KR20230020393A - Parts for electrical/electronic devices - Google Patents

Abstract

A component for electrical/electronic devices in which a plurality of plate materials made of copper-based materials are joined by welding, and a component for electrical/electronic devices having a high welded portion is provided. It is composed of a plurality of plate materials containing 90% by mass or more of Cu, and has a welding portion for joining and integrating the plurality of plate materials in a linear or dotted shape by welding in a state of facing each other or in a state of overlapping each other, and the welding portion has the entire thickness of the plate material. In a cross section when the welded part is cut in the direction in which the plurality of plate materials are extended and joined, the Vickers hardness of the welded part when measured at a position corresponding to half the thickness of the plate material is 60 or more. It is a component for electrical and electronic devices.

Description

Parts for electrical/electronic devices

The present invention relates to parts for electrical/electronic devices.

BACKGROUND OF THE INVENTION [0002] In recent years, the amount of heat generated tends to increase with the high functionality and high performance of electrical and electronic devices. In addition, as the miniaturization of electric/electronic devices progresses, heat generation density increases, so cooling the generated heat is becoming important. As a member for cooling the generated heat, a vapor chamber which is a planar heat pipe is exemplified. As the material of the vapor chamber, it is preferable to use a copper-based material (pure copper, copper alloy) having high thermal conductivity.

Here, the vapor chamber has an airtight structure in which a working liquid is put into an inner space formed by joining outer circumferential portions in a state where several sheets of plates are stacked, and then sealed under reduced pressure. Examples of such a bonding method include laser welding, resistance welding, diffusion bonding, and TIG welding.

In the case of joining by welding, since the welded part is formed by melting once by heating to a high temperature and then re-solidifying, it becomes softer as in the case of annealing the plate material, and there is a problem that the strength is lowered by being softer than the strength of the plate material itself. there is. When strength is low, it becomes easy to deform|transform.

Regarding this problem, in Patent Document 1, in a method for manufacturing a vapor chamber by joining various parts by diffusion bonding or brazing, a precipitation hardening type copper alloy is used as a material for the case, and precipitation hardening is performed by aging treatment to make the case Techniques for improving strength and the like are disclosed.

However, in the technique of Patent Document 1, there is a problem that it is necessary to use a precipitation hardening type copper alloy and cannot be applied to a non-precipitation type copper alloy or pure copper. In addition, the technology of Patent Literature 1 requires aging treatment, and there is a problem that productivity decreases due to an increase in the number of steps.

For this reason, it is preferable to increase the strength of the welded part by a method other than the method of precipitation hardening by aging treatment using a precipitation hardening type copper alloy.

The above-mentioned problem of lowering the strength of the welded part is not limited to the vapor chamber, and also exists in other electric/electronic devices such as bus bars.

In addition, Patent Document 2 discloses a technique for improving bonding strength by irradiating a laser with a specific trajectory, but the technique of Patent Document 2 is a technique for bonding aluminum and copper, and is applicable to bonding between copper-based materials. difficult. More specifically, since copper-based materials have high thermal conductivity, heat escapes easily, and laser light is easily reflected, copper-based materials are materials that are difficult to join by laser welding. For this reason, as in Patent Document 2, by simple welding using a laser beam, bonding strength is low and cannot be sufficiently bonded.

International Publication No. 2017/164013 Japanese Unexamined Patent Publication No. 2017-168340

The present invention has been made in view of the above situation, and is a component for electrical/electronic devices in which a plurality of plate materials made of copper-based materials are joined by welding, and the strength of the welded portion is high. It is an object to provide a component for electrical/electronic devices.

In addition, in the present invention, in parts for electric/electronic devices having welded parts such as vapor chambers and bus bars, by controlling the gradient of the hardness of the welded plate material and the overall hardness of the plate material, the welded part has rigidity and is difficult to locally deform. It aims to provide parts for electrical and electronic devices.

As a result of repeated studies, the inventors of the present invention have found that the Vickers hardness (HV) of the welded part can be increased by using a sheet material having a component composition containing 90% by mass or more of Cu and controlling the laser welding conditions. , The inventors of the present invention have found that the welded portion has rigidity and is difficult to locally deform by controlling the appropriate hardness and the slope of the hardness from the welded portion to the non-welded portion, and has completed the electrical/electronic device parts of the present invention. .

That is, the gist of the present invention is as follows.

(1) It is composed of a plurality of plate materials containing 90% by mass or more of Cu, and has a welding portion for joining and integrating the plurality of plate materials in a linear or dotted shape by welding in a state in which the plurality of plate materials are butted against each other or in a stacked state, and the weld portion Extends over the entire thickness of the plate material, and in a cross section when the welded part is cut in the direction in which the plurality of joined plate materials extend, the welded part has half the thickness of the plate material at the center of the weld width, which is the width of the weld mark. Parts for electrical and electronic devices with a Vickers hardness (HV1) of 60 or more when measured at the location corresponding to

(2) In the cross section, when a GAM value obtained from crystal orientation analysis data of the SEM-EBSD method is measured in a rectangular region partitioned by the weld width of the weld portion and the thickness of the plate material, the GAM value is 0.5° or more. The electrical/electronic device component according to (1), wherein the crystal grains having an area of less than 2.0 ° have an area ratio of 25% or more to all crystal grains present in the measurement area.

(3) composed of a plurality of plate materials containing 90% by mass or more of Cu;

The plurality of plate materials are joined to each other in a state of facing each other or in a state of being overlapped, and has a welding portion for joining and integrating the plurality of plate materials in a linear or point shape by welding, the weld portion extending over the entire thickness of the plate material, and the joined plurality of plate materials In the cross section when the weld is cut in the extending direction, the Vickers hardness at the weld when measured at a position corresponding to half the thickness of the plate at the center of the weld width, which is the width of the weld mark on the surface of the plate, is HV1 say,

When the Vickers hardness at the non-welded portion measured at a location spaced apart along the direction of the weld width by a distance corresponding to 1.5 times the half-width of the weld from the center position of the weld portion is HV2, at the non-weld portion The position where the Vickers hardness (HV2) is 75 or more and the difference between the Vickers hardness (HV2) at the non-welded part and the Vickers hardness (HV1) at the welded part is measured and the Vickers hardness (HV1 and HV2) is measured The electrical/electronic device component according to (1) or (2), wherein the hardness gradient ((HV2-HV1)/X) when divided by the indentation distance X (μm) between the spaces is 0.2/μm or less.

(4) In any one of (1) to (3), wherein the plate material contains at least one element selected from the group consisting of Ag, Fe, Ni, Co, Si, Cr, Sn, Zn, Mg, and P. Components for electrical and electronic devices listed.

(5) The electrical/electronic device component according to any one of (1) to (3), wherein the plate material is Cu of 99.96% by mass or more and unavoidable impurities.

(6) The components for electrical/electronic devices according to any one of (1) to (5), wherein the components for electrical/electronic devices are vapor chambers.

(7) The component for electrical/electronic device according to any one of (1) to (5), wherein the component for electrical/electronic device is a bus bar.

According to the present invention, a plurality of plate materials made of a copper-based material containing 90% by mass or more of Cu are joined by welding, and the strength of the welded portion is high. Electrical and electronic device components can be provided.

Further, according to the present invention, by obtaining appropriate hardness at the welded portion and controlling the inclination of the hardness between the welded portion and the non-welded portion, a component for electric/electronic devices having rigidity and being difficult to locally deform at the welded portion is provided. can do.

