray / collect fine rapidly solidified powder that exceeds 10 ⁶ ° C / second with good yield.

(3) Particle Size of Spray Powder When a powder is produced by a spray method, the particle size of the spray powder and the solidification rate are closely related. In other words, the finer the sprayed powder, the higher its solidification rate (quenching rate), so that the fine metastable phase / non-equilibrium phase and precipitates / crystallized substances are easily dispersed uniformly in the powder, As a result, the characteristics of the powder solidified body are improved. Specifically, in the spray powder of the present invention, the maximum particle size is 150 μm or less, and the average particle size is 50 μm.
It is preferably m or less. Maximum particle size of spray powder is 1
If it exceeds 50 μm or if the average grain size exceeds 50 μm, it becomes difficult to obtain the fine precipitates described above, and as a result, it becomes impossible to obtain a high hardness and wear resistant aluminum powder alloy.

(4) Hard particles in sprayed powder Especially when improvement of mechanical and physical properties is required, it can be improved by uniformly dispersing fine hard particles. As the dispersed particles, any particles that can improve the thermal expansion coefficient, rigidity, strength, wear resistance and the like by forming a composite may be used, and it is desirable that the dispersed particles do not decompose, diffuse or condense by sintering. Hard particles selected for this purpose are the following carbides, oxides,
Nitride and the like. Carbides: Aluminum Carbide, Silicon Carbide, Titanium Carbide, Boron Carbide, etc. Oxides: Alumina, Silica, Mullite, Zinc Oxide, etc. Nitride: Aluminum Nitride, Silicon Nitride, Titanium Nitride, etc.

[Particle Size of Dispersed Particles] Particle size is a weight factor. Macroscopically, in order to improve wear resistance and strength by dispersing hard particles, it is desirable that the particle size is 20 μm or less in maximum particle size and 10 μm or less in average particle size. It is difficult to obtain the above effects sufficiently by dispersing hard particles having a size exceeding such a range. On the other hand, when viewed microscopically, the dispersed particles also have the effect of stopping the movement of dislocations. In this case, a fine particle size of 0.1 to 1 μm is desirable.

[Amount of Dispersed Particles] In order to obtain the above effect, the amount of dispersed particles is preferably 2 to 40% by volume. Sufficient hardness, strength, rigidity, etc. cannot be obtained with the addition of less than 2% by volume, while on the contrary, the toughness of the solidified body is reduced when the addition is over 40% by volume.

[Means for Adding Dispersed Particles] As a means for adding dispersed particles, a mixing method of mixing these dispersed particles with a raw material powder is economical and easy, and is effective for improving physical property values. However, in the simple mixing method, the dispersed particles exist only in the original grain boundaries of the powder, the particles cannot be dispersed in the powder, and it is difficult to improve the characteristics by dispersing the particles. Further, when fine particles are dispersed, it hinders the sintering bond between the powder particles and is not suitable. To solve this, it is effective to disperse the dispersed particles in the powder particles,
There are the following two methods.

A method of powderizing a molten metal containing dispersed particles during powder production. This is a method in which a molten metal containing particles is pulverized by a rapid solidification method. Since the particles are added before pulverization, the particles are dispersed inside the powder. In order to prevent the particles from segregating or agglomerating, it is necessary to use an ingot produced by a melt casting method and which contains dispersed particles uniformly, or to add the dispersed particles to a molten metal to induce induction melting with a high stirring ability. A method of mechanically pulverizing and reaggregating a mixed powder to which dispersed particles are added. This is a method of adding particles to a rapidly solidified powder, mechanically crushing and re-aggregating. By this mechanical pulverization and reaggregation treatment, the added particles can be finely and uniformly integrated into the aluminum alloy powder particles. It is also possible to generate and disperse carbides, oxides or nitrides during the treatment by mechanical pulverization reaggregation treatment. This treatment is carried out by a dry method rather than a conventional wet method such as ball milling or mixing. In some cases, excessive aggregation may be prevented by adding a small amount of stearic acid or alcohol as a PCA (Process Control Agent). Attritors, vibration mills and planetary mills are suitable for high-speed processing. On the other hand, the ball mill requires a long treatment time, but the atmosphere control is easy, and it is relatively economical if the input energy is properly designed.

