Composite material

Abstract

This composite material is provided with a core material, a skin material that covers the core material, and a mixed layer that is formed between the core material and the skin material and is obtained by mixing the materials of the core material and the skin material. The thickness of the mixed layer is 1.0 [mu] m or less.

Description

Technical Field

[0001] The present invention relates to composite materials. Background Art

[0002] In the past, in response to the demand for lightweight and high-performance components in all industrial fields, many attempts have been made to reduce weight and increase performance for processing components from various viewpoints. On the other hand, if multiple required characteristics are to be met at the same time, it is sometimes impossible to take into account all the characteristics in a single material. In order to meet such required characteristics that are difficult to achieve with a single material, a technology that combines two or more materials to produce processing components has become popular. For example, Patent Documents 1 and 2 describe a wire material (hereinafter also referred to as a composite material) having a core material and a skin material covering the surface of the core material.

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2009-129550

[0004] Patent Document 2: Japanese Patent Publication No. 7-91627 Summary of the Invention

[0005] However, as a method of composite by coating different types or the same type of metal on the periphery of the metal core wire, it is well known to have extrusion (rolling) coating method, tape coating method, hot dip thick plating method, powder rolling method, etc. Any of the methods requires heating during joining, and therefore may cause the generation of intermetallic compounds at the joining interface. The intermetallic compound is very brittle compared to the base material (here is the metal core wire), so there is a risk that the joining strength cannot be ensured. At this time, patent document 2 records an invention that solves this problem, and in its manufacturing process, there is a time difference between the formation (joining) of the skin material at high temperature and the start of cooling, so there is a risk of generating intermetallic compounds at the joining interface.

[0006] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a composite material in which a core material and a skin material are firmly bonded to each other.

[0007] In order to solve the above problems and achieve the purpose, the composite material involved in the present invention comprises: a core material; a skin material that covers the core material; and a mixed layer formed between the core material and the skin material, which is a mixture of the materials of the core material and the skin material, and the thickness of the mixed layer is less than 1.0 μm.

[0008] Furthermore, the composite material according to the present invention is characterized in that, in the above invention, the thickness of the mixed layer is 0.5 μm or less.

[0009] Furthermore, the composite material according to the present invention is characterized in that, in the above invention, the thickness of the skin material is greater than the thickness of the mixed layer.

[0010] Furthermore, the composite material according to the present invention is the composite material according to the above invention, wherein the thickness of the skin material is 0.1 mm or more and 1.0 mm or less.

[0011] Furthermore, the composite material according to the present invention is the composite material according to the above invention, wherein the core material is formed of copper or a copper alloy, and the skin material is formed of aluminum or an aluminum alloy.

[0012] According to the present invention, the core material and the skin material in the composite material can be firmly bonded together. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a perspective view showing the structure of a composite material according to one embodiment of the present invention.

[0014] Figure 2 yes Figure 1 The AA line cross-sectional view is shown.

[0015] Figure 3 This is a flowchart showing a method for producing a composite material according to one embodiment of the present invention.

[0016] Figure 4 It is a perspective view showing the structure of a composite material production apparatus according to one embodiment of the present invention.

[0017] Figure 5 It is a cross-sectional view showing the structure of a composite material production apparatus according to one embodiment of the present invention.

[0018] Figure 6 is with Figure 5 The QQ line shown corresponds to a cross-sectional view of the apparatus for producing the composite material.

[0019] Figure 7 This is a secondary electron image of the composite material according to one embodiment of the present invention, including a region quantitatively analyzed by an electron probe micro analyzer (EPMA).

[0020] Figure 8 It means Figure 7 The graph shows the composition ratio in the direction of the arrow, with point B1 being the starting point.

[0021] Figure 9 This is a secondary electron image of a conventional composite material, including an area quantitatively analyzed by electron probe microanalyzer (EPMA).

[0022] Figure 10 It means Figure 9 The graph shows the composition ratio in the direction of the arrow, with point B2 being the starting point.

[0023] Figure 11 It is a cross-sectional view for explaining the structure of the main part of the composite material production apparatus and the structure of the wire rod according to Modification 1 of the embodiment of the present invention.

[0024] Figure 12 It is a diagram for explaining an example of processing a composite material according to Modification 2 of the embodiment of the present invention.

[0025] Figure 13 yes Figure 12 The BB line cross-sectional view is shown. DETAILED DESCRIPTION

[0026] Below, the embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited to the following embodiments. Furthermore, the figures referenced in the following description merely schematically illustrate shapes, dimensions, and positional relationships to facilitate understanding of the present invention. That is, the present invention is not limited to the shapes, dimensions, and positional relationships illustrated in the figures.

