Method for manufacturing a joint and joint

Abstract

This suppresses the occurrence of unjointed areas and improves the quality of the joints between materials. [Solution] The method for manufacturing the joint comprises: pressing the first workpiece 10 and the second workpiece 20 with a pair of pressing members 130 to form a recess 23 and push the insulating material 30 present at the contact position 50 to the outside of the contact position 50; after forming the recess 23, continuing to press the first workpiece 10 and the second workpiece 20 with the pair of pressing members 130 while supplying power to a pair of electrodes 140 to form an intermetallic compound 41 on the outer periphery 51 at the contact position 50; and even after forming the intermetallic compound 41, continuing to press the first workpiece 10 and the second workpiece 20 and supplying power to the pair of electrodes 140 to form the intermetallic compound 40 over substantially the entire area inside the outer periphery 51 at the contact position 50, thereby joining the first workpiece 10 and the second workpiece 20 in a solid state.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a joined body and a joined body.

Background Art

[0002] As a prior art document disclosing the configuration of a solid-phase resistance spot joining apparatus, there is JP 2024-8499 A (Patent Document 1). The solid-phase resistance spot joining apparatus described in Patent Document 1 includes a pressurizing shaft and an electrode. The pressurizing shaft presses a plurality of superimposed objects to be joined so as to be plastically deformable. The electrode is arranged around the pressurizing shaft and applies a voltage to the plurality of objects to be joined. By passing an electric current through the plurality of superimposed objects to be joined to form softened regions in the plurality of objects to be joined, the softened regions are plastically deformed to join the plurality of objects to be joined to each other while maintaining a solid-phase state.

[0003] As a prior art document disclosing a joining method for a steel material and an aluminum-based material, there is JP 06-55277 A (Patent Document 2). The joining method for a steel material and an aluminum-based material described in Patent Document 2 joins the steel material and the aluminum-based material by a weld bonding method. In the weld bonding method, an adhesive is interposed between the steel material and the aluminum-based material. After spot-welding the steel material and the aluminum-based material, the adhesive is cured.

[0004] As a prior art document disclosing a weld bonding method similar to the joining method described in Patent Document 2, there is JP 08-118031 A (Patent Document 3).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of Invention

[0006] When performing solid-phase resistance spot bonding using dissimilar metal materials, the difference in hardness between the materials at the contact point results in the formation of a convex portion in the harder material and a concave portion in the lower-hardness material. In this case, current flows more easily to the outer periphery of the contact point between the convex and concave portions, potentially causing unbonded areas in the center of each portion and reducing the quality of the bond.

[0007] The present invention has been made to solve the above problems, and aims to provide a method for manufacturing a joined body and a joined body that can suppress the occurrence of unjointed parts and improve the quality of joining between materials. [Means for solving the problem]

[0008] A method for manufacturing a joint according to the present invention involves forming a joint by joining a first workpiece, which forms an intermetallic compound with the other's contained materials, and a second workpiece, which has a lower hardness than the first workpiece, in a solid state using a solid-state bonding device. The solid-state bonding device comprises a pair of pressing members and a pair of electrodes. The pair of pressing members clamp and press the first workpiece and the second workpiece in the thickness direction. The pair of electrodes are arranged around the pair of pressing members. The method for manufacturing a joint comprises forming a first protrusion on the first workpiece and a second protrusion on the second workpiece by pressing the first workpiece and the second workpiece in the thickness direction with the pair of pressing members, with an insulating material interposed between the first workpiece and the second workpiece in the thickness direction. The method for manufacturing a joint comprises further pressing the first workpiece and the second workpiece with the pair of pressing members to form a recess at the contact position with the first protrusion on the second protrusion of the second workpiece, and pushing the insulating material present at the contact position outwards. A method for manufacturing a joined body includes forming a recess, then continuing to press the first and second workpieces with a pair of pressing members, while supplying power to a pair of electrodes, thereby forming an intermetallic compound on the outer periphery at the contact point. A method for manufacturing a joined body also includes continuing to press the first and second workpieces with a pair of pressing members and supplying power to a pair of electrodes even after the intermetallic compound has been formed, thereby forming an intermetallic compound over substantially the entire area inside the outer periphery at the contact point, and joining the first and second workpieces in a solid state.

