Metal matrix composite material, method for manufacturing the same, and heat dissipation mechanism

Abstract

This solves the problem of impaired heat dissipation caused by bonding composite materials with heat-dissipating metal materials. [Solution] A metal matrix composite material comprising at least a first region, a second region, and a boundary region between the first region and the second region, The first region is a metal matrix composite material comprising a porous framework and a metal matrix filling the pores of the framework, and has different physical properties from the material of the second region. The boundary region is a region where the volume fraction of the metal matrix composite material in the first region gradually decreases from the first region toward the second region. The problem is solved by using a metal matrix composite material.

Description

[[Technical Field]]

[0001] The present invention relates to a metal matrix composite material, a method for producing the same, and a heat dissipation mechanism. [[Background Art]]

[0002] In recent years, semiconductor heating elements such as GPUs and CPUs have increased in heat generation density, and there has been a demand for heat dissipators having high heat dissipation performance.

[0003] For example, Patent Document 1 discloses a technique for obtaining a metal-graphite composite material having high thermal conductivity in biaxial directions by utilizing the orientation of graphite or the like. Further, Patent Document 2 discloses a technique for obtaining a composite by pressure-impregnating a graphite-containing preform with a molten aluminum alloy or the like, and describes that a composite material having both high thermal conductivity and low thermal expansion coefficient can be obtained. [[Prior Art Documents]] [[Patent Documents]]

[0004] [[Patent Document 1]] Japanese Patent No. 4441768 [[Patent Document 2]] Japanese Unexamined Patent Publication No. 2024-031791 [[Summary of the Invention]] [[Problem to be Solved by the Invention]]

[0005] Composite materials having high thermal conductivity are bonded to heat-dissipating metal materials such as heat-dissipating fins, and are used for the purpose of dissipating heat from a heat source to the outside. In order to bond the composite material and the heat-dissipating metal material, solder bonding or bonding with an adhesive resin interposed is performed. As a result of studies by the present inventor, in bonding between a composite material and a heat-dissipating metal material, adhesive components such as solder and adhesive resin have significantly lower thermal conductivity than the composite material and the heat-dissipating metal material, and thus have been one of the factors that inhibit heat dissipation from a heat source. The present invention aims to solve the problem of impaired heat dissipation caused by bonding a composite material with a heat-dissipating metal material. [Means for solving the problem]

[0006] The inventors of the present invention have conducted extensive research to solve the above problems and have found that the above problems can be solved by configuring the boundary region between the composite material and the heat-dissipating metal material in a specific way. The present invention may include the following inventions.

[0007] [1] A metal matrix composite material comprising at least a first region, a second region, and a boundary region between the first region and the second region, The first region is a metal matrix composite material comprising a porous framework and a metal matrix filling the pores of the framework, and has different physical properties from the material of the second region. The boundary region is a region in which the volume fraction of the metal matrix composite material in the first region gradually decreases from the first region toward the second region, and is a metal matrix composite material. [2] The porous framework is selected from the group consisting of graphite, diamond, silicon carbide, aluminum borate, silicon, magnesium, alumina, and silicon nitride, and is the metal matrix composite material according to [1]. [3] The metal matrix of the first region is selected from the group consisting of an aluminum metal matrix and a copper metal matrix, The material of the second region is selected from the group consisting of aluminum, aluminum alloys, copper, copper alloys, silver, and silver alloys, and is a metal matrix composite material according to [1] or [2]. [4] The first region has at least a front surface and a back surface, and has a thickness between the front surface and the back surface, and when the thermal conductivity in the plane direction (XY direction) parallel to the front surface or back surface is λxy, and the thermal conductivity in the thickness direction (Z direction) perpendicular to the front surface or back surface is λz, A metal matrix composite material according to any of [1] to [3], wherein λxy / λz is 10 or greater. [5] The metal matrix composite material according to [4], wherein λxy is 200 W / (m·K) or more and λz is 10 W / (m·K) or more. [6] The first region comprises a plurality of porous frameworks having anisotropy in thermal conductivity, A metal matrix composite material according to any one of [1] to [5], wherein at least two of the plurality of porous skeletons are arranged so that their directions of high thermal conductivity are orthogonal to each other. [7] A metal matrix composite material according to any one of [1] to [6], having at least one stepped portion between the first region including the boundary region and the second region. [8] The metal matrix composite material according to [7], wherein the stepped portion comprises at least one selected from the group consisting of a stepped shape, a sawtooth shape, an undercut shape, a dovetail shape, and an uneven shape. [9] A heat dissipation mechanism comprising a heating element and a metal matrix composite material according to any one of [1] to [8], The first region of the metal matrix composite material and the heating element are thermally connected. The second region of the metal matrix composite material is a heat dissipation mechanism, which is a heat sink or a cold plate having a coolant flow path inside it.