[0027] Implementation Method

[0028] Figure 1 It is a perspective view showing the structure of a composite material according to one embodiment of the present invention. Figure 2 yes Figure 1 The composite material 1 includes a core material 2, a skin material 3 covering the outer periphery of the core material 2, and a mixed layer 4 provided between the core material 2 and the skin material 3 and containing a mixture of the materials of the core material 2 and the skin material 3.

[0029] The core material 2 is a cylindrical member formed of copper or a copper alloy. The copper alloy is an alloy having copper as a main component.

[0030] The composite material 1 is used as a conductive member for electric wires, for example, but is not limited to this use.

[0031] The skin material 3 is a tubular component formed using aluminum or an aluminum alloy. The thickness of the skin material 3 is greater than the thickness of the mixed layer 4. The thickness of the skin material 3 is, for example, not less than 0.1 mm and not more than 1.0 mm. Here, "thickness" corresponds to the distance from one end to the other end of the composite material 1 in the radial direction, that is, in a direction perpendicular to the length direction of the composite material 1. In addition, when an object exists discontinuously in the radial direction, the average value of one length or the length of both is taken as the thickness. Specifically, when the skin material 3 exists discontinuously in two places in the radial direction relative to the core material 2 on the cross section of the composite material 1, the length of one skin material 3, or the average value of the lengths of two skin materials 3 is taken as the thickness.

[0032] The mixed layer 4 is generated at the bonding interface between the core material 2 and the skin material 3 during the heat treatment in the production of the composite material 1. The mixed layer 4 is formed by a mixture of the materials of the core material 2 and the skin material 3. The thickness D1 of the mixed layer 4 is less than 1 μm, and more preferably less than 0.5 μm. In addition, the mixed layer 4 sometimes contains intermetallic compounds generated by heat treatment. The thinner the thickness D1 of the mixed layer 4, the more it can suppress the generation of intermetallic compounds. For example, if the thickness D1 exceeds 1 μm, the amount of intermetallic compounds generated increases, and there is a risk that the bonding strength cannot be ensured.

[0033] Next, a method for producing the composite material 1 will be described. Figure 3 1 is a flowchart showing a method for manufacturing a composite material according to a first embodiment of the present invention. A core material 2 is prepared and subjected to a heat treatment (step S101: core material heating step). In the core material heating treatment, the core material 2 is heated to a temperature at which the core material 2 and the skin material 3 can be sufficiently bonded. For example, when copper is used as the core material 2, the heating temperature is, for example, 400°C. The core material heating treatment can be performed using a known method such as an atmosphere furnace heating treatment, a high-frequency induction heating treatment, a resistance heating treatment, or an infrared heating treatment.

[0034] After heating the core material 2, a roll casting process is performed to produce a molded product in which the skin material 3 is wrapped around the core material 2 (step S102: roll casting step). The roll casting process will be described below.

[0035] After the formed object is formed, it is subjected to finishing processes such as burr removal to produce the composite material 1 (step S103). The finishing processes include cold drawing to achieve the desired diameter, peeling, cutting to a predetermined length, and surface processing such as polishing.

[0036] Next, refer to Figures 4 to 6 The roll casting process in step S102 will be described. Figure 4 It is a perspective view showing the structure of a composite material production apparatus according to one embodiment of the present invention. Figure 5 It is a cross-sectional view showing the structure of a composite material production apparatus according to one embodiment of the present invention. Figure 6 is with Figure 5 The QQ line shown corresponds to a cross-sectional view of the apparatus for producing the composite material.

[0037] Figures 4 to 6 The manufacturing apparatus 100 shown is an apparatus for roll casting and includes a roller member 110 , a guide member 120 , and a protective tube 130 .

[0038] The roller assembly 110 includes a first roller 111, a second roller 112, a third roller 113, and a fourth roller 114. The first roller 111 through the fourth roller 114 are each disc-shaped and arranged so that the side surfaces of adjacent rollers face each other. The first roller 111 through the fourth roller 114 are spaced evenly apart relative to the guide assembly 120. For example, the first roller 111 is rotated 90° relative to the adjacent second roller 112 and fourth roller 114. The first roller 111 extends in the plate thickness direction and is rotatable about an axis N1 passing through the center of the roller. The second roller 112 extends in the plate thickness direction and is rotatable about an axis N2 passing through the center of the roller. The third roller 113 extends in the plate thickness direction and is rotatable about an axis N3 passing through the center of the roller. The fourth roller 114 extends in the plate thickness direction and is rotatable about an axis (not shown) passing through the center of the roller. In addition, hereinafter, the surface with the largest area of the roller is referred to as a main surface. The roller has two main surfaces located on opposite sides of each other, and the surface connecting the two main surfaces is referred to as a side surface.