(Production conditions) (1) Cold molding of spray powder or warm molding at 300 ° C. or lower, [Flowability of spray powder] In the manufacturing method of the present invention, first, the spray powder is fed to a mold. Solidifies into a near net shape. As a result, economic effects such as improvement of raw material yield and reduction of processing cost can be expected. However, in order to realize this, flowability and filling property for powder are required. When the particle size of the sprayed powder is small, the fluidity of the powder into the mold becomes a problem. Specifically, in order for the manufacturing method of the present invention to economically produce a sliding member in a mass production process, the powder flowability is such that the powder fluidity at an orifice of 4 mmφ is 60 seconds / 50 g or less. Is desirable. However,
If the rapidly solidified aluminum alloy powder used or the mechanically pulverized and reaggregated aluminum alloy powder does not satisfy this condition, the powder is mechanically granulated and mixed to maintain the rapid cooling rate and physical properties of the powder. It is desirable to improve the fluidity in this state.

[Formability / Compressibility of Sprayed Powder] Depending on the alloy composition, the powder as sprayed has a high hardness, so it is necessary to feed the powder into the mold and pressurize it to ensure sufficient formability / compressibility. May require high molding pressure in the powder solidification process. Therefore, there arises a problem of economical efficiency such that the mold is worn or damaged and the life is shortened. Therefore, in the present invention, in the case where it is necessary to improve the moldability and compressibility of the spray powder, the preheat treatment before the powder feeding to the mold of the spray powder is effective in the range that does not deteriorate the characteristics of the powder. . As shown in Table 1, it can be seen that preheating significantly improves the moldability at room temperature, and a high powder compact density can be obtained even with a low compaction pressure.

[0035]

[Table 1]

(Preheating condition) Maintaining 24 hours at 220 ° C. in the atmosphere. Holds 24 hours at 300 ° C in the atmosphere. Powder alloy composition: Al-12Si-5Fe-6Ni-2
Cr-2Mo-3.5Cu-1Mg (weight% display).

As a result of various experiments, the powder temperature was set to 300 ° C. as a specific condition that can improve the moldability and compressibility without impairing the characteristics of rapid solidification of the sprayed powder.
It has been found that performing warm forming under the following conditions is effective. As a means for realizing this, the sprayed powder is preheated in advance to heat the powder to an extent that the powder temperature does not exceed 300 ° C. to soften the powder, and then the powder is molded. The mold is heated, and the sprayed powder is fed to the mold so that the temperature of the powder does not exceed 300 ° C. In such warm forming, the temperature of the sprayed powder is 300 ° C.
If it exceeds, the fine metastable phase, non-equilibrium phase, etc. in the sprayed powder cause phase conversion and coarsening, and as a result, strength is reduced due to remarkable embrittlement. Regarding the atmosphere in which the sprayed powder is preheated / annealed, the treatment at an atmospheric temperature of less than 250 ° C. may be performed in the air, nitrogen, or a reducing atmosphere, but the treatment at 250 ° C. to 300 ° C. It is desirable to perform in a nitrogen or reducing atmosphere from the viewpoint of suppressing the oxidation of the spray powder. (2) Hot forming and solidification by a heated mold

[Mold temperature: 350 to 550 ° C.] As described above, the feature of the powder solidification method according to the present invention is that aluminum alloy powder molding is inserted into the mold only by heat transfer from the mold held at high temperature. This is to instantly raise the temperature of the body to a temperature range in which it can be plastically deformed and to bond and solidify the powders. As a result, the transverse rupture strength of the powder solidified body can reach 650 MHv or more. In order to realize this, one or both of the upper mold and the lower mold that come into contact with the powder compact should be 35
0 ° C to 550 ° C and the die temperature is 350 ° C
It is essential that the temperature is 550 ° C. or higher. In the case of a low mold temperature that does not satisfy this temperature condition, the powder cannot be plastically deformed sufficiently, so the bonding force between the powders is small, and as a result, the strength of the powder solidification after pressurization
Toughness is significantly reduced. On the other hand, if the mold temperature exceeds 550 ° C., the metastable phase / non-equilibrium phase of the powder will be impaired, and the precipitates and crystallized substances dispersed in the matrix will become coarse, resulting in powder solidification. The hardness of the body is 350 Vickers hardness
It becomes impossible to achieve MHv or higher, and as a result, the wear resistance is significantly reduced and it cannot be used as a sliding member. still,
As a method for raising the temperature of the die (upper / lower punches and dies), a method of inserting a heater in each part, a direct induction heating method by high frequency, etc. are effective.

