WO2021246494A1 - Component for electrical/electronic equipment - Google Patents

Abstract

Provided is a component for electrical/electronic equipment, the component having a plurality of sheet materials that are joined by welding, the sheet materials comprising copper-based materials, wherein the strength of a welded section is high. The component for electrical/electronic equipment is configured by a plurality of sheet materials containing 90 mass% or more of Cu, and has a welded section at which the plurality of sheet materials are joined and integrated through welding in a linear or dot shape in a state of being mutually abutted or overlapped. The welded section extends across the entire thickness of the sheet materials, and in a cross section when the welded section is cut in the direction in which the plurality of joined sheet materials extend, the welded section has a Vickers hardness of 60 or more when measured at a position corresponding to a dimension of half the thickness of the sheet materials.

Description

Parts for electrical and electronic equipment

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

In recent years, the amount of heat generated tends to increase due to higher functionality and higher performance of electrical and electronic equipment. In addition, as the miniaturization of electric and electronic devices progresses, the heat generation density increases, so it is becoming important to cool the generated heat. Examples of the member for cooling the generated heat include a vapor chamber which is a planar heat pipe. As the material of the vapor chamber, it is desirable to use a copper-based material (pure copper, copper alloy) having high thermal conductivity.

Here, the vapor chamber has a closed structure in which a working liquid is put into an internal space formed by joining the outer peripheral portions in a state where a plurality of plates are stacked, and then sealed under reduced pressure. Examples of such a joining method include laser welding, resistance welding, diffusion welding, and TIG welding.
When joining by these welds, the welded part is formed by melting once by heating to a high temperature and then re-solidifying, so that it is softened and the plate itself is softened as in the case of annealing. There is a problem that it becomes softer than the strength and the strength becomes low. The lower the strength, the easier it is to deform.

To deal with such problems, Patent Document 1 describes a method of manufacturing a vapor chamber by joining a plurality of parts by diffusion joining or brazing, using a precipitation hardening copper alloy as a material of a housing and aging treatment. Then, a technique for improving the strength of the housing and the like by precipitation hardening is disclosed.
However, in the technique of Patent Document 1, it is necessary to use a precipitation hardening type copper alloy, and there is a problem that it cannot be applied to a non-precipitation type copper alloy or pure copper. Further, in the technique of Patent Document 1, it is necessary to perform aging treatment, and there is a problem that productivity is lowered due to an increase in the number of steps.
Therefore, it is desired to increase the strength of the welded portion by a method other than the method of precipitation hardening using a precipitation hardening type copper alloy by aging treatment.

The above-mentioned problem of low strength of the welded portion exists not only in the vapor chamber but also in other electric / electronic devices such as a bus bar.

Note that Patent Document 2 discloses a technique for improving the bonding strength by irradiating a laser with a specific trajectory, but the technique of Patent Document 2 is a technique relating to bonding between aluminum and copper. It is difficult to apply to joining copper-based materials. More specifically, the copper-based material has a high thermal conductivity, so that heat easily escapes, and the laser beam is easily reflected. Therefore, the copper-based material is a material that is difficult to join by laser welding. Therefore, as in Patent Document 2, simple welding using a laser beam has low bonding strength 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 circumstances, and is a component for an electric / electronic device in which a plurality of plates made of a copper-based material are joined by welding, and the electric / electronic device having a high weld strength. The subject is to provide parts for use.
Further, the present invention is rigid and rigid by controlling the hardness of the welded plate material and the inclination of the hardness of the entire plate material in the parts for electric / electronic equipment having a welded portion such as a vapor chamber and a bus bar. It is an object of the present invention to provide parts for electric / electronic equipment in which welded portions are not easily deformed locally.

As a result of diligent studies, the present inventors have found that the Vickers hardness HV of the weld can be increased by controlling the laser welding conditions using a plate material having a component composition containing 90% by mass or more of Cu. Further, the present inventors have found that by controlling the appropriate hardness from the welded portion to the non-welded portion and the inclination of the hardness, the welded portion is rigid and the welded portion is less likely to be locally deformed. , The parts for electric and electronic devices of the present invention have been completed.

That is, the gist structure 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 the plurality of plate materials are joined and integrated by welding in a state of being abutted against each other or in a state of being overlapped with each other. The welded portion has a welded portion, and the welded portion extends over the entire thickness of the plate material, and the welded portion is cut in a direction in which the plurality of joined plate materials extend. The welded portion is a component for electrical and electronic equipment having a Vickers hardness HV1 of 60 or more when measured at a position corresponding to half the thickness of the plate material at the center of the weld width, which is the width of the weld mark.
(2) When the GAM value obtained from the crystal orientation analysis data of the SEM-EBSD method is measured in the rectangular region defined by the welding width of the welded portion and the thickness of the plate material in the cross section, the GAM is measured. The component for electrical / electronic equipment according to (1), wherein the crystal grains having a value of 0.5 ° or more and less than 2.0 ° have an area ratio of 25% or more to all the crystal grains existing in the measurement area.
(3) It is composed of a plurality of plate materials containing 90% by mass or more of Cu.
It has a welded portion in which the plurality of plate materials are joined to each other in a linear or dot shape by welding in a state of being abutted against each other or overlapped with each other, and the welded portion covers the entire thickness of the plate material. The thickness of the plate material at the center of the weld width, which is the width of the weld mark on the surface of the plate material, in the cross section when the welded portion is cut in the direction in which the plurality of plate materials are extended and joined. The Vickers hardness at the weld when measured at a position corresponding to half the dimension is defined as HV1.
When the Vickers hardness in the non-welded portion measured at a position separated along the direction of the weld width by a distance corresponding to 1.5 times the weld half width from the center position of the welded portion is HV2, the above. The Vickers hardness HV2 in the non-welded portion was 75 or more, and the difference between the Vickers hardness HV2 in the non-welded portion and the Vickers hardness HV1 in the welded portion was measured by measuring the Vickers hardness HV1 and HV2. The electricity according to (1) or (2), wherein the hardness inclination rate ((HV2-HV1) / X) when divided by the indentation distance X (μm) between the positions is 0.2 / μm or less. Parts for electronic devices.
(4) Any of (1) to (3), wherein 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 equipment described in one.
(5) The component for electrical / electronic equipment according to any one of (1) to (3), wherein the plate material is 99.96% by mass or more of Cu and unavoidable impurities.
(6) The component for electrical / electronic equipment according to any one of (1) to (5), wherein the component for electrical / electronic equipment is a vapor chamber.
(7) The component for electrical / electronic equipment according to any one of (1) to (5), wherein the component for electrical / electronic equipment is a bus bar.

According to the present invention, a component for electrical / electronic equipment in which a plurality of plates made of a copper-based material containing 90% by mass or more of Cu are joined by welding, and for electrical / electronic equipment having a high weld strength. Parts can be provided.
Further, according to the present invention, by obtaining an appropriate hardness at the welded portion and controlling the inclination of the hardness between the welded portion and the non-welded portion, the welded portion is rigid and the welded portion is formed. It is possible to provide parts for electrical and electronic devices that are not easily deformed locally.

