JP2017150040A - Aluminum alloy-ceramic composite material and manufacturing method of aluminum alloy-ceramic composite material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aluminum alloy-ceramic composite material having high heat conductivity while having predetermined thermal expansibility and a manufacturing method suitable for manufacturing the aluminum alloy-ceramic composite material.SOLUTION: There is provided an aluminum alloy-ceramic composite material having a matrix consisting of Si:2.5-13 mass%, Mg:1-8 mass% and the balance Al with inevitable impurities and a plurality of SiC particles dispersed in the matrix, where the SiC particle has area percentage of 50-75%, circle equivalent particle diameter distribution of d10::25-100 μm, d50:75-200 μm and d90:130-320 μm and contains compound particles consisting of at least one element of Fe, Ti, Ni and V in the matrix and area percentage of a coagulation part with a diameter of 5 μm or more formed by the compound particles is 0.3-1.0%.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an aluminum alloy-ceramic composite material and a method for producing an aluminum alloy-ceramic composite material.

  In recent years, metal-ceramic composite materials that use ceramic fibers, particles, and the like as reinforcing materials have attracted attention as the base metal. In particular, an aluminum alloy-ceramic composite material (hereinafter, an aluminum alloy-ceramic composite material may be simply referred to as a composite material) has strength, ductility, toughness, and molding of a base metal such as aluminum or aluminum alloy. Mainly used for heat dissipation because it combines the strength and heat conductivity of the ceramics made of fibers and particles such as silicon carbide, aluminum nitride, and alumina, which are reinforcing materials. Products, for example, transportation equipment parts, electronic parts, and the like, which are required to be lighter, have higher thermal conductivity, lower thermal expansion, etc., in particular, have been used as heat dissipation boards for dissipating operating heat of semiconductor elements.

Examples of prior art related to such composite materials are disclosed in Patent Documents 1 to 3 below. The manufacturing method of the composite material disclosed in Patent Document 1 is “ceramics obtained by adding at least one of TiO ₂ powder, MgO powder, TiC powder, or TiN powder to ceramic powder or ceramic fiber as a reinforcing material, and mixing them. This is a method for producing a composite material, in which a preform is formed from powder or ceramic fibers, and molten aluminum or aluminum alloy as a matrix is infiltrated into the preform in a nitrogen atmosphere without pressure. According to the manufacturing method of Patent Document 1, it is described that “if a powder such as TiO ₂ powder is included in the preform, the permeation of aluminum or aluminum alloy can be improved”.

  Further, the method for producing a composite material disclosed in Patent Document 2 is “a metal-ceramic composite material in which a preform is formed from ceramic powder, and an aluminum alloy melted in the preform is permeated in a nitrogen atmosphere without pressure. In this manufacturing method, the ceramic powder is an alumina-based ceramic powder containing 1 to 3% by mass of titania powder, and the aluminum alloy is an Al—Mg-based aluminum alloy. ” is there. According to the manufacturing method of Patent Document 2, it is described that “a composite material can be obtained in which the number of pores of 500 μm or more present on the processed surface is significantly reduced”.

Further, the composite material disclosed in Patent Document 3 is “a SiC / Al based composite material having a structure in which a matrix mainly composed of aluminum is filled in pores of ceramic particles of silicon carbide. Is a SiC / Al composite material containing at least one of an aluminum-titanium compound and an aluminum-zirconium compound in addition to metallic aluminum and alumina. In Patent Document 3, as a method for producing the composite material, “(a) at least one impregnation promoting material of titania (TiO ₂ ) and zirconia (ZrO ₂ ) and silicon carbide powder are used to promote the impregnation of silicon carbide. A step of producing a mixed powder mixed so that the particle size ratio of the material is 1/10 or less and the volume ratio of the impregnation promoting material to silicon carbide is 0.15 or more, or molding the mixed powder into a preform And (b) aluminum or aluminum alloy by heating to 1000 ° C. or higher under reduced pressure or non-pressurized inert gas atmosphere in a state where the mixed powder or the preform is in contact with aluminum or an aluminum alloy. Impregnating the mixed powder or the preform into an impregnated body, and (c) cooling the impregnated body to produce a SiC / Al-based composite. And a method for producing a SiC / Al composite material including a step of obtaining a composite material.

JP 2002-241869 A JP 2003-277850 A JP 2010-64954 A

  Here, for example, a heat dissipation substrate, which is one application of a composite material, takes a semiconductor mounted on the heat dissipation substrate as the performance of a semiconductor element becomes higher and / or the power device becomes higher (for example, for an inverter module). It has a low coefficient of thermal expansion in the range of 6 to 10 (ppm / K), which is the same as that of the element and the insulating substrate, and the heat generated by the semiconductor element is released faster to the cooling body etc. via the heat dissipation substrate. There is a demand for a heat dissipation substrate having thermal conductivity. However, the composite material disclosed in Patent Documents 1 to 3 or the composite material obtained by the method for manufacturing a composite material is difficult to implement a heat dissipation substrate having higher thermal conductivity, and is sufficient for the above request. Could not cope with.

  The present invention has been made in view of the above demands, and its object is to provide an aluminum alloy-ceramic composite material having a predetermined thermal expansion coefficient and a high thermal conductivity, and such an aluminum alloy-ceramic composite material. It is providing the suitable manufacturing method in order to manufacture.

  One aspect of the present invention that achieves the above object is that a base composed of Si: 2.5 to 13% by mass, Mg: 1 to 8% by mass, the balance Al and inevitable impurity elements, and a plurality of bases dispersed in the base The SiC particles have an area ratio of 50 to 75%, a circle-equivalent particle size distribution of d10: 25 to 100 μm, d50: 75 to 200 μm, d90: 130 to 320 μm, and Fe particles , Ti, Ni, and V have compound particles composed of at least one element in the matrix, and the area ratio of the agglomerated portion formed by the compound particles having a diameter of 5 μm or more is 0.3 to 1 This is an aluminum alloy-ceramic composite that is 0.0%.