[Hot solidification pressure: 4 to 10 t / cm ² ] In order to secure the solid bonding state of the powders by plastically deforming the powder compact in the heated die as described above, It is essential that the solidification pressure is 4 t / cm ² or more and 10 t / cm ² or less. When the pressure is less than 4 t / cm ² , the powders are not firmly bonded to each other, and the strength of the powder solidified body is lowered. On the other hand, even if the pressure exceeds 10 t / cm ² , a stronger binding force cannot be obtained and the strength of the powder solidified product is saturated. On the contrary, when the pressure is increased, the wear of the mold and the seizure of the powder on the mold wall remarkably progress, so that the life of the mold is shortened, which causes an economic problem.

[Pressure time: 3 seconds to 60 seconds] The aluminum alloy powder compact, which was inserted only by heat transfer from the mold, was instantly heated to a temperature range in which it could be plastically deformed, and the powders were firmly bonded together. In order to solidify, the mold is held in the above temperature range while being pressed and compressed by the upper mold and the lower mold, and in order to mold and solidify, the pressing time at this time is 3 to 60 seconds. Mandatory. If the pressing time is shorter than 3 seconds, the powder cannot be heated to a temperature at which it can be sufficiently plastically deformed, so that the binding force between the powders becomes small, and as a result, the strength of the powder solidified body after pressing is increased. Is significantly reduced. On the other hand, pressurization time is 6
If the time exceeds 0 seconds, the metastable phase / non-equilibrium phase of the powder will be impaired due to excessive heat transfer from the mold, so that the hardness of the powder solidified body cannot reach the Vickers hardness of 350 MHv or more. As a result, the wear resistance is remarkably reduced and it cannot be used as a sliding member.

[Density ratio: 97% or more] The powder solidified body obtained by the above steps has sufficient strength and toughness, and is present in the solidified body in order not to be affected by the atmosphere in the use environment. The holes to be formed must not be connected holes, that is, they must be independent holes. For this purpose, it is essential that the solidified body has a density ratio of 97% or more.

[0042]

【Example】

(Example 1) Aluminum alloy powder was preliminarily molded at room temperature with a powder molding die shown in FIG. 2, and this powder compact 9 was hot-molded and solidified with a die shown in FIG.
2 and 3 are the upper mold, the lower mold, and the die, respectively,
A plate-like powder solidified body 4 having a size of 40 × 15 × 5 mm was produced by applying pressure and compression. Here, the mold (upper and lower punch,
The temperature was raised by inserting the heater 5 in the die. As shown in Table 2, the solidification conditions of the powder are No. 1 to No. 1 of the present invention.
6 and was molded and solidified under the conditions of Nos. 17 to 24 as a comparative example. The aluminum alloy powder used was 10 ³
It is a spray powder having a solidification rate of -10 ⁶ ° C / sec and its alloy composition is NO.6 in Table 3.

[0043]

[Table 2]

[0044]

[Table 3]

Next, in order to evaluate the wear resistance of the solidified body thus obtained, a test was conducted with a pin-on-disc type wear tester as shown in FIG. 3 using eutectic cast iron as a counter material. . Regarding the test conditions, the eutectic cast iron as the mating material was used as the disk material 11 (rotation side shape 105 mmφ × 5 mm).
The rotation speed V is 10 m / sec, and the pin 10 (8 mmφ
× 15mm) side load P (arrow in the figure) is 5kg
The abrasion test was carried out in ATF oil, with the f / mm ² being constant. Table 4 shows the physical and mechanical properties (coefficient of thermal expansion, Vickers hardness, and pile breaking force) of the powder solidified body and the wear test results (measurement results of the wear amount of the powder solidified body and the counterpart material, eutectic cast iron). .

[0046]

[Table 4]

