JP2002294357A - Method for manufacturing metal-matrix composite material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a metal-matrix composite material which is applicable even to a large-sized final product having complicated shape and by which manufacturing steps can be reduced and simplified. SOLUTION: This method is a method for manufacturing a metal-matrix composite material consisting of a reinforcement and a matrix. The reinforcement, such as Al2 O3 and AlN, and an active metal powder of Ti, Nb, Zr, Ta or Hf are mixed to prepare a powder mixture. A jig having prescribed shape is filled with the powder mixture, and the powder mixture filled into the jig is impregnated with molten metal of Ag, Cu, Ag alloy, Cu alloy, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a metal matrix composite composed of a reinforcing material and a matrix.

[0002]

2. Description of the Related Art A composite material is a composition aggregate in which a plurality of materials are macroscopically mixed, and by using the mechanical properties of each material in a complementary manner, it is possible to express characteristics that could not be realized by a single material. It was done. Basically, it is a technique of combining materials, and there are various combinations depending on the matrix and the reinforcing material, the purpose of use, the cost, and the like.

[0003] Among them, metal-based composite materials include Al,
It is a composite material using a metal such as Ag, Cu, Ti or the like as a matrix and an inorganic material such as ceramics as a reinforcing material. Therefore, the metal-based composite material takes advantage of the characteristics of each material constituting the metal-based composite material, for example, to the aerospace and aviation fields and the automobile industry, and in particular, in recent years, takes advantage of the characteristics of low thermal expansion and high thermal conductivity, and is represented by electronic devices. It is a material that is used in various fields such as the electronics field.

[0004] With respect to the method for producing a metal-based composite material as described above, a solid phase method and a liquid phase method are mentioned. A method for producing a composite material by a solid phase method is a method in which preforms are stacked and hot pressed (HP) or hot isostatic pressing (HIP) under high-temperature and high-pressure conditions. Further, as one type of a method for producing a composite material by a liquid phase method, there is a pressure impregnation method, a molten metal forging method, or the like, which is a method for impregnating a gap between reinforcing materials with a molten metal serving as a matrix under high-pressure conditions. In general, the solid-phase method is a higher cost composite material manufacturing process than the liquid-phase method in that high temperature and high pressure are applied. However, even in the liquid phase method, it is generally necessary to apply a high pressure against the capillary pressure from outside to a molten metal and a reinforcing material (particularly, an inorganic material) having poor wettability.

[0005]

Generally, the wettability between a reinforcing material such as an inorganic material and a matrix metal is low.
There is a problem that it is difficult to make a composite material. In order to improve this point, for example, a special surface treatment is applied to the reinforcing material to improve the wettability and the production temperature is set to a high temperature condition, or the above-described pressure infiltration method, such as the melt forging method, There was a need to adopt a method such as manufacturing under high pressure conditions.

However, in these manufacturing methods, not only the necessity of a pretreatment step but also the performance and scale of the manufacturing apparatus are restricted, and it is extremely difficult to manufacture a large-sized or complicated-shaped metal matrix composite material. In addition, there is a problem that a near net shape cannot be formed in consideration of the shape of the final product, and a machining process is required in a subsequent process.

Therefore, the conventional method for producing a metal-based composite material has a multi-step process,
Since it is necessary to carry out under severe conditions such as high pressure, the manufacturing method is extremely expensive.

Japanese Patent Application Laid-Open No. 1-273659 discloses a technique utilizing a non-pressurized infiltration phenomenon that does not require a high pressure. In this method, magnesium in a molten Al—Mg alloy is vaporized in a nitrogen gas atmosphere and reacted with nitrogen gas. There has been disclosed a chemical method that utilizes the reaction of the generated magnesium nitride on the surface of a ceramic dispersion material to improve the wettability between metal and ceramic. However, according to this method, the molten metal penetrates while the surface modification of the ceramic dispersion material occurs, and thus there is a problem that the penetration rate is low.

The present invention has been made in view of the above-mentioned problems of the related art, and has as its object to reduce and simplify the manufacturing process and to provide a final product having a large and complicated shape. Another object of the present invention is to provide a method for producing a metal matrix composite material applicable to the above.