(A) is a schematic perspective view of two Cu plates constituting the parts for electric / electronic devices according to the embodiment of the present invention, which are linearly laser-welded in a state of being butted against each other, and (b). Is a schematic perspective view of two Cu plates constituting the parts for electric / electronic devices according to the embodiment of the present invention, which are linearly laser-welded in a state of being overlapped with each other. It is an optical micrograph when observing the surface state of the laser-irradiated side of a Cu joint body (a joint body of two Cu plate materials) obtained by laser-welding a butt Cu plate material from the Z-axis. It is an optical micrograph when observing the surface state of the Cu junction body which laser-welded the butt Cu plate material on the side opposite to the side irradiated with the laser. It is an optical micrograph when observing the cross-sectional state of the Cu joint body which laser-welded the Cu plate material from the X-axis. (A) is a schematic perspective view when two Cu plates are abutted and laser-welded in a dot shape, and (b) is a case where two Cu plates are laser-welded in a dot-like state in a superposed state. It is a schematic perspective view of the above, and in each case, the welded portion is shown in a state where the cross section can be seen when the Cu joint is cut in the extending direction. It is a figure which shows the schematic structure of the laser welding apparatus. It is a figure which shows the spot diameter of the laser beam of a laser welding apparatus. (A) is a schematic perspective view when two Cu plates constituting parts for electric / electronic devices according to another embodiment of the present invention are linearly joined in a state of being butted against each other, and (b) is a schematic perspective view. It is a schematic perspective view when the two Cu plates constituting the parts for electric / electronic devices according to another embodiment of the present invention are joined in a linear manner in a state of being overlapped with each other. It is an optical micrograph when observing the cross-sectional state of the bonded Cu plate material.

Hereinafter, embodiments of the present invention will be described. The following description is an example of an embodiment of the present invention and does not limit the scope of claims.

The component for electric / electronic equipment 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 in a state of being abutted against each other or in a state of being overlapped with each other. It has a welded part that is joined and integrated in a linear or dot shape, and the welded part extends over the entire thickness of the plate material, and the welded part extends in the direction in which the plurality of joined plate materials extend. In the cross section when cut, the welded portion has a Vickers hardness of 60 or more when measured at a position corresponding to a dimension of half the thickness of the plate material.

FIG. 1A is a schematic perspective view when a Cu joint body 10 (a joint body of two Cu plate materials) is formed by laser welding linearly with two Cu plate materials 1 and 2 abutted against each other. FIG. 1B is a schematic perspective view of a Cu bonded body 10A formed by linear laser welding in a state where two Cu plates 1 and 2 are overlapped with each other. In the embodiment shown in FIG. 1 (a), there is a welded portion 3 in which the Cu plate members 1 and 2 are joined together in a linear manner in a state of being butted against each other, and the portions are joined by laser welding. Further, in the embodiment shown in FIG. 1 (b), there is a welded portion 3A in which Cu plate materials 1 and 2 are integrated in a superposed state, and the portions are joined by laser welding. The welded portion 3 extends over the entire thickness of the plate members 1 and 2. That is, in FIGS. 1 (a) and 1 (b), the welded portion 3 is melted and solidified so as to melt from the surface on the side irradiated with the laser to the surface (back surface) on the opposite side, and the plate materials 1 and 2 are formed. Exists so as to penetrate in the thickness direction. The term "Cu plate material" as used herein means a plate material containing 90% by mass or more of Cu (copper).

Here, the "plate material containing 90% by mass or more of Cu" may be any 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 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 balance of Cu. It is preferable to have a component composition in which 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 HV of the plate material is not particularly limited because it varies depending on the type and amount of the alloy component to be added, but is generally 75 or more and 240 or less.
When the plate material is pure Cu, the plate material has a Cu content of 99.96% by mass or more, and Cd, Mg, Pb, Sn, Cr, Bi, Se and Te as unavoidable impurities are 5 ppm in total. The total of Ag and O is 400 ppm or less. Pure Cu has excellent thermal conductivity, so it can exhibit excellent performance as a heat dissipation / cooling member. Examples of so-called pure Cu include electrolytic copper, oxygen-free copper (OFC), and TPC. 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.

Further, the "plate material" as used in the present invention is a material processed into a predetermined shape, for example, a plate, a strip, a foil, a rod, a flat wire, etc., and has a predetermined thickness, in a broad sense. Means to include strips. In the present invention, the thickness (plate thickness) of the plate material is not particularly limited, but is preferably 0.05 to 1.0 mm, more preferably 0.1 to 0.8 mm. The shape of the plurality of plate materials to be joined and the thickness (plate thickness) of the plate materials may be the same or different.

FIG. 2 is a photograph showing the surface state of the Cu-bonded body 10 obtained by laser-welding two butted Cu plates 1 and 2 on the side irradiated with the laser. It shows that the X-axis direction is the laser sweep direction, that is, the welding direction. In addition, it can be seen that there is a portion where the processing marks of rolling of the Cu plate material have disappeared due to the irradiation of the laser beam. Further, there is a portion where the Cu plate materials 1 and 2 are melted and solidified again, and this is referred to as a welded portion 3.
FIG. 3 is an optical micrograph when observing the surface state of the Cu junction 10 obtained by laser-welding two butted Cu plates 1 and 2 on the side opposite to the laser-irradiated side, and is the back surface of FIG. It is an optical micrograph when observing the surface state of.
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 on the side irradiated with the laser of the Cu junction 10. It appears on the surface (front) and the surface (back) opposite to the side irradiated with the laser. And usually, as shown in FIGS. 2 and 3, the width of the laser welding mark on the surface on the laser-irradiated side is wider than the laser welding mark on the surface opposite to the laser-irradiated side. Become. The width of the laser welding mark on the surface irradiated with this laser was defined as the welding width in the present invention, and the cross-sectional structure was observed by cutting at the dotted cross-sectional observation position.
FIG. 4 is an optical micrograph showing a cross-sectional state when a Cu plate material is laser welded to form a Cu bonded body. As shown in FIG. 4, the width of the surface of the welded portion that has been irradiated with the laser and melted and solidified again on the side irradiated with the laser corresponds to the weld width. The welding width can also be recognized from the cross-sectional view shown in FIG.

In the present invention, in the cross section when the welded portion is cut in the direction in which the two joined plates extend, the welded portion is measured at a position corresponding to half the thickness of the plate material. Vickers hardness is 60 or more. In this specification, the Vickers hardness HV is measured according to the method specified in JIS Z2244 (2009).

