TWI546139B - Method for making a composite material, and composite material - Google Patents

Description

Composite material manufacturing method and composite material

The present invention relates to a method and a composite material for a composite material comprising a plurality of metals.

In the conventional method for producing a composite material containing a plurality of metals, a calendering method, a sintering method, a melting method, and the like are known (for example, refer to Patent Document 1). The calendering method, the sintering method, the melting method, and the like have a step of bringing a different type of metal material into a state of being mixed or contacted to a high temperature (for example, a melting point or a softening point or more), and a combination of metal types is used. There is a case where an intermetallic compound is formed and the function of the composite material is lowered.

In recent years, a composite film has been proposed by applying a film forming method called a cold spray method (for example, see Patent Document 2). Here, the cold spray method is a method in which a metal or alloy powder is sprayed through a nozzle together with an inert gas in a state below a melting point or a softening point, and directly collides with a substrate in a solid phase state to form a film on the surface of the substrate. method. In the cold spray method, a metal bond and an anchor effect are generated by causing a powder to collide with a lower layer (a substrate or a powder deposited on a substrate), and a film having high adhesion and tightness to the lower layer is formed. . At the same time, compared with the spray method, since the step is performed at a relatively low temperature in the cold spray method, a film which has suppressed oxidation of metal or the like can be formed.

The above Patent Document 2 discloses the use of granulation or coating to make several metals or combinations The composite powder of the gold composite is formed into a heat resistant alloy film by performing the above-described cold spray method. More specifically, in Patent Document 2, a composite powder in which a material (pure metal) having good adhesion in a cold spray method is coated on the surface of a material (alloy powder) having poor adhesion in a cold spray method is used.

[Previous Technical Literature]

Patent Document 1: Japanese Laid-Open Patent Publication No. 2001-26856

Patent Document 2: Japanese Laid-Open Patent Publication No. 2011-132565

However, it is important in the cold spray method that the injection conditions, which are the temperature or pressure (flow rate) of the inert gas sprayed together with the powder, must be appropriately set. In this regard, for example, when the above composite powder is used, if the spraying conditions (for example, the melting point of the pure metal) are set in accordance with the material (pure metal) of the surface of the composite powder, the sprayed composite powder is caused to collide with the substrate. At the time of this, it is not possible to cause a sufficient reaction in the alloy powder on the inner side, and it is possible to form a film having insufficient adhesion or tightness to the lower layer. Conversely, if the spraying conditions are set to match the material inside the composite material (alloy powder), the material of the surface will be softened and the composite materials will adhere to each other and the suitable spraying conditions will be changed, so that the composite material adheres to the nozzle to cause clogging. As a result, there is a situation in which the injection cannot be operated normally. In this case, it is difficult to form a homogeneous film having adhesion or tightness to the lower layer.

In view of the above problems, an object of the present invention is to provide a method for producing a composite material, and a composite material produced by the same, which is stable in the production of a composite material containing a plurality of metals or alloys different from each other. A homogeneous composite material having sufficient adhesion and tightness to the underlying layer is produced.

In order to solve the above problems and achieve the object, the production method according to the present invention includes a film forming step including at least a first layer containing a powder of a first metal or alloy and a reactivity lower than the first metal Or the second metal or alloy of the alloy is coated with the second layer formed by the first layer, and in the film forming step, the composite powder composed of the second layer and the outermost layer is accelerated together with the gas, and at least the foregoing The surface of the composite powder is sprayed on the surface of the substrate while being held in a solid phase state, and is deposited to form a film.

In the method for producing a composite material, the film forming step is performed by spraying the composite powder onto the surface of the substrate in accordance with conditions set in accordance with characteristics of the second metal or alloy.

In the method for producing a composite material, the melting point of the first metal or alloy is lower than the melting point of the second metal or alloy.

In the method for producing a composite material, the ionization tendency of the first metal or alloy is greater than the ionization tendency of the second metal or alloy.

In the method for producing a composite material, the hardness of the first metal or alloy is lower than the hardness of the second metal or alloy.

In the method for producing a composite material, the second layer is formed around the first layer by a plating method.

In the method for producing a composite material, the film forming step includes a mixing powder preparation step of mixing the powder composed of the second metal or alloy with the composite powder, and spraying the mixed powder on the surface of the substrate.