[0039] The first through fourth rollers 111 through 114 can be made of steel, copper, copper alloys, tungsten-based alloys, superalloys, or cemented carbide. Forming a coating on the surface of these metals can suppress the reaction between the liquid 30 and the rollers. Examples of such coatings include ceramics such as titanium aluminum nitride and chromium nitride, or amorphous carbon films. Furthermore, to further minimize the reaction between the liquid 30 and the rollers, the first through fourth rollers 111 through 114 can also be made of ceramics such as silicon nitride, aluminum oxide, or zirconium oxide. Furthermore, the materials of the first through fourth rollers 111 through 114 can be the same or different, and some parts can be made of a different material than others.

[0040] The first roller 111 has a concave first groove 111a formed on its side surface (see Figure 6 ). A concave second groove 112a is formed on the side of the second roller 112. A concave third groove 113a is formed on the side of the third roller 113. A concave fourth groove 114a is formed on the side of the fourth roller 114. The first groove 111a to the fourth groove 114a are each formed by cutting an arc shape, and a cylindrical space P1 is formed by making the grooves face each other. In addition, Figure 5 , an example is shown in which the space P1 is filled with the core material 2 and the skin material 3 (or the liquid 30 ).

[0041] The first to fourth rollers 111 to 114 may have the same shape as each other or different shapes (for example, different roller diameters) as long as they can form the space P1.

[0042] The guide member 120 includes a main body 121 having a tapered end and an internal space extending through the end and the end opposite to the tapered end, and a clamping portion 122 disposed on the outer periphery of the main body 121 for clamping the first to fourth rollers 111 to 114 .

[0043] In addition, the guide member 120 is formed with an opening 123, which is formed into a hole-like shape with the opening size gradually decreasing from the opening of the main body 121 toward the clamping portion 122. The end of the opening 123 on the clamping portion 122 side is connected to the space P1 formed by the first roller 111 to the fourth roller 114. The liquid 30 in the melted state of the leather material 3 can be poured into the opening 123 of the guide member 120 using the container 140 (see Figure 5 The guide member 120 guides the core material 2 and the liquid 30 to the space P1 formed by the first to fourth rollers 111 to 114. The guide member 120 may be manufactured by combining a plurality of members or integrally formed from one member.

[0044] Protective tube 130 is cylindrical, with a portion located within guide member 120. The central axis of protective tube 130 passes through the center of space P1 formed by first through fourth grooves 111a, 114a. Core material 2 is guided by protective tube 130 into space P1 formed by first through fourth rollers 111, 114.

[0045] During the roller casting process, the core material 2 and liquid 30 move together from the guide member 120 side to the roller side, passing through space P1. After being poured into the guide member 120, the liquid 30 solidifies due to a drop in temperature as it passes through space P1. This temperature drop is due to cooling caused by heat dissipation from contact with the surfaces of the first to fourth rollers 111 to 114 and the surface of the core material 2, thereby forming the aforementioned molded object (skin material 3).

[0046] At this time, a mixed layer 4 is formed between the core material 2 and the skin material 3. In order to prevent the excess liquid 30 overflowing from the opening 123 or the space P1 from accumulating, a notch connected to the space P1 may be provided. The notch is formed in a part of the roller, for example.

[0047] In the roll casting process, the core material or the skin material is not heated to coat the skin material on the core material. Instead, the melted skin material is allowed to cool and adhere to the core material as it passes through the rollers. Therefore, compared with other known production methods, the influence of heat is less, and the formation of intermetallic compounds is less likely. In addition, when manufacturing composite materials through wire drawing / rolling, the material must be heated for each wire drawing / rolling process, and intermetallic compounds are formed due to repeated heat treatment. However, in the roll casting process, the heating step (passing the molten metal) is only required once, thus suppressing the formation of intermetallic compounds. Furthermore, in the roll casting process, the time span from heating to cooling (heating time) is shorter, which has the effect of suppressing the formation of intermetallic compounds.