[10] The heat-generating element is a GPU or a CPU, A heat dissipation mechanism, as described in [9], which is part of an electronic device.

[11] A step of preparing a mold and placing a porous skeleton in the mold, A process of pouring molten metal into the mold to impregnate the porous framework with the molten metal and form a composite material part, and casting a metal part consisting only of molten metal, and A method for manufacturing a metal matrix composite material, comprising the step of cooling the molten metal, The boundary region between the composite material portion and the metal portion is a region where the volume fraction of the composite material gradually decreases from the composite material portion toward the metal portion. A method for manufacturing a metal matrix composite material, wherein there is no bonding layer between the composite material portion and the metal portion. [Effects of the Invention]

[0008] According to the present invention, the problem of heat dissipation being inhibited by bonding a composite material and a heat-dissipating metal material can be solved, and a metal matrix composite material with extremely high heat dissipation effect can be obtained. Furthermore, when the metal matrix composite has the boundary region as described above, it is possible not only to reduce heat dissipation inhibition caused by bonding of dissimilar materials, but also to reduce peeling caused by the difference in coefficient of thermal expansion. Furthermore, mechanical properties such as bending strength and shear strength are also improved. [BRIEF DESCRIPTION OF THE DRAWINGS]

[0009] [Figure 1] It is a schematic diagram showing the metal matrix composite according to an embodiment. [Figure 2] They are an enlarged schematic diagram of the region 13a and electron micrographs at points A to E (drawings substituted for photographs). [Figure 3] It is an enlarged schematic diagram of the region 13a and a graph showing EDX analysis results at points A to E. [Figure 4] It is a graph showing EDX analysis results of the adhesive layer of Comparative Example 2. [Figure 5] They are top views [(a) and (c)] showing heat conduction of samples of Example 1 and Comparative Example 2, and graphs [(b) and (d)] showing temperature distribution on the surface of the Al-graphite composite side of the samples. [Figure 6] It is a schematic cross-sectional outline diagram of a heat sink according to an embodiment. [Figure 7] It is a schematic perspective outline diagram of a cold plate according to an embodiment. [MODE FOR CARRYING OUT THE INVENTION]

[0010] Hereinafter, embodiments of the present invention will be described in detail. When description is made with reference to the drawings, the drawings are schematic diagrams, and dimensional ratios may differ from actual ones. In addition, the same reference numerals are assigned to the same or corresponding components.

[0011] The present embodiment is a metal matrix composite including at least a first region, a second region, and a boundary region between the first region and the second region. The metal matrix composite may consist only of the first region, the second region, and the boundary region between the first region and the second region, or may further have other regions and configurations.