More specifically, as shown in FIG. 1 (a), when the welded portion 3 is provided by linearly joining and integrating the two Cu plates 1 and 2 in a state of being butted against each other, the welding direction (laser sweep direction). ) Is the X-axis direction, the direction perpendicular to the welding direction (width direction of the plate material) is the Y-axis direction, and the plate material normal direction (thickness direction of the plate material) is the Z-axis direction. The direction L in which the plate members 1 and 2 extend is the direction in which the plate members are brought closer to each other in order to bring them into a butt state, that is, the Y-axis direction. In the case of the electric / electronic device parts of the present embodiment having such a structure of the bonded body 10, the welded portion 3 existing in the cross section A when the Cu bonded body 10 is cut in the Y-axis direction is the Cu plate material 1. It is necessary that the Vickers hardness is 60 or more at the position b corresponding to the half dimension of the thickness a of 2.

Further, as shown in FIG. 1 (b), when the welded portion 3A is formed by linearly joining and integrating the two Cu plates 1 and 2 in a state of being overlapped with each other, the two joined plates are joined. The direction in which 1 and 2 extend is the direction perpendicular to the welding direction, that is, the Y-axis direction. For parts for electrical and electronic equipment of the present embodiment having the configuration of such a conjugate 10A, when cutting the Cu assembly 10A in the Y axis direction, welds present in cross-section A ₁ of the Cu plate 1 _{Position b 1} corresponding to half the size of the thickness a ₁ of the Cu plate material 1 and the position corresponding to half the size of _{the thickness a 2} of the Cu plate material 2 of the welded portion existing in _{the cross section A 2 of the Cu plate material 2.} in both the b _2, Vickers hardness is required to be 60 or more.

When joining by welding, the welded part is formed by melting once by heating to a high temperature and then re-solidifying. Therefore, in the conventional joining method, the plate material is softened as in the case of annealing. Therefore, there is a problem that the strength becomes lower than the strength of the plate material itself. The lower the strength, the easier it is to deform.
However, as shown in Examples described later, by using a plate material having a composition containing 90% by mass or more of Cu and controlling the laser welding conditions, it is possible to suppress a decrease in strength due to softening of the welded portion. Depending on the laser welding conditions, the strength may be higher than that of the plate material itself.
Therefore, in the present embodiment, the Vickers hardness of the welded portion can be 60 or more, further 65 or more. Since the Vickers hardness of the welded portion is 60 or more, which is high, it is possible to provide parts for electric and electronic devices having high strength and excellent deformation resistance. Since there is a proportional relationship between Vickers hardness and strength, the higher the Vickers hardness, the higher the strength. When the aging treatment is performed as in Patent Document 1, the entire Cu joint including the welded portion tends to be heated and softened unless a curable copper alloy is used. Therefore, the Vickers hardness of the welded portion is present. It is considered difficult to maintain 60 or more.

The upper limit of the Vickers hardness HV of the welded portion is not particularly limited, but in the case of pure Cu, it is, for example, 90 or less, and in the case of 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 5 (b). FIG. 5 (a) is a schematic perspective view of the case where two Cu plates 1 and 2 are abutted and laser welded in a dot shape to form a Cu bonded body 10B, and FIG. 5 (b) is a schematic perspective view of 2. It is a schematic perspective view when the Cu bonded body 10C is formed by laser welding in the form of dots in the state where the Cu plate materials 1 and 2 are superposed.

As shown in FIG. 5A, in the case of the parts for electrical and electronic equipment of the present embodiment having the configuration of the Cu joint body 10B having the welded portions 3B that are joined and integrated in a dot shape in a state of being butted against each other. The thickness a of the Cu plates 1 and 2 of the welded portion 3B existing in the cross section A when the joint 10B is cut in the extending direction L of the Cu plates 1 and 2 through the center c of the welded portion 3B on the surface of the plate material. It is necessary that the Vickers hardness is 60 or more at the position b corresponding to the half dimension of.

Further, as shown in FIG. 5 (b), the parts for electrical and electronic equipment of the present embodiment having the configuration of the Cu bonded body 10C having the welded portions 3B that are joined and integrated in a dot shape in a state of being overlapped with each other. for passes through the center c of the welded portion in the plate surface, obtained by cutting the welded portion in the stacking direction of the plate, the Cu plate 1 of the welded portion present in the cross section a ₁ of the Cu plate 1 having a thickness of a ₁ a position b ₁ corresponding to half the size, in both positions b ₂ corresponding to half of the thickness dimension a ₂ of Cu plate 2 of the welded portion present in the cross section a ₂ of the Cu plate 2, Vickers hardness It is necessary to be 60 or more.

In the present specification, the Vickers hardness HV in the case of linear laser welding is measured in five cross sections A (YZ planes) cut at intervals of 1 mm in the welding direction (X-axis direction), and these measurements are taken. Calculate as the average value of the results.

In the present invention, in the cross section when the welded portion is cut in the direction in which the plurality of joined plate materials extend, the SEM-EBSD is formed in a rectangular region divided by the weld width of the welded portion and the thickness of the plate material. When the GAM value obtained from the crystal orientation analysis data of the method is measured, the crystal grains having a GAM value of 0.5 ° or more and less than 2.0 ° have an area ratio of 25% to all the crystal grains existing in the measured area. The above is preferable.

The GAM (grain average misorientation) value is a value obtained from the crystal orientation analysis data of the SEM-EBSD method, and is a value between measurement points in a crystal grain distinguished by a large angle grain boundary having an orientation difference of 15 ° or more. The distance (hereinafter, also referred to as step size) is measured at 0.1 μm, the orientation difference between adjacent measurement points is calculated, 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 in the crystal grains is small, the uniform crystal grains have very little strain, the crystal grains have a continuous orientation gradient, and the like, and the strain in one crystal grain is Indicates that it is small. On the other hand, a large GAM value means that the average orientation difference in the crystal grains is large, and indicates that the strain in one crystal grain is large. Crystal grains having a GAM value of 0.5 ° or more and less than 2.0 ° are crystal grains having characteristics between them, and indicate that the strain in one crystal grain is large to some extent. When the plate material is annealed, the GAM value is usually 0 ° or more and less than 0.5 °, and the local strain in one crystal grain becomes small.

In this way, the area ratio of the crystal grains having the GAM value of 0.5 ° or more and less than 2.0 ° is 25% or more, that is, the crystal grains having a certain degree of strain in one crystal grain. When the area ratio is 25% or more, in the case of pure Cu, the Vickers hardness of the welded portion can be 65 or more.