  In the aluminum alloy-ceramic composite material, it is desirable that an average diameter of the aggregated portions having a diameter of 5 μm or more among the aggregated portions is 5 to 15 μm, and in addition, of the aggregated portions having a diameter of 5 μm or more. More preferably, the maximum diameter is 20 μm or less.

  In addition, the area ratio of pores having an equivalent circle diameter of 10 μm or more is desirably 1.5% or less.

  According to the aluminum-ceramic composite material, a composite material having a thermal conductivity of 180 to 240 W / m · K and a thermal expansion coefficient of 6 to 10 ppm / K can be configured.

  The production method according to the present invention suitable for producing the composite material comprises molding a molding powder comprising SiC particles having a particle size distribution of D10: 30 to 120 μm, D50: 90 to 250 μm, and D90: 160 to 400 μm. A preform forming step for forming a preform having a volume fraction of SiC particles of 50 to 75% by volume, and Si: 2.5 to 13% by mass, Mg: 1 to 8% by mass, and the balance being Al. And a permeation step of forming an infiltrated body by infiltrating the molten aluminum alloy composed of inevitable impurity elements in an air atmosphere, and a cooling step for solidifying the molten aluminum alloy by cooling the infiltrated body. The aluminum alloy-ceramic composite in which the powder and the molten aluminum both contain Fe, Ti, Ni or V in a total amount of 0.36 to 0.90% by mass. The method of manufacture is,.

  In addition, in the said manufacturing method, D10: 5-20 micrometers with respect to 100 mass parts of 1st raw material powder which consists of SiC particle | grains which have a particle size distribution of D10: 50-150 micrometers, D50: 100-300 micrometers, D90: 170-450 micrometers, The preform forming step includes a mixing step of mixing 1 to 20 parts by mass of a second raw material powder composed of SiC particles having a particle size distribution of D50: 10 to 40 μm and D90: 15 to 60 μm to obtain a mixed powder. Then, it is desirable to use the mixed powder obtained in the mixing step as the molding powder.

  The present invention provides an aluminum alloy-ceramic composite material having a low thermal expansion coefficient and a high thermal conductivity, and a production method suitable for producing such an aluminum alloy-ceramic composite material.

It is a micro structure photograph which shows an example of the cut surface of the aluminum alloy ceramic composite material which concerns on Example 1 of this invention. It is a figure which shows the image of each element of Al, Si, and C among the results of having analyzed the structure | tissue of Example 1 by EDX. It is a figure which shows the image of O and Mg among the results of having analyzed the structure | tissue of Example 1 by EDX. It is a figure which shows the image of each element of Fe, Ti, and Ni among the results of having analyzed the structure | tissue of Example 1 by EDX. It is a conceptual diagram for demonstrating the definition of the aggregation part which concerns on this invention.

  Hereinafter, the present invention will be described based on the embodiments and examples with reference to the drawings. Here, FIG. 1 is a microstructure photograph showing an example of a cut surface of an aluminum alloy-ceramic composite material according to Example 1 of the present invention. FIG. 2 is a diagram showing images of each element of Al, Si, and C among the results of analyzing the structure of Example 1 by EDX. FIG. 3 is a diagram showing images of O and Mg among the results of analyzing the structure of Example 1 by EDX. FIG. 4 is a diagram showing images of Fe, Ti, and Ni elements among the results of analyzing the structure of Example 1 by EDX. FIG. 5 is a conceptual diagram for explaining the definition of the aggregation portion according to the present invention. In addition, FIGS. 2-4 has shown the EDX analysis result of each element in gray scale as above-mentioned, and has shown that element content is increasing in order of black, gray, and white.

  As shown in FIG. 1, the composite material 10 according to the present invention includes a base 12 made of Si: 2.5 to 13 mass%, Mg: 1 to 8 mass%, the balance Al and inevitable impurity elements, and the base 12 The SiC particles 11 have an area ratio of 50 to 75%, a circle equivalent particle size distribution of d10: 25 to 100 μm, d50: 75 to 200 μm, d90: Aggregation part 13 which is 130-320 micrometers, has a compound particle which consists of at least one element in the element of Fe, Ti, Ni, and V in said base 12, and the diameter formed with said compound particle is 5 micrometers or more Is a composite material having an area ratio of 0.3 to 1.0%. According to such a composite material, by incorporating compound particles at a predetermined ratio as described above, a composite material having a low coefficient of thermal expansion in the range of 6 to 10 ppm / K and a high thermal conductivity is realized. Is done.

As is apparent from the configuration described above, the composite material according to the present invention refers to a member in which SiC particles having a predetermined particle size distribution are dispersed at a predetermined area ratio in a base made of an aluminum alloy. For example, for the purpose of adjusting the elastic modulus, the following compound particles not containing the present compound element (for example, SiO ₂ ) may be added. Hereinafter, components of the composite material according to the present invention will be described in detail.

(base)
The reasons for limiting the composition of the aluminum alloy constituting the base of the composite material are as follows. When Si is less than 2.5% by mass, the strength of the aluminum alloy constituting the base structure is lowered, and the strength of the composite material may be lowered comprehensively. On the other hand, if it exceeds 13% by mass, primary Si may crystallize during solidification and the strength of the composite material may decrease. On the other hand, when Mg is less than 1% by mass, the molten aluminum alloy does not sufficiently permeate into the preform in the permeation process described in detail below, which may increase the pore area ratio and reduce the strength of the composite material. On the other hand, when Mg exceeds 8 mass%, there exists a possibility that thermal conductivity may fall.

(SiC particles)
The equivalent-circle particle size distribution of the SiC particles is desirably d10: 25 to 100 μm, d50: 75 to 200 μm, and d90: 130 to 320 μm. The reason is as follows. When d10 to d90 of the SiC particles are less than the lower limit, the pore area ratio is increased, and the strength of the composite material may be reduced. On the other hand, if all of d10 to d90 exceed the upper limit, the strength of the composite material may similarly decrease. “D10”, “d50”, and “d90” are the 10% cumulative particle size, 50% cumulative particle size, and 90% cumulative particle size in the area-based cumulative distribution of the equivalent particle size distribution of SiC particles. Refers to that.

