JPH0892672A - Production of dispersion strengthened alloy - Google Patents

Abstract

PURPOSE: To produce a dispersion strengthened alloy good in all of electric conductivity, thermal conductivity and mechanical strength by selectively reducing a metal to form into a basal phase in a mixture and sintering the mixture. CONSTITUTION: As the raw material powder of a basal phase, cupric oxide particles having 1μm average particle size are used, and the raw material powder of dispersion particles is mixed thereto. This mixture are pulverized and mixed in a ball mill. After that, the mixture using hydride as the raw material powder of the dispersion particles is heated at 750 deg.C for 2hr in the air to convert the hydride into oxide. The obtd. mixture is held at 700 deg.C for 2hr in a mixed air flow of hydrogen and argon under one atmospheric pressure and is selectively reduced. After that, the mixture is sintered. Thus, the dispersion strengthened alloy in which fine dispersion particles are dispersed into the baser phase and having high 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 a method for producing a dispersion strengthened alloy in which dispersed particles are uniformly dispersed in a metal serving as a matrix phase.

[0002]

2. Description of the Related Art In recent years, dispersion-strengthened copper alloys in which dispersed particles such as metal oxides are uniformly dispersed in a copper matrix are known as slip rings, magnetic field generating coils, semiconductor lead frames, welding electrodes, etc. Widely used in. Further, as a method for producing such a dispersion-strengthened copper alloy, an internal oxidation method in which the additive metal element in the copper alloy powder is selectively oxidized to form dispersed particles of a metal oxide and then sintered, and an oxidation method A selective reduction method in which copper and a metal oxide to be dispersed particles are mixed and pulverized, and then copper is selectively reduced and sintered is known. In particular, among these, the dispersion-strengthened copper alloy produced by the selective reduction method rarely mixes the metal component of the metal oxide, which becomes the dispersed particles, into the copper mother phase. Good characteristics can be expected.

However, in the conventional dispersion-strengthened copper alloy produced by the selective reduction method, it is difficult to uniformly disperse fine dispersed particles in the copper matrix phase, and it is difficult to obtain sufficient mechanical strength. There is a problem. That is, in the case of producing a dispersion-strengthened copper alloy by the selective reduction method, when mixing and pulverizing the copper oxide and the metal oxide to be dispersed particles as described above, the strength is particularly high in a commonly used low-energy mixing pulverizer. The powder of high metal oxide is scarcely ground, resulting in fairly coarse dispersed particles dispersed in the copper matrix. On the other hand, when a high-energy mixing and crushing machine is used as disclosed in, for example, JP-A-62-93321, the copper oxide and the metal oxide to be dispersed particles are sufficiently mixed and crushed to finely divide the metal oxide to a certain degree. However, conversely, due to the influence of contamination due to the mixing of the constituent materials of the mixing and crushing machine, the electrical and thermal conductivity of the dispersion-strengthened copper alloy and the deterioration of workability are unavoidable. Furthermore, even if fine metal oxide particles and copper oxide particles are used in advance as the raw material powder, secondary particles having strong bond tend to be formed in such fine particles. It is difficult to uniformly disperse such dispersed particles in the copper matrix.

Further, JP-A-2-118036 and JP-A-6-18036.
No. 145844 and the like do not directly mix and pulverize copper oxide and metal oxide to be dispersed particles, and after forming a coating layer made of metal hydroxide or metal hydrate on the surface of copper oxide particles, A metal hydroxide or metal hydrate forming the coating layer is converted into a metal oxide, and a dispersion-strengthened copper alloy is produced by a selective reduction method from a mixture of the obtained copper oxide and a metal oxide to be dispersed particles. The technology is disclosed. However, even in the dispersion-strengthened alloy produced by such a technique, it is not possible to sufficiently refine the metal oxide to be copper oxide or dispersed particles, or the metal oxide particles or the copper oxide particles Since the secondary particles having a strong bond are formed, the coarse dispersed particles are dispersed in the copper mother phase, and the mechanical strength thereof is still unsatisfactory.

[0005]

When a dispersion-strengthening alloy is produced by the selective reduction method as described above, it has been difficult to disperse finely dispersed particles uniformly in the matrix phase. Although good characteristics can be expected in terms of electrical conduction, thermal conduction, etc., there is a problem that it is difficult to obtain sufficient mechanical strength.

In view of the above problems, it is an object of the present invention to provide a dispersion-strengthened alloy production method capable of producing a dispersion-strengthened alloy having good electrical conductivity, heat conduction, and mechanical strength. .