The composite material according to the present invention is a composite material having at least a first layer formed of a first metal or alloy and a second layer or alloy having a lower reactivity than the first metal or alloy. Forming the second layer and making the second layer The composite powder which constitutes the outermost layer of the layer is accelerated together with the gas, and at least the surface of the composite powder is adhered to the surface of the substrate in a solid phase state and deposited.

The composite material according to the present invention is a composite material containing a first metal or alloy and a second metal or alloy having lower reactivity than the first metal or alloy, wherein the second metal or alloy has a network structure. The first metal or alloy is filled in the inner side of the mesh-like structure.

In the above composite material, the melting point of the first metal or alloy is lower than the melting point of the second metal or alloy.

In the above composite material, the first metal or alloy is aluminum or an aluminum alloy, and the second metal or alloy is copper or a copper alloy.

According to the present invention, a second layer formed by coating a first layer formed of a first metal or alloy and a second metal or alloy having a lower reactivity than the first metal or alloy is used, and Since the second layer is the composite powder of the outermost layer and the film is formed by the so-called cold spray method, a homogeneous composite material having sufficient adhesion and tightness to the lower layer can be stably produced.

10, 30‧‧‧Composite powder

11, 31‧‧‧ core layer

12‧‧‧ Cover

20‧‧‧Layered body

21‧‧‧Substrate

22‧‧‧film (composite)

23‧‧‧Metal or alloy of core material

24‧‧‧ mesh structure

32‧‧‧1st coating

33‧‧‧2nd coating

40‧‧‧Cold spray device

41‧‧‧ gas heater

42‧‧‧Powder supply unit

43‧‧‧ spray gun

44‧‧‧ gas nozzle

45, 46‧‧‧ valve

D‧‧‧ path length

D‧‧‧thickness

Fig. 1 is a flow chart showing a method of producing a composite material according to an embodiment of the present invention.

Fig. 2 is a cross-sectional view showing a composite powder used in the method for producing a composite material according to the first embodiment of the present invention.

Fig. 3 is a schematic view showing the outline of a cold spray device used in the film forming step shown in Fig. 1.

Fig. 4 is a cross-sectional view schematically showing the structure of the composite material of the first embodiment.

Fig. 5 is a cross-sectional view showing the structure of a composite material in a first modification of the first embodiment.

Fig. 6 is a scanning electron micrograph of the composite powder used in the photographing examples.

Fig. 7 is a scanning electron micrograph of a cross section of the composite material of the photographing example.

Fig. 8 is a scanning electron micrograph of a cross section of the vicinity of the interface between the composite material of the example and the substrate.

Hereinafter, embodiments for carrying out the invention will be described in detail with reference to the drawings. Further, the present invention is not limited to the following embodiments. In addition, each drawing referred to in the following description only shows the shape, size, and positional relationship of the extent to which the content of the present invention can be understood. That is, the present invention is not limited to the shapes, sizes, and positional relationships illustrated in the respective drawings.

(Form 1)

Fig. 1 is a flow chart showing a method of producing a composite material according to Embodiment 1 of the present invention.

First, in step S1, a composite powder which is a raw material of a composite material is produced. As shown in FIG. 2, the composite powder 10 has a particle diameter of, for example, about 5 to 100 μm, and contains the inner core material layer 11 and the coating layer 12 around the core material layer 11. The core material layer 11 and the coating layer 12 are formed of metals or alloys different from each other. In addition, the composite powder 10 is described in detail later.

A substrate formed of a composite material is produced in the next step S2. Substrate material The material for forming a film by a cold spray method, which will be described later, is not particularly limited. It is preferably a substrate formed of a metal or an alloy. At this time, the material of the base material may be the same type as the metal material or alloy of the core material layer 11 or the coating layer 12, or may be different types. Meanwhile, the size or shape of the substrate is not particularly limited as long as it has a surface which can be formed by a cold spray method.

In the next step S3, the formation of a film is performed on the substrate by a cold spray method using the composite powder 10. The cold spray method is a method in which a raw material powder is accelerated together with a gas, and is directly sprayed on a surface of a substrate in a solid phase state and deposited to form a film. For example, it is performed by the cold spray device 40 shown in Fig. 3.