  The area ratio of the SiC particles is less than 50% and more than 75%, and the balance between the distribution of the base and the SiC particles is poor, and the thermal characteristics (thermal conductivity which is a characteristic required as a member for heat radiation use) , Thermal expansion coefficient, etc.) and mechanical properties (strength, rigidity, toughness, etc.) may not be satisfied. Therefore, the area ratio of SiC particles is desirably 50 to 75%. The area ratio of SiC particles refers to the ratio of the area of SiC particles existing in the visual field to the entire area of the visual field to be observed.

  Although the crystal structure of the SiC particles is polymorphic, as the SiC particles used in the composite material according to the present invention, it is preferable to use SiC particles having a crystal type of 4H or more, and impurities that lower the thermal conductivity. It is desirable to use SiC particles having a low content (for example, Fe, Mg, Mn, Al, B, etc.), preferably 500 ppm or less.

(This compound particle, agglomerated part)
The compound particles according to the present invention (hereinafter, the compound particles may be referred to as the present compound particles) are elements of Fe, Ti, Ni, and V (hereinafter, these elements may be referred to as the present compound elements). Of these compounds (hereinafter, this compound may be referred to as this compound), specifically oxides (FeO, TiO ₂ , NiO, etc.), nitrides (AlN, TiN, etc.), carbides (TiC or the like), oxynitride, carbonitride, or the like. Here, it is not necessary that all of the present compound particles are composed of the present compound, and it is sufficient that an area of approximately 50% or more is occupied by the present compound in a sectional view of the particles. That is, a layer containing the present compound element may be formed on the outer peripheral portion of the SiC particle, but the area of the layer in the cross-sectional view of the SiC particle is only about 20% at most. Thus, the SiC particle in which the thin layer containing the present compound element is formed on the outer peripheral portion is excluded from the present compound particle defined in the present invention, and is regarded as the SiC particle. In addition, the said compound particle | grain can be identified by EDX (Energy dispersive X-ray spectroscopy: Energy dispersive X-ray analysis), for example. Specifically, as shown in FIGS. 2 to 4, the present compound element (Fe, Ti, Ni and V) and O, N and C other elements bonded to the present compound element are mapped by EDX, and the present compound element is mapped. Can be identified as the present compound particles.

  One feature of the composite material according to the present invention is that, among the agglomerated parts composed of the compound particles, the agglomerated parts having a diameter of 5 μm or more are arranged in the base with an area ratio of 0.3 to 1.0%. There is to do. Here, the agglomerated part having a diameter of less than 5 μm does not affect the thermal conductivity and the coefficient of thermal expansion, so the diameter of the agglomerated part of the target compound particles is limited to 5 μm or more. In addition, when the area ratio of the agglomerated part is less than 0.3% and exceeds 1.0%, the thermal conductivity is lowered in all cases, and therefore the area ratio may be 0.3 to 1.0%. desirable. According to the composite material according to the present invention, a composite material having a thermal expansion coefficient of 6 to 10 ppm / K and a thermal conductivity of 180 W / m · K or more can be realized by the composite effect of the above-described constituent elements. In addition, as shown in FIG. 5 which is a conceptual diagram of a cross section of the composite, the aggregation portion 13 according to the present invention refers to a portion where a plurality of the present compound particles 13a are gathered together, specifically adjacent to each other. This refers to an aggregate portion of the present compound particles 13a having a gap S between the particles of 1 μm or less. Moreover, the diameter L of the aggregation part 13 means the diameter of the smallest circle containing the aggregation part 13 as shown in the figure.

  In addition, in order to construct a composite material having a higher thermal conductivity, it is desirable that the average diameter of the aggregated portions having a diameter of 5 μm or more among the aggregated portions is 5 to 15 μm, and the diameter of the aggregated portions is More preferably, the maximum diameter of the compound particles having a diameter of 5 μm or more is 20 μm or less.

  Furthermore, since the composite material according to the present invention is composed of the base, SiC particles, and the present compound particles blended in an appropriate range as described above, the area ratio (pore area ratio) of pores having an equivalent circle diameter of 10 μm or more. ) Is as low as 1.5% or less. The lower limit value of the area ratio of the pores may be 0 in terms of the characteristics of the composite material (that is, pores having an equivalent circle diameter of 10 μm or more do not exist), but the composite material may be used at a reasonable cost in industrial production. It is preferable that it is 0.1% or more from the surface of providing.

The manufacturing method of the composite material described above is not particularly limited and can be manufactured by applying, for example, a powder method or a pressure infiltration method, but the manufacturing method according to the present invention, that is,
(1) A molding powder composed of SiC particles having a particle size distribution of D10: 30 to 120 μm, D50: 90 to 250 μm, D90: 160 to 400 μm, and a volume fraction of SiC particles is 50 to 75% by volume. Forming a preform, and
(2) The preform is infiltrated with a molten aluminum alloy composed of Si: 2.5 to 13% by mass, Mg: 1 to 8% by mass, and the balance of Al and inevitable impurity elements in an air atmosphere to form a permeation body. An infiltration process to
(3) a cooling step of cooling the permeate to solidify the molten aluminum alloy;
Have
The molding powder and the molten aluminum are both applied with a method for producing an aluminum alloy-ceramic composite material containing Fe, Ti, Ni or V (present compound element) in a total amount of 0.36 to 0.90 mass%, It is preferable to manufacture.

  According to such a method for producing a composite material, a molding powder composed of SiC particles having the predetermined particle size distribution is used to form a preform of 50 to 75% by volume in the preform forming step, and the infiltration step and the cooling step. By forming a composite material through the above, a composite material having both a low thermal expansion coefficient and a high thermal conductivity is realized. More specifically, in the method for producing a composite material according to the present invention, the SiC particles to be dispersed in the composite material are filled with a high density by using a molding powder having a particle size distribution defined in the predetermined range. Thus, the thermal conductivity is increased and a low thermal expansion coefficient is realized. Further, the present compound elements in the molding powder and molten aluminum are both limited to a total amount of 0.36 to 0.90 mass%, in other words, the present compound particles contained in the molding powder and molten aluminum. By defining the content within a predetermined range, the thermal conductivity is further improved. In addition, in the method for producing a composite material according to the present invention, since the molten aluminum alloy is infiltrated into the preform in an air atmosphere, operations such as pressure control and atmosphere control in the infiltration process are not required, and the composite material is manufactured at low cost. Since a material can be formed, it is preferable.