[0007]

In order to achieve the above object, the present invention firstly provides a method for producing a dispersion-strengthened alloy in which dispersed particles are uniformly dispersed in a metal serving as a matrix phase. There, at least one of the steps of mixing and pulverizing the raw material powder of the mother phase containing hydrogen and the raw material powder of the dispersed particles,
Heating the resulting mixture in an atmosphere containing at least one of oxygen, nitrogen and carbon; and selectively reducing the metal to be the parent phase in the mixture in the reducing atmosphere after the heating. And a step of sintering the mixture, a method for producing a dispersion-strengthening alloy (hereinafter referred to as a first production method).
I will provide a. That is, the method for producing the dispersion strengthened alloy is such that the raw material powder containing hydrogen is mixed and pulverized in the form of, for example, a hydride, and the resulting mixture is oxidized, nitrided, or carbonized, and then the metal serving as the matrix phase is selectively It is to return to.

In the first manufacturing method as described above, a raw material powder containing hydrogen such as a hydride having a generally low strength is easily prepared by mixing and pulverizing a hydride containing hydrogen as a raw material powder. The particles are pulverized into fine particles. Therefore, by oxidizing, nitriding or carbonizing the obtained mixture and then selectively reducing and sintering the metal serving as the mother phase, fine dispersed particles having a high strength formed by being uniformly dispersed in the mother phase. A dispersion strengthened alloy is produced.

Here, at least one of the raw material powder of the mother phase and the raw material powder of the dispersed particles may be, for example, a hydride containing hydrogen, and the other may be an oxide or the like and is not particularly limited. However, since a substance having high strength is usually used as the dispersed particles of the dispersion strengthening alloy, at least the dispersed particles contain hydrogen such as a hydride having low strength from the viewpoint of pulverizing until the material powder is sufficiently refined. It is preferable to use a raw material powder that Furthermore, unless it is difficult to prepare a raw material powder containing hydrogen for one of the mother phase and the dispersed particles, it is preferable to use a raw material powder containing hydrogen with low strength for both the mother phase and the dispersed particles, because a uniform mixture can be obtained during mixing and pulverization. It is more preferable because it can be easily obtained and is excellent in safety. Further, in the mixing and pulverization of the raw material powder, it is also possible to appropriately cool the mixture to a low temperature to promote the atomization of the particles, and in particular, while using the raw material powder containing hydrogen for the dispersed particles, the raw material powder of the mother phase As an example, when a copper or silver oxide is used to produce a dispersion-strengthened alloy in which the metal serving as the mother phase is copper, silver, or an alloy thereof, cooling of the mixture as described above is effective.

At this time, the hydrogen content in the raw material powder containing hydrogen is not particularly limited, but the hydrogen content is preferably 10 atomic% or more. This is because if the content of hydrogen in the raw material powder containing hydrogen is too small, the ductility of the raw material powder is high, and it becomes difficult to pulverize the raw material powder until the particles are sufficiently miniaturized during mixed pulverization. Because. Specifically, in order to prepare such a raw material powder containing hydrogen, for example, a powder containing a metal serving as a mother phase of a dispersion-strengthened alloy or a metal component in dispersed particles is replaced with hydrogen in an atmosphere containing hydrogen. It suffices to maintain the temperature at or above the temperature at which it is taken. However, it is necessary to suppress the partial pressure of oxidizing components such as oxygen and water vapor in the hydrogen-containing atmosphere so that the powder held in the hydrogen-containing atmosphere is not oxidized. Further, the preferable particle size of the raw material powder containing hydrogen is different depending on which raw material powder the strength is usually different between the mother phase and the dispersed particles, but the dispersed particles are uniformly dispersed in the mother phase. From the viewpoint, it is about 5 μm or less.

Further, in the first manufacturing method, the raw material powder of the mother phase and the raw material powder of the dispersed particles are mechanically mixed and pulverized, and then the obtained mixture is mixed with the atmosphere, H ₂ O, CH ₄ ,
By heating in an atmosphere containing at least one of oxygen such as NH ₃ and nitrogen and carbon, the raw material powder containing hydrogen as described above is easily oxidized, nitrided or carbonized. Subsequently, for example, the metal serving as the mother phase is reduced to the metal simple substance, but the metal component in the dispersed particles is not reduced to the metal simple substance in a reducing atmosphere having a reduction potential,
The resulting mixture of oxides, nitrides or carbides is heated. At this time, since the mother phase metal is selectively reduced, if this is sintered, dispersion strengthening is achieved by uniformly dispersing dispersed particles of oxide, nitride or carbide in the mother phase metal. A mold alloy is produced.