[0012] The first region is a metal matrix composite material region comprising a porous framework and a metal matrix filling the pores of the porous framework. The porous framework only needs to be able to form a metal matrix composite material by filling the pores of the porous framework with a metal matrix, and the material is not limited. Examples include graphite, diamond, silicon carbide, aluminum borate, silicon, magnesium, alumina, and silicon nitride. Furthermore, the volume percentage of the porous framework is not particularly limited and is usually in the range of 40 to 90 volume%, but may also be in the range of 50 to 80 volume%. The porous framework may have a coating layer on its surface. Having a coating layer can improve the wettability of the porous framework, suppress reactions with the matrix layer, and contribute to stabilizing the boundary region. The coating layer is not particularly limited, but examples include ceramic layers, oxide layers, carbide layers, nitride layers, and metal plating layers.

[0013] The second region consists of a material having different physical properties from the first region, and is typically a metallic material. The metal in the second region may be the same metal as the metal matrix in the first region, or it may be a different metal. The metal matrix of the first region is preferably selected from the group consisting of aluminum metal matrix and copper metal matrix, and the metal material of the second region is preferably selected from the group consisting of aluminum, aluminum alloy, copper, copper alloy, silver, and silver alloy. From the viewpoint of manufacturing efficiency, it is preferable that the metal matrix in the first region and the material in the second region are made of the same metal material.

[0014] The metal matrix composite material in the first region and the metal material in the second region have different physical properties, such as thermal conductivity, density, melting point, elastic modulus, and thermal expansion coefficient. Of these, at least one is different, and two or more may be different.

[0015] The boundary region is the region where the volume fraction of the metal matrix composite material in the first region gradually decreases from the first region toward the second region. The boundary region will be explained using Figures 1 to 3.

[0016] Figure 1 is a schematic diagram showing a metal matrix composite material according to one embodiment of the present invention, and is a schematic diagram of a metal matrix composite material formed from the material described below. The metal matrix composite material 10 shown in Figure 1 consists of a first region 11, a second region 12, and a boundary region 13. The first region 11 consists of a porous framework formed of graphite and aluminum (metal matrix) filling the pores of the porous framework. The second region 12 consists of aluminum, which is the same material as the metal matrix of the first region.

[0017] Figures 2 and 3 show enlarged views of the dotted line portion 13a, which includes the boundary region 13 in Figure 1. Figures 2 and 3 are enlarged schematic diagrams of region 13a. The lower part of the diagrams is the side of the first region 11, and the upper part is the side of the second region 12. Figure 2 shows electron microscope images of five locations A to E in region 13a, starting from the second region side. Boundary region 13 is formed by moving from the first region side toward the second region, and the metal group of the first region The volume fraction of the composite material gradually decreases. Specifically, in micrograph E, which is the first region, the area of ​​the porous framework, which is shown darkly in the image, is large, and as you move towards the second region, the area of ​​the porous framework, which is shown darkly in the image, gradually decreases. Furthermore, since the area gradually decreases, it can be inferred that the volume fraction is gradually decreasing.

[0018] Furthermore, the boundary region 13 has a three-dimensional interpenetration structure, similar to those commonly found in regions B, C, and D. In this embodiment, this structure, in which different materials interpenetrate three-dimensionally, significantly reduces thermal resistance due to differences in thermal conductivity, even in regions where different materials are present. It also significantly reduces delamination between different materials due to differences in thermal expansion coefficients.

[0019] Figure 3 shows the EDX analysis results for five locations, A to E, in region 13a, starting from the second region side. In boundary region 13, E, which is closest to the first region among A to E, is mainly composed of graphite (carbon) and aluminum, which are constituent materials of the first region. It can be seen that the peak of carbon, which is not a constituent material of the second region, gradually decreases from E towards B.

[0020] Furthermore, EDX analysis results show that the peaks caused by oxygen (O) are extremely small in the boundary region. That is, when joining two different types of materials, for example, in the case of diffusion bonding, when the joining surfaces are joined, tiny voids or unjointed areas exist at the interface, allowing air to be mixed in, resulting in the presence of an O peak in the EDX analysis. Also, when using adhesive resins, there are O peaks caused by epoxy groups, etc.