[0009] In this case, by forming an intermetallic compound on the outer periphery of the contact area between materials, the contact area is not extended too far outward, and by placing the insulating material outside the contact area between materials, it is possible to suppress the flow of current between materials outside the contact area. As a result, the current can be concentrated at the contact area, thereby suppressing the occurrence of unjointed areas and improving the quality of the joint between materials.

[0010] In one embodiment of the present invention, the intermetallic compound formed on the outer periphery has an annular shape when viewed from the thickness direction.

[0011] This allows the pinning effect of the intermetallic compound to work uniformly in the circumferential direction of the annular shape.

[0012] In one embodiment of the present invention, the number of recesses is one.

[0013] In this case, because the surface shape of the contact area between the first workpiece and the second workpiece is smooth, when the first and second protrusions come into contact and a recess is formed, the insulating material between the first and second workpieces is easily discharged to the outside of the contact area. As a result, the insulating material can be removed and the first and second workpieces can be reliably brought into contact, thereby suppressing the occurrence of unjointed areas.

[0014] The joint according to the present invention comprises a first workpiece, a second workpiece, and an insulating material. The first and second workpieces form an intermetallic compound with respect to their respective constituent materials. The second workpiece has lower hardness than the first workpiece. The insulating material is interposed between the first and second workpieces in the thickness direction of the first and second workpieces. The first workpiece has a first protrusion that projects toward the second workpiece in the thickness direction. The second workpiece has a second protrusion that projects toward the first workpiece in the thickness direction and contacts the first protrusion. The second protrusion has a recess formed in the thickness direction that conforms to the shape of the first protrusion at the contact point with the first protrusion. The insulating material is located between the first and second workpieces outside the contact point. The first and second workpieces are joined via the intermetallic compound formed over substantially the entire contact area.

[0015] In this case, by joining dissimilar metal materials via an intermetallic compound, the occurrence of unjointed areas can be suppressed, thereby improving the quality of the joint between materials.

[0016] In one embodiment of the present invention, the number of recesses is one.

[0017] In this case, since the surface shape at the contact position between the first workpiece and the second workpiece is smooth, the first workpiece and the second workpiece can be brought into reliable contact with each other, so that the occurrence of unjoined portions can be suppressed. Effects of the Invention

[0018] According to the present invention, it is possible to suppress the occurrence of unjoined portions and improve the joining quality between materials. Brief Description of the Drawings

[0019] [Figure 1] It is a front view showing the configuration of a solid-state joining apparatus according to one embodiment of the present invention. [Figure 2] It is a cross-sectional view showing the configuration of a joined body according to one embodiment of the present invention. [Figure 3] It is a flowchart showing a method for manufacturing a joined body according to one embodiment of the present invention. [Figure 4] It is a cross-sectional view showing a step of preparing workpieces constituting a joined body. [Figure 5] It is a cross-sectional view showing a step in which the workpiece is pressed to form a convex portion. [Figure 6] It is a cross-sectional view showing a step in which the workpiece is pressed to form a concave portion in the workpiece. [Figure 7] It is a cross-sectional view showing a step of forming an intermetallic compound on the outer peripheral portion of the contact position between the workpieces. [Figure 8] It is a schematic diagram showing the shape of the intermetallic compound formed on the outer peripheral portion of the contact position between the workpieces. [Figure 9] It is a cross-sectional view showing a step of forming an intermetallic compound on substantially the entire contact position between the workpieces. Modes for Carrying Out the Invention

[0020] Hereinafter, a method for manufacturing a joined body and the joined body according to one embodiment of the present invention will be described with reference to the drawings. In the following description of the embodiments, the same reference numerals are assigned to the same or corresponding parts in the drawings, and the description thereof will not be repeated.

[0021] In the drawings, the direction in which the main surface of the workpiece extends is defined as the X direction. The thickness direction of the workpiece is defined as the Y direction. Furthermore, the direction perpendicular to both the direction in which the main surface of the workpiece extends and the thickness direction of the workpiece is defined as the Z direction. In the drawings, hatching of a pair of pressing members, etc., which will be described later, is omitted in some places as appropriate.