  In addition, if the powder for shaping | molding used at a preform shaping | molding process is adjusted so that it may become the said predetermined particle size distribution and this compound element content, the manufacturing method in particular will not be limited. However, D10: 5 to 20 μm, D50: 10 to 40 μm with respect to 100 parts by mass of the first raw material powder composed of SiC particles having a particle size distribution of D10: 50 to 150 μm, D50: 100 to 300 μm, D90: 170 to 450 μm. , D90: 1 to 20 parts by mass of a second raw material powder composed of SiC particles having a particle size distribution of 15 to 60 μm, and a mixing step for obtaining a mixed powder. In the preform forming step, the mixing step It is desirable to use the mixed powder obtained in the above as the molding powder. Hereinafter, the manufacturing method according to the present invention will be described in detail by taking a manufacturing method including a mixing step as a preferred embodiment as an example.

(Mixing process)
In the mixing step, the first raw material powder (D10: 50 to 150 μm, D50: 100 to 300 μm, D90: 170 to 450 μm) made of SiC particles having a predetermined particle size distribution is added to the second raw material powder (D10: 5 to 20 μm). , D50: 10-40 μm, D90: 15-60 μm) at a predetermined ratio to obtain a molding powder. Here, “D10”, “D50” and “D90” are 10% cumulative particle diameter and 50% cumulative particle in the volume-based cumulative distribution when the particle size distribution is measured in accordance with JIS Z 8825: 2013. Diameter, 90% cumulative particle diameter. In the first raw material powder and the second raw material powder, when D10 to D90 are both less than the lower limit, the proportion of fine SiC particles increases, and the penetration of the molten aluminum alloy into the preform in the infiltration process is difficult to proceed. There is a risk that the area ratio of the metal will increase and the thermal conductivity will decrease. On the other hand, in the first raw material powder and the second raw material powder, when D10 to D90 both exceed the upper limit, the ratio of coarse SiC particles increases, and the thermal conductivity may similarly decrease.

  The mixing ratio of the first raw material powder and the second raw material powder is preferably 1 to 20 parts by mass of the second raw material powder with respect to 100 parts by mass of the first raw material powder. Then, at this blending ratio, the first and second raw material powders having the above particle size distribution are mixed, and a molding powder having a predetermined particle size distribution (D10: 40 to 120 μm, D50: 80 to 300 μm, D90: 100 to 500 μm) and forming a predetermined preform with the molding powder, a composite material having a desired level of thermal expansion coefficient and thermal conductivity can be obtained.

  In the method for producing a composite material according to the present invention, the total amount of the present compound elements (Fe, Ti, Ni and V) contained in the molding powder and the molten aluminum is 0.06 to 0.60 mass% in total. This is one of the characteristics. Here, although the SiC particles themselves that mainly constitute the molding powder contain a small amount of this compound element (Fe, Ti, Ni, V), the compound element contained in the SiC particles having a crystal type of 4H or more. The total amount is at most about 500 ppm. That is, the present compound element contained in the molding powder is not substantially contained in the SiC particles, and in addition to the SiC particles, compound (oxide, nitride, carbide, oxynitride or carbonitride) particles containing the present compound element or It exists in the form of metal particles composed of this compound element.

  The forming method of the molding powder containing the present compound element with the content as described above is not particularly limited. In particular, the compound particles or metal particles containing the present compound element contained in the molding powder are particles having a relatively small particle size relative to the SiC particles mainly constituting the molding powder. For example, the molding powder is classified. However, only fine particles may be removed. This classification treatment may be applied to the first raw material powder or the second raw material powder before the mixing step, which is the raw material of the molding powder.

In the mixing step according to the present invention, operations other than those described above are not particularly limited. For example, a binder (binder) or a dispersant may be added to the mixed powder in the mixing step if the strength of the preform after molding is insufficient with only the molding powder. When the binder is added, it is desirable to use an aqueous solution containing 0 to 0.5 parts by mass of SiO ₂ when the molding powder is 100 parts by mass. Here, the aqueous solution when SiO ₂ is 0 part by mass is an aqueous solution not containing SiO ₂ , that is, water. In the case of an aqueous solution containing SiO ₂ can be used commercially available colloidal silica, water glass or the like as a SiO ₂ source.

  The method for mixing the first raw material powder and the second raw material powder is not particularly limited, and a well-known wet or dry mixing apparatus that is commonly used can be used. For example, when an aqueous solution is added as a binder as described above, various wet mixing apparatuses such as a ball mill and a mixer can be used.

(Preform molding process)
In the preform molding step, the mixed powder obtained in the mixing step is molded to form a preform having a particle volume ratio of 50 to 75% by volume. This preform is a porous body having a large number of pores occupying 25 to 50% by volume, and in the permeation step, the molten aluminum alloy penetrates so as to fill the pores. In order to smoothly penetrate the molten aluminum alloy and obtain a composite material having a low pore area ratio, the average pore diameter is preferably 10 to 45 μm, and the specific surface area of the pores is 0.15 mm ² / g. The following is desirable.

  The preform molding method is not particularly limited, and various wet and dry molding methods such as a known pressure method, extrusion method, injection method, and mud casting method can be used. For example, when an aqueous solution is added to the mixed powder as a binder to form a slurry as described above, the slurry is supplied to the cavity from the opening of the mold, filled by pressurization, and solidified appropriately and then removed. What is necessary is just to shape | mold by the method. In addition, what is necessary is just to use for a osmosis | permeation process by using a molded object as a preform, even if the molded object only formed is sufficient. On the other hand, when the strength of the molded body is insufficient, the molded body is subjected to a heating (firing) treatment to form a fired body or calcined body having sufficient strength, and these are used as a preform for the infiltration step. You may provide.