[0021] On the other hand, in the boundary region of this embodiment, the ratio of the "O peak" to the "peak of the material showing the maximum peak" in EDX analysis (the ratio of the oxygen peak to the maximum peak) is extremely low, usually 0.01 or less, preferably 0.005 or less, more preferably 0.001 or less, even more preferably 0.0008 or less, and particularly preferably 0.0006 or less. That is, in this embodiment, no joining means are used when combining different materials, and the first region and the second region are formed integrally, so there is no joining surface between the materials.

[0022] A metal matrix composite material of this form having such a structure can be manufactured, for example, by the following method. Note that the following method is an example of manufacturing a carbon-aluminum composite material. (a) Prepare a porous framework (preform) containing graphite, and place a metal matrix composite material including a first region and a second region in a moldable mold. (b) Molten aluminum is supplied into the mold to impregnate the preform and form the first region, and simultaneously form the second region. (c) The molten aluminum is solidified to form a boundary region between the first region and the second region, where the volume fraction of the metal matrix composite material in the first region gradually decreases from the first region towards the second region.

[0023] In Figure 1, the first region 11 has a front surface, which is the bottom surface in the figure, and a back surface, which is on the side of the second region 12 in the figure. The front surface and back surface may be reversed. The first region 11 is substantially rectangular in shape, with a thickness (in the z direction in the figure) between the front surface and the back surface. The shape with the thickness between the front surface and the back surface may be cylindrical or prismatic.

[0024] In the first region having thickness, when the thermal conductivity in the plane direction (XY direction) parallel to the front or back surface is λxy and the thermal conductivity in the thickness direction (Z direction) perpendicular to the front or back surface is λz, it is preferable that λxy / λz is 10 or more, more preferably 50 or more, and even more preferably 100 or more. Having αxy / αz of 10 or more can contribute to the mitigation of hot spots. Furthermore, λxy is preferably 200 W / (m·K) or more, more preferably 300 W / (m·K) or more, and λz is preferably 10 W / (m·K) or more, more preferably 20 W / (m·K) or more.

[0025] To create a first region where λxy / λz is 10 or greater, for example, a porous framework made of a material with anisotropic thermal conductivity, such as graphite, can be used in the manufacturing of the first region. Alternatively, a filler with high thermal conductivity can be incorporated into the matrix and oriented in the xy direction.

[0026] When using a porous framework made of a material with anisotropic thermal conductivity, such as graphite, multiple porous frameworks may be used. At least two of the multiple porous frameworks may be arranged so that their high-thermal-conductivity directions are orthogonal to each other. This configuration makes it possible to suppress the bias in the direction of thermal diffusion in the metal matrix composite material. Furthermore, by appropriately setting the orientation of the high-thermal-conductivity directions of the multiple porous frameworks, the way heat spreads can be optimized according to the application of the metal matrix composite material.

[0027] It is preferable to have at least one stepped portion between the first region, which includes the boundary region, and the second region. Having a stepped portion can improve peel resistance, shear strength, and thermal cycle resistance. Examples of stepped portions include staircase-shaped, sawtooth-shaped, undercut-shaped, dovetail-shaped, and uneven shapes. The height h of the stepped portion (indicating the maximum distance between the first and second regions in the thickness direction of the metal matrix composite material; if it is uneven, it indicates the distance between the convex portion and the concave portion in the thickness direction of the metal matrix composite material) may be 0.05 mm or more and 30 mm or less, or 0.05 mm or more and 5 mm or less.

[0028] The metal matrix composite material in this embodiment, due to its structure as described above, exhibits extremely high thermal conductivity overall, even though it is a composite material containing different materials. The thermal conductivity of the metal matrix composite material from the first region, including the boundary region, to the second region can be 400 W / (m·K) or higher, preferably 450 W / (m·K) or higher, and more preferably 500 W / (m·K) or higher. Therefore, it is possible to efficiently dissipate heat from high-heat-generating components such as CPUs and GPUs.