In Examples 1 to 16 of the present invention, the Vickers hardness of the powder solidified product is the target value of 350 MHv, and the transverse rupture strength sufficiently satisfies the target value of 650 MPa. Also in the results of the wear test, the amount of wear damage of the solidified powder itself and the eutectic cast iron material of the partner is small, and therefore the wear resistance and the attacking property of the partner are excellent. On the other hand, regarding Comparative Examples 1 to 8, Comparative Example 1; the powders were not sufficiently bonded to each other because the temperature of the upper and lower molds was low, and the strength of the solidified body was reduced, resulting in cracking of the solidified body during the abrasion test. . Comparative Example 2; As the temperature of the upper and lower molds was low, the powders were not sufficiently bonded to each other and the strength of the solidified body was reduced, resulting in cracking of the solidified body during the abrasion test. Comparative Example 3; The powder was not sufficiently bonded to each other due to the low temperature of the mortar, and the strength of the solidified body was lowered. As a result, the solidified body cracked during the abrasion test. Comparative Example 4; The powders were not sufficiently bonded to each other because the pressurizing time was short, and the strength of the solidified body was reduced. As a result, the sliding surface of the solidified body was partially damaged during the abrasion test. Comparative Example 5: Since the metastable phase / precipitated phase was coarsened by heating for a long time, and the powder solidified body was reduced in strength due to embrittlement,
The sliding surface of the solidified body was partially damaged during the abrasion test. Comparative Example 6; The metastable phase / precipitated phase was coarsened by heating for a long time, and the solidified powder had a strength reduction due to embrittlement.
The sliding surface of the solidified body was partially damaged during the abrasion test. Comparative Example 7: The powders were not sufficiently bonded to each other due to the low solidification surface pressure, and the strength of the solidified product was reduced. As a result, cracking occurred in the solidified product during the abrasion test. Comparative Example 8: Since the solidification pressure was too high, there was a problem that the powder solidified body was seized with the inner wall of the die. Comparative Example 9: The metastable phase / precipitated phase was coarsened due to the high molding temperature, and the powder solidified body was weakened due to embrittlement, and the sliding surface of the solidified body was partially damaged during the wear test. Comparative Example 10: The metastable phase / precipitated phase was coarsened due to the high molding temperature, and the powder solidified body had a decrease in strength due to embrittlement. Therefore, the sliding surface of the solidified body was partially damaged during the wear test.

(Example 2) At room temperature, an aluminum alloy powder was preliminarily molded with a powder molding die shown in FIG. 2, and this powder compact was hot-solidified with a die (upper / lower die) shown in FIG. And a mortar), and pressed and compressed to produce a plate-shaped powder solidified body of 40 × 15 × 5 mm.
Here, the temperature was raised by inserting a heater into the mold (upper and lower punches, dies). The alloy composition of the sprayed powder, the solidification rate, and the powder particle size (maximum / average) after spraying are as shown in Table 3. The present invention examples are Nos. 1 to 15, and N is a comparison.
The powder of o.16 to 33 was molded and solidified. In addition, as the solidification condition of the powder, No. 2 in Table 2 was applied.

Next, in order to evaluate the wear resistance of the solidified body thus obtained, a test was conducted by the same pin-on-disk wear test as described above in Example 1. Table 5 shows the physical / mechanical properties (coefficient of thermal expansion, Vickers hardness and transverse rupture strength) of the solidified powder and wear test results (measurement results of the amount of wear of the solidified powder and the eutectic cast iron as the mating material). .

[0050]

[Table 5]

In Examples 1 to 15 of the present invention, the Vickers hardness of the solidified powder is the target value of 350 MHv, and the transverse rupture strength sufficiently satisfies the target value of 650 MPa. Also in the results of the wear test, the amount of wear damage of the solidified powder itself and the eutectic cast iron material of the partner is small, and therefore the wear resistance and the attacking property of the partner are excellent. On the other hand, with respect to Comparative Examples 1 to 18, Comparative Example 1; sufficient rigidity because the amount of Si added is 0%
Hardness is not obtained, and as a result wear resistance is significantly reduced. Comparative Example 2 Sufficient rigidity and hardness could not be obtained because the amount of Si added was as small as 4%, resulting in a marked decrease in wear resistance. Comparative Example 3; The powder solidified body was embrittled due to a large Si addition amount of 17%, and as a result, the solidified body cracked during the abrasion test. Comparative Example 4; The powder solidified body was embrittled due to a large Si addition amount of 20%, and as a result, the solidified body cracked during the abrasion test. Comparative Example 5: Since the total amount of Fe and Ni added was as small as 4%, sufficient rigidity and hardness of the powder solidified body could not be obtained, and as a result, the wear resistance was significantly reduced. Comparative Example 6; Since the total amount of Fe and Ni added was as large as 14%, the powder solidified body was embrittled, resulting in cracking of the solidified body during the wear test. Comparative Example 7: Since the added amount of the refractory metal element X is 0%, sufficient hardness cannot be obtained, and as a result, the wear resistance is significantly reduced. Comparative Example 8: Since the total addition amount of the refractory metal element X is 1%, sufficient hardness cannot be obtained, and as a result, the wear resistance is significantly reduced. Comparative Example 9: The total addition amount of the refractory metal element X was as large as 9%, so that the powder solidified body was embrittled, and as a result, the solidified body cracked during the abrasion test. Comparative Example 10: Since the total amount of the refractory metal element X added was as large as 8%, the powder solidified body was embrittled, resulting in cracking of the solidified body during the abrasion test. Comparative Example 11: Since the amount of Cu added was 0%, sufficient strength of the powder solidified body was not obtained, and as a result, the sliding surface of the solidified body was partially damaged during the abrasion test. Comparative Example 12: Since the amount of added Mg was 0%, the powders were not sufficiently bonded to each other, which reduced the strength of the powder solidified body, and the sliding surface of the solidified body partially lost during the abrasion test. Example 13: The average particle size of the sprayed powder was 90 μm, and the solidification rate was less than 10 ³ ° C./sec. Therefore, the precipitation phase and the crystallization phase in the powder were coarsened and sufficient hardness could not be obtained. Abrasion resistance is significantly reduced. Comparative Example 14; the maximum particle size of the spray powder is 250 μm,
Since the solidification rate is less than 10 ³ ° C / sec, the precipitated phase / crystallized phase in the powder becomes coarse and sufficient hardness cannot be obtained, resulting in a marked decrease in wear resistance. Comparative Example 15: Since the total amount of hard particles added was 1% by volume, sufficient effect of improving rigidity and hardness was not obtained, and as a result, abrasion resistance was not further improved. Comparative Example 16: Since the total amount of hard particles added was as large as 50% by volume, the powder solidified body was embrittled, resulting in cracking of the solidified body during the abrasion test. Comparative Example 17: The average particle diameter of the hard particles was 13 μm, which caused brittleness of the powder solidified body, and as a result, the solidified body was defective due to a decrease in strength of the powder solidified body. Comparative Example 18: Since the maximum particle diameter of the hard particles was 35 μm, the powder solidified body was embrittled, and as a result, the solidified body was deficient due to the strength reduction of the powder solidified body.