Fig. 3 is a schematic view showing an outline of the cold spray device 40. As shown in Fig. 3, the cold spray device 40 includes a gas heater 41 that heats a compressed gas, a powder supply device 42 that stores the composite powder 10 and supplies it to the spray gun 43, a heated compressed gas, and a composite powder 10 supplied thereto. The gas nozzles 44 that are ejected toward the substrate 21, and the valves 45 and 46 that individually adjust the supply of the compressed gas with respect to the gas heater 41 and the powder supply device 42.

Helium, nitrogen, air, etc. can be used as the compressed gas. The compressed gas supplied to the gas heater 41 is, for example, 50 ° C or higher, and is heated to a temperature lower than the melting point of the coating layer 12, and then supplied to the spray gun 43. The heating temperature of the compressed gas is preferably from 300 to 900 °C.

On the other hand, the compressed gas supplied to the powder supply device 42 is supplied so that the composite powder in the powder supply device 42 becomes a predetermined discharge amount in the spray gun 43.

The heated compressed gas can be made into a supersonic flow (about 340 m/sec) by the end wide gas nozzle 44. The gas pressure of the compressed gas at this time is preferably set to 1 to 5 MPa. The pressure of the compressed gas is adjusted to such an extent that the adhesion strength between the substrate 21 and the film 22 formed thereon can be improved. These injection conditions (compressed gas) The temperature and pressure of the body, the discharge amount of the composite powder 10, and the like can be determined in accordance with the characteristics of the coating layer 12 which is in direct contact with the outermost layer of the compressed gas.

The composite powder 10 supplied to the spray gun 43 is introduced into the supersonic flow of the compressed gas and accelerated, and at least the surface of the composite powder is maintained in a solid phase state, and the substrate 21 is collided at a high speed and deposited, thereby forming the film 22. At this time, the composite powder 10 is heated by the surface by the heated compressed gas. However, since the time during which the composite powder 10 is injected into the spray gun 43 to the substrate 21 is extremely short, it is generated inside the composite powder 10. The possibility of intermetallic compounds is extremely low.

In addition, as long as the surface of the composite powder 10 is allowed to adhere to the substrate 21 in a solid phase, a film is formed, that is, the cold spray device 40 shown in Fig. 3 is not limited.

Fig. 4 is a cross-sectional view schematically showing the structure of a film 22 (composite material) formed on the substrate 21 by the method for producing a composite material according to the first embodiment. In the method for producing a composite material described above, the core material layer 11 is directly deposited on the substrate 21 in a state in which the core material layer 11 is covered by the coating layer 12. Therefore, the film 22 has a structure in which the metal or alloy 23 of the core layer 11 is filled inside the mesh structure 24 in which the metal or alloy of the coating layer 12 is meshed (lattice or flat lattice shape).

The film 22 can be used in a state in which the layered body 20 is laminated on the substrate 21. Alternatively, the substrate 21 is removed by polishing, cutting, or the like by the film 22, and a portion of the film 22 is used alone as a composite material.

Next, the composite powder 10 shown in Fig. 2 will be described in detail.

The composite powder 10 is produced by coating a periphery of a powder formed of a metal or an alloy with a metal or an alloy different from the powder. Further, various methods such as a plating method or a CVD method can be used for the coating method. At this time, in order to suppress formation of an intermetallic compound by heating, it is preferable to use a coating which does not increase the temperature of the metal or alloy as much as possible. Method (for example, plating method).

The overall size of the composite powder 10 is not particularly limited as long as it is applicable to the above-described cold spray method (about 10 to 100 μm). Further, the diameter D of the core material layer 11 and the thickness d of the coating layer 12 are determined in accordance with the composition to be achieved in the film 22. For example, the diameter D of the core material layer 11 is 30 to 40 μm, and the thickness d of the coating layer is 0.7 μm, so that the ratio of the metal or alloy of the portion of the network structure 24 constituting the film 22 is about 24% by weight. Thus, by adjusting the diameter D of the core material layer 11 or the thickness d of the coating layer, the metal composition ratio in the film 22 can be controlled.

As the material of the core material layer 11 and the coating layer 12, for example, copper, copper alloy, zinc, zinc alloy, aluminum, aluminum alloy, magnesium, magnesium alloy, nickel, nickel alloy, iron, iron alloy, titanium, titanium alloy, or the like can be used. Chromium, chromium alloy, niobium, tantalum alloy, molybdenum, molybdenum alloy, silver, silver alloy, niobium, tantalum alloy, tungsten or tungsten alloy.