[0022] First, the configuration of the solid-phase bonding apparatus will be described. Figure 1 is a front view showing the configuration of a solid-phase bonding apparatus according to one embodiment of the present invention. Figure 2 is a cross-sectional view showing the configuration of a bonded body according to one embodiment of the present invention. Note that the insulating material in the workpiece is not shown in Figure 1.

[0023] As shown in Figures 1 and 2, the solid-phase bonding apparatus 100 according to one embodiment of the present invention is a device that forms softened regions in multiple stacked objects to be bonded by passing an electric current through them, and then plastically deforms these softened regions to bond the multiple objects to be bonded together while they remain in a solid state. In other words, the solid-phase bonding apparatus 100 is capable of bonding multiple objects to be bonded by solid-phase resistance spot bonding. The bonded body 1 is manufactured by the solid-phase bonding apparatus 100.

[0024] The solid-phase bonding apparatus 100 comprises a first bonding unit 110 and a second bonding unit 120.

[0025] The first joining unit 110 is a unit for pressing multiple objects to be joined in a way that allows for plastic deformation, and for applying voltage to the multiple objects to be joined. The first joining unit 110 is driven axially (in the Y direction) by a drive source such as a servo press (not shown).

[0026] The second bonding unit 120 is a unit that, together with the first bonding unit 110, presses multiple objects to be bonded and applies voltage to multiple objects to be bonded. The second bonding unit 120 is fixed to a housing (not shown) of the solid-phase bonding apparatus 100.

[0027] In this embodiment, the second joining unit 120 has the same configuration as the first joining unit 110, but is symmetrical with respect to the XZ plane. However, the second joining unit 120 is not limited to this configuration and may be configured to be driveable in the axial direction (Y direction) by providing a drive source.

[0028] Voltage is applied to the first bonding unit 110 and the second bonding unit 120 from a power supply unit (not shown). The power supply unit is electrically connected to a pair of electrodes 140, which will be described later.

[0029] In this embodiment, the multiple objects to be joined are the first workpiece 10 and the second workpiece 20. The first workpiece 10 and the second workpiece 20 are plate materials extending on the XZ plane.

[0030] The first workpiece 10 and the second workpiece 20 are made of dissimilar metals. The second workpiece 20 has lower hardness than the first workpiece 10. The first workpiece 10 is, for example, a steel plate such as high-tensile steel. The second workpiece 20 is, for example, an aluminum plate.

[0031] The first workpiece 10 and the second workpiece 20 are capable of forming intermetallic compounds with each other due to the materials they contain. Note that the first workpiece 10 and the second workpiece 20 are not limited to a combination of steel and aluminum plates, as long as they are made of dissimilar metals and are materials that can form intermetallic compounds.

[0032] In one embodiment of the present invention, the first joining unit 110 and the second joining unit 120 include a pair of pressing members 130 and a pair of electrodes 140.

[0033] As shown in Figure 2, the pair of pressing members 130 includes a first pressing member 131 and a second pressing member 132. The first pressing member 131 is provided on the first joining unit 110. The second pressing member 132 is provided on the second joining unit 120.

[0034] The pair of pressing members 130 clamp the first workpiece 10 and the second workpiece 20 in the thickness direction (Y direction). The pair of pressing members 130 press the first workpiece 10 and the second workpiece 20 in a way that allows for plastic deformation from the thickness direction (Y direction). In this embodiment, the pair of pressing members 130 press the first workpiece 10 and the second workpiece 20 with a pressing force of 30 to 50 kN.

[0035] In this embodiment, the pair of pressing members 130 are cylindrical members extending in the Y direction. The Y direction is the axial direction of the pair of pressing members 130. The X direction is one direction perpendicular to the axial direction of the pair of pressing members 130. The Z direction is one direction perpendicular to the axial direction of the pair of pressing members 130 and one direction perpendicular to that axial direction.

[0036] The material of the pair of pressing members 130 is, for example, tungsten carbide. However, the material of the pair of pressing members 130 is not particularly limited as long as it can apply the necessary pressing force to the first workpiece 10 and the second workpiece 20, and may be tool steel, heat-resistant steel, or ceramics, etc.

[0037] The pair of electrodes 140 includes a first electrode 141 and a second electrode 142. The first electrode 141 is provided in the first bonding unit 110. The second electrode 142 is provided in the second bonding unit 120.