Example 3 A spray powder having an alloy composition No. 2 in Table 3 was subjected to mechanical pulverization / re-agglomeration treatment such as a granulation method or a mixing method to obtain a fluidity as shown in Table 6. The powders that were possessed were classified, and each was powdered into the die using the powder molding die (upper / lower die and die) in FIG. A plate-shaped molded body having a size of 8 × 14.8 × 7.5 mm was produced. The solidification status is also shown in Table 6.

[0053]

[Table 6]

With respect to Examples 1 to 3 of the present invention, powder solidified bodies having a suitable shape were obtained. On the other hand, in Comparative Examples 1 to 3, the fluidity was not sufficient, so that the powder was not sufficiently filled into the end and the corner of the mold, and as a result, the part of the powder solidified body was missing after the mold was released from the mold.・ It is chipped and a good shape cannot be obtained.

[0055]

According to the present invention, a high density sintered aluminum alloy having excellent physical and mechanical properties, particularly high hardness and excellent wear resistance can be produced with high economic efficiency. As a result, it can be applied to vanes, shoes, side plates, etc. of conventional iron compressor parts, oil pump rotors, etc. of automobile parts, or sliding parts such as rollers, gears, bearings of office equipment, etc. Can be achieved.

[Brief description of drawings]

FIG. 1 is a front view showing an apparatus for producing a powder solidified body.

FIG. 2 is a front view showing a molding die for molding a powder solidified body.

FIG. 3 is a front view of a pin-on-disk wear test device for a powder solidified body.

[Explanation of symbols] 1: Upper mold 2: Lower mold 3: Mortar 4: Powder solidified body 5: Heater 6: Upper mold 7: Lower mold 8: Mortar 9: Powder compact 10: Pin 11: Disc

Claims (13)