In the first manufacturing method as described above, the metal serving as the mother phase is copper, silver, iron, nickel, cobalt, chromium,
Although it can be widely applied to the case of zinc, molybdenum, tungsten, etc., it is particularly preferably applied to a dispersion strengthening type alloy in which a metal serving as a matrix phase is copper, silver or an alloy thereof. In this case, what is necessary is to combine copper, silver, or an alloy originally having a high electric conductivity and a sufficient mechanical strength due to the dispersed particles being uniformly dispersed,
This is because it becomes possible to produce a dispersion strengthened alloy having extremely excellent characteristics. Further, iron is used as a metal serving as a matrix phase,
Nickel and cobalt are preferable in that a raw material powder containing hydrogen such as hydride can be easily prepared.

On the other hand, the dispersed particles which are uniformly dispersed in the metal serving as the mother phase are, for example, metals which are more stable than oxides, nitrides or carbides of the metal serving as the mother phase in a reducing atmosphere. A compound can be used, and specifically, aluminum, zirconium, beryllium, hafnium, thorium, magnesium, titanium or yttrium,
Oxides, nitrides and carbides of rare earth elements such as lanthanum, cerium and neodymium are suitable. Of these,
Zirconium, hafnium, thorium, magnesium,
With metal components such as titanium, yttrium, lanthanum, and cerium, it is easy to synthesize, for example, a hydride containing hydrogen as a raw material powder of dispersed particles.

Here, specifically, in the case where the metal serving as the mother phase is copper and the dispersed particles are oxides of a metal component that facilitates the synthesis of the hydride, in the first manufacturing method, first, for example, the raw material powder of the mother phase is used. As a raw material powder of dispersed particles composed of copper oxide and hydride of the metal component as described above, 0.5 to 6% by volume of dispersed particles are dispersed in the matrix phase of the finally obtained dispersion strengthened copper alloy. These are compounded in such an amount as described above. As the copper oxide, cuprous oxide (Cu ₂ O), cupric oxide (Cu
O) or non-stoichiometric copper oxide (CuO _x ). From the viewpoint of uniformly dispersing the dispersed particles, the raw material powder of the mother phase has a particle size of 5 μm or less, further 1 μm.
It is preferable that the raw material powder of the dispersed particles has a particle diameter of 5 μm or less.

Subsequently, the above-mentioned mixing and pulverization can be carried out by using a known mixing device such as a ball mill or an attritor. At this time, it is preferable that the container and the ball are made of non-metal. This is because when crushing and mixing is performed using a metal container or balls, a metal such as iron may be mixed in the mixture, and the electric conductivity of the dispersion-strengthened alloy may be significantly reduced. Further, as in this case, when producing a dispersion-strengthened copper alloy in which the metal serving as the mother phase is copper, the surface of the container or the ball in contact with at least the raw material powder should have a strong strength such as a dispersion-strengthened copper alloy or beryllium copper alloy. Forming a copper alloy is also effective in preventing contamination. Here, it is preferable that the mixture is sufficiently mixed and pulverized until the particle size of the raw material powder of the mother phase and the raw material powder of the dispersed particles becomes about 0.05 μm or less. Before the raw material powder of the mother phase and the raw material powder of the dispersed particles are blended, they may be pulverized individually until they have desired particle diameters.

Next, the obtained mixture is heated in an oxidizing atmosphere such as air. Here, the mixture is heated for a sufficiently long time until the hydride in the mixture is completely converted to the oxide. At this time, the heating temperature is preferably 400 ° C. or higher and 900 ° C. or lower. This is because if the temperature is lower than 400 ° C, it takes a considerably long time before the hydride in the mixture is converted into the oxide. This is because it becomes difficult to manufacture a high-strength dispersion-strengthening alloy in which fine dispersed particles are uniformly dispersed. Next, the mixture is charged into a reducing furnace kept in a reducing atmosphere, and the copper in the mixture is selectively reduced from copper oxide to metallic copper by a reducing gas such as hydrogen or carbon monoxide. At this time, it is preferable to keep all of the mixture at a temperature not exceeding 1065 ° C., which is the eutectic temperature of copper and copper oxide, until the reduction of copper is completed. This is because even if a part of the mixture is heated to more than 1065 ° C, the dispersed particles undergo remarkable aggregation and coarsening, and thus, a high strength dispersion strengthened alloy in which fine dispersed particles are uniformly dispersed is produced. Because it will be difficult. Further, from the viewpoint of completely reducing copper from copper oxide to metallic copper without requiring a long time, it is more preferable to hold the mixture at a temperature of 150 ° C. or higher and 1065 ° C. or lower.