The type combination of the metal or alloy constituting the core material layer 11 and the coating layer 12 is a combination of a metal or an alloy which is a coating layer 12 having a low reactivity as compared with a metal or an alloy which is the core material layer 11, that is, no special combination Limited. Here, the reactivity of the metal or alloy can be evaluated by melting point, ionization tendency, hardness, and the like.

For example, a metal or an alloy which is more easily melted than the coating layer 12 can be disposed in the core material layer 11. That is, among the metals or alloys constituting the composite material, a metal or alloy having a low melting point is used as the core material layer 11, and a metal or alloy having a high melting point is used as the coating layer 12. Specifically, when a composite material is produced by using aluminum (melting point: about 660 ° C) and copper (melting point: about 1,083 ° C) as a component, aluminum may be used as the core material layer 11 and copper as the coating layer 12 in the composite powder 10 .

In this case, even when the injection condition is determined in accordance with the characteristics of the copper of the coating layer 12 (the temperature of the inert gas), the composite powder 10 can be maintained in the powder state until it is touched. The substrate 21 is hit. Therefore, the composite powder 10 is sufficiently heated to a temperature at which the copper can adhere to the lower layer, and the composite powder 10 can be ejected by the gas nozzle 44. Thereby, a homogeneous composite material having sufficient adhesion and tightness to the lower layer can be stably produced.

At the same time, a metal or an alloy which is more oxidizable than the coating layer 12 can be disposed in the core material layer 11. In other words, among the metals constituting the composite material, a metal having a large ionization tendency is used as the core material layer 11 and a metal having a small ionization tendency is used as the coating layer 12. Specifically, when aluminum and copper are used as components for producing a composite material, aluminum is used as the core material layer 11 and copper is used as the coating layer 12 in the composite powder.

Here, if a powder such as an aluminum monomer or a powder of aluminum and other metals is compounded by a mechanical alloy method or an atomization method, a powder which exposes aluminum to the surface is used. When the gas nozzle 44 is sprayed, the aluminum on the surface is violently oxidized, and it is considered that there is a dust explosion. Further, the aluminum-containing composite material can be safely produced by a cold spray method by using aluminum as a film, for example, without exposing the aluminum to the surface.

At the same time, a metal or an alloy having a lower hardness than the coating layer 12 can be disposed in the core material layer 11. That is, among the metals constituting the composite material, a metal having a small hardness is used as the core material layer 11, and a metal having a high hardness is used as the coating layer 12. Specifically, when a composite material is produced by using copper and molybdenum as components, the composite powder 10 has copper as the core material layer 11 and molybdenum as the coating layer 12. At this time, the injection condition (for example, the gas pressure) is determined by blending the characteristics of the molybdenum which becomes the coating layer 12, whereby the sufficient kinetic energy for allowing the molybdenum to adhere to the lower layer can be provided to the composite powder 10 while maintaining the powder shape until the powder shape is maintained. It collides with the substrate 21. As a result, the composite powder 10 can be stably ejected by the gas nozzle 44 under suitable ejection conditions.

As described above, according to the first embodiment, since the composite powder coated with a metal or alloy having a lower reactivity than the core material layer 11 around the core material layer 11 formed of a metal or an alloy is used, the cold spray method can be performed. When the temperature of the outer metal or alloy having low reactivity is sufficiently increased, the film is normally sprayed, and a homogeneous composite material having sufficient adhesion and tightness to the lower layer can be stably produced.

In addition, at this time, since the metal or alloy on the side of the core material layer 11 having high reactivity does not use the composite powder, high-temperature injection which is difficult to be performed by a usual cold spray method can be performed, so that adhesion and tightness can be obtained. More improved. That is, a general powder of a metal or an alloy containing only the core material layer 11 has a melting point of the metal or alloy, so that the molten or softened metal or alloy adheres and cannot be ejected, but even in the temperature region where the ejection cannot be performed, It is also possible to perform ejection in a temperature region beyond the appropriate ejection temperature region of the metal or alloy of the core layer 11 by forming the composite powder. Thereby, the core material layer 11 can be sufficiently softened to form a dense film.

Further, the production method of the first embodiment differs from the conventional production method of the calendering method, the sintering method, and the melting method, or a manufacturing method different from the post-film heat treatment by the cold spray method, since it does not contain adjacent ones. The step of heating the metal or alloy to a high temperature (for example, a melting point or higher) suppresses the formation of an intermetallic compound. Therefore, the function reduction of the so-called composite material in which the thermal conductivity is lowered or the mechanical strength is lowered can be suppressed. Thereby, a combination of two kinds of metals or alloys can be expanded.