[Claims] 1. A Young's modulus of 100 GPa or more, a Vickers hardness of 350 MHv or more, and a transverse rupture strength of 65.
A high-hardness wear-resistant aluminum powder alloy characterized by having a pressure of 0 MPa or more. 2. The general formula Al-a-Si-b-T-c-X.
-D-Cu-e-Mg (however, T; either one or both of Fe and Ni elements, X; Ti, Cr, V, Mo,
One or more elements of Zr, and a, b,
c, d, and e are each weight% a; 5 to 15%, b; 5
.About.12%, c; 2 to 6%, d; 0.4 to 8%, e;
The high hardness wear-resistant aluminum powder alloy according to claim 1, wherein the composition is 2 to 4%, and the balance is substantially aluminum and unavoidable impurities). 3. The aluminum powder alloy having the composition according to claim 2, wherein the Si component is a Si crystal having a grain size of 1 μm or less, and the T component is Al and 3 μ in the longest diameter portion.
m is an Al-Fe, Al-Ni, Al-Fe-Ni-based intermetallic compound having a particle size of 1 μm or less, and these components are uniformly dispersed in the matrix in the above-mentioned form. The high-hardness wear-resistant aluminum powder alloy according to claim 2, wherein 4. The aluminum powder alloy having the composition according to claim 2, wherein at least one hard material selected from a carbide, an oxide and a nitride having a maximum particle size of 20 μm and an average particle size of 10 μm or less. 2 to 2 particles in the substrate
The high hardness wear-resistant aluminum powder alloy according to claim 2 or 3, wherein the aluminum powder alloy is dispersed uniformly at 40% by volume. 5. A rapidly solidified aluminum alloy powder as a raw material powder or a mechanically pulverized and reaggregated aluminum alloy powder is cold-formed or warm-formed at 300 ° C. or less, and the powder compact has an inner surface temperature of 350 ° C. to 550. It is inserted into a mold (mill) held at ℃, and either or both of them are held at 350 ℃ to 550 ℃ by an upper mold (upper punch) and a lower mold (lower punch), pressure of 4 to 10 t / cm ² The method for producing a high-hardness wear-resistant aluminum powder alloy according to claim 1, wherein hot compaction and solidification to a true density ratio of 97% or more is performed by pressure compression for 3 seconds to 60 seconds. 6. The powder solidified body after molding and solidification by pressure compression according to claim 5, at 0.5 to 4 at 300 to 500 ° C.
The method for producing a high hardness wear-resistant aluminum powder alloy according to claim 5, wherein the aging treatment is performed at 200 ° C. or lower after heating with Hr or further cooling with water. 7. The rapidly solidified aluminum alloy powder or the mechanically pulverized and reaggregated aluminum alloy powder as a raw material has a general formula of Al-a.Si-b.Tc.Xd.Cu.
-E.Mg (however, T: either one or both of Fe and Ni elements, X: one or more elements of Ti, Cr, V, Mo, Zr, and a, b, c , D, e
Are in weight%, respectively; a; 5 to 15%, b; 5 to 12%,
c; 2 to 6%, d; 0.4 to 8%, e; 0.2 to 4%, the balance being substantially aluminum and unavoidable impurities). Alternatively, the method for producing the high hardness wear-resistant aluminum powder alloy according to claim 6. 8. The solidification rate of the rapidly solidified aluminum alloy powder, which is a raw material powder, is 10 ³ ° C./sec or more, and 10 ⁶
The method for producing a high-hardness wear-resistant aluminum powder alloy according to claim 5 or 6, characterized in that the temperature does not exceed ° C / sec. 9. The rapidly solidified aluminum alloy powder as a raw material powder is a powder produced by a spraying method, and has a maximum particle size of 150 μm or less and an average particle size of 50 μm or less. The method for producing the high hardness wear-resistant aluminum powder alloy according to claim 8. 10. The rapidly solidified aluminum alloy powder or the mechanically pulverized and re-agglomerated aluminum alloy powder, which is a raw material powder, has a fluidity of 60 seconds at an orifice 4 mmφ as it is or by mechanical granulation processing or mixing processing. /
The method for producing a high-hardness wear-resistant aluminum powder alloy according to claim 5, wherein the weight is 50 g or less. 11. A rapidly solidified aluminum alloy powder or a mechanically pulverized reaggregated aluminum-based composite powder, which is a raw material powder, is heated to 300 ° C. or lower before powder feeding in cold forming or warm forming according to claim 5. The method for producing a high-hardness wear-resistant aluminum powder alloy according to claim 5, which is characterized in that 12. A rapidly solidified aluminum alloy powder having the composition according to claim 7 or a mechanically ground and reaggregated aluminum-based composite powder having the same composition, after adding and mixing the hard particles according to claim 4, Mechanical grinding
12. A rapidly solidified aluminum alloy powder or a mechanically pulverized reaggregated aluminum-based composite powder in which these particles are uniformly dispersed in the matrix by a combination of the mixing and reaggregation methods is used. A method for producing a high hardness and wear resistant aluminum powder alloy. 13. An aluminum alloy melt having the composition according to claim 7, to which the hard particles according to claim 4 are added, and the particles are uniformly dispersed in the melt by a melt casting method or an induction melting method. After that, a rapidly solidified aluminum alloy powder produced by a spraying method or a mechanically pulverized reaggregated aluminum-based composite powder is used to produce a high-hardness wear-resistant aluminum powder alloy according to claim 7. Method.