[0010]

That is, according to the present invention, there is provided a method for producing a metal-based composite material comprising a reinforcing material and a matrix, comprising the reinforcing material, and a metal powder active with respect to the reinforcing material. , A mixed powder is prepared, and the mixed powder is filled in a jig having a predetermined shape, and the filled mixed powder is impregnated with a molten metal. A method is provided.

Further, in the present invention, it is preferable that the reinforcing material is an inorganic material having any shape of fiber, particle, or whisker, and the inorganic material is Al ₂
Preferably, it is any of O ₃ , AlN, SiC, and Si ₃ N ₄ .

In the present invention, the molten metal is A
g, Cu, an Ag alloy, or a Cu alloy, and the metal powder is preferably one of Ti, Nb, Zr, Ta, and Hf.

In the present invention, the average particle size of the metal powder is preferably 5 to 80% of the average particle size of the reinforcing material, and the amount of the metal powder added to the molten metal is 5 to 30%.
% By mass, and more preferably the volume ratio of the reinforcing material in the manufactured metal matrix composite material is 20 to 70%.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail based on embodiments, but the present invention is not limited to these embodiments.

The present invention relates to a method for producing a metal matrix composite material comprising a reinforcing material and a matrix, and premixes the reinforcing material and an active metal powder by dispersing and adhering to the reinforcing material to form a mixed powder. A composite material in which the matrix is a metal is prepared by filling it into a jig having a predetermined shape, and then impregnating the filled mixed powder with a molten metal that does not form an intermetallic compound with the metal powder. It is characterized by obtaining. Hereinafter, the details will be further described.

The metal powder dispersed and attached in advance to the gaps between the reinforcements forms a solid solution with the impregnated molten metal. At this time, since this metal powder is very active for oxygen (O), nitrogen (N) and carbon (C), immediately after being solid-dissolved in the molten metal, it diffuses to the surface of the reinforcing material and It acts to improve the wettability between the material and the molten metal, and segregates at the interface between the reinforcing material and the molten metal. FIG. 1 is a scanning electron micrograph showing a microstructure of a metal matrix composite material manufactured according to an embodiment of the present invention.
This figure shows a state in which Ti powder is mixed in the particle gap and then impregnated with an Ag-Cu alloy.

FIGS. 2 to 4 show the microstructure of the metal matrix composite material manufactured according to one embodiment of the present invention,
2 is for Ti, FIG. 3 is for Ag, and FIG.
5 is a scanning electron micrograph showing the result of performing EDS elemental analysis mapping on. As is clear from FIGS. 2 to 4, Ag is spread over the entire matrix, whereas Ti, which is an active metal, does not spread over the whole matrix, but preferentially aggregates and segregates only on the surface of SiC particles. Can be confirmed.

Therefore, according to the present invention, in order to improve the wettability between the reinforcing material and the molten metal, the molten metal penetrates into the gap between the reinforcing materials without pressure to form a dense structure,
It is possible to produce a metal-based composite material in which the bonding strength between the reinforcing material and the metal as the matrix is enhanced.

In addition, since the wettability between the reinforcing material and the molten metal is improved, it is necessary to perform a special surface treatment on the reinforcing material to improve the wettability, or the pressure infiltration method. Also, there is no need to manufacture the metal matrix composite under high pressure conditions such as a melt forging method. Therefore, since there is no restriction on the performance and scale of the manufacturing apparatus, it is easy to manufacture a large-sized and complex-shaped metal matrix composite material, and it is possible to perform near net shaping in consideration of the shape of the final product, This has the effect of eliminating the need for machining processing in subsequent steps.

Next, the present invention will be described in detail with reference to an example of a manufacturing method. First, a reinforcing material having a predetermined shape,
A metal powder which is active with respect to the reinforcing material is prepared, and both are mixed so as to have a predetermined compounding ratio. At this time, in the present invention, it is preferable to use an inorganic material having any shape of fiber, powder, or whisker as the reinforcing material. By using an inorganic material having such a shape, a metal-based composite material having strength and characteristics suitable for the intended use as a final product can be produced.