[0029] Furthermore, even in composite materials containing different materials, the amount of He leakage in He leakage tests at the boundary region is extremely small because there are no bonding surfaces between the materials. Specifically, 1.0 × 10⁻⁶ -9 Pa·m 3 It can be set to less than / s, 1.0 × 10 -10 Pa·m 3 It is preferable that the value be less than or equal to / s.

[0030] The following provides further details and explanations of specific embodiments. Figure 6 is a schematic diagram showing a heat sink 20 according to one embodiment of the present invention. The heat sink 20 has a first region 21, a second region 22, and a boundary region 23. The first region 21, which is made of a metal matrix composite material, can be positioned on the heat receiving surface side, and the second region 22, which has a fin shape, can be positioned on the atmospheric side to dissipate heat to the outside. Since the first region 21 and the second region 22 have a structure in which different materials intersect three-dimensionally in their boundary region, the thermal resistance is extremely low, and efficient heat dissipation from the heat source is possible.

[0031] Figure 7 shows a schematic perspective view of a cold plate 30 according to one embodiment of the present invention. The semiconductor 34 placed on the circuit board 35 generates heat as a heat source. The metal matrix composite material consists of a first region 31, a second region 32, and a boundary region 33, and the second region is provided with a flow path 36 through which a coolant flows. The first region 31 of the metal matrix composite material is placed on the semiconductor 34, thereby transferring heat from the semiconductor to the second region 32, and heat exchange occurs with the coolant passing through the flow path 36.

[0032] The method for manufacturing the metal matrix composite material described above is another embodiment of the present invention. That is, A step of preparing a mold and placing a porous framework into the mold, A process of pouring molten metal into the mold to impregnate the porous framework with the molten metal and form a composite material part, and casting a metal part consisting only of molten metal, and A method for manufacturing a metal matrix composite material, comprising the step of cooling the molten metal, The manufacturing method is such that the boundary region between the composite material portion and the metal portion is a region where the volume fraction of the composite material gradually decreases from the composite material portion toward the metal portion.

[0033] Thus, since molten metal is poured into a porous framework and the composite material and metal parts are integrally cast within the mold, there is no bonding layer between the composite material and the metal parts. Therefore, the problem of heat transfer being blocked by an adhesive layer such as adhesive resin, wax, or solder between different materials, thereby hindering the overall heat dissipation of the metal matrix composite material, can be solved. [Examples]

[0034] The present invention is not limited to the following examples, which will be described in more detail. <Examples> Aluminum (A6061) was prepared as the base material. After degreasing the surface (washing with acetone), the oxide film was removed by weak alkaline washing, followed by washing with pure water and drying. A graphite preform (a porous skeleton with a volume ratio of approximately 60%) was placed on the aluminum base material, and the surrounding area was enclosed with iron material to prevent the molten metal from flowing out. The same aluminum (A6061) as the base material was heated in a nitrogen atmosphere to produce molten aluminum at a temperature of 700°C. The molten aluminum was poured into the preform to impregnate it, and the composite was formed by high-pressure casting at 10 MPa. The composite material was then furnace-cooled from 700°C to 500°C, and subsequently air-cooled to room temperature to obtain a metal matrix composite material in which the metal matrix and second region are made of aluminum and the porous framework is made of graphite.

[0035] Figure 2 shows the results of observing the boundary region of the obtained metal matrix composite material using an electron microscope. The graphite region is shown as darker in the photograph, and the aluminum region is shown as lighter. From Figure 2, it can be seen that the volume fraction of graphite in the metal matrix composite material in the first region gradually decreases from the first region, where molten aluminum was poured into the porous framework, toward the second region, which is the aluminum matrix material. The region indicated by the dotted line in Figure 2 is the boundary region.

[0036] Furthermore, Figure 3 shows the results of elemental analysis performed by EDX at various points in the boundary region of the resulting composite material cross-section. From Figure 3, it can be seen that the carbon peak indicating the presence of graphite in the porous framework gradually decreases from the first region, where molten aluminum was poured into the porous framework, toward the second region, which is the aluminum matrix. The region indicated by the dotted line in Figure 3 is the boundary region. The elemental analysis results obtained by EDX in Figure 3 are shown in Table 1 below.