1 (a) is a schematic perspective view of laser welding in a line shape in a state where two sheets of Cu plate materials constituting a component for electric/electronic devices according to an embodiment of the present invention are butted to each other, and (b) is a schematic perspective view of the present invention. It is a schematic perspective view when laser welding is performed linearly in the state where the Cu plate material of 2 sheets which comprises the electrical/electronic device component used as one embodiment is piled up.
Fig. 2 is an optical microscope photograph when observing from the Z-axis the surface state of the laser-irradiated side of a Cu joined body (two Cu plate joined bodies) obtained by laser welding the butted Cu plate materials.
Fig. 3 is an optical micrograph when the surface state of the opposite side to the laser irradiated side of a Cu bonded body obtained by laser welding the facing Cu plate materials is observed.
Fig. 4 is an optical microscope photograph when a cross-sectional state of a Cu bonded body obtained by laser welding a Cu plate material is observed from the X-axis.
Figure 5 (a) is a schematic perspective view when two sheets of Cu plate materials are laser welded in a dot shape in a state of facing each other, (b) is a schematic perspective view when laser welding is performed in a dot shape in a state in which two sheets of Cu plate materials are overlapped, All welded parts are shown in a state in which the cross section when cut in the direction in which the Cu bonded body extends is visible.
6 is a diagram showing a schematic configuration of a laser welding device.
Fig. 7 is a diagram showing the spot diameter of the laser beam of the laser welding device.
Fig. 8 (a) is a schematic perspective view when two Cu plates constituting a component for electric/electronic devices according to another embodiment of the present invention are joined in a linear shape while facing each other, and (b) is a schematic perspective view of another embodiment of the present invention. It is a schematic perspective view at the time of joining in a linear shape in the state which the Cu board material of 2 sheets which comprises the component for electrical/electronic devices used as an embodiment was piled up.
Fig. 9 is an optical micrograph when the cross-sectional state of the joined Cu plate materials is observed.

EMBODIMENT OF THE INVENTION Embodiment of this invention is described below. The following description is an example of embodiment in the present invention, but does not limit the scope of the claims.

A component for electrical/electronic devices according to an embodiment of the present invention is composed of a plurality of plate materials containing 90% by mass or more of Cu, and the plurality of plate materials are welded to each other in a state in which they are buttted against each other or in a state in which they are stacked, so that they are formed in a linear or dotted shape by welding. It has a welded portion to be joined and integrated, and the welded portion extends throughout the entire thickness of the plate material, and in a cross section when the welded portion is cut in the direction in which the plurality of joined plate materials extend, the welded portion is measured at a position corresponding to half the thickness of the plate material. The Vickers hardness when done is 60 or more.

Fig. 1 (a) is a schematic perspective view when a Cu bonded body 10 (two sheets of Cu sheet joined body) is formed by laser welding in a line shape with two sheets of Cu plate materials 1 and 2 facing each other, (b) is a schematic perspective view when the Cu plate materials 1 and 2 of 2 sheets are laser welded in a linear shape in a stacked state to form the Cu bonded body 10A. In the embodiment shown in Fig. 1 (a), there is a welded portion 3 that joins the Cu plate materials 1 and 2 in a linear manner in a state of facing each other and integrates them, and the portion is joined by laser welding. Moreover, in embodiment shown in FIG.1(b), it has 3 A of welding parts which integrate the Cu plate materials 1 and 2 in the overlapping state, and the part was joined by laser welding. And, the welded portion 3 extends over the entire thickness of the plate materials 1 and 2 . That is, in Fig. 1 (a) and Fig. 1 (b), the welding portion 3 is melted and solidified so as to melt from the surface on the side irradiated with the laser to the surface (rear surface) on the opposite side, and the plate material 1, 2) in the thickness direction. In addition, a "Cu plate material" here means a plate material containing 90 mass % or more of Cu (copper).

Here, the "plate material containing 90 mass % or more Cu" may be a plate material having a Cu content of 90 mass % or more, and may be pure Cu or any Cu alloy, and is not particularly limited.

When the plate material is a Cu alloy, the plate material contains one to two or more elements selected from Ag, Fe, Ni, Co, Si, Cr, Sn, Zn, Mg, and P as alloy components, and the remainder is Cu. It is preferable to have a component composition of 90% by mass or more. The Cu alloy may be a precipitation hardening type Cu alloy or a non-precipitation hardening type Cu alloy. When the plate material is a Cu alloy, the Vickers hardness (HV) of the plate material varies depending on the type and amount of the alloy component to be added, so it is not particularly limited, but is generally 75 or more and 240 or less.

In addition, when the plate material is pure Cu, the plate material has a Cu content of 99.96% by mass or more, and a total of 5 ppm or less of Cd, Mg, Pb, Sn, Cr, Bi, Se, and Te as unavoidable impurities, and Ag and O The sum of is less than 400 ppm. Since pure Cu has excellent thermal conductivity, it can exhibit excellent performance as a heat dissipation/cooling member. Further, so-called pure Cu includes electrolytic copper, oxygen-free copper (OFC), TPC, and the like. When the plate material is pure Cu, the Vickers hardness of the plate material is not particularly limited, but is generally 65 or more and 120 or less, for example.

In the present invention, "plate material" refers to a material processed into a predetermined shape, for example, a plate, strip, foil, bar, flat wire, etc., and has a predetermined thickness. meaning to include In the present invention, the thickness of the plate material (plate thickness) is not particularly limited, but is preferably 0.05 to 1.0 mm, more preferably 0.1 to 0.8 mm. In addition, the shapes of the plurality of plate materials to be joined and the thickness (plate thickness) of the plate materials may be the same or different.

2 : is a photograph which shows the surface state of the laser-irradiated side of the Cu joined body 10 which laser-welded the Cu board|plate materials 1 and 2 of 2 sheets butt-to-match. It is shown that the X-axis direction is a laser sweeping direction, that is, a welding direction. In addition, it is understood that there is a portion where the traces of the rolling process of the Cu plate material are lost by irradiation with the laser beam. Furthermore, there is a portion where the Cu plates 1 and 2 are melted and solidified again, which is called a welded portion 3.

Fig. 3 is an optical microscope photograph when observing the surface state of the opposite side to the laser irradiated side of the Cu bonded body 10 obtained by laser welding two Cu plates 1 and 2 facing each other, and the surface of the back side of Fig. 2 It is an optical microscope picture when the state was observed.

As shown in FIGS. 2 and 3, since the welded portion 3 extends over the entire thickness of the plate materials 1 and 2, the laser welding mark is the surface of the Cu bonded body 10 on the laser irradiated side (front ) and on the surface (back) on the opposite side to the side irradiated with the laser. And, normally, as shown in FIG. 2 and FIG. 3, the width of the laser welding scar on the surface on the laser irradiation side is wider than the laser welding scar on the surface on the opposite side to the laser irradiation side. The width of the laser welding mark on the side surface irradiated with this laser was defined as the welding width in the present invention, and was cut at the cross-sectional observation position in the shape of a dotted line to observe the cross-sectional structure.

4 is an optical micrograph showing a cross-sectional state when a Cu bonded body is formed by laser welding a Cu plate material. As shown in FIG. 4 , the width of the laser-irradiated side surface of the welded portion melted by laser irradiation and solidified again corresponds to the welding width. The welding width can be recognized also from the sectional view shown in FIG.

In the present invention, the Vickers hardness when measured at a position corresponding to half the thickness of the plate in the cross section when the weld is cut in the direction in which the two joined plates are extended is 60 or more. In addition, in this specification, Vickers hardness (HV) is measured based on the method prescribed|regulated by JIS Z2244 (2009).

More specifically, as shown in Fig. 1 (a), in the case of having a welding portion 3 for joining and integrating two Cu plates 1 and 2 in a line shape while facing each other, the welding direction (laser sweeping direction) When the X-axis direction, the direction perpendicular to the welding direction (the width direction of the plate material) is the Y-axis direction, and the normal direction of the plate material (the thickness direction of the plate material) is the Z-axis direction, two joined plate materials (1, 2) The direction (L) in which is extended is the direction in which the plates are approached to face each other, that is, the Y-axis direction. In the case of the electrical/electronic device parts of the present embodiment having such a structure of the joined body 10, the weld portion 3 present in the cross section A when the Cu joined body 10 is cut in the Y-axis direction is a Cu plate material ( 1, 2) It is necessary that the Vickers hardness is 60 or more at the position (b) corresponding to the half dimension of the thickness (a).

In addition, as shown in Fig. 1 (b), in the case where the two Cu plate materials 1 and 2 are overlapped with each other and have a welding portion 3A joining them in a linear shape to integrate them, the joined two plate materials 1 and 2 ) is a direction perpendicular to the welding direction, that is, the Y-axis direction. In the case of the electrical/electronic device components of the present embodiment having such a structure of the joined body 10A, the Cu joined body 10A is cut in the Y-axis direction, present in the end face A ₁ of the Cu plate 1 The thickness (a 2) of the Cu plate (2) of the weld that exists at the position (b ₁ ) corresponding to the half dimension of the thickness (a ₁ ) of the Cu plate (1) of the weld and the cross section (A ₂ ) of the Cu plate ( ₂₎ ), it is necessary that the Vickers hardness is 60 or more at both positions (b ₂ ) corresponding to the half dimension of.