(Penetration process)
In the infiltration step according to the present invention, the preform formed in the preform molding step is infiltrated with an aluminum alloy molten metal that becomes a base after solidification in an air atmosphere. Here, “under atmospheric atmosphere” means in the atmosphere (air) under atmospheric pressure (non-pressurized / non-depressurized). In the infiltration process according to the present invention, since it is processed in the air atmosphere as described above, a large-scale apparatus such as a casting method, a powder metallurgy method or a pressure infiltration method is not required, and a composite material is manufactured at a low cost. It becomes possible. In addition, according to the infiltration method in the air atmosphere according to the present invention, since the lower limit combined with both the compounding powder in the molding powder and the molten aluminum forming the preform as described above, Due to the presence of the present compound particles composed of the present compound element, the molten aluminum alloy penetrates more smoothly into the pores of the preform. As a result, large pores are not easily formed between the SiC particles and the like constituting the composite material and the aluminum alloy, and the heat transfer loss between the two is small, so that a composite material having high thermal conductivity can be obtained.

  As described above, the molten aluminum alloy used in the infiltration step is limited to the amount of the present compound element together with the molding powder, and then Si: 2.5 to 13% by mass, Mg: 1 to 8% by mass, and the balance Al And a molten metal composed of inevitable impurity elements. When Si is less than 2.5% by mass, the strength of the aluminum alloy constituting the base structure is lowered, and the strength of the composite material may be lowered comprehensively. On the other hand, if it exceeds 13% by mass, primary Si may crystallize during solidification and the strength of the composite material may decrease. On the other hand, if Mg is less than 1% by mass, the molten aluminum alloy does not sufficiently permeate into the preform in the infiltration step, and the strength of the composite material may be reduced. On the other hand, when Mg exceeds 8 mass%, there exists a possibility that thermal conductivity may fall.

  As inevitable impurity elements, elements such as Mn, Sr, Sn, P, Cr, Cu, and Zn are also mixed as inevitable impurity elements derived from dissolved raw materials. For this reason, these elements may basically have an allowable content of each impurity in accordance with JIS standards, etc., but it is allowable to include a significant amount within a content range that does not impair the object of the present invention. Is done. Moreover, the impurity element which has a more preferable effect with respect to the object of the present invention does not prevent the active addition and inclusion thereof.

  In addition, the melting method and molten metal processing method of an aluminum alloy molten metal are not specifically limited. For example, reducing the amount of hydrogen dissolved in the molten aluminum alloy is effective in suppressing pores contained in the composite material. Specifically, the amount of dissolved hydrogen can be reduced by a method of blowing an argon gas at an appropriate flow rate into the molten aluminum alloy or a method of appropriately selecting an input flux amount and a treatment time for the flux treatment.

(Cooling process)
After the permeation step, a composite material is formed by cooling a permeation body in which the molten aluminum alloy penetrates into the pores of the preform and solidifying the molten aluminum alloy. The method for cooling the penetrating body is not particularly limited, and for example, it may be gradually cooled in the air, or may be rapidly cooled by placing the penetrating body on an appropriate cooling metal. In addition, in order to suppress the occurrence of shrinkage cavities during solidification, a molten metal replenishment unit may be disposed at a necessary portion of the penetrant.

(Examples and Comparative Examples)
Next, specific examples and comparative examples of the present invention will be described below with reference to tables and drawings. However, the present invention is not limited to these. Further, production conditions and measurement conditions without particular notice are common to both the examples and comparative examples shown in the table.

(Molding powder)
As shown in Table 1, a first raw material powder and a second raw material powder having a predetermined particle size distribution (D10, D50, D90) are prepared, and at a predetermined mixing ratio with respect to 100 parts by mass of the first raw material powder. The second raw material powder was mixed (mixing step) to obtain molding powders of model numbers A to E used in the examples and model numbers F to I used in the comparative examples. Table 1 shows the particle size distribution of the first raw material powder, the second raw material powder and the molding powder, and the ratio (mass%) of the present compound elements (Fe, Ti, Ni and V) contained in the molding powder. It is as follows. In addition, the measuring method of a particle size distribution was based on JIS Z8825: 2013, and measured with the Nikkiso Co., Ltd. microtrack (model | form: MT3100II). Moreover, the ratio of this compound element in the powder for shaping | molding was measured with the Shimadzu Corporation ICP emission-spectral-analysis apparatus (model | form: ICPS-8000).

Example 1
To the 100 g of molding powder A obtained in the mixing step, an aqueous solution obtained by further diluting sodium silicate (manufactured by Fuji Chemical, No. 2) and water at a volume ratio of 1: 2 is added at a ratio of 4.5 ml. And then stirred and mixed for 3 minutes to obtain a slurry.

  MC nylon molds with a cavity shape of 50 mm long, 150 mm wide, and 50 mm deep are filled with the slurry, molded, carbon dioxide gas is passed through to harden the slurry, and then removed from the mold. The preform was obtained by heat treatment (holding) at 2 ° C. for 2 hours and firing (pull foam molding step). As shown in Table 2, the volume fraction of SiC particles in the preform of Example 1, that is, the ratio of SiC particles in the volume of the outer shape was 61.0%. This SiC particle volume fraction was obtained by dividing the mass of the produced preform by the product of the cavity volume of the mold and the density of SiC.

  As shown in Table 2, Si: 9% by mass, Mg: 4.5% by mass, the total amount of the present compound element: 0.27% by mass, and the aluminum alloy melt composed of the balance Al and inevitable impurity elements are composed of a graphite crucible. Hold at 830 ° C. in a holding furnace, hold the preform obtained in the molding step in the held molten aluminum alloy bath for 30 minutes in an atmospheric atmosphere (non-pressurized), Penetration (penetration process). In addition, before the preform was immersed in the molten metal bath, the molten metal was dehydrogenated in advance. The dehydrogenation treatment was performed by blowing argon gas into the molten metal. After the infiltration step was completed, the preform infiltrated with the molten aluminum alloy was taken out of the molten bath and cooled to obtain a composite material (cooling step).