The GAM value is preferably 0.5 ° or more and less than 2.0 °, and the area ratio of the crystal grains is preferably 45% or more, more preferably 65% or more. The upper limit of the area ratio of the crystal grains having a temperature 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 analyzed from the crystal orientation data continuously measured using the EBSD detector attached to the high-resolution scanning analytical electron microscope (JSM-7001FA, manufactured by Nippon Denshi Co., Ltd.) (OIM Analysis, manufactured by TSL). It can be obtained from the crystal orientation analysis data calculated using. "EBSD" is an abbreviation for Electron Backscatter Diffraction, which is a crystal orientation analysis technique using reflected electron Kikuchi line diffraction generated when a copper plate material as a sample is irradiated with an electron beam in a scanning electron microscope (SEM). Is. "OIM Analysis" is data analysis software measured by EBSD.
In the present invention, the measurement region is the _{entire rectangular region of the surfaces of the cross sections A, A 1} , and A ₂ which is divided by the weld width of the welded portion and the thickness of the plate material on the surface mirror-finished by electrolytic polishing. be. The area ratio of crystal grains with GAM values within the specified range is defined as the first category with GAM values of 0 ° or more and less than 0.25 °, 15 categories in 0.25 ° increments, and 0 ° or more and less than 3.75 °. The GAM value is used as a measurement target, and it can be calculated from the total area ratio of crystal grains in each category to the entire SEM image obtained by the SEM-EBSD method.

The Cu plate material used for this component for electrical and electronic equipment 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 pure Cu which is an unavoidable impurity. It is preferable to have. Thermal conductivity can be provided by using a Cu plate material of 90% by mass or more. Originally, Cu has high thermal conductivity, but the amount of added elements increases, and the appearance of the second phase lowers the thermal conductivity. Therefore, the Cu plate material used for the parts for electric and electronic devices of the present embodiment contains 90% by mass or more of Cu, so that deterioration of thermal conductivity can be suppressed and high strength can be provided.

Further, when viewed in cross section when a plurality of integrated plate materials are cut in a direction crossing the welded portion, the welded portion is formed on the surface of the plate material in the welded portion and the non-welded portion located adjacent to the welded portion. The width of the weld mark is taken as the weld width, and the center of the weld width and the non-welded portion are 1.5 times the weld width along the width direction of the weld width from the center of the weld. When the hardness HV1 and HV2 are measured, the Vickers hardness HV2 at the heat-affected portion is 75 or more, and the difference between the Vickers hardness HV2 at the heat-affected portion and the Vickers hardness HV1 at the welded portion. Is divided by the indentation distance X (μm) between the positions where the Vickers hardnesses HV1 and HV2 are measured (hereinafter, may be referred to as “hardness inclination rate”) ((HV2-HV1) / X). However, it is 0.2 / μm or less.

(Linear welding)
As shown in FIG. 8A (only the description of FIG. 8 is numbered), the Cu member 10D is arranged so that the two Cu plates 101 and 102 are butted against each other. By irradiating the center of the abutted state with a laser beam and sweeping, the two Cu plates 101 and 102 are linearly welded, and the two Cu plates 101 and 102 are abutted and joined at the center 121 of the welded portion 12. Here, the laser beam is swept to form a linear joint. Melted liquid Cu is formed in the portion irradiated with the strong laser beam. After that, after the laser beam passes through the Cu, the liquid Cu rapidly cools and changes to a solid Cu due to its high thermal conductivity. When this progresses continuously, a welded portion 12 having a wavy bead is formed. Since it is once melted and solidified, it is clearly in a state different from that of the base material 11 of the Cu plate materials 101 and 102. Further, a portion 13 affected by heat is formed around the welded portion 12 in a state different from the surface of the base material 11 of the Cu plate materials 101 and 102 under the influence of heat. The heat-affected portion 13 is also affected by the heat, and the characteristics of the base material 11 of the Cu plate materials 101 and 102 are also altered. The heat to the heat-affected zone 13 includes both the heat generated by the irradiation of the laser beam and the heat generated from the welded portion 12. As shown in FIG. 8B, it is a Cu member 10D in which the surface of the Cu plate material is linearly welded by irradiating and sweeping the two Cu plate materials 101 and 102 in a state of being overlapped with each other and irradiating with a laser beam. .. In order to obtain sufficient bonding strength, the stacked Cu plates 101 and 102 are welded so that the width in the Y-axis direction of the bonded Cu plates is ½ or more of the welding width of the surface.

(Dot-shaped welding)
A point-shaped joint can be formed by irradiating and joining the centers of two Cu plates in a state where they are butted together without sweeping the laser beam. The shape of the laser beam may be any of a circular shape, an elliptical shape, a barrel shape, and a rectangular shape. Further, the point shape may be a broken line shape as long as the welded portions are present separately from each other. In the point-shaped welding, in the case of butt welding, the Cu plate material may be penetrated in the plate thickness direction, or the metal Cu may be stopped from melting in the middle. Further, the two Cu plates may be overlapped with each other and irradiated with a laser beam to join them in a dot shape. Also in this case, in order to obtain sufficient bonding strength, the overlapped Cu plates are welded so that the width in the Y-axis direction of the bonded members is ½ 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 formed by laser welding and joining butt Cu plates, and shows that the X-axis direction is the laser sweep direction. In addition, it can be seen that there is a portion where the processing traces of rolling of the Cu plate material have disappeared due to the irradiation of the laser beam. Further, it can be clearly seen that the Cu plate material has a melted and solidified portion, which is a welded portion. The width of the welded portion of the laser welding mark shown in the figure is defined as the welding width in the present invention, and the cut is cut at the dotted line cross-sectional observation position to observe the cross-sectional structure.

(Position of measuring Vickers hardness of linear joint)
FIG. 9 is an optical micrograph showing a cross-sectional state of a Cu member formed by laser welding a Cu plate material. As shown in FIG. 9, the welded portion joined by irradiating a laser beam to melt and then solidifying is represented as a weld width. Even when viewed from the cross-sectional view from FIG. 9, the width of the welding mark on the surface of the Cu plate material on the side irradiated with the laser beam can be clearly recognized. A point advanced along the direction of the weld width by a distance 1.5 times the length of half the weld width (half-width of the weld) from the center of the weld is called a non-weld part, and in the plate thickness direction at these two points. As shown by the arrows in FIG. 9, the depth in the plate thickness direction at the center of the weld width is the Vickers hardness HV1 and HV2 of the welded portion and the non-welded portion at the position of 1/2 of the plate thickness, respectively. Measure.

(Vickers hardness)
Vickers hardness is a measurement method standardized by "JIS Z 2244". The Vickers hardness HV is a numerical value indicating whether a rigid body (indenter) made of diamond is pressed against a test object and the area of a dent (indentation) formed at that time is large or small, and whether it is hard or soft. The indentation is ideally square because the indenter has a quadrangular pyramid shape that resembles an inverted pyramid. The test force is variable, and the JIS standard specifies 10 gf to 100 kgf.