Here, as described above, in order to keep all the parts of the mixture at a temperature not exceeding 1065 ° C., specifically, the temperature of the heating furnace is taken into consideration in consideration of a large amount of heat generated by the reduction reaction of copper. May be set to a lower temperature side, and the partial pressure and flow rate of the reducing gas may be adjusted so as to prevent a rapid reduction reaction. However, at the time when the reduction of copper is almost completed, the heat accompanying the reduction reaction of copper is no longer generated, so even if the temperature of the heating furnace is raised to, for example, about 1065 ° C.
It is never heated above 65 ° C.

This reduction is carried out in a reducing atmosphere having a reduction potential such that copper oxide can be reduced to the state of metallic copper and the metal component in the dispersed particles is not completely reduced. However, it is not necessary to create a reducing atmosphere having a reduction potential in which the metal component of the dispersed particles is not reduced at all. For example, when the mixture is composed of copper oxide and TiO _2, there is no problem even if Ti is reduced up to TiO.

Next, the mixture after the reduction is molded into a predetermined shape by a press or the like to form a molded body. Then, the obtained compact is sintered in a reducing atmosphere or an inert atmosphere (including a vacuum) to produce a dispersion strengthened alloy. The dispersion-strengthened alloy may be molded and sintered at the same time by hot pressing or hot isostatic pressing (HIP). In particular, it is possible to obtain a dispersion-strengthened alloy that can be sintered at low temperature and has excellent mechanical strength. Hot press and HIP which can be produced are preferred. It is also possible to manufacture a dispersion-strengthened copper alloy by subjecting the mixture before reduction to hot pressing in the reducing atmosphere in which copper is selectively reduced as described above, and simultaneously performing reduction, molding and sintering. Is.

Secondly, in the present invention, dispersed particles are uniformly dispersed in a metal serving as a mother phase, and the metal serving as a mother phase is any one selected from copper, silver and alloys thereof. A method for producing a dispersion-strengthened alloy, comprising a metal component as a raw material for dispersed particles and having a viscosity of 5 cp at 25 ° C.
A step of obtaining a mixture of the raw material of the mother phase and the raw material of the dispersed particles by impregnating the following fluid with the oxide of the metal serving as the mother phase of the raw material of the mother phase, the metal oxide corresponding to the metal component, the metal Exposing the mixture to an atmosphere that can be converted to at least one of nitride and metal carbide; selectively reducing the matrix metal in the mixture in a reducing atmosphere; and sintering the mixture. And a method for producing a dispersion strengthened alloy (hereinafter referred to as a second production method). That is, the method for producing this dispersion-strengthened alloy is such that copper, silver, or an oxide of these alloys is impregnated with a solution of a raw material of dispersed particles, and the resulting mixture is roasted to form oxides as dispersed particles. While generating, copper, silver or alloys of these are selectively reduced from oxides to simple metal.

In the second manufacturing method as described above, for example, the raw material of the mother phase is impregnated with a low-viscosity solution in which a metal compound as a starting material for the dispersed particles is dissolved to contain a specific metal component. The solution penetrates into the particles through microscopic holes, cracks, etc. in the raw material of the matrix phase. Therefore, when exposed to an atmosphere in which oxides, nitrides or carbides of the metal components can be formed and then selectively reducing and sintering the metal serving as the mother phase, especially the raw material of the mother phase and the raw material of the dispersed particles A high-strength dispersion-strengthened alloy in which fine dispersed particles are uniformly dispersed in the matrix phase is manufactured without mixing and pulverizing and. Moreover, it is possible to completely avoid the contamination that occurs when the raw material of the mother phase and the raw material of the dispersed particles are mixed and pulverized, and to completely prevent the reduction of the electric conductivity of the dispersion strengthening alloy due to the contamination when the raw material is mixed and pulverized. It is possible. Therefore, the second manufacturing method is effectively applied when the metal serving as the mother phase itself is copper, silver or an alloy thereof having high electric conductivity, and the metal serving as the mother phase is copper, silver or these alloys. It is possible to produce a dispersion-strengthened alloy having extremely high properties, which has both high electrical conductivity derived from being an alloy and sufficient mechanical strength resulting from the dispersed particles being uniformly dispersed. Become.