In the case of joining by welding, since the welded part is formed by melting once by heating to a high temperature and then re-solidifying, in the conventional joining method, the plate material is softened as in the case of annealing, and the plate material itself is softer than the strength of the plate material itself. There is a problem with lower strength. When strength is low, it becomes easy to deform|transform.

However, as shown in examples described later, by using a sheet material having a composition containing 90% by mass or more of Cu and controlling the laser welding conditions, the reduction in strength due to softening of the weld zone can be suppressed. Further, depending on the laser welding conditions, the strength may be higher than that of the plate material itself.

For this reason, in this embodiment, the Vickers hardness of a welded part can be made into 60 or more, and also 65 or more. Since the Vickers hardness of the welded part is as high as 60 or more, parts for electric/electronic devices having high strength and excellent deformation resistance can be provided. Since the Vickers hardness and strength are in a proportional relationship, the higher the Vickers hardness, the higher the strength. In addition, when the aging treatment is performed as in Patent Document 1, unless a hardenable copper alloy is used, the entire Cu bonded body including the welded portion tends to be heated and softened, so it is difficult to maintain the Vickers hardness of 60 or more at the welded portion. I think it is difficult.

Although the upper limit of the Vickers hardness (HV) of a welded part is not specifically limited, In the case of pure Cu, it is, for example, 90 or less, and in the case of a Cu alloy, it is, for example, 130 or less.

In the above, the case of linear laser welding has been described, but the case of point laser welding is shown in FIGS. 5(a) and (b). Fig. 5 (a) is a schematic perspective view of a case in which a Cu bonded body 10B is formed by point-shaped laser welding in a state where two sheets of Cu plate materials 1 and 2 are buttted, and Fig. 5 (b) is a schematic perspective view of two sheets of Cu It is a schematic perspective view when the Cu bonded body 10C is formed by laser welding in a point shape in a state where the plate materials 1 and 2 are stacked.

As shown in (a) of FIG. 5, in the case of components for electric/electronic devices of this embodiment having a configuration of a Cu bonded body 10B having a welding portion 3B joined in a dotted state in abutting state and integrated, Of the weld portion 3B present in the cross section A when the joined body 10B is cut in the extension direction L of the Cu plate materials 1 and 2 through the center c of the weld portion 3B on the plate material surface. At the position (b) corresponding to the half dimension of the thickness (a) of the Cu plate materials 1 and 2, it is necessary that the Vickers hardness is 60 or more.

Further, as shown in FIG. 5(b), the electrical/electronic device components of the present embodiment having a configuration of a Cu bonded body 10C having a welded portion 3B joined in a point-like manner in a state of being overlapped and integrated. In this case, the thickness of the Cu plate 1 of the weld that exists in the cross section _A 1 of the Cu plate 1 when the weld is cut in the stacking direction of the plate through the center (c) of the weld on the surface of the plate ( a ₁ ) and a position corresponding to the half dimension of the thickness (a 2 ) of the Cu plate 2 of the welded portion (b ₁ ) and the cross section (A ₂ ) of the Cu plate ₂ ( b ₂ ) In both cases, it is necessary that the Vickers hardness is 60 or more.

In addition, in this specification, the Vickers hardness (HV) in the case of linear laser welding is measured in five cross sections A (YZ plane) cut at 1 mm intervals in the welding direction (X-axis direction), and these measurements It is calculated as the average value of the results.

In the present invention, in a cross section when a weld is cut in the direction in which a plurality of joined plate materials extend, in a rectangular region partitioned by the welding width of the weld and the thickness of the plate, from the crystal orientation analysis data of the SEM-EBSD method. When the obtainable GAM value is measured, it is preferable that the area ratio of the crystal grains having a GAM value of 0.5° or more and less than 2.0° to all crystal grains present in the measurement area is 25% or more.

GAM (grain average misorientation) value is a value obtained from the crystal orientation analysis data of the SEM-EBSD method, and the distance between measurement points (hereinafter referred to as step size) ) is measured at 0.1 μm, the orientation difference is calculated for each measurement point adjacent to each other, and the calculated orientation difference is a value calculated as an average value within the same crystal grain.

A small GAM value means that the average orientation difference within a crystal grain is small, the crystal grain is uniform with very little strain, has a continuous orientation gradient, and the like, and indicates that the strain within one crystal grain is small. On the other hand, a large GAM value means a large average orientation difference within a crystal grain, and indicates a large strain within one crystal grain. Crystal grains with a GAM value of 0.5° or more and less than 2.0° are crystal grains having in-between characteristics, indicating that the strain within one crystal grain is somewhat large. Further, when the sheet material is annealed, the GAM value is usually 0° or more and less than 0.5°, and the local strain within one crystal grain becomes small.

As such, if the area ratio of crystal grains with the GAM value of 0.5 ° or more and less than 2.0 ° is 25% or more, that is, if the area ratio of crystal grains with a large deformation in one crystal grain is 25% or more, in the case of pure Cu, the welded part can have a Vickers hardness of 65 or more.

The GAM value is preferably 45% or more, more preferably 65% or more, in which the area ratio of crystal grains of 0.5° or more and less than 2.0° is. In addition, the upper limit of the area ratio of crystal grains of 0.5° or more and less than 2.0° is not particularly limited, but is, for example, 95% or less, preferably 90% or less.

The GAM value is a crystal calculated using analysis software (OIM Analysis, manufactured by TSL) from crystal orientation data continuously measured using an EBSD detector attached to a high-resolution scanning electron microscope (manufactured by Nippon Electronics Co., Ltd., JSM-7001FA). It can be obtained from orientation analysis data. "EBSD" is an abbreviation of Electron BackScatter Diffraction, and is a crystal orientation analysis technique using reflection electron Kikuchi line diffraction generated when an electron beam is irradiated to a copper sheet as a sample in a scanning electron microscope (SEM). "OIM"Analysis" is analysis software of the data measured by EBSD.

In the present invention, the measurement area is the entire rectangular area defined by the welding width of the welded portion and the thickness of the sheet material on the surfaces mirror-finished by electropolishing with respect to the surfaces of the cross sections A, A ₁ , and A ₂ . The area ratio of crystal grains of GAM values within a predetermined range refers to GAM values of 0 ° or more and less than 0.25 ° as the first division, 15 divisions every 0.25 °, and GAM values of 0 ° or more and less than 3.75 ° as measurement targets, SEM-EBSD method It can be calculated from the sum of the area ratios of crystal grains in each division occupying the entire SEM image obtained by

It is preferable that the Cu plate material used for this electrical/electronic device component is a Cu alloy containing 90% by mass or more of Cu and containing other metal elements, or 99.96% by mass or more of Cu and unavoidable impurity pure Cu. Thermal conductivity can be provided by using a Cu plate material of 90% by mass or more. Originally, Cu has high thermal conductivity, but when the number of added elements increases and a second phase appears, the thermal conductivity decreases. Therefore, by containing 90% by mass or more of Cu, the Cu plate material used for the electrical/electronic device components of the present embodiment can suppress a decrease in thermal conductivity and can be provided with high strength.

Furthermore, in a cross-sectional view when a plurality of integrated plate materials are cut in a direction transverse to the weld part, in the weld part and the non-weld part located adjacent to the weld part, the weld part uses the width of the weld mark on the surface of the plate material as the welding width , in the heat affected zone when the respective Vickers hardnesses (HV1 and HV2) are measured at the center of the weld width and the non-welded portion at a distance of 1.5 times the weld width along the width direction of the weld from the center of the weld portion. has a Vickers hardness (HV2) of 75 or more, and the difference between the Vickers hardness (HV2) in the heat-affected zone and the Vickers hardness (HV1) in the weld zone is measured by measuring the Vickers hardness (HV1 and HV2). The value (hereinafter sometimes referred to as "hardness inclination rate") ((HV2-HV1)/X) when divided by the indentation distance X (μm) between positions is 0.2/μm or less.