(Inclination rate of hardness)
In the case of the butting shown in FIG. 8A, the measurement of the non-welded portion is performed by measuring the points on both sides perpendicular to the traveling direction of the laser beam from the center of the welded portion and measuring the average value of the non-welded portion. Vickers hardness is HV2. Further, in the case of superposition shown in FIG. 8B, the Vickers hardness HV2 of the non-welded portion is measured from the center of the welded portion at a right angle to the direction in which the laser beam travels and at a point opposite to the near end portion. ..
The Cu plate material at this time measures the Vickers hardness HV1 and HV2 at two points, the center of the welded portion and the non-welded portion. The value when the difference between the Vickers hardness HV2 at the non-welded portion and the Vickers hardness HV1 at the center of the weld is divided by the indentation distance X μm between the measured positions of the Vickers hardness HV1 and HV2. ((HV2-HV1) / X) is defined as the hardness inclination rate.

(Measurement position of Vickers hardness of point joint)
In dot-shaped welding, the welding width is defined as the widest portion of the dotted welded portion as the welding width and the surface on which the cross section of that portion is measured. Therefore, the non-welded portion is a portion adjacent to the dotted welded portion and 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 point shape and the point of the non-welded part at a certain distance from the center point. Thereby, the Vickers hardness HV1 and HV2 can be measured, and the hardness inclination rate can be obtained.

(Hardness distribution)
The hardness represents the difficulty of deforming the object and the resistance of the object to be scratched, especially when the surface of the Cu plate is about to be deformed or scratched. In particular, in a joined body obtained by welding and joining two Cu plates, if the hardness is distributed, cracks are likely to occur and the joints are easily cracked. This is because when stress is applied to a plate material in which a hard part with high hardness and a soft part with low hardness coexist, the deformation stress is concentrated, so that the low hardness part is easily deformed and cracks may occur. .. Therefore, the Cu plate material, which has a large difference in the effect of heat between the part affected by heat and the welded part that has melted and solidified due to the rapid heating and quenching of the laser welding process, is easily deformed by stress. , Cracks tend to enter easily. Therefore, if the hardness inclination ratio is large during the manufacture of parts for electrical and electronic equipment, cracks may occur and the parts may be damaged.

Therefore, it is desirable that the hardness inclination rate, which indicates the change in hardness in the base material, non-welded portion, and welded portion of the Cu plate material, is small. The larger the hardness inclination ratio, the larger the difference in hardness between the base material, the non-welded part, and the welded part of the Cu plate material. It will be easier. Therefore, the difference between the Vickers hardness HV1 at the weld and the Vickers hardness HV2 at the non-welded portion located adjacent to the weld is the indentation distance X (indentation distance X) between the positions where the Vickers hardness HV1 and HV2 are measured. 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.

Further, in order to put it into practical use as a component for electrical and electronic equipment, there is a practical problem if it is easily deformed, and rigidity due to the hardness of the base material of the Cu plate material itself is required. Therefore, in the present invention, the welded portion. It is preferable that the Vickers hardness HV2 in the Cu plate material portion other than the above, particularly in the non-welded portion located adjacent to the welded portion, is 75 or more.

(Cu alloy plate material)
A plate material having a Cu content of 90% by mass or more may be used, and may be pure Cu or any Cu alloy, and is not particularly limited.
When the Cu plate material used as a component for electrical and electronic equipment is a Cu alloy, one to two or more types selected from Ag, Fe, Ni, Co, Si, Cr, Sn, Zn, Mg, and P as alloy components. It is preferable to have a component composition containing an element and having a residual Cu 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 HV2 in 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 ratio is set to 0.2 / μm or less to suppress the occurrence of cracks. Further, it is preferable that not only the hardness inclination rate but also the base material, the non-welded portion, and the welded portion of the Cu plate material are hard, and in particular, the Vickers hardness HV2 in the non-welded portion is in the range of 75 to 240. Is preferable. If the Vickers hardness HV2 at the non-welded portion is less than 75, the Cu alloy plate material is likely to be deformed during processing. When the Vickers hardness HV2 in the non-welded portion exceeds 240, deformation of the welded portion and cracks easily occur at the boundary between the non-welded portion and the base metal and the welded portion at the boundary.

(Pure Cu plate material)
Further, when the Cu plate material used as a component for electric / electronic equipment is pure Cu containing 99.96% by mass or more of Cu and unavoidable impurities, the Vickers hardness HV2 in the non-welded portion is in the range of 75 to 120. Is preferable. It is preferable that the hardness inclination of the base material, the welded portion, and the non-welded portion of the Cu plate material is small. By using the pure Cu plate material, the hardness inclination ratio can be reduced to 0.1 / μm or less, and the welded portion. Local deformation of is difficult. In particular, in a pure Cu plate material, if the Vickers hardness HV2 in the non-welded portion is less than 75, it is likely to be deformed during processing. When the Vickers hardness HV2 in the non-welded portion exceeds 120, deformation of the welded portion and cracks easily occur at the boundary between the non-welded portion and the base metal and the welded portion and the non-welded portion.

Next, the reasons for limiting the suitable component composition of the plate material constituting the parts for electric and electronic devices of the present invention will be described below.
The plate material constituting the parts for electric and electronic devices of the present invention may be any plate material containing 90% by mass or more of Cu, and may be either a Cu alloy or pure Cu.

First, the component composition when the plate material is a Cu alloy will be described.
(1) When the plate material is a Cu alloy The plate material preferably contains one or more elements 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 action of improving mechanical properties without impairing electrical properties, and in order to exert such actions, the Ag content is preferably 0.05% by mass or more. .. Further, it is not necessary to set an upper limit of the Ag content in particular, but since Ag is expensive, it is preferable to set the upper limit of the Ag content to 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 action of improving mechanical properties. In order to exert such an effect, the Fe content is preferably 0.05% by mass or more. However, even if Fe is contained in an amount of more than 0.50% by mass, no further improvement effect can be expected, and there is a concern that the corrosion resistance is further lowered. Therefore, the Fe content is preferably 0.05 to 0.50% by mass.

(Ni: 0.05 to 5.00% by mass)
Ni (nickel) is finely precipitated in the matrix of Cu as a precipitate of second-phase particles composed of a simple substance or a compound with Si, for example, in a size of about 50 to 500 nm, and this precipitate is formed. It is a component having an action of precipitation hardening by suppressing dislocation movement, further suppressing grain growth, and increasing material strength by refining crystal grains. In order to exert such an effect, the Ni content is preferably 0.05% by mass or more. On the other hand, when the Ni content exceeds 5.00% by mass, the conductivity and the thermal conductivity are significantly lowered. Therefore, the upper limit of the Ni content is preferably 5.00% by mass.

(Co: 0.05 to 2.00% by mass)
Co (cobalt) is finely precipitated in the matrix of Cu as a precipitate of second-phase particles composed of a simple substance or a compound with Si, for example, in a size of about 50 to 500 nm, and this precipitate is formed. It is a component having an action of precipitation hardening by suppressing dislocation movement, further suppressing grain growth, and increasing material strength by refining crystal grains. In order to exert such an effect, the Co content is preferably 0.05% by mass or more. On the other hand, when the Co content exceeds 2.00% by mass, the conductivity and the thermal conductivity are significantly lowered. Therefore, 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 in the matrix of Cu as a precipitate of second-phase particles composed of compounds together with Ni and Co, and this precipitate is precipitated and hardened by suppressing dislocation movement. Furthermore, it is an important component having an action of suppressing grain growth and increasing the material strength by refining the crystal grains. In order to exert such an effect, the Si content is preferably 0.05% by mass or more. On the other hand, when the Si content exceeds 1.10% by mass, the conductivity and the thermal conductivity are significantly lowered. Therefore, the upper limit of the Si content is preferably 1.10% by mass.