Here, the metal compound as the starting material for the dispersed particles is an inorganic or organic compound having the same metal component as in the first production method as described above, specifically, nitrates, sulfates, chlorides, carvone. Fatty acid salts such as acid salts, complex compounds such as acetylacetonato chelate, and alkoxides such as propoxide can be used. On the other hand, as the solvent for dissolving the metal compound, water, alcohol, benzene and the like having good wettability with the oxide of the metal serving as the mother phase that is the raw material of the mother phase are exemplified, and the metal compound is dissolved in these solvents. Let me 25
A solution having a viscosity at 5 ° C. of 5 cp (centipoise) or less may be prepared. At this time, if the concentration of the solution is too high, the viscosity of the solution tends to increase, and if the concentration of the solution is too low, before the mixture obtained by impregnating the raw material of the mother phase with the solution is roasted, for example. The concentration of the solution is preferably set to about 0.1 to 1 mol / l because the mixture may need to be dried for a very long time in order to evaporate and remove a large amount of the solvent.

In the second production method, the viscosity of the fluid such as the solution impregnated into the raw material of the mother phase is specified to be 5 cp or less at 25 ° C. because the viscosity of the solution is too high. Because it does not penetrate sufficiently into the particles of
It is more preferably 1 cp or less. Further, in order to sufficiently permeate the solution into the particles of the raw material of the mother phase, it is better that the particles of the raw material of the mother phase have more pores and cracks. Further, in the solvent, water is preferable because the viscosity of the solution hardly rises even if a relatively large amount of the metal compound is dissolved. However, when a metal compound, which is a liquid having a viscosity of 5 cp or less at 25 ° C. itself, is used as a starting material for dispersed particles, the metal compound is directly dissolved in a solvent to prepare a solution, and the metal compound is directly used as a raw material for the mother phase. It may be impregnated with an oxide of a metal serving as a mother phase.

On the other hand, it is preferable to use a powder having a particle size of 1 μm or less, more preferably 0.5 μm or less, as a raw material of the mother phase composed of the metal oxide as described above. The powder may be synthesized, for example, by adjusting the pH from an aqueous solution of the corresponding metal salt to precipitate particles of the metal oxide, followed by filtration, washing with water, and drying. However, the particle size here is the particle size of the primary particles, and even if the particles are aggregated to form secondary particles having a large particle size, it is possible to penetrate the solution through the pores or cracks of the particles. Therefore there is no particular problem.

In the second production method, the raw material of the mother phase impregnated with the fluid is dried if necessary, and then the mixture of the obtained raw material of the mother phase and the raw material of the dispersed particles is mixed in a desired atmosphere, for example. By roasting in the inside, a metal oxide, a metal nitride, or a metal carbide corresponding to the metal component as the raw material of the dispersed particles as described above is generated on the surface and inside the particle of the raw material of the mother phase. At this time, when the raw material powder of the mother phase is impregnated with a solution prepared by dissolving a metal compound as a starting raw material of the dispersed particles in a solvent, it is heated to 100 ° C. before roasting in a desired atmosphere. It is preferable to evaporate and remove the solvent of the solution impregnated in the raw material powder of the mother phase under moderate heating or reduced pressure to dry the raw material powder of the mother phase. Further, during the drying, the solution concentrated with evaporation of the solvent may partially agglomerate, which may cause segregation of dispersed particles in the dispersion-strengthened alloy, so that the raw material powder of the mother phase should be appropriately stirred. Is preferred.

The roasting of the mixture as described above may be carried out in an atmosphere in which the metal component of the raw material of the dispersed particles can finally be converted into the corresponding metal oxide, metal nitride or metal carbide. At this time, in the mixture, the decomposition of the metal compound as the starting material of the dispersed particles, the formation of oxides, etc. proceed in parallel or continuously. Specifically, for example, even when heated in the air, a metal oxide corresponding to the metal component of the raw material of the dispersed particles can be produced, but the temperature at the time of roasting the mixture is in the range of 400 ° C to 900 ° C. It is preferably set. The reason for this is that in the case of roasting at less than 400 ° C., it may take a long time to form the above-mentioned metal oxide, metal nitride or metal carbide, or these may not be sufficiently formed. When the temperature exceeds 900 ° C., the dispersed particles are aggregated or coarsened, which makes it difficult to produce a high strength dispersion strengthened alloy in which fine dispersed particles are uniformly dispersed.