(linear welding)

As shown in Fig. 8 (a) (numbers are assigned only to the description of Fig. 8), it is Cu member 10D which arranges two Cu plate materials 101 and 102 in a state of facing each other. By irradiating and sweeping the center of the abutted state with a laser beam, the two Cu plate materials 101 and 102 are welded in a linear shape, and abutted to the center 121 of the welded portion 12 to join. Here, a linear junction is formed by sweeping a laser beam. In the portion irradiated with strong laser light, molten liquid Cu is formed. Then, after the laser light passes through, because Cu has high thermal conductivity, liquid Cu is rapidly cooled and changed to solid Cu. If this proceeds continuously, a welded portion 12 having a corrugated bead is formed. Since it once melted and solidified, it is obviously in a different state from the base material 11 of the Cu plate materials 101 and 102. Further, around the welded portion 12, a heat-affected portion 13 in a different state from the surface of the base material 11 of the Cu plate materials 101 and 102 is formed under the influence of heat. This heat-affected portion 13 was affected by heat, and the properties of the base material 11 of the Cu plate materials 101 and 102 were also altered. Heat to the heat-affected portion 13 includes both heat due to laser light irradiation and heat emitted from the welded portion 12 . As shown in Fig. 8(b), it is a Cu member 10D in which the Cu plate material surface is linearly welded by irradiating and sweeping a laser beam in a state where two sheets of Cu plate materials 101 and 102 are stacked. In order to obtain sufficient joint strength, the overlapping Cu plate materials 101 and 102 are welded so that the width in the Y-axis direction joined by welding is 1/2 or more of the welding width of the surface.

(point shape welding)

A point-like junction can be formed by irradiating and joining the center of two sheets of Cu plate materials facing each other without sweeping the laser beam. Any of a circular shape, an elliptical shape, a cylindrical shape, and a rectangular shape may be sufficient as the shape of a laser beam. In addition, even if it is a dotted line shape, it should just be a state in which a welding part exists separately from each other. In the point-like welding, in the joint in the case of butt-to-butting, even if the Cu plate material is penetrated in the plate thickness direction, melting of the metal Cu may be stopped in the middle. Moreover, in the state where two sheets of Cu plate materials are stacked, a laser beam may be irradiated to join them in a dotted fashion. Also in this case, in order to obtain sufficient joint strength, the overlapping Cu plate materials are welded so that the width in the Y-axis direction joined by welding is 1/2 or more of the welding width of the surface.

(Surface condition of Cu member)

Fig. 2 is a photograph showing the surface state of a Cu member joined by laser welding of butted Cu plate materials, showing that the X-axis direction is the laser sweeping direction. In addition, it is understood that there is a portion where the traces of the rolling process of the Cu plate material have disappeared by irradiation with the laser beam. Moreover, since there is a part where the Cu plate material has melted and solidified again, it can be clearly seen that it is a welded part. The width of the welded part of the laser welding mark seen in the drawing is defined as the welding width in the present invention, and also cut at the cross-sectional observation position in the shape of a dotted line, and the cross-sectional structure was observed.

(Measurement position of Vickers hardness of linear joint)

9 is an optical micrograph showing a cross-sectional state of a Cu member joined by laser welding Cu plate materials. As shown in Fig. 9, the welded portion joined by irradiation of a laser beam to melt and then to solidify is indicated by a welding width. Even when viewed from the cross-sectional view from FIG. 9, the width of the weld mark on the surface of the Cu plate material on the side irradiated with the laser beam can be clearly recognized. A point extending along the direction of the weld width by a distance of 1.5 times the half length of the weld width (half weld width) from the center of the weld is called a non-weld portion, and as indicated by the arrow in FIG. Likewise, the depth in the plate thickness direction at the center of the weld width is measured by the Vickers hardness (HV1, HV2) of the welded and non-welded portions, respectively, at 1/2 of the plate thickness.

(Vickers Hardness)

Vickers hardness is a measurement method standardized by "JIS 　Z 2244". Vickers hardness (HV) is a numerical value indicating whether a rigid body (indenter) made of diamond is pushed against a test object, and whether it is hard or soft by the size of the area of the indentation (indentation) formed at that time. Since the indenter has the shape of a square pyramid like an inverted pyramid, the indentation is ideally square. The test force is variable, and is specified from 10 gf to 100 kgf in the JIS standard.

(Inclination rate of hardness)

The measurement of the non-welded part is measured at both sides of the point perpendicular to the direction in which the laser beam travels from the center of the welded part in the case of butting as shown in FIG. ) is called In addition, in the case of overlapping as shown in Fig. 8(b), the near end and the point on the opposite side are measured at right angles in the direction in which the laser beam travels from the center of the welded portion, and the Vickers hardness (HV2) of the non-welded portion is taken. .

The Cu plate material at this time is measured for Vickers hardness (HV1, HV2) at two points: the center of the welded portion and the non-welded portion. The difference between the Vickers hardness (HV2) at the non-welded part and the Vickers hardness (HV1) at the center of the welded part was divided by the indentation distance (X㎛) between the positions where the Vickers hardness (HV1 and HV2) were measured. The numerical value ((HV2-HV1)/X) at the time is used as the hardness inclination rate.

(Measurement position of Vickers hardness of point joint)

In spot welding, the welding width is the widest part in the spot welding part, and the cross section of the part is measured. Therefore, the non-welded portion is adjacent to the point-shaped welded portion, and refers to a portion at a distance of 1.5 times the half-width of the weld along the width direction of the weld width from the center of the welded portion.

Therefore, the hardness is measured at the center point of the widest part of the dot shape and at the point of the non-welded part spaced a certain distance therefrom. By this, the Vickers hardness (HV1, HV2) can be measured and the hardness inclination rate can be obtained.

(distribution of hardness)

Hardness indicates that an object is difficult to deform and that an object is difficult to be damaged when deformation or damage is applied to the surface of the Cu plate material in particular. Particularly, in a joined body in which two Cu plate materials are joined by welding, if there is a distribution in hardness, it becomes easy to crack or the like. This is because when stress is applied to a plate material in which a hard portion with high hardness and a soft portion with low hardness are mixed, the deformation stress is concentrated, so the portion with low hardness is easily deformed and cracks may occur. Therefore, in the case of a Cu plate material in which there is a large difference in the effect of heat between the portion affected by heat due to rapid heating and cooling in the laser welding process and the welded portion that is melted and solidified, deformation with respect to stress becomes easy and cracks tend to easily enter. there is Therefore, when the hardness inclination rate is large at the time of manufacturing components for electric/electronic devices, cracks may enter and breakage may occur.

Therefore, it is preferable that the hardness inclination rate representing the change in hardness in the base material, the non-welded portion, and the welded portion of the Cu plate is small. The larger the hardness inclination rate, the larger the difference in hardness between the base material of the Cu plate, the non-welded portion, and the welded portion, and is weakened by forming a stress-concentrated portion, making cracks easier to enter. Therefore, the difference between the Vickers hardness (HV1) at the welded portion and the Vickers hardness (HV2) at the non-welded portion located adjacent to the welded portion, the indentation distance X ( The hardness inclination rate ((HV2-HV1)/X), which is a numerical value when divided by μm), is set to 0.2/μm or less, more preferably 0.15/μm or less.

Furthermore, in order to be used as a component for electrical/electronic devices, it is a practical problem that it is easily deformed, and rigidity due to the hardness of the base material itself of the Cu plate material is required. It is preferable to set the Vickers hardness (HV2) at the non-welded part located adjacent to the welded part to 75 or more.

(Plate of Cu alloy)

It may be a plate material having a Cu content of 90% by mass or more, and may be pure Cu or any Cu alloy, and is not particularly limited.

When the Cu plate material used as a component for electric/electronic devices is a Cu alloy, one to two or more elements selected from Ag, Fe, Ni, Co, Si, Cr, Sn, Zn, Mg, and P are used as alloy components. Including, it is preferable to have a component composition in which Cu of the remainder is 90% by mass or more. The Cu alloy may be a precipitation hardening type Cu alloy or a non-precipitation hardening type Cu alloy. When the plate material is a Cu alloy, the Vickers hardness (HV2) at the non-welded portion is in the range of 75 to 240.