In the present invention, Al ₂ O ₃ , A
It is preferable to use any of 1N, SiC, and Si ₃ N ₄ as the inorganic material. The metal matrix composite material exhibits various characteristics depending on the combination of the matrix and the reinforcing material that constitute the metal matrix composite material. Table 1 shows the characteristics of metal-based composite materials manufactured using reinforcing materials made of various inorganic materials. As described above, by selecting various inorganic materials as the reinforcing material, it is possible to appropriately produce a metal-based composite material according to the intended use.

[0022]

[Table 1]

In the present invention, the metal powder is preferably any one of Ti, Nb, Zr, Ta, and Hf. These metal powders have the property of being active against the various reinforcing materials described above under high temperature conditions,
The effect of segregation at the interface between the reinforcing material and the molten metal without remaining in the matrix is remarkably exhibited. Therefore,
The need for special surface treatment to improve wettability,
Alternatively, there is no need to manufacture under high-pressure conditions such as pressure infiltration and melt forging.

Further, the average particle size of the metal powder used at this time is preferably 5 to 80%, more preferably 10 to 70% of the average particle size of the reinforcing material.
It is particularly preferred that it is 0 to 60%. When the average particle size of the metal powder is less than 5% of the average particle size of the reinforcing material, handling becomes inconvenient because it is difficult to obtain the metal powder itself and there is a risk of dust explosion. If it is too high, impregnation of the molten metal into the reinforcing material gap will occur,
It is not preferable because the resulting metal matrix composite cannot be densified.

In the present invention, the amount of the metal powder to be added is preferably 5 to 30% by mass, more preferably 5 to 20% by mass, and more preferably 10 to 20% by mass based on the molten metal to be impregnated. % Is particularly preferred. When the content is less than 5% by mass, a sufficient activation effect of the metal powder on the various reinforcing materials described above cannot be obtained,
It becomes difficult to form a dense composite material. On the other hand, if the content exceeds 30% by mass, when the metal powder dissolves in the molten metal, the melting point is extremely increased, which causes a problem in permeability into the reinforcing material gaps and an excessive amount in the formed matrix. Metal powder may remain. Therefore, characteristics such as electrical conductivity and thermal conductivity may not be expected, which is not preferable.

Further, in the present invention, the volume ratio of the reinforcing material in the metal-based composite material as the final product is 20 to 70.
%, More preferably 25 to 45%, particularly preferably 30 to 40%. When the volume ratio of the reinforcing material is less than 20%, sufficient strength as a metal-based composite material cannot be exhibited, and
If it exceeds 0%, impairment of the molten metal impregnation occurs,
This is because it is difficult to densify the molten metal in a state in which the gap is filled with the molten metal. Therefore, the present invention is a manufacturing method which can be suitably adopted in the content of the reinforcing material constituting a general composite material.

The mixture of the reinforcing material and the metal powder is filled into a jig having an appropriate shape. At this time, it is preferable to increase the filling rate by applying pressure to the powder filled in the jig. A metal to be impregnated is placed on the filled powder and heated to a predetermined temperature under a vacuum of about 0.001 to 0.004 Pa. The heating temperature at this time is set to an appropriate value depending on the melting point of the metal to be impregnated. Specifically, the heating temperature may be about 200 ° C. or 300 ° C. higher than the melting point. Further, after holding for about 0.5 to 10 minutes, the resultant is gradually cooled to produce a metal-based composite material. Further, regarding the holding time, if the holding time is less than 0.5 minute, there is a possibility that impregnation failure may occur when impregnating a thick product, which is not preferable. On the other hand, if it exceeds 10 minutes, the reaction between the reinforcing material and the metal powder proceeds excessively, and the reinforcing material is decomposed, which is not preferable.

Here, the molten metal used in the method for producing a metal-based composite material according to the present invention is Ag, Cu, an Ag alloy, C
It is preferably one of u alloys. These metals do not react with the above-mentioned metal powders to form an intermetallic compound, and it is possible to produce a metal matrix composite whose matrix is a metal. In addition, regarding the metal elements other than Ag and Cu contained in the Ag alloy and Cu alloy used at this time, metal elements that do not form an intermetallic compound with metal powder are preferable from the viewpoint of using the matrix as a metal.