Further, for example, the metal serving as the mother phase is reduced to the metal alone, but the metal component in the dispersed particles is not reduced to the metal alone. In the reducing atmosphere having a reducing potential, the metal serving as the mother phase is selectively selected. Reduction and subsequent sintering of the mixture after the reduction produces a dispersion-strengthened alloy in which dispersed particles of a metal oxide, a metal nitride or a metal carbide are uniformly dispersed in a metal serving as a matrix phase. To be done. At this time, the preferable temperature, atmosphere, etc. for the reduction and sintering of the mixture are in accordance with the first production method, but the agglomeration and coarsening of dispersed particles are further taken into consideration while appropriately considering the temperature at the time of roasting. It is more preferable to set the temperature during the reduction so that In addition, here, hydrogen capable of proceeding in parallel with the conversion of the metal component to the metal oxide, the metal nitride or the metal carbide as described above and the selective reduction of the metal oxide serving as the mother phase to the simple metal. It is also possible to simultaneously generate a metal oxide, a metal nitride or a metal carbide to be dispersed particles and a metal to be a matrix phase in an atmosphere containing carbon monoxide or carbon monoxide. Further, similarly to the first manufacturing method, for example, if the mixture is previously molded by pressing before sintering, a dispersion strengthened alloy having a predetermined shape can be manufactured.

The second manufacturing method as described above can be applied to the case where the metal serving as the mother phase is copper, silver or an alloy thereof as described above. When the metal serving as the mother phase is an alloy of copper or silver, iron, lead, zinc, tin capable of reducing to a metal in a reducing atmosphere of about 1000 ° C. or less as an alloying component for copper and silver. Etc. are illustrated,
The content of the alloying component is preferably about 0.01 wt% or less for iron, 0.10 wt% or less for lead, 0.5 wt% or less for zinc, and 0.06 wt% or less for tin. What is more, when the alloying components exceed the above-mentioned contents respectively, the amount of decrease in the electrical conductivity from the simple metal as the parent phase in the parent phase of the dispersion strengthened alloy exceeds 5% IACS, and the result This is because the decrease in the electric conductivity of the dispersion strengthened alloy becomes large. When the metal as the mother phase is an alloy, before impregnating the solution of the metal component as the raw material of the dispersed particles into the oxide of the metal as the mother phase, the oxide of each metal as the raw material of the mother phase is previously prepared. It is necessary to prepare a mixture by mixing, but it is desirable to use a mixing device such as a V mixer which is less likely to be contaminated here.

Further, in the second production method, a copper-silver alloy is particularly preferable as a matrix phase because it is expected that the strength of the dispersion-strengthened alloy can be enhanced by solid solution without significantly lowering the electric conductivity thereof. More preferred is a copper-silver alloy consisting of 0.1 to 3 wt% silver and the balance copper. This means that if the content of silver in the copper-silver alloy is less than 0.1% by weight,
This is because it is not possible to expect a remarkable increase in strength of the dispersion-strengthened alloy by solid solution strengthening, and if the content of silver exceeds 3% by weight, the electrical conductivity of the dispersion-strengthened alloy may be significantly reduced. .

In the present invention as described above, it is preferable that the total amount of solid solution elements in the matrix phase of the dispersion strengthened alloy is small. Specifically, in the parent phase, the amount of decrease in the electrical conductivity from the single metal that is the parent phase is within 5% IACS (in the case of the copper parent phase, the absolute value of the electrical resistivity is 1.77 μΩcm or less).
Therefore, it is desirable to control the total amount of solid solution elements.

As the dispersed particles that can be used in the present invention, as described above, aluminum, zirconium, beryllium, hafnium, thorium, magnesium, titanium and oxides, nitrides and carbides of rare earth elements can be used. , Specifically, aluminum oxide, zirconium oxide, titanium oxide, hafnium oxide, thorium oxide,
Examples thereof include silicon oxide, magnesium oxide, yttrium oxide, lanthanum oxide, cerium oxide, chromium oxide, aluminum nitride, silicon nitride, titanium nitride, boron nitride, titanium carbide, boron carbide and titanium boride. Aluminum oxide is particularly preferable, and for this reason, the solid solution amount of aluminum in the mother phase is preferably 0.04% by weight or less. Furthermore, the preferable dispersion amount of the dispersed particles in the present invention is 0.5 to 6% by volume, and
If it is less than 5% by volume, sufficient mechanical strength cannot be obtained, and if it exceeds 6% by volume, the electrical conductivity is lowered and the secondary processing becomes difficult.