[0048] Here, refer to Figures 7 to 10 , a mixed layer of the present embodiment and conventional composite materials will be described. Figures 7 to 10 This figure shows a composite material made of copper as the core material, aluminum as the skin material, and a thickness of 500 to 800 nm. Figure 4 An example of a composite material produced by the manufacturing apparatus 100 shown in FIG. In addition, an example of a composite material produced by a rolling process is shown in FIG. Figure 7 This is a secondary electron image of the composite material according to one embodiment of the present invention, including a region subjected to quantitative analysis, acquired by an electron probe microanalyzer (EPMA). Figure 8 It means Figure 7 The graph shows the composition ratio in the direction of the arrow, with point B1 being the starting point. Figure 9 This is a secondary electron image of a conventional composite material, including an area quantitatively analyzed by electron probe microanalyzer (EPMA). Figure 10 It means Figure 9 The graph shows the composition ratios in the direction of the arrow, with point B2 being the starting point. Each composition ratio represents the composition ratio in each composition region of copper and aluminum, including the boundary between copper and aluminum.

[0049] like Figure 8 As shown, in the composite material of this embodiment, the region R1 where the composition ratios of copper and aluminum alternate corresponds to the region where the intermetallic compound is generated, that is, the region where the mixed layer is formed. In this case, the region where the mixed layer is formed is set according to the ratio of the specified components. Here, the region where the composition ratio of copper or aluminum is set is, for example, set to a range of 10% or more and 90% or less of aluminum as the region where the mixed layer is formed. On the other hand, Figure 10 As shown in FIG, in the conventional composite material, the region R2 where the composition ratios of copper and aluminum alternate corresponds to the region where the intermetallic compound is generated, that is, the region where the mixed layer is formed. Figure 8 and Figure 10 It can be seen that the thickness of the mixed layer of the composite material of this embodiment is thinner. Figure 8 In the example shown, the thickness of the mixed layer is less than about 1.0 μm. Figure 10 In the example shown, the thickness of the mixed layer is greater than 1.0 μm.

[0050] According to the embodiment described above, by making the thickness (thickness D1) of the mixed layer 4 formed between the core material 2 and the skin material 3 in the composite material 1 less than 1 μm, there is a very small amount of or no intermetallic compound between the core material 2 and the skin material 3, thereby obtaining a composite material in which the core material and the skin material are firmly bonded.

[0051] In addition, in this embodiment, the composite material 1 is produced by passing the heated core material 2 and the liquid 30 through the space P1 formed by the four rollers while solidifying the liquid 30. According to this embodiment, the liquid skin material 3 is brought into contact with the heated core material 2, thereby producing a composite material 1 in which the core material 2 and the skin material 3 are bonded with high bonding strength.

[0052] Furthermore, according to the present embodiment, unlike conventional methods, it is not necessary to join a core material and a skin material that are separately manufactured, or to repeat annealing and cold drawing, and thus it is possible to manufacture a composite material with fewer working steps.

[0053] Modification 1

[0054] Next, refer to Figure 11 Modification 1 of the embodiment will be described. Figure 11 This is a cross-sectional view illustrating the main components of a composite material production apparatus and the structure of a wire rod according to Modification 1 of an embodiment of the present invention. Composite material 1A in Modification 1 comprises a prismatic core material 2A and a skin material 3A covering core material 2A, with a mixed layer formed between core material 2A and skin material 3A. Furthermore, grooves corresponding to the composite material are formed in the rollers used in the roller casting process. The remaining structure is identical to that of the aforementioned embodiment, and therefore, description thereof will be omitted.

[0055] In this first variation, a first V-shaped groove 115b is formed on the side of the first roller 115. A second V-shaped groove 116b is formed on the side of the second roller 116. A third V-shaped groove 117b is formed on the side of the third roller 117. A fourth V-shaped groove 118b is formed on the side of the fourth roller 118. The first through fourth grooves 115b through 118b are each formed by two circumferentially extending inclined surfaces, each forming a 90° angle. The first through fourth grooves 115b through 118b form a rectangular (square) space P2 by aligning the grooves.

[0056] As in the first embodiment, during the roller casting process, the core material 2A and liquid 30 move together from the guide member 120 side to the roller side, passing through space P2. While passing through space P2, the liquid 30 solidifies near the surface of the core material 2A and the surfaces of the first to fourth rollers 115, 118, forming the skin material 3A. At this point, a mixed layer forms between the core material 2A and the skin material 3A. This produces the molded article of this first variation.