[0038] The pair of electrodes 140 are driven in the Y direction by a drive source together with the pair of pressing members 130. The pair of electrodes 140 are positioned around the pair of pressing members 130 with a gap between them. In this embodiment, the tips of the pair of electrodes 140 have a cylindrical shape when viewed from the Y direction.

[0039] The pair of electrodes 140 apply a voltage to the first workpiece 10 and the second workpiece 20. By applying a voltage to the first workpiece 10 and the second workpiece 20, the pair of electrodes 140 heat the first workpiece 10 and the second workpiece 20 by passing a current of 3500 to 10000 A through them. The pair of electrodes 140 are made of, for example, copper.

[0040] Next, the configuration of the bonded body 1 manufactured by the solid-phase bonding apparatus 100 will be described. As shown in Figure 2, the bonded body 1 comprises a first workpiece 10, a second workpiece 20, and an insulating material 30.

[0041] The first workpiece 10 has a first main surface portion 11. The first main surface portion 11 extends on the XZ plane.

[0042] A first protrusion 12 is formed on the first workpiece 10. The first protrusion 12 projects toward the second workpiece 20 in the thickness direction (Y direction).

[0043] The second workpiece 20 has a second main surface portion 21. The second main surface portion 21 extends on the XZ plane. The second main surface portion 21 faces the first main surface portion 11 in the thickness direction (Y direction) of the workpiece.

[0044] A second protrusion 22 is formed on the second workpiece 20. The second protrusion 22 projects toward the first workpiece 10 in the thickness direction (Y direction). The second protrusion 22 is provided so as to be in contact with the first protrusion 12.

[0045] A recess 23 is formed in the second protrusion 22. The recess 23 is recessed in the thickness direction (Y direction) so as to conform to the shape of the first protrusion 12 at the contact position 50 with the first protrusion 12.

[0046] In this embodiment, there is one recess 23. However, the number of recesses 23 may be multiple, depending on the shape of the tips of the pair of pressing members 130.

[0047] The insulating material 30 is interposed between the first workpiece 10 and the second workpiece 20 in the thickness direction (Y direction) of the first workpiece 10 and the second workpiece 20. The insulating material 30 is located between the first workpiece 10 and the second workpiece 20 outside the contact position 50.

[0048] The insulating material 30 functions as an adhesive that fixes the first workpiece 10 and the second workpiece 20 at locations other than where they are joined. This improves the joint strength of the first workpiece 10 and the second workpiece 20.

[0049] Furthermore, the insulating material 30 functions as a corrosion inhibitor for the workpiece. Specifically, the insulating material 30 prevents galvanic corrosion caused by contact between dissimilar metal materials.

[0050] An intermetallic compound 40 is formed at the contact position 50 between the first workpiece 10 and the second workpiece 20. The intermetallic compound 40 is formed over substantially the entire contact position 50. The first workpiece 10 and the second workpiece 20 are joined together via the intermetallic compound 40. The intermetallic compound 40 is, for example, FeAl.

[0051] In this embodiment, the joint 1 is shown with one first protrusion 12 and one second protrusion 22, but the embodiment is not limited to this configuration. Each of the first protrusion 12 and the second protrusion 22 may be provided in multiples on the joint 1. In this case, it is desirable that one recess 23 be provided on each of the multiple second protrusions 22.

[0052] Furthermore, the protrusion amounts of the first protrusion 12 and the second protrusion 22 in the Y direction, and the depth of the recess 23, are formed to the extent that they are created by the pressure of the workpiece. For this reason, the first protrusion 12, the second protrusion 22, and the recess 23 in this embodiment are not intended to be minute irregularities that may be formed on the flat surface of a workpiece due to manufacturing tolerances.

[0053] Next, a method for manufacturing the joined body 1 using the solid-phase bonding apparatus 100 will be described. The method for manufacturing the joined body 1 mainly comprises a step of forming protrusions and a step of joining the workpieces together. The step of forming protrusions is performed to restrict the path of the current flowing from the pair of electrodes 140. The step of joining the workpieces together is performed by applying a high load to the workpieces with a pair of pressing members 130 and by inputting heat to the workpieces by supplying power to the pair of electrodes 140.

[0054] Figure 3 is a flowchart showing a method for manufacturing a joined body according to one embodiment of the present invention. Figure 4 is a cross-sectional view showing the process of preparing the workpieces that constitute the joined body.