On the other hand, the particle diameter of such dispersed particles in the present invention is preferably 0.1 μm or less, more preferably 0.1 μm or less from the viewpoint of mechanical strength, ductility, workability, etc. of the dispersion strengthened alloy.
It is set to 005 μm or more and 0.05 μm or less. Further, in the present invention, the average diameter of the matrix region where dispersed particles do not exist is 0.
It is preferably 3 μm or less. This is because if the average diameter exceeds 0.3 μm, the mechanical strength of the dispersion-strengthened alloy may be insufficient. Here,
A method of calculating the average diameter of the matrix region in which dispersed particles do not exist will be described. First, a thin film sample is prepared from a dispersion-strengthened alloy sample, and a 100,000-fold photograph of the thin film sample obtained by a transmission electron microscope is taken. A micrograph at this time is schematically shown in FIG. Next, as shown in FIG. 1, 10 arbitrary points on the photograph other than the dispersed particles 1 are selected, and 10 maximum circles including each point and not including the dispersed particles 1 are drawn (provided that each point is The average value of the diameters of these circles is not necessarily the center of these circles, and the average diameter of the region of the matrix phase 2 in which the dispersed particles 1 do not exist is used.

Further, in the method for producing a dispersion strengthened alloy of the present invention, a third component such as a deoxidizer and a solid reducing agent is added up to about 0.5% by weight with respect to the raw material of the mother phase and the raw material of the dispersed particles. It doesn't matter. The produced dispersion strengthened alloy may be used as it is, or may be used after being subjected to secondary working such as mechanical working, cold working and hot working, if necessary. In processing the dispersion-strengthened alloy here, ordinary forging, rolling, extrusion, wire drawing, etc. may be carried out. In particular, according to the second manufacturing method as described above, contamination due to mixing and grinding of raw materials is performed. It is possible to produce a dispersion-strengthened alloy that is completely free of defects and has excellent secondary workability.

[0034]

【Example】

Example 1 First, cupric oxide particles having an average particle size of 1 μm were used as a raw material powder of a mother phase, and the raw material powders of dispersed particles shown in Table 1 below were used after the reduction of the cupric oxide. The compounding amount was such that 2% by volume of dispersed particles were dispersed in the copper mother phase. Then, the mixture was dry-ground and mixed for 5 days in a ball mill consisting of an aluminum oxide container and balls. After this, sample No. 1 using hydride as the raw material powder of the dispersed particles. For mixtures of 1 and 2, 75 in air
The hydride was converted to the oxide by heating at 0 ° C. for 2 hours.

Then, the obtained mixture was put into a boat made of aluminum oxide and kept at 700 ° C. for 2 hours in a mixed gas stream of hydrogen and argon at 1 atm until the cupric oxide became metallic copper. Selectively reduced. After cooling, the generated dispersion-strengthened alloy powder was filled in a carbon / carbon composite mold, and the temperature was set to 400 at 900 ° C. in a hydrogen atmosphere.
Hot press molding was performed at a pressure of kg / cm ² , and sample No. Billets of 1-5 dispersion strengthened alloys were produced.

Next, regarding the billets of these five kinds of dispersion strengthening alloys, the electrical conductivity at room temperature, 0.2% proof stress and tensile elongation as mechanical strength, and 0.2% proof stress and tensile elongation at 800 ° C. Was measured. The results are shown in Table 1.
Are also shown. As shown in Table 1, the sample No. manufactured by the first manufacturing method of the present invention using a hydride as the raw material powder of the dispersed particles. It was found that the dispersion-strengthened alloys 1 and 2 have high electric conductivity and also have sufficient mechanical strength based on the fact that the dispersed particles are uniformly dispersed in the copper matrix.

[0037]

[Table 1] Example 2 First, the pH of an aqueous solution of copper sulfate was adjusted to precipitate copper oxide, washed with water, and dried to prepare cupric oxide particles having a particle diameter of 0.5 μm or less as a raw material for a mother phase. On the other hand, aluminum nitrate nonahydrate 13.3 as a starting material for dispersed particles
g in 100 ml of pure water to prepare an aqueous solution having a viscosity of 1.3 cp at 25 ° C. and impregnating the aqueous solution with the raw material of the mother phase to prepare a mixture of the raw material of the mother phase and the raw material of the dispersed particles. Obtained. Then, the mixture is heated to about 100 ° C. and dried to evaporate and remove water, and then 700 ° C. in the atmosphere.
The aluminum component was converted into an oxide by roasting for 2 hours.