  The resulting composite material of each Example and Comparative Example, the morphology (base area ratio, SiC particle equivalent circle average particle diameter and particle size distribution, area ratio of the agglomerated portion of the compound particles, diameter, maximum diameter, circle The pore area ratio with an equivalent diameter of 10 μm or more), density, bending strength, bending elastic modulus, linear expansion coefficient, and thermal conductivity at room temperature were measured by the following methods.

  The organization form was determined as follows. First, EDX analysis was performed as described above for any five visual fields magnified by 250 times with a SEM (Scanning Electron Microscope). And the area ratio of the SiC particle was calculated | required by remove | dividing the area of the SiC particle identified as follows by the area of each whole visual field. And the average value of 5 visual fields was made into the SiC particle area ratio. As shown in Table 3, the SiC particle area ratio of Example 1 was 60.8%.

  For SiC particles, particles in which both Si and C are detected by EDX analysis are identified as SiC particles, and an image analysis device (Asahi Kasei Engineering Co., Ltd., trade name “A image kun”, the same in the following image analysis), The equivalent circle particle size and particle size distribution (d10, d50, d90) were obtained for each of the five fields of view, and the average value of the five fields of view was defined as the circle equivalent particle size distribution (d10, d50, d90). The SiC particles of Example 1 had d10 of 73 μm, d50 of 111 μm, and d90 of 162 μm.

  As shown in FIGS. 2 to 4, the present compound particles were identified as the present compound particles by EDX analysis in which particles of the present compound element (Fe, Ti, Ni or V) and O, N or C were detected. In addition, since V contained in each Example and a comparative example is detected in the same place as Ti by EDX analysis, the display of the EDX analysis result of V is abbreviate | omitted. Then, in the image analyzer, the present compound particles having a gap between adjacent particles of 1 μm or less are selected to confirm the agglomerated part, the diameter of the agglomerated part is obtained, and the diameter of the identified agglomerated part is 5 μm or more. The area of the agglomerated part was calculated, and the average value of the five fields was defined as the area ratio (%) of the agglomerated part. Further, the average diameter of the agglomerated part having a diameter of 5 μm or more was the average value of 5 visual fields, and the maximum diameter was the maximum value of 5 visual fields. The area ratio of the agglomerated part having a diameter of 5 μm or more in Example 1 in which the total amount of the present compound element contained in the molding powder and the molten aluminum alloy was 0.38% by mass (hereinafter simply referred to as the area ratio of the agglomerated part) As shown in Table 3, the average diameter and the maximum diameter were 0.6%, the average diameter was 10 μm, and the maximum diameter was 14 μm.

  The pore area ratio was determined as follows. In the cross section of the obtained composite material, arbitrary five visual fields magnified 100 times with an optical microscope were observed. For each field of view, binarized into pores with an equivalent circle diameter of 10 μm or more that affect product characteristics (strength, thermal conductivity, etc.) and other parts, and the area ratio of the pores was measured with an image analyzer. . The average value of the pore area ratios of the five visual fields thus measured was defined as the pore area ratio having an equivalent circle diameter of 10 μm or more. As shown in Table 3, the pore area ratio of the composite material of Example 1 was 0.6%.

As shown in Table 4, the density of the composite material of Example 1 obtained by geometric measurement in accordance with the solid specific gravity measurement method specified in JISZ8807: 2012 was 2.92 × 10 ³ kg / m ³ . Bending strength is 3 points according to JIS R1601: 2008 using a test piece cut out of 45 mm × 4 mm × 3 mm from the obtained composite material with an Instron universal testing machine (Instron, model 5565, maximum load 5 kN). It was measured by a bending test. As shown in Table 4, the bending strength of the composite material of Example 1 was 300 MPa.

  The linear expansion coefficient was measured by a method based on JIS R1618: 2002 using a thermomechanical analyzer (manufactured by Netzsch, model: TMA4000) for a test piece cut out to 5 mm × 5 mm × 15 mm from the obtained composite material. The linear expansion coefficient of the composite material of Example 1 was 8 ppm / K.

  The density required for calculating the thermal conductivity was determined as follows. About the test piece cut out to 20 mm x 20 mm x 20 mm from the obtained composite material, the mass was measured at room temperature, and from this mass, the mass of industrial purified water in an amount corresponding to the volume of the same dimension as the test piece was measured at room temperature. The value obtained by dividing was taken as the density.

  The thermal conductivity at room temperature was determined by measuring a disk-shaped test piece cut out from the obtained composite material into a diameter of 10 mm and a thickness of 3.0 mm using a laser flash method (thermal diffusivity measuring device manufactured by Nezsch, model: NFL-447). Mold) was used to measure the thermal diffusivity and specific heat at 25 ° C. ± 1 ° C., and the product of the product of both and the density determined above was defined as the thermal conductivity at room temperature. The thermal conductivity of the composite material of Example 1 was 208 W / m · K.

(Example 2)
In Example 2, the molding powder B shown in Table 1 was used, and as shown in Table 2, a molded body having a SiC volume ratio of 61.5% was formed, and the molten aluminum alloy was Si: 11.8. A composite material was produced in the same manner as in Example 1, except that the mass%, Mg: 1.3 mass%, and the present compound element: 0.25 mass%. The area ratio of the SiC particles of the composite material of Example 2 was 61.5%, and the d10 · d50 · d90 of the SiC particles were 29 μm, 79 μm, and 138 μm, respectively. Further, the area ratio of the agglomerated part of Example 2 in which the total amount of the present compound element contained in the molding powder and the molten aluminum alloy was 0.38% by mass was 1.0%, the average diameter was 11 μm, and the maximum diameter was It was 15 μm. Furthermore, the pore area ratio is 1.4%, and the density, bending strength, linear expansion coefficient and thermal conductivity at room temperature are 2.85 × 10 ³ kg / m ³ , 320 MPa, 9 ppm / K and 189 W / There was m · K.