[0037] [Table 1]

[0038] The physical properties of the obtained metal matrix composite material were measured as follows. The results are shown in Table 2. (1)Interfacial thermal resistance The measurement was performed using the temperature gradient method. Specifically, the measurement was taken using a device in which a metal matrix composite material was placed on a temperature-controlled stage, and a heating element was placed on top of it. (2) Thermal conductivity • Similar to the interfacial thermal resistance, it was measured using the temperature gradient method. (3) Bending strength • Measurements were taken at 25°C in accordance with JIS R 1601 (2008). (4) Shear strength • Measurements were taken at 25°C in accordance with JIS K 6580 (1999). (5) Thermal cycle The metal matrix composite material was cooled from room temperature to -40°C, then heated to 150°C, and cooled back down to room temperature to complete one cycle. After each cycle, the composite material was visually inspected for cracks. (6) Helium leak In accordance with JIS Z 2331, helium gas was sprayed into a vacuum, and the amount of helium gas leakage was measured. The results for each are shown in Table 2.

[0039] <Comparative Example 1> An Al-graphite composite material (ACM-H1), with a graphite volume fraction of 70% and an Al volume fraction of 30%, and an Al material (AC3A material) were stacked and joined using Sn-Cu-Ni solder (HAKO, HEXSOL) as the soldering material. The soldering material was heated on a hot plate, held at a bonding interface temperature of 250°C for 120 seconds, and then air-cooled to join the materials and obtain a composite material related to the comparative example. The thickness of the soldering material layer of the obtained composite material was measured cross-sectionally and found to be an average of 200 μm. Visual inspection of the composite material revealed localized unwetting and minute voids. The properties of the obtained composite material were measured in the same manner as in the examples. The results are shown in Table 2.

[0040] <Comparative Example 2> The surfaces of the Al-graphite composite material (ACM-H1) and Al material (AC3A) were degreased and then roughened with sandblasting equivalent to #120 grit. Then, heat-dissipating silicone (SVC-22) was applied to the surface, and the Al-graphite composite material and Al material were bonded together. The thickness was adjusted using spacers to achieve an adhesive layer thickness of 200 μm. The adhesive layer was cured at 150°C for 60 minutes, and then cured at room temperature for 24 hours. The properties of the obtained composite material were measured in the same manner as in the examples. The results are shown in Table 2.

[0041] [Table 2]

[0042] Figure 4 shows the results of elemental analysis performed by EDX on the Al material side (point F) and the Al-graphite composite material side (point G) of the silicone resin layer used for bonding in Comparative Example 2, in the same manner as in Example 1. From these results, it can be confirmed that the adhesive layer using adhesive resin contains oxygen and other elements due to air introduced during the bonding process. It can be inferred that the interfacial thermal resistance of the comparative example is higher than that of the example due to the inclusion of these impurity elements in the adhesive layer.

[0043] <Reference example> For each of the composite materials in Example 2 and Comparative Example 2, thermal conductivity simulations were performed using COMSOL Multiphysics Ver.6.4 from COMSOL AB. Rectangular samples (20°C) representing each composite material were prepared, with the aluminum side at the bottom and the aluminum-graphite composite side at the top. A simulation of heat conduction was performed when the surface of the aluminum side of each sample was heated to 100°C. The results are shown in Figure 5. Figures (a) and (c) show the temperature distribution on the top surface (Al-graphite side) of the sample. Figures (b) and (d) are graphs of the temperature distribution on the top surface of the sample (showing the temperature distribution at the sample centerline (AA') on the top surface of the sample at 0 seconds, 60 seconds, and 120 seconds after the start of the simulation). From (b) and (d), it can be seen that after heating for 60 seconds, the composite material side of the sample in Example was 72°C, while the composite material side of the sample in Comparative Example 2 was 44°C, confirming that the heat conduction in Example was good. [Industrial applicability]