[0055] As shown in Figures 3 and 4, first, the workpiece is prepared (step S1). Specifically, the workpiece is transported between the first joining unit 110 and the second joining unit 120. The workpiece is transported with an insulating material 30 interposed between the first workpiece 10 and the second workpiece 20.

[0056] The insulating material 30 is in a liquid state before the first workpiece 10 and the second workpiece 20 are joined together. In this embodiment, the insulating material 30 is applied between the first workpiece 10 and the second workpiece 20 in a liquid state. Because the insulating material 30 is in a liquid state, it is easy for the insulating material 30 to reach every corner of the gap between the first workpiece 10 and the second workpiece 20. This allows the insulating material 30 to be placed adjacent to the outer periphery 51 at the contact position 50 of the first workpiece 10 and the second workpiece 20, as described later. As a result, current from the pair of electrodes 140 is less likely to flow outside the outer periphery 51, and the area of ​​the intermetallic compound 40 that is formed is not expanded too much.

[0057] The insulating material 30 may be in a solid state, such as an insulating sheet. If the insulating material 30 is in a solid state, it is fixed to the first workpiece 10 and the second workpiece with tape or the like. Furthermore, if the insulating material 30 is in a solid state, it is desirable that through holes be provided in the portion of the insulating material 30 corresponding to the joint between the first workpiece 10 and the second workpiece 20. This suppresses the remaining insulating material 30 between the first workpiece 10 and the second workpiece, thereby suppressing the occurrence of unjointed areas.

[0058] Figure 5 is a cross-sectional view showing the process in which a workpiece is pressed to form a protrusion. As shown in Figures 3 and 5, next, with an insulating material 30 interposed between the first workpiece 10 and the second workpiece 20 in the thickness direction (Y direction), the first workpiece 10 and the second workpiece 20 are pressed in the thickness direction (Y direction) by a pair of pressing members 130. As a result, a first protrusion 12 is formed on the first workpiece 10 and a second protrusion 22 is formed on the second workpiece 20 (S2 step).

[0059] Figure 6 is a cross-sectional view showing the process in which a workpiece is pressed and a recess is formed in the workpiece. As shown in Figures 3 and 6, the first workpiece 10 and the second workpiece 20 are further pressed by a pair of pressing members 130. This forms a recess 23 at the contact position 50 with the first protrusion 12 in the second protrusion 22 of the second workpiece 20, and pushes the insulating material 30 that was present at the contact position 50 outwards (step S3).

[0060] Because the second workpiece 20 has lower hardness than the first workpiece 10, the first protrusion 12 and the second protrusion 22 come into contact, and when the first protrusion 12 and the second protrusion 22 are further pressed by the pair of pressing members 130, the second workpiece 20 deforms and a recess 23 is formed. The recess 23 is recessed in the thickness direction (Y direction) to conform to the shape of the first protrusion 12 at the contact position 50 with the first protrusion 12, so that no insulating material 30 is interposed between the first protrusion 12 and the recess 23. Note that in the above process of forming the first protrusion 12, the second protrusion 22 and the recess 23, the pair of electrodes 140 do not come into contact with the first workpiece 10 and the second workpiece.

[0061] Figure 7 is a cross-sectional view showing the process of forming an intermetallic compound on the outer periphery of the contact area between the workpieces. As shown in Figures 3 and 7, after forming the recess 23, the pair of electrodes 140 are supplied with power while continuing to press the first workpiece 10 and the second workpiece 20 with the pair of pressing members 130.

[0062] Specifically, after the pair of electrodes 140 come into contact with the first workpiece 10 and the second workpiece 20, current flows from the pair of electrodes 140 to the first workpiece 10 and the second workpiece 20. Because the first convex portion 12, the second convex portion 22 and the concave portion 23 are formed, the path of the current flowing from the pair of electrodes 140 is limited to the area of ​​the contact position 50. Since the current flows along the shortest path at the contact position 50 (dotted line in the figure), the current mainly flows through the outer periphery 51 at the contact position 50.

[0063] The first workpiece 10 and the second workpiece 20 are heated by the application of current, and intermetallic compounds 41 (IMC) are formed on the outer periphery 51 at the contact position 50 (Step S4).