By using a Cu alloy as the Cu plate material, the hardness inclination rate is 0.2/μm or less, and generation of cracks is suppressed. Furthermore, it is preferable that not only the hardness inclination rate, but also the base material of the Cu plate, the non-welded portion, and the welded portion are all hard, and in particular, it is preferable that the Vickers hardness (HV2) at the non-welded portion is in the range of 75 to 240. If the Vickers hardness (HV2) at the non-welded portion of the Cu alloy sheet material is less than 75, it becomes easy to deform during processing. If the Vickers hardness (HV2) at the non-welded part exceeds 240, cracks tend to enter at the boundary between the non-welded part, the base material, and the welded part at the boundary or deformation of the welded part.

(Plate of pure Cu)

In addition, when the Cu plate material used as a component for electrical/electronic devices is pure Cu containing 99.96% by mass or more of Cu and unavoidable impurities, the Vickers hardness (HV2) at the non-welded portion is preferably in the range of 75 to 120. It is preferable that the gradient of the hardness of the base material, the welded portion, and the non-welded portion of the Cu sheet material is small. By using a pure Cu sheet material, the hardness gradient rate can be set to 0.1/μm or less, and local deformation of the welded portion becomes difficult. In particular, in a pure Cu plate material, if the Vickers hardness (HV2) at the non-welded part is less than 75, it becomes easy to deform during processing. When the Vickers hardness (HV2) at the non-welded portion exceeds 120, deformation of the welded portion or cracks tend to enter at the boundary between the non-welded portion and the base material and the welded portion and the non-welded portion.

Next, the reasons for limiting the suitable component composition of the plate material constituting the electrical/electronic device components of the present invention will be described below.

The plate material constituting the parts for electric/electronic devices of the present invention may be a plate material containing 90% by mass or more of Cu, and may be a Cu alloy or pure Cu.

First, the component composition in case the plate material is a Cu alloy is explained.

(1) When the plate is a Cu alloy

The plate material preferably contains at least one element selected from the group consisting of Ag, Fe, Ni, Co, Si, Cr, Sn, Zn, Mg, and P.

(Ag: 0.05 to 5.00% by mass)

Ag (silver) is a component having an effect of improving mechanical properties without impairing electrical properties, and when exhibiting such an effect, the Ag content is preferably 0.05% by mass or more. In addition, although there is no need to set an upper limit for the Ag content, since Ag is expensive, it is preferable to set the upper limit for the Ag content at 5.0% by mass from the viewpoint of material cost.

(Fe: 0.05 to 0.50% by mass)

Fe (iron) is a component having an effect of improving mechanical properties. When exhibiting such an action, it is preferable to make Fe content into 0.05 mass % or more. However, even if Fe is contained in a greater amount than 0.50% by mass, no further improvement effect can be expected, and furthermore, there is a risk of deterioration in corrosion resistance. For this reason, it is preferable to make Fe content into 0.05-0.50 mass %.

(Ni: 0.05 to 5.00% by mass)

Ni (nickel) is a precipitate of second-phase particles composed of a single substance or a compound with Si in the parent phase (matrix) of Cu, and is finely precipitated, for example, with a size of about 50 to 500 nm, and this precipitate prevents dislocation movement. It is a component having an effect of suppressing precipitation hardening, suppressing grain growth, and increasing material strength by refining crystal grains. When exhibiting such an action, it is preferable to make Ni content into 0.05 mass % or more. On the other hand, when the Ni content exceeds 5.00% by mass, the electrical conductivity and thermal conductivity decrease significantly, so the upper limit of the Ni content is preferably 5.00% by mass.

(Co: 0.05 to 2.00% by mass)

Co (cobalt) is a precipitate of second-phase particles composed of a single substance or a compound with Si in the parent phase (matrix) of Cu, and is finely precipitated, for example, with a size of about 50 to 500 nm, and this precipitate prevents dislocation movement. It is a component having an effect of suppressing precipitation hardening, suppressing grain growth, and increasing material strength by refining crystal grains. When exhibiting such an action, it is preferable to make Co content into 0.05 mass % or more. On the other hand, when the Co content exceeds 2.00% by mass, the electrical conductivity and thermal conductivity decrease significantly, so the upper limit of the Co content is preferably 2.00% by mass or less.

(Si: 0.05 to 1.10% by mass)

Si (silicon) is finely precipitated as a precipitate of second-phase particles made of a compound together with Ni or Co in the parent phase (matrix) of Cu, and this precipitate suppresses dislocation movement to cause precipitation hardening, and further suppresses grain growth It is an important component that has the effect of increasing material strength by refining crystal grains. When exhibiting such an action, it is preferable to make Si content into 0.05 mass % or more. On the other hand, when the Si content exceeds 1.10% by mass, the electrical conductivity and thermal conductivity decrease significantly, so the upper limit of the Si content is preferably 1.10% by mass.

(Cr: 0.05 to 0.50% by mass)

Cr (chrome) is finely precipitated in the form of a precipitate having a size of about 10 to 500 nm, for example, as a compound or single substance in the parent phase (matrix) of Cu, and the precipitate suppresses dislocation movement to cause precipitation hardening, furthermore, It is a component having an effect of suppressing growth and increasing material strength by miniaturizing crystal grains. When exhibiting this effect|action, it is preferable to make Cr content into 0.05 mass % or more. In addition, when the Cr content exceeds 0.50% by mass, the electrical conductivity and thermal conductivity decrease significantly, so the Cr content is preferably 0.05 to 0.50% by mass.

(Sn: 0.05 to 9.50% by mass)

Sn (tin) is a component that is dissolved in the parent phase (matrix) of Cu and contributes to the strength improvement of the Cu alloy, and the Sn content is preferably 0.05% by mass or more. On the other hand, when the Sn content exceeds 9.50% by mass, embrittlement tends to occur. For this reason, it is preferable to make Sn content into 0.05-9.50 mass %. Moreover, since containing of Sn tends to reduce electrical conductivity and thermal conductivity, it is more preferable to make Sn content into 0.05-0.50 mass % when suppressing electrical conductivity and thermal conductivity decline.

(Zn: 0.05 to 0.50% by mass)

Zn (zinc) is a component having an effect of improving the adhesion and migration characteristics of Sn plating or solder plating. When exhibiting such an effect, it is preferable to make Zn content into 0.05 mass % or more. On the other hand, when the Zn content exceeds 0.50% by mass, the amount of zinc vapor increases during welding, which may cause defects in the welded portion. For this reason, it is preferable to make Zn content into 0.05-0.50 mass %.

(Mg: 0.01 to 0.50% by mass)

Mg (magnesium) is a component having an action to improve mechanical properties. When exhibiting such an action, it is preferable to make Mg content into 0.01 mass % or more. On the other hand, when the Mg content exceeds 0.50% by mass, the electrical conductivity and thermal conductivity tend to decrease. For this reason, it is preferable to make Mg content into 0.01-0.50 mass %.

(P: 0.01 to 0.50% by mass)

P (phosphorus) not only contributes as a deoxidizer for Cu alloys, but also finely precipitates in the form of precipitates with a size of about 20 to 500 nm as a compound with Fe or Ni, etc., and these precipitates suppress dislocation movement to cause precipitation hardening, furthermore, Growth is suppressed, and material strength can be increased by refinement of crystal grains. In order to exert such an action, it is preferable to make the P content 0.01 mass % or more. On the other hand, when the P content exceeds 0.50% by mass, cracks tend to easily occur in the solidified portion after welding. For this reason, P content is made into 0.01-0.50 mass %.

(2) When the plate is made of pure Cu with excellent conductivity and heat dissipation

The plate material is pure Cu having a composition of 99.96% or more Cu and unavoidable impurities, for example, a total of 5 ppm or less of Cd, Mg, Pb, Sn, Cr, Bi, Se, and Te, and 400 ppm or less of Ag and O, respectively. desirable.

(Method of manufacturing parts for electrical/electronic devices)

In one embodiment of the present invention, a method for manufacturing components for electric/electronic devices sets a plurality of plate materials containing 90% by mass or more of Cu in a state in which they face each other or in a state in which they are overlapped. A first laser light having a spot diameter of 100 to 500 μm is irradiated, and a second laser light having a wavelength of 800 to 1200 nm is irradiated with a spot diameter of 10 to 300 μm. A welding step of joining and integrating a plurality of plate materials in a linear shape by welding while spraying an inert gas contained in to 50 ppm at a flow rate of 10 to 50 L/min is included.