[0057] As described above, similar to the embodiment, this variation 1 makes the thickness of the mixed layer formed between the core material 2A and the skin material 3A in the composite material 1A less than 1 μm, so that there is very little or no intermetallic compound between the core material 2A and the skin material 3A, thereby obtaining a composite material in which the core material and the skin material are firmly bonded.

[0058] Modification 2

[0059] Next, refer to Figure 12 and Figure 13 Modification 2 of the embodiment will be described. In this modification 2, the composite material 1 produced in the embodiment is processed to obtain a composite material having a changed shape. Specifically, the composite material 1 is rolled to obtain a composite material in the form of a flat plate.

[0060] Figure 12 It is a diagram for explaining an example of processing a composite material according to Modification 2 of the embodiment of the present invention. Figure 13 yes Figure 12 In this modification 2, the cylindrical first rolling member 201 and the second rolling member 202 are rotated to extrude the composite material 1 fed in sequence, thereby obtaining a flat composite material 1B. The composite material 1B is formed by a flat core material 2B covered by a skin material 3B, and a mixed layer 4A is formed between the core material 2B and the skin material 3B (see FIG. Figure 13 ). Figure 13 The cross-sectional shape shown is an example in which the portion not in contact with the first rolling member 201 and the second rolling member 202 is curved in an arc shape. Alternatively, for example, the composite material 1B may be rolled while being rotated about its longitudinal axis.

[0061] Thus, for example, by rolling the composite material 1 produced by the manufacturing apparatus 100, a composite material 1B having a shape different from that of the composite material 1 can be obtained. Therefore, a composite material having very little or no intermetallic compound between the core material 2B and the skin material 3B can be processed into a desired shape for use.

[0062] Furthermore, the processing of the composite material is not limited to the above-mentioned rolling process, and a known processing method can be employed.

[0063] In addition, in the above-mentioned embodiments and modifications, examples are described in which the space formed by the plurality of rollers is circular or rectangular. However, in addition thereto, it may also be an ellipse, a trapezoid, a polygon larger than a pentagon, a shape with arc-shaped corners of the polygon, or other shapes such as a star. In addition, the number of rollers is not limited to four, as long as it is two or more. From the perspective of suppressing the generation of burrs on the outer surface of the skin material 3 or the formation of gaps between the core material 2 and the skin material 3, it is preferred to have three or more rollers. Furthermore, in the cross section, the shapes of the core material and the skin material may also be different. For example, a skin material with a circular outer edge may be covered on a core material with a rectangular cross section. In this case, it is possible to produce the core material with a rectangular cross section by passing it through the manufacturing device 100. Furthermore, as long as the thickness of the mixed layer 4 meets the conditions, the device for manufacturing is not limited to Figure 4 The manufacturing device shown.

[0064] Thus, the present invention may include various embodiments and the like that are not described herein, and various design changes and the like can be implemented without departing from the scope of the technical concept defined by the claims.

[0065] Industrial Applicability

[0066] As described above, the composite material of the present invention is suitable for firmly bonding a core material and a skin material.

[0067] Explanation of symbols:

[0068] 1.1A, 1B composite materials

[0069] 2, 2A, 2B core material

[0070] 3. 3A and 3B leather materials

[0071] 4. 4A mixed layer

[0072] 100 Manufacturing Equipment

[0073] 110 Roller parts

[0074] 111, 115 first roller

[0075] 111a, 115b first groove

[0076] 112, 116 second roller

[0077] 112a, 116b second slot

[0078] 113, 117 third roller

[0079] 113a, 117b third slot

[0080] 114, 118 fourth roller

[0081] 114a, 118b fourth slot

[0082] 120 guide components

[0083] 121 Main body

[0084] 122 clamping part

[0085] 130 protective tube

[0086] 140 containers

[0087] 201 First rolling part

[0088] 202 Second rolled component.

Claims

1. A composite material comprising: core material; a leather material covering the core material; and A mixed layer is formed between the core material and the skin material and is made of a mixture of the core material and the skin material. The composite material is characterized in that The thickness of the mixed layer is 1.0 μm or less.

2. The composite material according to claim 1, characterized in that The thickness of the mixed layer is 0.5 μm or less.

3. The composite material according to claim 1, characterized in that The thickness of the leather material is greater than the thickness of the mixed layer.

4. The composite material according to claim 2, characterized in that The leather material has a thickness of 0.1 mm or more and 1.0 mm or less.

5. The composite material according to claim 1, characterized in that The core material is formed of copper or copper alloy. The leather material is formed of aluminum or an aluminum alloy.

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