[0064] Figure 8 is a schematic diagram showing the shape of the intermetallic compound formed on the outer periphery of the contact point between the workpieces. As shown in Figure 8, when viewed from the thickness direction (Y direction), the intermetallic compound 41 formed on the outer periphery 51 has an annular shape. In the state where the intermetallic compound 41 is formed only on the outer periphery 51, the first workpiece 10 and the second workpiece inside the intermetallic compound 41 at the contact point 50 are not joined.

[0065] In this embodiment, the outer diameter of the outer circumference 51 is approximately the same as the outer diameter of the pair of pressing members 130. The outer diameter of the outer circumference 51 is preferably as small as possible in order to facilitate the concentration of current flowing at the contact position 50.

[0066] The first workpiece 10 and the second workpiece 20 are pressed by a pair of pressing members 130, causing the recess 23 to expand outward and the range of the contact position 50 to expand in a direction (in the direction of the arrows in Figures 7 and 8). However, intermetallic compounds are generally harder than pure metals. By forming an intermetallic compound 41 on the outer circumference 51 of the contact position 50, a so-called pinning effect is created that prevents the contact position 50 between the materials from expanding outward.

[0067] Furthermore, by placing the insulating material 30 outside the contact point 50 between the materials, it is possible to suppress the flow of current between the materials outside the contact point 50. Due to the pinning effect of the cyclic intermetallic compound 41 and the insulating effect of the insulating material 30 outside the contact point 50, the contact point 50 between dissimilar metal materials is not expanded too much, and the range in which current flows can be limited. As a result, it is possible to concentrate the current at the contact point 50 between the materials.

[0068] Figure 9 is a cross-sectional view showing the process of forming an intermetallic compound over substantially the entire contact area between the workpieces. As shown in Figures 3 and 9, after forming the intermetallic compound 41 on the outer periphery 51, the pressing of the first workpiece 10 and the second workpiece 20 by the pair of pressing members 130 and the supply of power to the pair of electrodes 140 are continued. This causes the intermetallic compound 40 to form over substantially the entire area inside the outer periphery 51 at the contact area 50 (step S5). As a result, the first workpiece 10 and the second workpiece 20 are joined in a solid-state state.

[0069] Due to the pinning effect of the intermetallic compound 41 on the spread of the contact position 50, and the insulating effect of the insulating material 30 outside the contact position 50, it is possible to concentrate the current at the contact position 50 between the materials. As a result, sufficient current flows over almost the entire contact position 50 (dotted line in the figure), and the first workpiece 10 and the second workpiece 20 are heated. This allows the intermetallic compound 40 to be formed over almost the entire contact position 50 between the materials, thus improving the bonding quality without creating any unbonded areas.

[0070] The intermetallic compound formed inside the intermetallic compound 41 formed on the outer periphery 51 is made of the same material as the intermetallic compound 41 formed on the outer periphery 51. Therefore, the intermetallic compound 40 formed over substantially the entire contact position 50 includes the intermetallic compound 41 formed on the outer periphery 51 and the intermetallic compound formed inside the intermetallic compound 41 formed on the outer periphery 51.

[0071] As shown in Figure 3, after the joining of the first workpiece 10 and the second workpiece 20 is completed, the pressing and power supply to the workpieces are stopped (step S6). After the insulating material 30 becomes solid, the joined body 1 is completed.

[0072] In the manufacturing method of the jointed body 1 and in the jointed body 1 of this embodiment, an intermetallic compound 41 is formed on the outer periphery 51 of the contact position 50 between dissimilar metal materials, thereby preventing the contact position 50 from spreading too far outward. The insulating material 30 is placed outside the contact position 50 between the materials to suppress the flow of current between the materials outside the contact position 50. As a result, the current can be concentrated at the contact position 50, thereby suppressing the occurrence of unjointed areas and improving the quality of the joint between the materials.

[0073] In the manufacturing method of the joint 1 of this embodiment, since the intermetallic compound 41 formed on the outer circumference 51 is formed in an annular shape, the pinning effect of the intermetallic compound 41 can be uniformly applied in the circumferential direction of the annular shape. Furthermore, because the intermetallic compound 41 is annular in shape, compared to cases where the intermetallic compound is square in shape, the intermetallic compound 41 can uniformly distribute the pressing force from the pair of pressing members 130 in the circumferential direction. As a result, the intermetallic compound 41 is less likely to be damaged, and the contact area 50 between the materials can not be expanded too much.