According to such a welding process, after making it easy to weld Cu plate materials, which was previously difficult, the Vickers hardness of the welded part can be set to 60 or more, and a welded part with high strength can be obtained.

Furthermore, when the first laser light having a wavelength of 400 to 500 nm is irradiated with a spot diameter of 100 to 500 μm, and the second laser light having a wavelength of 800 to 1200 nm is irradiated with a spot diameter of 10 to 300 μm. The gradient of the hardness was controlled by setting the irradiation time of 0.1 to 10 msec/spot (speed for sweeping a distance corresponding to one spot diameter in the case of a line shape, irradiation time per spot in the case of a point shape).

(laser welding method)

The laser welding method is a welding method in which light of a wavelength with good directivity or concentration is collected by a lens and a laser beam of extremely high energy density is used as a heat source. By adjusting the output of the laser beam, penetration welding with a narrow width compared to the depth is also possible. In addition, the laser beam can be constricted extremely small compared to the arc of arc welding. With the high-density energy of the condensing lens, the laser welding device is capable of local welding and bonding of materials with different melting points. Since the heat effect by welding is small, the shape of the weld is thin, and no machining reaction force is generated, it is also suitable for fine welding.

(laser welding device)

6 is a diagram showing an example of a schematic configuration of a laser welding device. The laser welding device 20 includes a laser control unit 21, oscillators 221 and 222, a laser head 29, a processing table 24, and a gas supply nozzle 30. On the work table 24, the Cu plates 111 and 112, which are workpieces, are disposed in a state of facing each other or overlapped. The laser controller 21 controls the laser oscillators 221 and 222 that oscillate laser light, a scanner (not shown), a laser head 29, a processing table, and the like. The controller 21 controls the direction of travel of the Cu plates 111 and 112 as workpieces by controlling rotation of, for example, an X-axis motor and a Y-axis motor (not shown). Moreover, the control part 21 may control by moving the laser beams 231 and 232. This can be appropriately selected according to the size of the workpiece. The controller 21 oscillates a plurality of first and second laser lights 231 and 232 oscillated from the oscillators 221 and 222 . The oscillated first and second laser beams 231 and 232 are collected into parallel lights by the respective first and second condensing lenses 261 and 262 in the laser head 29 through the glass fiber 25. lose The first and second laser beams 231 and 232 are changed in the direction of the processing table by the first and second mirrors 271 and 272, and the first and second laser beams 231 and 232 are directed through a focusing lens ( 28), the Cu plate materials 111 and 112 are converged to the position to be joined and irradiated to perform welding. At this time, an inert gas is supplied from the gas supply nozzle 30 to prevent oxidation caused by heating by the laser beam. The inert gas can be appropriately selected from argon, helium, nitrogen and the like.

The laser can be appropriately selected from those known as lasers for welding. As an example of a laser, a _CO2 laser, a Nd:YAG laser, a semiconductor laser, a fiber laser, etc. are mentioned. It is preferable to use a fiber laser from points, such as output and the condensing property of a laser beam. Other configurations of the laser welding device can be selected from all conventionally known configurations.

(laser welding)

7 is a diagram showing an example of a spot diameter of a laser beam of a laser welding device. As shown in FIG. 7, the first laser light 231 having a wavelength of 400 to 500 nm is irradiated with a spot diameter of 100 to 500 μm. Then, the second laser light 232 having a wavelength of 800 to 1200 nm is irradiated with a spot diameter of 10 to 300 μm. 7 shows an example in which the first laser beam 231 and the second laser beam 232 are irradiated so as to overlap on the surface of the plate material. By simultaneously irradiating a plurality of laser beams of a specific wavelength and spot diameter, it became possible to easily weld a Cu plate material, which was previously difficult. Furthermore, by welding while spraying an inert gas containing 1 to 50 ppm of oxygen into the molten zone at 10 to 50 L/min, a welded part having a Vickers hardness of 60 or more can be obtained.

The inert gas supplied to the melting section contains 10 to 50 ppm of oxygen. As an inert gas, nitrogen gas, argon gas, etc. are mentioned. By laser welding while spraying an inert gas containing 10 to 50 ppm of such oxygen at a flow rate of 10 to 50 L/min, after covering the molten part with the inert gas, appropriate oxygen can be sent into the molten part, thereby generating fine oxides and welding It is presumed that an appropriate strain is introduced into the crystal grains by increasing the hardness of and also by quenching. When the oxygen content of the inert gas is less than 10 ppm, since sufficient oxygen cannot be supplied, the hardness may be lowered. On the other hand, when it exceeds 50 ppm, internal oxidation becomes excessive and embrittlement may arise. In addition, if the flow rate of the insoluble gas containing 10 to 50 ppm of oxygen is less than 10 L/min, sufficient shielding effect cannot be obtained and the cooling rate of the molten zone decreases while oxidation proceeds excessively, so that sufficient strain cannot be obtained inside the crystal. does not exist. In addition, when the flow rate exceeds 50 L/min, the shape of the molten pool becomes unstable due to blowing a large amount of gas into the melting section, which may cause solidification failure.

Furthermore, the first laser light 231 having a wavelength of 400 to 500 nm is irradiated with a spot diameter of 100 to 500 μm, and the second laser light 232 having a wavelength of 800 to 1200 nm is irradiated with a spot diameter of 10 to 300 μm. The irradiation time when irradiating with is 0.1 to 10 msec/spot (in the case of a line shape, the speed of sweeping a distance corresponding to one spot diameter, in the case of a point shape, the irradiation time per spot). When it is shorter than 0.1 msec, bonding becomes difficult and the gradient of hardness tends to become steep. On the other hand, if it exceeds 10 msec, there is a possibility that the metal melts from the welded part and is damaged, or the strength is insufficient due to softening.

In the electrical/electronic device component of the present invention, after setting a plurality of plate materials in a state of facing each other or overlapping each other, irradiating the junction between the plurality of plate materials with first and second laser beams 231 and 232 to obtain a plurality of The plate materials are joined together in a linear or dotted shape to integrate them. The first laser light 231, which penetrates only the surface of the Cu plate material efficiently, heats the Cu plate material in a wider range than the second laser light 232, and almost simultaneously with the heating, the second laser light penetrates deeply into the Cu plate material ( 232), it is possible to perform welding processing in which defects such as blowholes and internal defects hardly occur.

Outside the range of the wavelength and spot diameter of the first and second laser beams 231 and 232, the surface quality deteriorates or welding cannot be performed, so it is not suitable. In addition, controlling the heating by the first laser beam 231 affects the cooling rate at the time of melting and solidifying the plate material by the second laser beam 232, and as a result of rigorous study, it is 0.1 to 10 msec/spot or less. By doing this, it was found that the hardness change in the base material, the non-welded portion, and the welded portion of the Cu plate material can be suppressed, and furthermore, the inclination of the hardness of the non-welded portion and the welded portion of the Cu plate material can be suppressed low.

(Effect of welding)

In this way, by controlling the base material, the non-welded portion, and the welded portion of the Cu sheet material having a predetermined component composition, electrical/electronic device components having hardness and rigidity and hardly causing local deformation of the welded portion can be obtained.

(Applicable to electrical and electronic devices)

Components for electrical/electronic devices of the present invention can be used in semiconductor devices, LSIs, or many electronic devices using these, and further, for example, home game machines, medical devices, and workpieces that require miniaturization and high integration in particular. Stations, servers, personal computers, car navigation systems, mobile phones, robot connectors, battery terminals, jacks, relays, switches, autofocus camera modules, lead frames, and other electrical and electronic devices can be used.

(vapor chamber)

Components for electrical/electronic devices according to an embodiment of the present invention are made of pure Cu or Cu alloys having excellent thermal conductivity, and are also highly strong and excellent in deformation resistance, so they are preferably applied to heat pipes or vapor chambers. .