(Example 3)
In Example 3, the molding powder C shown in Table 1 was used, and as shown in Table 2, a molded body having a SiC volume fraction of 70.1% was formed, and the molten aluminum alloy was Si: 12% by mass. A composite material was produced in the same manner as in Example 1, except that Mg: 4.5% by mass and the present compound element: 0.28% by mass. The area ratio of the SiC particles of the composite material of Example 3 was 68.5%, and d10, d50, and d90 of the SiC particles were 77 μm, 174 μm, and 281 μm, respectively. Further, the area ratio of the agglomerated part of Example 3 in which the total amount of the present compound element contained in the molding powder and the molten aluminum alloy was 0.37% by mass was 0.3%, the average diameter was 7 μm, and the maximum diameter was It was 10 μm. Furthermore, the pore area ratio is 0.3%, and the density, bending strength, linear expansion coefficient, and thermal conductivity at room temperature are 2.96 × 10 ³ kg / m ³ , 250 MPa, 6.5 ppm / K and It was 223 W / m · K.

Example 4
In Example 4, the molding powder D shown in Table 1 was used, and as shown in Table 2, a molded body having a SiC volume fraction of 58.0% was formed, and the aluminum alloy melt was Si: 6% by mass. A composite material was produced in the same manner as in Example 1, except that Mg: 7.6% by mass and the present compound element: 0.28% by mass. The area ratio of the SiC particles of the composite material of Example 4 was 58.0%, and d10, d50, and d90 of the SiC particles were 80 μm, 112 μm, and 159 μm, respectively. Further, the area ratio of the agglomerated part of Example 4 in which the total amount of the present compound element contained in the molding powder and the molten aluminum alloy was 0.37% by mass was 0.7%, the average diameter was 12 μm, and the maximum diameter was 18 μm. Furthermore, the pore area ratio is 0.9%, and the density, bending strength, linear expansion coefficient, and thermal conductivity at room temperature are 2.91 × 10 ³ kg / m ³ , 280 MPa, 9.5 ppm / K and It was 200 W / m · K.

(Example 5)
In Example 5, the molding powder E shown in Table 1 was used, and as shown in Table 2, a molded body having a SiC volume fraction of 54.0% was formed, and the molten aluminum alloy was Si: 3.5. A composite material was produced in the same manner as in Example 1 except that the mass%, Mg: 4.5 mass%, and the present compound element: 0.31 mass%. The area ratio of SiC particles of the composite material of Example 5 was 56.9%, and d10 · d50 · d90 of the SiC particles were 40 μm, 85 μm, and 137 μm, respectively. The area ratio of the agglomerated part of Example 5 in which the total amount of the present compound element contained in the molding powder and the molten aluminum alloy was 0.8% by mass was 1.0%, the average diameter was 15 μm, and the maximum diameter was It was 20 μm. Furthermore, the pore area ratio is 1.3%, and the density, bending strength, linear expansion coefficient and thermal conductivity at room temperature are 2.90 × 10 ³ kg / m ³ , 310 MPa, 8.5 ppm / K and It was 190 W / m · K.

(Comparative Example 1)
In Comparative Example 1, as shown in Table 2, a composite material was produced in the same manner as in Example 1 using the molding powder A except that a molded body having a SiC volume ratio of 49.4% was molded. The area ratio of SiC particles of the composite material of Comparative Example 1 was 49.1%, and d10, d50, and d90 of the SiC particles were 80 μm, 115 μm, and 168 μm, respectively. The area ratio of the agglomerated part in Comparative Example 1 was 0.9%, the average diameter was 15 μm, and the maximum diameter was 18 μm. Furthermore, the pore area ratio is 1.3%, and the density, bending strength, linear expansion coefficient and thermal conductivity at room temperature are 2.88 × 10 ³ kg / m ³ , 245 MPa, 11.3 ppm / K and It was 184 W / m · K.

(Comparative Example 2)
In Comparative Example 2, as shown in Table 2, a composite material was manufactured in the same manner as in Example 1 using the molding powder A except that a molded body having a SiC volume ratio of 76.8% was molded. The area ratio of SiC particles of the composite material of Comparative Example 2 was 76.2%, and d10, d50, and d90 of the SiC particles were 64 μm, 109 μm, and 172 μm, respectively. The area ratio of the agglomerated part in Comparative Example 2 was 1.3%, the average diameter was 14 μm, and the maximum diameter was 17 μm. Furthermore, the pore area ratio is 2.4%, and the density, bending strength, linear expansion coefficient and thermal conductivity at room temperature are 2.85 × 10 ³ kg / m ³ , 240 MPa, 5.8 ppm / K and It was 169 W / m · K.

(Comparative Example 3)
In Comparative Example 3, the molding powder F shown in Table 1 was used, and as shown in Table 2, a molded body having a SiC volume ratio of 68.9% was formed, and the molten aluminum alloy was Si: 12% by mass. A composite material was produced in the same manner as in Example 1, except that Mg: 2.5 mass% and the present compound element: 0.25 mass%. The area ratio of the SiC particles of the composite material of Comparative Example 3 was 68.9%, and the d10 · d50 · d90 of the SiC particles were 10 μm, 71 μm, and 127 μm, respectively. Further, the area ratio of the agglomerated part of Comparative Example 3 in which the total amount of the present compound element contained in the molding powder and the molten aluminum alloy was 0.36% by mass was 0.8%, the average diameter was 11 μm, and the maximum diameter was 18 μm. Furthermore, the pore area ratio was 7.8%, and the density, bending strength, linear expansion coefficient and thermal conductivity at room temperature were 2.80 × 10 ³ kg / m ³ , 220 MPa, 7 ppm / K and 159 W / m · K.