The composite material produced in the first embodiment described above has the characteristics of the metal or alloy of the core material layer 11 and the coating layer 12. For example, a composite material made of aluminum as the core material layer 11 and copper as the coating layer 12 has electrical properties (conductivity) and thermal properties (thermal conductivity) of aluminum and copper, and has thermal expansion similar to that of copper. rate. In addition, the composite material maintains the original softness of the metal due to the small amount of metal compounds. and so, Such a composite material can be suitably used, for example, as a heat sink (heat release member such as a substrate) using aluminum. At this time, the lightweight property of aluminum can be utilized while improving the thermal conductivity. Further, since the above composite material can be applied to a conventional conductive portion using aluminum, the resistance value can be lowered.

(Modification 1)

Next, a modification 1 of the first embodiment will be described.

Fig. 5 is a cross-sectional view showing the structure of the composite powder 30 in the first modification. The composite powder 30 shown in Fig. 5 has a core material layer 31, a first coating layer 32 formed around the core layer 31, and a second coating layer 33. A composite powder having such a three-layer structure can also be used in the film forming step S3 by the cold spray method. In addition, the first coating layer 32 and the second coating layer 33 are formed by sequentially coating the core material layer 31 by a plating method or the like. At the same time, the ejection conditions in the cold spray method are determined in accordance with the characteristics of the second coating layer 33 of the outermost layer.

Specifically, for example, aluminum may be used as the core material layer 31, and a nickel layer as the first coating layer 32 may be formed around the aluminum layer, and a copper layer as the second cladding layer 33 may be formed. At this time, since nickel is interposed therebetween, an intermetallic compound can be reliably prevented from being formed between aluminum and copper.

Further, two kinds of metals or alloys may be alternately arranged in the core material layer 31, the first coating layer 32, and the second coating layer 33. For example, copper is disposed in the core material layer 31 and the second coating layer 33, and aluminum is disposed in the first coating layer 32. Thereby, the composition ratio in the Al-Cu composite can be easily adjusted.

Further, the number of coating layers formed around the core material layer 31 may be three or more. At this point it is easier to achieve the composition ratios found in the composite, while also allowing several metals or alloys in the composite to be more uniformly dispersed.

(Embodiment 2)

Next, a second embodiment of the present invention will be described.

In the second embodiment, in the film formation step S3 described above, the composite powder 10 (or the composite powder 30 shown in Fig. 5) shown in Fig. 2 is mixed with the same metal or alloy as the outermost layer. A mixed powder of powder.

At this time, the composition in the composite material can be controlled by adjusting the diameter D of the core material layer 11 and the thickness d of the coating layer 12 as described above. However, the thickness d of the coating layer 12 is limited. In addition, there are cases where it is difficult to finely adjust the thickness d. Therefore, if the blend ratio of the metal or alloy of the coating layer 12 is to be increased, or when the blend ratio of the metal or alloy is to be finely adjusted between the core material layer 11 and the coating layer 12, the coating layer and the coating layer may be modulated. 12 A powder of the same kind of metal or alloy is mixed with the mixed powder of the composite powder 10. For example, the composite powder coated with aluminum around copper is mixed with the same copper powder as the outermost layer.

Here, when a cold spray method is used using a mixed powder in which only a plurality of metals or alloys are mixed, it is necessary to mix a metal or alloy having high reactivity (for example, a low melting point) in the ejection conditions (for example, gas temperature). Therefore, the ejection conditions of the metal or alloy having low reactivity (for example, a high melting point) become insufficient (for example, the gas temperature is too low), so that it is difficult to form a compact film. Further, even when a plurality of metals or alloys are mixed by a ball mill or the like, the metal or alloy having high reactivity is exposed on the surface of the powder, so that the spraying conditions must be subject to a metal or alloy having high reactivity.