Electrical/electronic device components according to another embodiment of the present invention have high rigidity and, in particular, low cracking characteristics, and therefore are preferably applied to heat pipes and vapor chambers. In particular, since cracks are less likely to occur as a structural material for vapor chamber products, leakage and corrosion during use resulting from cracks are improved, thereby suppressing a decrease in thermal conductivity, contributing to suppression of deterioration and longevity of vapor chamber products. can do.

(bus bar)

Components for electric/electronic devices according to one embodiment of the present invention are made of pure Cu or a Cu alloy having excellent thermal conductivity, and have high strength and excellent deformation resistance, so they are suitable as bus bars. The bus bar can be applied as an electrical path for electrical connection and also as a transport path for heat dissipation. In particular, it can be applied as a cooling device by providing a path from a heating part to a heat dissipating part or to the outside following the bus bar.

In addition, since the bus bar formed from the electrical/electronic device components of another embodiment of the present invention has excellent local deformation characteristics, it can be applied as an electrical path for electrical connection and a transport path for heat dissipation. In particular, it is applicable also as a cooling device by providing a path from the heat generating part to the heat radiating part or the outside following the bus bar.

[Example]

Examples of the present invention will be described below. Various aspects of the present invention are possible, and are not limited to the following examples.

(Examples 1 to 6 and Comparative Examples 1 to 9) Joining two identical plate materials made of pure Cu

In Examples 1 to 5 and Comparative Examples 1 to 9, two plates were cut out to have a thickness of 0.15 mm, a width of 20 mm and a length of 1000 mm and made of pure Cu having the component composition shown in Table 1. With respect to the two sheet materials cut out, the end faces extending in the longitudinal direction were moved in a direction to bring them closer to each other, and they were placed in a facing state as shown in Fig. 1(a). Then, a first laser light having a wavelength of 400 to 500 nm and a spot diameter (hereinafter sometimes referred to as “beam diameter”) of 100 to 500 μm, and a wavelength of 800 to 1200 nm and a spot diameter of 10 to 300 μm Laser welding was performed with the second laser beam having a diameter of .mu.m while maintaining the positional relationship of the spot diameter as shown in FIG. 8 . Table 1 shows the laser conditions. Laser welding was performed while supplying an inert gas containing oxygen described in Table 1 to the fusion zone. As the inert gas, a mixed gas of nitrogen gas and oxygen gas of G1 grade manufactured by Taiyo Nissan was used.

Further, in Example 6, laser welding was performed under the same conditions as in Example 1 as a stacked arrangement shown in Fig. 1(b) instead of facing each other.

Then, the Vickers hardness and GAM value of the welded part were measured by the following method. The results are shown in Table 1. Further, in Table 1, when the Vickers hardness (Hv1) is 60 or more and the GAM value is 0.5° or more and less than 2.0°, the area ratio of all crystal grains present in the measurement area of crystal grains is 25% or more, the deformation resistance characteristics The case where the area ratio of all crystal grains present in the measured area is less than 25% is described as "◎" for being excellent, and the Vickers hardness (Hv1) is 60 or more, and the GAM value is 0.5° or more and less than 2.0°. , The deformation resistance was described as "○" as being good, and the case where the Vickers hardness (Hv1) was less than 60 was described as "x" as the deformation resistance was poor.

In addition, the local deformation characteristics of the weld zone were also evaluated. When the hardness of the non-welded part, the hardness of the welded part, and the hardness inclination rate obtained from the indentation distance thereof are 0.2/μm or less, the welded part and the non-welded part become small inclined materials, so that local deformation is difficult and the local deformation resistance is good. It was evaluated as "○". On the other hand, when it was more than 0.2/μm, it was said that it was likely to be locally deformed, and it was set as “Δ”.

[Vickers Hardness]

Vickers hardness (HV) was measured based on the method specified in JIS Z2244 (2009). The load (test force) at this time was selected from the range of 20 to 100 gf and the diagonal length of the indentation did not exceed 0.03 mm, and the test was conducted. In addition, the pressing down time (pushing time) of the indenter is 15 sec.

In Examples 1 to 5 and Comparative Examples 1 to 9 in which the plates are butted together, as shown in Fig. 1 (a), the welding direction is the X-axis direction, the direction perpendicular to the welding direction is the Y-axis direction, and the sheet material normal direction At a position (b) corresponding to the half dimension of the plate thickness (a) of the welded portion existing in the cross section (A) when the welded portion is cut in the Y-axis direction when in the Z-axis direction, the Vickers hardness (Hv1 ) was measured. Measurements were made on five cross sections (A) (YZ plane) cut at 1 mm intervals in the welding direction (X-axis direction), and the average value of these measurement results was obtained.

Further, in Example 6 _in which the plate materials are stacked, as shown in FIG _. ) corresponding to the half dimension of the position (b ₁ ), and, when the weld is cut in the Y-axis direction, the cross section (A ₂ ) corresponding to the half dimension of the thickness (a 2) of the plate ( ₂ ) of the weld Vickers hardness (Hv1) was measured at position (b ₂ ). Measurements were made on five cross sections (A ₁ , A ₂ ) (YZ plane) each cut at 1 mm intervals in the welding direction (X-axis direction), and the average of the measurement results was obtained.

[GAM value]

The GAM value is a crystal calculated using analysis software (OIM Analysis, manufactured by TSL) from crystal orientation data continuously measured using an EBSD detector attached to a high-resolution scanning electron microscope (manufactured by Nippon Electronics Co., Ltd., JSM-7001FA). Obtained from orientation analysis data. The measurement was performed with a step size of 0.1 µm. The measurement area is the entire rectangular area defined by the welding width of the welded portion and the thickness of the sheet material on the surfaces of the cross sections A, A ₁ , and A ₂ mirror-finished by electrolytic polishing.

The area ratio of crystal grains of GAM values within a predetermined range is determined by the SEM-EBSD method, with GAM values of 0 ° or more and less than 0.25 ° as the first division, 15 divisions every 0.25 °, and GAM values of 0 ° or more and less than 3.75 ° as measurement targets. It was calculated from the sum of the area ratios of crystal grains in each division occupying the entire SEM image obtained by

Further, in Example 6, the average value of the crystal grain area ratio of the GAM values measured for each of the two sheet materials was obtained, and the average value is shown in Table 1.

According to Examples 1 to 6, in bonding two identical plate materials made of pure Cu, a first laser light having a wavelength of 400 to 500 nm was irradiated with a spot diameter of 100 to 500 μm, and a wavelength of 800 to 1200 nm was applied. While irradiating the second laser beam with a spot diameter of 10 to 300 μm and spraying an inert gas containing 1 to 50 ppm of oxygen into the melting part at a flow rate of 10 to 50 L/min, 0.1 to 3 msec/spot It turns out that the Vickers hardness (Hv1) of a welded part can be made into 60 or more by welding. Among them, Examples 1 to 3, 5 and 6 in which the area ratio of crystal grains of the GAM value was 25% or more had a Vickers hardness (Hv1) of 65 or more, which was particularly high. Moreover, it can be seen that the slope becomes smaller when the irradiation time is 2 msec or longer.

On the other hand, Comparative Example 1 in which the oxygen content of the inert gas was less than 10 ppm had low Vickers hardness. Further, in Comparative Example 2 in which the oxygen content of the inert gas was greater than 50 ppm and in Comparative Example 3 in which the flow rate of the inert gas was less than 10 L/min, internal oxidation was excessive, resulting in embrittlement and great damage. In Comparative Example 4, where the flow rate of the inert gas was greater than 50 L/min, solidification defects were caused, and the thickness of the welded portion was greatly reduced. A comparative example in which laser conditions are not irradiation of a first laser light having a wavelength of 400 to 500 nm with a spot diameter of 100 to 500 μm and irradiation of a second laser light having a wavelength of 800 to 1200 nm with a spot diameter of 10 to 300 μm. In Nos. 5 to 9, the plate materials made of pure Cu could not be joined to each other.

(Examples 7 to 26 and Comparative Examples 10 to 12) Joining two identical plate materials made of Cu alloy

In Examples 7 to 26 and Comparative Examples 10 to 12, the same as in Example 1 except that two sheets of sheet materials made of a Cu alloy having the component composition shown in Table 2 were used and welded under the welding conditions shown in Table 2. made it The results are shown in Table 2.