[0074] In the manufacturing method of the jointed body 1 and the jointed body 1 of this embodiment, since there is only one recess 23, the surface shape of the contact position 50 is smoother compared to the case where multiple recesses are formed and the surface of the contact position 50 becomes uneven. Therefore, when the first protrusion 12 and the second protrusion 22 come into contact and the recess 23 is formed, the insulating material 30 between the first workpiece 10 and the second workpiece 20 is easily discharged to the outside of the contact position 50. As a result, the insulating material 30 can be removed and the first workpiece 10 and the second workpiece 20 can be reliably brought into contact, thereby suppressing the occurrence of unjointed areas.

[0075] The embodiments disclosed herein are illustrative in all respects and do not constitute a limiting interpretation. Therefore, the technical scope of this disclosure is not limited to the embodiments described above. Furthermore, all modifications within the meaning and scope of equivalence to the claims are included. In the description of the embodiments above, combinatorial configurations may be combined with each other. [Explanation of Symbols]

[0076] 1 Joint, 10 First workpiece, 11 First main surface, 12 First protrusion, 20 Second workpiece, 21 Second main surface, 22 Second protrusion, 23 Recess, 30 Insulating material, 40 Intermetallic compound, 41 Intermetallic compound formed on the outer periphery, 50 Contact position, 51 Outer periphery, 100 Solid-phase bonding device, 110 First bonding unit, 120 Second bonding unit, 130 Pair of pressing members, 131 First pressing member, 132 Second pressing member, 140 Pair of electrodes, 141 First electrode, 142 Second electrode.

Claims

1. A method for manufacturing a joined body formed by joining a first workpiece, which forms an intermetallic compound with respect to the materials it contains, and a second workpiece, which has a lower hardness than the first workpiece, in a solid state using a solid-state joining device, The solid-phase bonding apparatus is A pair of pressing members that clamp and press the first workpiece and the second workpiece in the thickness direction, The system comprises a pair of electrodes arranged around the pair of pressing members, The aforementioned manufacturing method is With an insulating material interposed between the first workpiece and the second workpiece in the thickness direction, the first workpiece and the second workpiece are pressed in the thickness direction by the pair of pressing members, thereby forming a first protrusion on the first workpiece and a second protrusion on the second workpiece. By further pressing the first workpiece and the second workpiece with the pair of pressing members, a recess is formed at the contact position with the first protrusion on the second workpiece, and the insulating material present at the contact position is pushed outwards from the contact position. After forming the recess, the intermetallic compound is formed on the outer periphery at the contact position by supplying power to the pair of electrodes while continuing to press the first and second workpieces with the pair of pressing members. A method for manufacturing a joined body, comprising: after forming the intermetallic compound, continuing to press the first workpiece and the second workpiece with the pair of pressing members and supplying power to the pair of electrodes, thereby forming the intermetallic compound over substantially the entire area inward from the outer periphery at the contact position, and joining the first workpiece and the second workpiece in a solid state.

2. The method for manufacturing a bonded body according to claim 1, wherein the intermetallic compound formed on the outer periphery has an annular shape when viewed from the thickness direction.

3. The method for manufacturing a joined body according to claim 1 or claim 2, wherein the number of recesses is one.

4. A first workpiece in which intermetallic compounds are formed by the materials contained in each other, and a second workpiece in which the hardness is lower than that of the first workpiece, The first workpiece and the second workpiece are provided with an insulating material interposed between them in the thickness direction of the first workpiece and the second workpiece, The first workpiece has a first protrusion formed thereon that protrudes toward the second workpiece in the thickness direction. The second workpiece has a second protrusion formed thereon that protrudes toward the first workpiece in the thickness direction and contacts the first protrusion. The second protrusion has a recess formed in the thickness direction that conforms to the shape of the first protrusion at the contact position with the first protrusion. The insulating material is located outside the contact position between the first workpiece and the second workpiece. A joined body in which the first workpiece and the second workpiece are joined via the intermetallic compound formed over substantially the entire contact area.

5. The joint according to claim 4, wherein the number of recesses is one.

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