Next, further details of the present invention will be described. As described above, in the present invention, when a reinforcing material including ceramics or the like and a molten metal are composited to produce a metal-based composite material, the active metal (Ti, Z
r, Nb, Hf, etc.) are very active on oxygen, nitrogen and carbon, so that the wettability between the reinforcing material and the molten metal is improved. At this time, microscopically, an interfacial reaction with the molten metal containing the active metal occurs on the surface of the reinforcing material. That is, when the reinforcing material is SiC and the molten metal is a Cu-Ti alloy, a reaction represented by the following formula (1) occurs. SiC + Ti → TiC + Si (in copper) (1)

The reaction shown in the above formula (1) is an exothermic reaction accompanying the production of TiC. Thus, in the present invention, the penetration rate of the molten metal is increased by the local exothermic reaction, and the metal matrix composite can be manufactured in a very short time.

According to the method for producing a metal-based composite material according to the present invention described above, various metal-based composite materials can be produced by utilizing the features. In addition, it is extremely easy to manufacture a metal matrix composite material having a large or complicated shape, and it is possible to perform near net shaping in consideration of the shape of the final product, so that subsequent machining is unnecessary. is there. Further, the surface treatment of the reinforcing material, which is a pretreatment step, is not required, and the number of steps can be reduced, so that the production cost can be easily reduced.

[0032]

EXAMPLES Hereinafter, the present invention will be described with reference to examples, but it is needless to say that the present invention is not limited to these examples. (Examples 1 to 10, Comparative Examples 1 and 2) Various reinforcing materials (crushed particles) having the average particle diameters shown in Table 2 and metal powder were prepared, and the amount of the metal powder added to the impregnated molten metal was 14
The two were mixed so as to be in mass%, and the metal powder was dispersed and attached to the surface of the reinforcing material. Fill this into a given jig,
Pure Ag (> 99.9%) was placed on top of it. 0.00
After being kept under a vacuum of 133 Pa for a while,
It was heated to 060 ° C. and impregnated with Ag. In addition, the volume ratio of the reinforcing material in the obtained metal matrix composite material (hereinafter, referred to as
"Particle volume ratio") was 40%.

In Table 2, for the evaluation symbols in the “synthesis and densification results” column, the maximum penetration distance is “L”.
a ", when the penetration distance of the molten metal is" Lb ", the permeability α (%) is defined as the following equation (2), and the permeability is 100%
Is less than “×”, and the permeability is 100%. However, when the molten metal is not completely spread in the interparticle space and the porosity of the matrix is high, “△”, the permeability is 100%. In addition, a matrix having a low porosity and a high density was marked with “○”. Here, “when the porosity is high” means that the porosity measurement result by the Archimedes method is about 2 to 3% or more, and the same definition is used in the following tables. α = 100 × (La−Lb) / La (2)

[0034]

[Table 2]

As shown in Table 2, when the average particle size of the reinforcing material is smaller than the average particle size of the metal powder (Comparative Examples 1 and 2), it is difficult to synthesize and densify the metal-based composite material. it is obvious.

(Examples 11 and 12) Average particle size is 80 μm
(Pulverized particles) and three kinds of metal powders (Ti, Zr, Nb) having a size of 44 μm are prepared, and they are mixed so that the amount of the metal powder added to the impregnated molten metal is 1 to 30% by mass. By mixing, the metal powder was dispersed and attached to the surface of the reinforcing material (SiC). This was filled in a predetermined jig, and pure Ag (> 99.9%) or pure Cu (tough pitch copper, C1100:> 99.9%) was placed thereon. 0.0
After holding under a vacuum of 0133 Pa for a while, it is heated to 1060 ° C. under the same pressure to impregnate Ag, or 1183 ° C.
The material was impregnated with Cu by heating to about 3 minutes, and then slowly cooled after holding for 3 minutes to produce a metal-based composite material having a matrix of Ag and Cu. In addition, the particle volume ratio of the obtained metal-based composite material was 40%.