However, in the second embodiment, the composite powder having a highly reactive metal or alloy (core layer 11) is coated with a metal or alloy (coating layer 12) having low reactivity, so that the spray conditions can be combined with the reactivity. Cold spray method with low metal or alloy. Further, a powder of the same kind of metal or alloy as the coating layer 12 is mixed for the composite powder. Finally, the ejection conditions can be directly matched to the coating layer 12, and the blending ratio of the metal or alloy can be easily adjusted. Therefore, according to the second embodiment, a plurality of metals or alloys different from each other can be contained in a desired ratio, and a homogeneous composite material having sufficient adhesion and tightness to the lower layer can be stably produced.

(Modification 2)

Next, a modification 2 of the second embodiment will be described.

In the second embodiment, a mixed powder of a general powder containing a metal or an alloy and a composite powder is used, but a mixed powder in which a plurality of different types of composite powders are mixed with each other may be used, and a cold spray method may be used. In this case, the type of the metal or the alloy of the core layer or the intermediate layer may be different between the plurality of composite powders, as long as the types of the metal or the alloy of the outermost coating layer are common. . For example, by mixing a powder of a composite powder of a copper-clad aluminum core layer and a composite powder of a composite powder of a nickel-clad core layer, a cold spray method can be used, whereby aluminum, nickel, and copper can be produced. Composite material. When the powder thus mixed is used, the ejection conditions of the common metal or alloy as the outermost layer can be applied regardless of the type of the internal metal or alloy.

(Example)

An experiment of forming a film by a cold spray method using a composite powder having a two-layer structure of a core layer and a coating layer was carried out.

The aluminum powder of an average particle diameter of about 30 μm was subjected to copper plating to obtain a composite powder. Fig. 6 is a scanning electron microscope (SEM) photograph of a composite powder containing aluminum powder and copper plating. In addition, the average thickness of copper plating is about 0.74 μm.

Using such a composite powder, the injection conditions are set at a temperature of about 500 ° C for an inert gas (nitrogen), a gas pressure of 5 MPa, and a pure aluminum by a cold spray method. A film is formed on the substrate of (A1050).

Fig. 7 is a SEM photograph of a cross section of the film formed as described above. Further, Fig. 8 is a SEM photograph of a cross section of the vicinity of the interface between the photographing substrate and the film formed thereon. As shown in Fig. 7, a structure in which aluminum (Al) is filled inside the network structure (Cu mesh structure) of copper can be observed in the film. Further, as shown in Fig. 8, a network of copper (Cu mesh structure) and aluminum (Al) filled therein are observed in the vicinity of the interface between the film and the substrate, and are engaged by the anchoring effect. The appearance of the substrate and the adhesion to the substrate.

The representative figure has no component symbols and the meaning of its representation.

Claims (10)

A method for producing a composite material comprising a film forming step comprising at least a first layer containing a powder formed of a first metal or alloy and a second metal or alloy having a lower reactivity than the first metal or alloy a second layer formed by coating the first layer, and in the film forming step, the composite powder composed of the second layer and the outermost layer is accelerated together with the gas, and at least the surface of the composite powder is kept solid. In the case of a phase state, it is sprayed on the surface of the substrate and deposited to form a film. The method for producing a composite material according to claim 1, wherein the film forming step is to spray the composite powder onto the surface of the substrate in accordance with a condition set corresponding to a characteristic of the second metal or alloy. . The method for producing a composite material according to claim 1 or 2, wherein a melting point of the first metal or alloy is lower than a melting point of the second metal or alloy. The method for producing a composite material according to claim 1 or 2, wherein the ionization tendency of the first metal or alloy is greater than the ionization tendency of the second metal or alloy. The method for producing a composite material according to claim 1 or 2, wherein the hardness of the first metal or alloy is lower than the hardness of the second metal or alloy. The method for producing a composite material according to claim 1, wherein the second layer is formed around the first layer by a plating method. The method for producing a composite material according to the above aspect of the invention, wherein the film forming step comprises mixing the second gold in the foregoing composite powder The powder formed by the genus or the alloy to prepare a mixed powder, and the mixed powder is sprayed on the surface of the aforementioned substrate. A composite material comprising a first metal or alloy and a second metal or alloy having a lower reactivity than the first metal or alloy, wherein the second metal or alloy has a mesh structure, and the The first metal or alloy is filled in the inner side of the aforementioned mesh-like structure. The composite material according to claim 8, wherein the melting point of the first metal or alloy is lower than the melting point of the second metal or alloy. The composite material according to claim 9, wherein the first metal or alloy is aluminum or an aluminum alloy, and the second metal or alloy is copper or a copper alloy.