(Cr: 0.05 to 0.50% by mass)
Cr (chromium) is finely precipitated in the matrix of Cu as a compound or a single substance in the form of a precipitate having a size of, for example, about 10 to 500 nm, and this precipitate suppresses dislocation movement. It is a component that has the effect of precipitating and hardening, further suppressing grain growth, and increasing the material strength by refining the crystal grains. In order to exert this effect, the Cr content is preferably 0.05% by mass or more. Further, when the Cr content exceeds 0.50% by mass, the conductivity and the thermal conductivity are significantly lowered. Therefore, 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 solid-solved in the matrix of Cu and contributes to the improvement of the strength 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 is likely to occur. Therefore, the Sn content is preferably 0.05 to 9.50% by mass. Further, since the Sn content tends to decrease the conductivity and the thermal conductivity, the Sn content is set to 0.05 to 0.50% by mass in the case of suppressing the decrease in the conductivity and the thermal conductivity. Is more preferable.

(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 and solder plating. In order to exert such an effect, the Zn content is preferably 0.05% by mass or more. On the other hand, if the Zn content exceeds 0.50% by mass, the amount of zinc vapor increases during welding, which may cause defects in the welded portion. Therefore, the Zn content is preferably 0.05 to 0.50% by mass.

(Mg: 0.01 to 0.50% by mass)
Mg (magnesium) is a component having an action of improving mechanical properties. In order to exert such an effect, the Mg content is preferably 0.01% by mass or more. On the other hand, when the Mg content exceeds 0.50% by mass, the conductivity and the thermal conductivity tend to decrease. Therefore, the Mg content is preferably 0.01 to 0.50% by mass.

(P: 0.01 to 0.50% by mass)
P (phosphorus) not only contributes as a deoxidizing material for Cu alloys, but also finely precipitates in the form of precipitates having a size of about 20 to 500 nm as compounds with Fe, Ni, etc., and these precipitates suppress dislocation movement. By doing so, precipitation hardening can be performed, and further, grain growth is suppressed and the material strength can be increased by refining the crystal grains. In order to exert such an effect, the P content is preferably 0.01% by 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. Therefore, the P content is set to 0.01 to 0.50% by mass.

(2) When the plate material is pure Cu with excellent conductivity and heat dissipation The plate material is 99.96% or more Cu and, as unavoidable impurities, for example, Cd, Mg, Pb, Sn, Cr, Bi, Se, Te. Is preferably 5 ppm or less in total, and pure Cu having a component composition in which Ag and O are each 400 ppm or less is preferable.

(Manufacturing method of parts for electrical and electronic equipment)
In the method for manufacturing a component for an electric / electronic device according to an embodiment of the present invention, a plurality of plate materials containing 90% by mass or more of Cu are set in a state of being abutted against each other or in a state of being overlapped with each other, and then joined. The spot is irradiated with a first laser beam having a wavelength of 400 to 500 nm with a spot diameter of 100 to 500 μm, and a second laser beam having a wavelength of 800 to 1200 nm is irradiated with a spot diameter of 10 to 300 μm. It includes a welding step of linearly joining and integrating a plurality of plate materials by welding while injecting an inert gas containing 1 to 50 ppm of oxygen into the molten portion at a flow rate of 10 to 50 L / min.
According to such a welding process, it is possible to easily weld Cu plates to each other, which has been difficult in the past, and to increase the Vickers hardness of the welded portion to 60 or more, thereby obtaining a welded portion having high strength. can.

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

(Laser welding method)
The laser welding method is a welding method in which light having a wavelength with good directivity and concentration is collected by a lens and laser light having an extremely high energy density is used as a heat source. By adjusting the output of the laser beam, penetration welding with a narrow width with respect to the depth is also possible. In addition, the laser beam can be narrowed down to a very small size as compared with the arc of arc welding. With the energy densified by the condenser lens, the laser welding device can perform local welding and joining materials with different melting points. It is suitable for fine welding because it has little heat effect due to welding, the welding pattern is fine, and no processing reaction force is generated.

(Laser welding equipment)
FIG. 6 is a diagram showing an example of a schematic configuration of a laser welding apparatus. The laser welding apparatus 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. Cu plate materials 111 and 112, which are the materials to be processed, are arranged on the processing table 24 in a butt or overlapped state. The laser control unit 21 controls laser oscillators 221 and 222 that oscillate laser light, a scanner (not shown), a laser head 29, a processing table, and the like. The control unit 21 controls the course directions of the Cu plate members 111 and 112, which are the workpieces, by controlling the rotation of the X-axis motor and the Y-axis motor (not shown), for example. Further, the control unit 21 may move and control the laser beams 231 and 232. This can be appropriately selected depending on the size of the work material. The control unit 21 oscillates a plurality of first and second laser beams 231 and 232 oscillated from the oscillators 221 and 222. The oscillated first and second laser beams 231 and 232 are collected in parallel light through the glass fiber 25 by the first and second condenser lenses 261 and 262 in the laser head 29, respectively. 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 passed through the focusing lens 28 to the Cu plate material 111. Welding is performed by focusing and irradiating the positions of 112 to be joined. At this time, the inert gas is supplied from the gas supply nozzle 30 in order 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 welding lasers. Examples of _{lasers include CO 2} lasers, Nd: YAG lasers, semiconductor lasers, fiber lasers and the like. It is preferable to use a fiber laser from the viewpoint of output and condensing property of laser light. Other configurations of the laser welder can be selected from any conventionally known configuration.

(Laser welding)
FIG. 7 is a diagram showing an example of the spot diameter of the laser beam of the laser welding apparatus. As shown in FIG. 7, the first laser beam 231 having a wavelength of 400 to 500 nm is irradiated with a spot diameter of 100 to 500 μm. Then, the second laser beam 232 having a wavelength of 800 to 1200 nm is irradiated with a spot diameter of 10 to 300 μm. FIG. 7 shows an example in which the first laser beam 231 and the second laser beam 232 are irradiated so as to overlap each other on the surface of the plate material. By simultaneously irradiating a plurality of laser beams having a specific wavelength and spot diameter, it has become possible to easily weld a Cu plate material, which has been difficult in the past. Further, by welding while injecting the inert gas containing 1 to 50 ppm of oxygen into the molten portion at 10 to 50 L / min, a welded portion having a Vickers hardness of 60 or more can be obtained.