(Comparative Example 4)
In Comparative Example 4, the molding powder G shown in Table 1 was used, and as shown in Table 2, a molded body having a SiC volume ratio of 54.0% was formed, and the molten aluminum alloy was Si: 9% by mass. A composite material was produced in the same manner as in Example 1, except that Mg: 4.4% by mass and the present compound element: 0.25% by mass. The area ratio of SiC particles of the composite material of Comparative Example 4 was 54.0%, and d10 · d50 · d90 of the SiC particles were 163 μm, 272 μm, and 340 μm, respectively. Further, the area ratio of the agglomerated part of Comparative Example 4 in which the total amount of the present compound element contained in the molding powder and the molten aluminum alloy was 0.4% by mass was 0.6%, the average diameter was 16 μm, and the maximum diameter was It was 21 μm. Further, the pore area ratio is 0.7%, and the density, bending strength, linear expansion coefficient and thermal conductivity at room temperature are 2.88 × 10 ³ kg / m ³ , 120 MPa, 9.8 ppm / K and It was 184 W / m · K.

(Comparative Example 5)
In Comparative Example 5, the molding powder H shown in Table 1 was used, and as shown in Table 2, a molded body having a SiC volume ratio of 61.3% was formed, and the molten aluminum alloy was Si: 8.8. A composite material was produced in the same manner as in Example 1, except that the mass%, Mg: 4.3 mass%, and the present compound element: 0.30 mass%. The area ratio of SiC particles of the composite material of Comparative Example 5 was 60.8%, and d10 · d50 · d90 of the SiC particles were 73 μm, 111 μm, and 162 μm, respectively. Further, the area ratio of the agglomerated part of Comparative Example 5 in which the total amount of the present compound element contained in the molding powder and the molten aluminum alloy was 0.34% by mass was 0.25%, the average diameter was 4 μm, and the maximum diameter was It was 6 μm. Further, the pore area ratio is 5.2%, and the density, bending strength, linear expansion coefficient and thermal conductivity at room temperature are 2.82 × 10 ³ kg / m ³ , 250 MPa, 8.2 ppm / K and It was 167 W / m · K.

(Comparative Example 6)
In Comparative Example 6, the molding powder I shown in Table 1 was used, and as shown in Table 2, a molded body having a SiC volume ratio of 61.0% was formed, and the aluminum alloy melt Si: 9.2 A composite material was produced in the same manner as in Example 1, except that the mass%, Mg: 4.6 mass%, and the present compound element: 0.32 mass%. The area ratio of SiC particles of the composite material of Comparative Example 6 was 60.8%, and d10 · d50 · d90 of the SiC particles were 73 μm, 111 μm, and 162 μm, respectively. Further, the area ratio of the agglomerated part of Comparative Example 6 in which the total amount of the present compound element contained in the molding powder and the molten aluminum alloy was 1.11% by mass was 1.6%, the average diameter was 22 μm, and the maximum diameter was It was 34 μm. Furthermore, the pore area ratio is 0.4%, and the density, bending strength, linear expansion coefficient, and thermal conductivity at room temperature are 2.92 × 10 ³ kg / m ³ , 300 MPa, 7.8 ppm / K and It was 175 W / m · K.

As is clear from the results of the above Examples and Comparative Examples, in Examples 1 to 5 which are within the scope of the present invention, a composite material having both a low thermal expansion coefficient and a high thermal conductivity could be obtained. On the other hand, in Comparative Examples 1-3, 5, and 6, which are outside the scope of the present invention, the thermal expansion coefficient was high or the thermal conductivity was low. In Comparative Example 4, it was found that although the thermal expansion coefficient was low and the thermal conductivity was high, the bending strength was extremely low.

DESCRIPTION OF SYMBOLS 10 Aluminum alloy-ceramics composite material 11 SiC particle 12 Base 13 Aggregation part 13a This compound particle 14 Pore

Claims (7)

Si: 2.5 to 13% by mass, Mg: 1 to 8% by mass, balance Al and inevitable impurity elements, and a plurality of SiC particles dispersed in the matrix,
The SiC particles have an area ratio of 50 to 75%, a circle-equivalent particle size distribution of d10: 25 to 100 μm, d50: 75 to 200 μm, d90: 130 to 320 μm,
The matrix has compound particles composed of at least one of the elements Fe, Ti, Ni and V, and the area ratio of the agglomerated portion formed of the compound particles and having a diameter of 5 μm or more is 0.3 to 1.0% aluminum alloy-ceramic composite.   2. The aluminum alloy-ceramic composite material according to claim 1, wherein an agglomerated portion having a diameter of 5 μm or more among the agglomerated portions has an average diameter of 5 to 15 μm.   The aluminum alloy-ceramic composite material according to claim 1 or 2, wherein a maximum diameter of an agglomerated portion having a diameter of 5 µm or more among the agglomerated portions is 20 µm or less.   The aluminum alloy-ceramic composite material according to any one of claims 1 to 3, wherein an area ratio of pores having an equivalent circle diameter of 10 µm or more is 1.5% or less.   The aluminum alloy-ceramic composite material according to any one of claims 1 to 4, which has a thermal conductivity of 180 to 240 W / (m · K) and a thermal expansion coefficient of 6 to 10 ppm / K. D10: 30 to 120 μm, D50: 90 to 250 μm, D90: 160 to 400 μm, forming a molding powder composed of SiC particles to form a preform having a volume fraction of SiC particles of 50 to 75% by volume. A preform molding process;
A permeation step of forming a permeation body by impregnating the preform with an aluminum alloy melt consisting of Si: 2.5 to 13% by mass, Mg: 1 to 8% by mass, and the balance being Al and inevitable impurity elements in the atmosphere. When,
A cooling step of cooling the permeation body to solidify the molten aluminum alloy;
Have
The said forming powder and aluminum molten metal are both the manufacturing method of an aluminum alloy-ceramics composite material which contains Fe, Ti, Ni, or V in total 0.36-0.90 mass%.   D10: 5 to 20 μm, D50: 10 to 40 μm, D90 with respect to 100 parts by mass of the first raw material powder composed of SiC particles having a particle size distribution of D10: 50 to 150 μm, D50: 100 to 300 μm, D90: 170 to 450 μm 1 to 20 parts by mass of the second raw material powder composed of SiC particles having a particle size distribution of 15 to 60 μm, and a mixing step for obtaining a mixed powder. In the preform forming step, the mixing step is performed. The method for producing an aluminum alloy-ceramic composite material according to claim 6, wherein the mixed powder is used as the molding powder.

Images