According to Examples 7 to 26, in joining two identical plate materials made of Cu alloy, the first laser light having a wavelength of 400 to 500 nm was irradiated with a spot diameter of 100 to 500 μm, and a wavelength of 800 to 1200 nm was applied. While irradiating the second laser beam with a spot diameter of 10 to 300 μm and spraying an inert gas containing 1 to 50 ppm of oxygen into the melting part at a flow rate of 10 to 50 L/min, welding is performed at 0.2 to 10 msec/spot. By doing so, it can be seen that the Vickers hardness (Hv1) of the welded part can be set to 60 or more. Among them, Examples 7, 8, 10, 12, 14, 15, 16, 18, 20, 22, 24, and 26 in which the area ratio of crystal grains of the GAM value is 25% or more are the ratio of the Vickers hardness of the welded part to the plate material ( The Vickers hardness of the welded portion/the Vickers hardness of the sheet material) could be set to 0.5 or more, and the decrease in Vickers hardness of the welded portion could be particularly suppressed.

In Comparative Example 10, since the amount of oxygen was small, the strength of the welded portion could not be increased, and in Comparative Example 11, welding was not performed because the irradiation time was short. Moreover, in Comparative Example 12, since the irradiation time was long, the weld was melted and thinned, so that a clean cross section could not be obtained.

(Examples 27 to 28) Bonding two sheet materials made of pure Cu and having different component compositions

In Example 27, it was carried out in the same manner as in Example 1 (butting) except that a sheet material made of a Cu alloy having the component composition shown in Table 3 was used and welded under the welding conditions described in Table 3.

In Example 28, it was carried out in the same way as in Example 6 (overlapping) except that a sheet material made of a Cu alloy having the component composition described in Table 3 was used and welded under the welding conditions described in Table 3. In addition, the plate materials described at the upper end of Table 3 were stacked so that they were on the laser irradiation side.

The results are shown in Table 3.

According to Examples 27 to 28, in bonding two sheet materials made of pure Cu and having different component compositions, a first laser beam having a wavelength of 400 to 500 nm was irradiated with a spot diameter of 100 to 500 μm, and further, 800 While irradiating the second laser light having a wavelength of ~1200 nm with a spot diameter of 10 to 300 μm, while spraying an inert gas containing 1 to 50 ppm of oxygen into the melting part at a flow rate of 10 to 50 L/min, 1 msec/spot It can be seen that the Vickers hardness (Hv1) of the welded portion can be set to 60 or more by welding with an irradiation time of .

(Examples 29 to 31) Joining two sheet materials made of Cu alloy and having different component compositions

In Examples 29 to 31, it was carried out in the same manner as in Example 1 except that a sheet material made of a Cu alloy having the component composition described in Table 4 was used and welded under the welding conditions described in Table 4. The results are shown in Table 4.

According to Examples 29 to 31, in bonding two sheet materials made of Cu alloy and having different component compositions, a first laser light having a wavelength of 400 to 500 nm was irradiated with a spot diameter of 100 to 500 μm, and further, 800 While irradiating the second laser light having a wavelength of ~1200 nm with a spot diameter of 10 to 300 μm, while spraying an inert gas containing 1 to 50 ppm of oxygen into the melting part at a flow rate of 10 to 50 L/min, 1 msec/spot It can be seen that the Vickers hardness (Hv1) of the welded portion can be set to 60 or more by welding with an irradiation time of .

(Examples 32 to 33) Bonding of plate materials made of pure Cu and plate materials made of Cu alloy

In Example 32, the same as in Example 1 (butting) except that a sheet material made of pure Cu and a sheet material made of a Cu alloy having the component composition shown in Table 5 were used and welded under the welding conditions shown in Table 5. did

In Example 33, the same as in Example 6 (overlapping) except that a sheet material made of pure Cu and a sheet material made of a Cu alloy having the component composition shown in Table 5 were used and welded under the welding conditions shown in Table 5. did In addition, the first plate material described at the upper end of Table 5 was overlapped so as to be on the laser irradiation side.

The results are shown in Table 5.

According to Examples 32 to 33, in the bonding of the plate material made of pure Cu and the plate material made of Cu alloy, the first laser light having a wavelength of 400 to 500 nm was irradiated with a spot diameter of 100 to 500 μm, and further, 800 While irradiating the second laser light having a wavelength of ~1200 nm with a spot diameter of 10 to 300 μm, while spraying an inert gas containing 1 to 50 ppm of oxygen into the melting part at a flow rate of 10 to 50 L/min, 1 msec/spot It can be seen that the Vickers hardness (Hv1) of the welded portion can be set to 60 or more by welding with an irradiation time of .

As described above, by increasing the area ratio of the GAM value of 0.5° or more and less than 2.0° according to these Examples and Comparative Examples, the hardness of the welded portion can be controlled to 60 or more, and the hardness inclination rate of the welded portion and the non-welded portion is 0.2/ If it is less than μm, it is more resistant to deformation, so it can be seen that there is no problem in practical use. Therefore, according to the present invention, in parts for electric/electronic devices having welded portions such as vapor chambers and bus bars, by controlling the hardness of the welded portion and non-welded portion, there is rigidity and resistance to local deformation at the welded portion. It can be seen that parts for electronic devices can be obtained.

1, 2 plate
3, 3A, 3B, 3C welds
10, 10A, 10B, 10C junction
10D Cu member
101, 102 Cu plate
20 laser welding device
21 Laser Control
24 processing table
25 fiberglass
26 condensing lens
28 focusing lens
29 laser head
30 gas supply nozzle
221, 222 laser oscillator
231 first laser light
232 second laser light
261 first condensing lens
262 second condensing lens
271 first mirror
272 second mirror

Claims (7)

It is composed of a plurality of plate materials containing 90% by mass or more of Cu,
Has a welding portion for joining and integrating the plurality of plate materials in a linear or dotted shape by welding in a state of facing each other or overlapping each other,
The weld extends over the entire thickness of the plate material,
In the cross section when the welded portion is cut in the direction in which the plurality of plate materials joined are extended,
The weld has a Vickers hardness (HV1) of 60 or more when measured at a position corresponding to half the thickness of the plate at the center of the weld width, which is the width of the weld mark.
Parts for electrical and electronic devices. According to claim 1,
In the cross section, when a GAM value obtained from crystal orientation analysis data of the SEM-EBSD method is measured in a rectangular region partitioned by the welding width of the welded portion and the thickness of the plate material, the GAM value is 0.5° or more and less than 2.0°. The crystal grains have an area ratio of 25% or more for all crystal grains present in the measured area,
Parts for electrical and electronic devices. According to claim 1 or 2,
It is composed of a plurality of plate materials containing 90% by mass or more of Cu,
Has a welding portion for joining and integrating the plurality of plate materials in a linear or dotted shape by welding in a state of facing each other or overlapping each other,
The weld extends over the entire thickness of the plate material,
In the cross section when the welded portion is cut in the direction in which the plurality of plate materials joined are extended,
The Vickers hardness at the weld when measured at a position corresponding to half the thickness of the plate at the center of the weld width, which is the width of the weld mark on the surface of the plate, is HV1,
When the Vickers hardness at the non-welded portion when measured at a location spaced apart along the direction of the weld width by a distance corresponding to 1.5 times the half-width of the weld from the center of the weld portion is HV2,
The Vickers hardness (HV2) at the non-welded part is 75 or more,
When the difference between the Vickers hardness (HV2) at the non-welded portion and the Vickers hardness (HV1) at the welded portion is divided by the indentation distance X (μm) between the positions where the Vickers hardness (HV1 and HV2) are measured The hardness gradient ((HV2-HV1) / X) of is 0.2 / μm or less,
Parts for electrical and electronic devices. According to any one of claims 1 to 3,
The plate material contains one or more elements selected from the group consisting of Ag, Fe, Ni, Co, Si, Cr, Sn, Zn, Mg and P,
Parts for electrical and electronic devices. According to any one of claims 1 to 3,
The plate material is 99.96 mass% or more of Cu and unavoidable impurities,
Parts for electrical and electronic devices. According to any one of claims 1 to 5,
The electric/electronic device component is a vapor chamber,
Parts for electrical and electronic devices. According to any one of claims 1 to 5,
The electric/electronic device component is a bus bar,
Parts for electrical and electronic devices.

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