The inert gas supplied to the molten part contains 10 to 50 ppm of oxygen. Examples of the inert gas include nitrogen gas and argon gas. By laser welding such an inert gas containing 10 to 50 ppm of oxygen at a flow rate of 10 to 50 L / min, the melted portion is covered with the inert gas, and an appropriate amount of oxygen is applied to the melted portion. It is presumed that it can be sent to the inside, thereby generating fine oxides to increase the hardness of the welded portion, and by quenching, an appropriate strain is introduced into the crystal grains. If the oxygen content of the inert gas is less than 10 ppm, sufficient oxygen cannot be supplied and the hardness may be low. On the other hand, if it exceeds 50 ppm, internal oxidation may become excessive and embrittlement may occur. Further, if the flow rate of the non-volatile gas containing 10 to 50 ppm of oxygen is less than 10 L / min, a sufficient shielding effect cannot be obtained, oxidation proceeds excessively, and the cooling rate of the molten portion decreases, so that the inside of the crystal is sufficient. No strain can be obtained. Further, when the flow rate exceeds 50 L / min, the shape of the molten pool becomes unstable by blowing a large amount of gas on the molten portion, which may cause poor solidification.

Further, irradiation when the first laser beam 231 having a wavelength of 400 to 500 nm is irradiated with a spot diameter of 100 to 500 μm and the second laser beam 232 having a wavelength of 800 to 1200 nm is irradiated with a spot diameter of 10 to 300 μm. The time is 0.1 to 10 msec / spot. (In the case of a linear shape, the speed of sweeping a distance corresponding to the diameter of one spot, in the case of a point shape, the irradiation time per spot) If it is shorter than 0.1 msec, it is difficult to join and the hardness is inclined. Tends to be steep. On the other hand, if it exceeds 10 msec, the metal may be melted down from the welded portion and chipped, or the metal may be softened and the strength may be insufficient.

In the parts for electrical and electronic equipment of the present invention, after setting a plurality of plate materials in a state of being butted or overlapped with each other, the joints between the plurality of plate materials are irradiated with the first and second laser beams 231 and 232. Then, a plurality of plate materials are joined to each other in a linear or dot shape to be integrated. The first laser beam 231 that efficiently penetrates only the surface of the Cu plate material heats the Cu plate material in a wider range than the second laser light 232, and when heated, the second laser beam 232 that penetrates deeply into the Cu plate material is irradiated almost at the same time. Welding can be performed with almost no defects such as blow holes and internal defects.

If the wavelengths and spot diameters of the first and second laser beams 231 and 232 are out of the range, the surface quality deteriorates and welding cannot be performed, which is inappropriate. Further, controlling the heating by the first laser beam 231 affects the cooling rate when the plate material is melted and solidified by the second laser beam 232, and as a result of diligent examination, it is 0.1 to 10 msec / spot or less. By doing so, it is possible to suppress changes in the hardness of the Cu plate base material, the non-welded portion, and the welded portion of the Cu plate material, and further suppress the inclination of the hardness of the non-welded portion and the welded portion of the Cu plate material to be low. understood.

(Effect of welding)
By controlling the base material, non-welded portion, and welded portion of the Cu plate material having a predetermined component composition in this way, electricity and electrons that are hard and rigid and that local deformation of the welded portion is unlikely to occur. Equipment parts can be obtained.

(Application to electrical and electronic equipment)
The parts for electrical and electronic devices of the present invention can be considered to be used in semiconductor devices, LSIs, or many electronic devices using these, and further, for example, homes that need to be particularly miniaturized and highly integrated. Use for electrical and electronic equipment such as game consoles, medical equipment, workstations, servers, personal computers, car navigation systems, mobile phones, robot connectors, battery terminals, jacks, relays, switches, autofocus camera modules, lead frames, etc. Is possible.

(Vapor chamber)
The component for an electric / electronic device according to an embodiment of the present invention is made of pure Cu or Cu alloy having excellent thermal conductivity, and has high strength and excellent deformation resistance, so that it is applied to a heat pipe or a vapor chamber. It is preferable to do so.
The parts for electric and electronic devices of other embodiments of the present invention are preferably applied to heat pipes and vapor chambers because they have high rigidity and have characteristics of less generation of cracks. In particular, since cracks are less likely to occur as a structural material for vapor chamber products, leakage and corrosion during use due to cracks are improved, which suppresses deterioration of thermal conductivity and deteriorates vapor chamber products. It can contribute to suppression and extension of life.

(Busbar)
The component for an electric / electronic device according to an embodiment of the present invention is made of pure Cu or a Cu alloy having excellent thermal conductivity, and is suitable as a bus bar because of its high strength and excellent deformation resistance. The bus bar can be applied as an electric path for electrically connecting and as a transportation path for heat dissipation. In particular, the bus bar can also be used as a cooling device by connecting the bus bar from the heat generating portion and providing a path to the heat dissipation portion or the outside. Applicable.
Further, the bus bar formed of the parts for electric / electronic devices of another embodiment of the present invention has excellent characteristics for local deformation, so that it can be used for electrically connecting electric paths and for heat dissipation. It can also be applied as a transportation route. In particular, it can also be applied as a cooling device by connecting a bus bar from a heat generating portion and providing a path to a heat radiating portion or the outside.

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

(Examples 1 to 6 and Comparative Examples 1 to 9) Joining of two same plates made of pure Cu Examples 1 to 5 and Comparative Examples 1 to 9 are made of pure Cu having the component composition shown in Table 1. Two plates were cut out to a thickness of 0.15 mm, a width of 20 mm, and a length of 1000 mm. The two cut out plates were moved in a direction in which the end faces extending in the length direction were brought closer to each other, and arranged in a butt state as shown in FIG. 1 (a). The first laser beam having a wavelength of 400 to 500 nm and a spot diameter (hereinafter, may be 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. The second laser beam was laser-welded while maintaining the positional relationship of the spot diameters as shown in FIG. The laser conditions are shown in Table 1. Laser welding was performed while supplying the fused portion with an inert gas containing oxygen as shown in Table 1. As the inert gas, a mixed gas of G1 grade nitrogen gas manufactured by Taiyo Nippon Sanso and oxygen gas was used.
Further, in Example 6, instead of the butt arrangement, the overlapping arrangement shown in FIG. 1 (b) was used, and laser welding was performed under the same conditions as in Example 1.