Then, the mixture was put into a boat made of aluminum oxide and kept at 700 ° C. for 2 hours in a mixed gas of hydrogen and argon at a total pressure of 1 atm, and the cupric oxide was selected until it became metallic copper. Reduced. After cooling, the generated dispersion-strengthened alloy powder is filled in a carbon / carbon composite mold, and 600 kg / cm at a temperature of 900 ° C. in vacuum.
Hot press molding was performed at a pressure of ² , and sample No. A dispersion strengthened alloy billet No. 1 was produced. On the other hand, for comparison, aluminum isoamylate as a starting material for the dispersed particles was dropped into water at 85 ° C. and then hydrolyzed to prepare an AlO (OH) gel having a viscosity of 12 cp at 25 ° C. Sample No. 3 was prepared in the same manner except that the raw material was impregnated to obtain a mixture of the raw material of the mother phase and the raw material of the dispersed particles.
A sample dispersion strengthened alloy billet No. 2 was manufactured. Also,
Except that the mixture of the raw material of the mother phase and the raw material of the dispersed particles was roasted to convert the aluminum component to an oxide, and then pulverized in an attritor consisting of a SUS304 or zirconia pot, blade and ball for 8 hours. Sample No. 1
Billets of dispersion-strengthening type alloy were manufactured in exactly the same manner as in the above, and sample No. 3 and sample No. 3 It was set to 4.

Next, the billets of these four kinds of dispersion strengthening alloys were measured for electrical conductivity at room temperature, 0.2% proof stress and tensile elongation as mechanical strength, and the content of iron as an impurity. Further, a cylindrical test piece having a diameter of 10 mm cut out by machining was forged and drawn to calculate a limit diameter that can be processed as a wire rod to evaluate the secondary workability. In the wire drawing die used for processing at this time, 25 μm was the lower limit of the limit diameter for processing. The results are also shown in Table 2. As shown in Table 2, the sample No. manufactured by the second manufacturing method of the present invention using an aqueous solution containing an aluminum component as a raw material of dispersed particles and having a viscosity at 25 ° C. of 5 cp or less. The dispersion-strengthened alloy of No. 1 has a high electric conductivity with less contamination by impurities, and has sufficient mechanical strength based on the fact that the dispersed particles are uniformly dispersed in the copper matrix, and further the secondary processing is performed. It was found that the property was also good.

[0040]

[Table 2]

[0041]

As described above in detail, according to the present invention, it is possible to produce a dispersion strengthening alloy having good electric conduction, heat conduction, and mechanical strength.

[Brief description of drawings]

FIG. 1 is a schematic diagram for explaining a method of calculating an average diameter of a copper matrix region.

[Explanation of symbols]

 1 ... Dispersed particles, 2 ... Copper mother phase.

Claims (3)

[Claims] 1. A method for producing a dispersion-strengthened alloy in which dispersed particles are uniformly dispersed in a metal serving as a mother phase, at least one of which contains hydrogen-containing mother-phase raw material powder and dispersed-particle raw material powder. And pulverizing the mixture, heating the obtained mixture in an atmosphere containing at least one of oxygen, nitrogen and carbon, and heating the metal to be the mother phase in the mixture in a reducing atmosphere. A method for producing a dispersion-strengthened alloy, comprising: a step of selectively reducing with 1. and a step of sintering the mixture. 2. The method for producing a dispersion-strengthened alloy according to claim 1, wherein the metal serving as the mother phase is any one selected from copper, silver and alloys thereof. 3. A dispersion-strengthened alloy in which dispersed particles are uniformly dispersed in a metal serving as a mother phase, and the metal serving as a mother phase is any one selected from copper, silver and alloys thereof. A method for producing a mother phase, comprising impregnating a fluid containing a metal component as a raw material of dispersed particles and having a viscosity at 25 ° C. of not more than 5 cp into a metal oxide serving as a mother phase of a mother phase And a raw material of dispersed particles, a step of exposing the mixture to an atmosphere in which the metal component can be converted into at least one of a corresponding metal oxide, metal nitride and metal carbide, and a mother in the mixture. A method for producing a dispersion strengthened alloy, comprising: a step of selectively reducing a phase metal in a reducing atmosphere; and a step of sintering a mixture.