With respect to these composite materials, the results of synthesis and densification were observed. Table 3 (Example 11) shows the results for the metal-based composite material in which the matrix is Ag, and Table 4 (Example 12) shows the results for the metal-based composite materials in which the matrix is Cu.

[0038]

[Table 3]

[0039]

[Table 4]

As shown in Tables 3 and 4, the amount of the metal powder added to the molten metal is 5 to 30% by mass, preferably 1%.
When the content was 0 to 30% by mass, a dense metal-based composite material could be produced. In addition, if the impregnation temperature of the molten metal is set higher than the above-mentioned temperature, it is possible to manufacture even if the addition amount of the metal powder exceeds 30% by mass, but the reactivity between the reinforcing material and the metal powder is required. This is not preferable because brittle reaction products may be formed at the interface between the reinforcing material and the matrix.

(Examples 13 and 14) The average particle size was about 80 μm.
m and SiC (pulverized particles) and a metal powder (Ti) of about 44 μm are prepared, and the two are mixed so that the amount of the metal powder added to the molten metal to be impregnated is 1 to 30% by mass. Metal powder (Ti) was dispersed and attached to the surface of (SiC). This is filled in a predetermined jig, and about 1 MPa
At a pressure of 20 to 50%. Thereafter, a metal-based composite material in which the matrix was Ag and Cu was manufactured by the same operation as in Examples 11 and 12 described above.

With respect to these composite materials, the results of synthesis and densification were observed. Table 5 (Example 13) shows the results for the metal matrix composite in which the matrix is Ag, and Table 6 (Example 14) shows the results for the metal matrix composite in which the matrix is Cu.

[0043]

[Table 5]

[0044]

[Table 6]

As is clear from Tables 5 and 6, the amount of the metal powder added to the molten metal is preferably 5 to 30% by mass, and the particle volume ratio is preferably 20 to 50%. Also, as the particle volume ratio is increased,
There is a need to increase the amount of metal powder added to the molten metal.

(Measurement and Test of Various Physical Properties of the Produced Metal Matrix Composite) SiC / Ag, SiC / Cu metal matrix composite material The addition amount of metal powder to the molten metal to be impregnated is 10-3.
A metal-based composite material having a matrix of Ag and Cu was produced in the same manner as in Examples 11 and 12, except that the amount was set to 0% by mass. Sample pieces were cut out from these metal-based composite materials, and the thermal conductivity, the coefficient of thermal expansion, and the bending strength were measured. Table 7 shows the results of the metal matrix composite in which the matrix is Ag, and Table 8 shows the results of the metal matrix composite in which the matrix is Cu. In addition, the measuring method of each said physical property value is as showing below.

[Measurement of Thermal Conductivity]: A sample having a predetermined shape was cut out from the obtained composite material, and the thermal conductivity was measured according to a laser flash method using a thermal constant measuring device (TC-7000, manufactured by Vacuum Riko). The rate was measured. The measurement was performed at room temperature.

[Measurement of coefficient of thermal expansion]: A sample having a predetermined shape was cut out from the obtained composite material, and then, using a thermal dilatometer (manufactured by Mac Science: TD-5000S) in an Ar gas atmosphere at room temperature. To 800 ° C.

[Measurement of flexural strength]: A sample having a predetermined shape was cut out from the obtained composite material, and then subjected to JIS R160.
The strength of the four-point bending test was measured according to 1.

[0050]

[Table 7]

[0051]

[Table 8]

As shown in Tables 7 and 8, it was confirmed that the composite material manufactured by the practice of the present invention had good physical property values. Further, it was found that as the amount of the metal powder added increased, the compounding became easier, but at the same time, phenomena such as a decrease in thermal conductivity and bending strength were caused.