[0044] The metal matrix composite material according to this embodiment is suitably used for heat dissipation in GPUs, CPUs, AI accelerators, power modules, power devices, drive systems, etc., and can be widely used as a heat dissipation means. [Explanation of symbols]

[0045] 10: Metal matrix composite material 20: Heatsink 30: Cold Plate 11, 21, 31: First area 12, 22, 32: Second area 13, 23, 33: Boundary area 13a: Enlarged portion of the area 34: Semiconductors 35: Circuit board 36: Refrigerant flow path

Claims

1. A metal matrix composite material molded body comprising at least a first region, a second region, and a boundary region between the first region and the second region, The composite material molded body is composed of a porous framework and a metallic material selected from the group consisting of aluminum, aluminum alloys, copper, copper alloys, silver, and silver alloys. The first region is a metal matrix composite material region comprising a porous framework and a metal matrix filling the pores of the framework, and has different physical properties from the metal material in the second region. The boundary region is a region in which the volume fraction of the composite material constituting the first region gradually decreases from the first region towards the second region. A metal matrix composite material molded body in which there is no material-to-material bonding surface between the composite material of the first region and the material of the second region.

2. The porous framework is selected from the group consisting of graphite, diamond, silicon carbide, aluminum borate, silicon, magnesium, alumina, and silicon nitride, as described in claim 1.

3. The metal matrix of the first region is selected from the group consisting of an aluminum metal matrix and a copper metal matrix, as described in claim 1.

4. The first region has at least a front surface and a back surface, and has a thickness between the front surface and the back surface. When the thermal conductivity in the plane direction (XY direction) parallel to the front surface or back surface is λxy, and the thermal conductivity in the thickness direction (Z direction) perpendicular to the front surface or back surface is λz, A metal matrix composite material molded article according to claim 1, wherein λxy / λz is 10 or more.

5. The metal matrix composite material molded article according to claim 4, wherein λxy is 200 W / (m·K) or more and λz is 10 W / (m·K) or more.

6. The first region includes a plurality of porous frameworks having anisotropic thermal conductivity, The metal matrix composite material molded article according to claim 1, wherein at least two of the plurality of porous skeletons are arranged so that their high thermal conductivity directions are orthogonal to each other.

7. The metal matrix composite material molded article according to claim 1, having at least one stepped portion between the first region including the boundary region and the second region.

8. The metal matrix composite material molded article according to claim 7, wherein the stepped portion includes at least one selected from the group consisting of a stepped shape, a sawtooth shape, an undercut shape, a dovetail shape, and an uneven shape.

9. A heat dissipation mechanism comprising a heating element and a metal matrix composite material molded body according to any one of claims 1 to 8, The first region of the metal matrix composite material and the heating element are thermally connected. A heat dissipation mechanism wherein the second region of the metal matrix composite material is a heat sink or a cold plate having a coolant flow path inside the second region.

10. The heat-generating element is a GPU or CPU, A heat dissipation mechanism according to claim 9, which is part of an electronic device.

11. A step of preparing a mold and placing a porous framework into the mold, A process of pouring molten metal into the mold to impregnate the porous framework with the molten metal and form a composite material part, and integrally casting a metal part consisting only of molten metal with the composite material part, and A method for manufacturing a metal matrix composite molded article, comprising the step of cooling the molten metal, The molten metal is selected from the group consisting of aluminum, aluminum alloys, copper, copper alloys, silver, and silver alloys. The boundary region between the composite material portion and the metal portion is a region where the volume fraction of the composite material constituting the composite material portion gradually decreases from the composite material portion toward the metal portion. A method for manufacturing a metal matrix composite molded article, wherein the composite material portion and the metal portion are integrally formed, and there are no material-to-material bonding surfaces between the composite material portion and the metal portion.

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