2. Al ₂ O ₃ .AlN.Si ₃ N ₄ / Ag metal matrix composite Al ₂ O ₃ , AlN, Si ₃ having an average particle size of about 80 μm
N ₄ (crushed particles) and a metal powder (T
i) was prepared, the two were mixed so that the amount of the metal powder added to the molten metal to be impregnated was 15% by mass, and pure Ag was used as the molten metal. An Ag-based metal-based composite material was manufactured. For these metal matrix composites, thermal conductivity,
The coefficient of thermal expansion and bending strength were measured. Table 9 shows the results.

[0054]

[Table 9]

As shown in Table 9, it was confirmed that the composite material manufactured according to the present invention had good physical property values.

3. Al ₂ O ₃ .AlN.Si ₃ N ₄ / Cu metal-based composite material The same operation as in the above 2 was performed except that Zr having an average particle size of about 44 μm was used as the metal powder and pure Cu was used as the molten metal. Produced a metal matrix composite in which the matrix was Cu. The thermal conductivity, coefficient of thermal expansion, and bending strength of these metal-based composite materials were measured. Table 10 shows the results.

[0057]

[Table 10]

As shown in Table 10, it was confirmed that the composite material manufactured according to the present invention had good physical properties.

[0059]

As described above, according to the method for manufacturing a metal-based composite material of the present invention, since the metal powder is previously mixed with various reinforcing materials, the wettability between the reinforcing material and the molten metal is reduced. It is possible to produce a metal matrix composite material at a lower temperature and under no pressure as compared with a conventional production method. Further, since it is possible to form a near net shape in consideration of the shape of the final product, it is possible to reduce the number of manufacturing steps and the manufacturing cost.

[Brief description of the drawings]

FIG. 1 is a scanning electron micrograph showing the microstructure of a metal matrix composite material manufactured according to an embodiment of the present invention.

FIG. 2 is a scanning electron micrograph showing a microstructure of a metal-based composite material manufactured according to an embodiment of the present invention, showing a result of performing EDS elemental analysis mapping on Ti.

FIG. 3 is a scanning electron micrograph showing the microstructure of a metal-based composite material manufactured according to an embodiment of the present invention, showing the result of performing EDS elemental analysis mapping on Ag.

FIG. 4 is a scanning electron micrograph showing a microstructure of a metal-based composite material manufactured according to an embodiment of the present invention, showing a result of performing EDS elemental analysis mapping on Si.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) C22C 49/14 C22C 49/14 // (C22C 49/14 101: 04 101: 04 101: 16 101: 16 101: 18 101: 18 101: 14 101: 14) F term (reference) 4K018 AA02 AA03 AB01 AB02 AB03 AC03 BA03 BA20 BB04 BC15 FA35 FA36 KA70 4K020 AA02 AA06 AA08 AA22 AC04 AC05 BA08 BB04 BB22

Claims (8)

[Claims] 1. A method for producing a metal matrix composite material comprising a reinforcing material and a matrix, comprising: mixing the reinforcing material with a metal powder active with respect to the reinforcing material to prepare a mixed powder; A method for producing a metal matrix composite material, comprising filling a mixed powder into a jig having a predetermined shape, and impregnating the filled mixed powder with a molten metal. 2. The method for producing a metal-based composite material according to claim 1, wherein the reinforcing material is an inorganic material having any shape of fiber, particle, or whisker. 3. The method according to claim 1, wherein the inorganic material is Al ₂ O ₃ , AlN, SiC,
Method for producing a metal matrix composite material according to claim 2 is either Si ₃ N _4. 4. The molten metal is Ag, Cu, Ag alloy, Cu
The method for producing a metal-based composite material according to any one of claims 1 to 3, which is one of an alloy. 5. The method according to claim 1, wherein the metal powder is Ti, Nb, Zr, Ta, H
The method for producing a metal-based composite material according to any one of claims 1 to 4, which is any one of (f) and (f). 6. The method according to claim 1, wherein the average particle size of the metal powder is 5 to 80% of the average particle size of the reinforcing material. 7. The amount of metal powder added to the molten metal is 5
The method for producing a metal-based composite material according to any one of claims 1 to 6, wherein the content is from 30 to 30% by mass. 8. The method for producing a metal-based composite material according to claim 1, wherein the volume ratio of the reinforcing material in the metal-based composite material is 20 to 70%.