Then, the Vickers hardness and the GAM value of the welded portion were measured by the following methods. The results are shown in Table 1. Further, in Table 1, the area ratio to all the crystal grains existing in the measured area of the crystal grains having the Vickers hardness Hv1 of 60 or more and the GAM value of 0.5 ° or more and less than 2.0 ° is 25%. The above cases are described as "◎" as having excellent deformation resistance characteristics, and the crystal grains having a Vickers hardness Hv1 of 60 or more and a GAM value of 0.5 ° or more and less than 2.0 ° are described. , The case where the area ratio to all the crystal grains existing in the measurement area is less than 25% is described as "○" as having good deformation resistance, and the case where the Vickers hardness Hv1 is less than 60. , It is described as "x" because it has poor deformation resistance.
In addition, the local deformation characteristics of the weld were also evaluated. When the hardness of the non-welded part, the hardness of the welded part, and the hardness inclination ratio obtained from the indentation distance are 0.2 / μm or less, the welded part and the non-welded part become a small inclined material, so that they are locally deformed. It became difficult and was evaluated as "○" because of its good local deformation resistance. On the other hand, when it exceeds 0.2 / μm, it is easily deformed locally and is set as “Δ”.

[Vickers hardness]
Vickers hardness HV was measured according to the method specified in JIS Z2244 (2009). The load (test force) at this time was selected from between 20 and 100 gf within a range in which the diagonal length of the indentation did not exceed 0.03 mm and tested. The pressing time (pushing time) of the indenter is 15 sec.
In Examples 1 to 5 and Comparative Examples 1 to 9 in which the plate materials are butted, 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 plate material method. When the linear direction is the Z-axis direction, the Vickers hardness Hv1 at the position b corresponding to half the thickness a of the plate material of the welded portion existing in the cross section A when the welded portion is cut in the Y-axis direction. Was measured. Measurements were made on five cross sections A (YZ planes) cut at intervals of 1 mm in the welding direction (X-axis direction), and the average values of those measurement results were obtained.
In Example 6 was superimposed a plate, as shown in FIG. 1 (b), of the plate 1 of the welded portion present in the cross section A ₁ obtained by cutting the welded portion in the Y-axis direction of the thickness of a ₁ At the position b ₁ corresponding to half the dimension and at the position b _{2 corresponding to half the thickness a 2} of the plate material 2 of the weld portion existing in _{the cross section A 2} when the weld portion is cut in the Y-axis direction. , Vickers hardness Hv1 was measured. Measured in the welding direction (X axis direction) respectively were cut at intervals of 1mm to five cross A _1, A 2 _(YZ plane) was determined as an average of the measurement results.

[GAM value]
The GAM value is analyzed from the crystal orientation data continuously measured using the EBSD detector attached to the high-resolution scanning analysis electron microscope (JSM-7001FA, manufactured by Nippon Denshi Co., Ltd.) (OIM Analysis, manufactured by TSL). It was obtained from the crystal orientation analysis data calculated using. The measurement was performed with a step size of 0.1 μm. The measurement region is the _{entire rectangular region of the surfaces of the cross sections A, A 1} , and A ₂ which is divided by the weld width of the welded portion and the thickness of the plate material on the surface mirror-finished by electrolytic polishing.
The area ratio of crystal grains with GAM values within the specified range is defined as the first category with GAM values of 0 ° or more and less than 0.25 °, 15 categories in 0.25 ° increments, and 0 ° or more and less than 3.75 °. The GAM value was used as a measurement target, and it was calculated from the total area ratio of crystal grains in each category to the entire SEM image obtained by the SEM-EBSD method.
In Example 6, the average value of the area ratio of the crystal grains of the GAM value measured for each of the two plate materials was obtained, and the average value is shown in Table 1.

According to Examples 1 to 6, in the joining of two identical plates made of pure Cu, a first laser beam having a wavelength of 400 to 500 nm is irradiated with a spot diameter of 100 to 500 μm, and 800 to 1200 nm. While irradiating a second laser beam having a wavelength with a spot diameter of 10 to 300 μm and injecting an inert gas containing 1 to 50 ppm of oxygen into the molten portion at a flow rate of 10 to 50 L / min, 0.1 to 3 msec. It can be seen that the Vickers hardness Hv1 of the welded portion can be set to 60 or more by welding at the spot. Among them, in Examples 1 to 3, 5 and 6 in which the area ratio of the crystal grains having the GAM value was 25% or more, the Vickers hardness Hv1 was 65 or more, which was particularly high. Further, it can be seen that when the irradiation time is 2 msec or more, the inclination becomes small.
On the other hand, in Comparative Example 1 in which the oxygen content of the inert gas was less than 10 ppm, the Vickers hardness was low. Further, in Comparative Example 2 in which the oxygen content of the inert gas was more than 50 ppm and Comparative Example 3 in which the flow rate of the inert gas was less than 10 L / min, internal oxidation became excessive and embrittlement occurred, resulting in great damage. In Comparative Example 4 in which the flow rate of the inert gas was more than 50 L / min, poor solidification occurred and the thickness of the welded portion was greatly reduced. Comparative Example 5 in which the laser conditions are such that the first laser beam having a wavelength of 400 to 500 nm is irradiated with a spot diameter of 100 to 500 μm and the second laser beam having a wavelength of 800 to 1200 nm is not irradiated with a spot diameter of 10 to 300 μm. In No. 9, the plates made of pure Cu could not be joined to each other.

(Examples 7 to 26 and Comparative Examples 10 to 12) Joining of two same plates made of Cu alloy In Examples 7 to 26 and Comparative Examples 10 to 12, 2 made of Cu alloy having the component composition shown in Table 2. The same procedure as in Example 1 was carried out except that the sheets were welded under the welding conditions shown in Table 2. The results are shown in Table 2.

According to Examples 7 to 26, in the joining of two identical plates made of Cu alloy, a first laser beam having a wavelength of 400 to 500 nm is irradiated with a spot diameter of 100 to 500 μm, and 800 to 1200 nm. A second laser beam having a wavelength is irradiated with a spot diameter of 10 to 300 μm, and an inert gas containing 1 to 50 ppm of oxygen is injected into the molten portion at a flow rate of 10 to 50 L / min at a flow rate of 0.2 to 10 msec / min. It can be seen that the Vickers hardness Hv1 of the welded portion can be set to 60 or more by welding at the spot. Among them, in Examples 7, 8, 10, 12, 14, 15, 16, 18, 20, 22, 24, and 26 in which the area ratio of the crystal grains having the GAM value is 25% or more, the Vickers hardness of the welded portion with respect to the plate material is obtained. The Vickers hardness of the welded portion (Vickers hardness of the welded portion / Vickers hardness of the plate material) could be set to 0.5 or more, and the decrease in the 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, the irradiation time was short, so welding was not performed. Further, in Comparative Example 12, since the irradiation time was long, the welded portion was melted down, and the wall thickness was reduced, so that a clean cross section could not be obtained.

(Examples 27 to 28) Joining of two plates made of pure Cu and having different component compositions In Example 27, a plate made of a Cu alloy having the component composition shown in Table 3 was used, and the welding conditions shown in Table 3 were used. It was the same as in Example 1 (butting) except that it was welded in.
In Example 28, a plate material made of a Cu alloy having the component composition shown in Table 3 was used, and the same as in Example 6 (superimposition) except that welding was performed under the welding conditions shown in Table 3. The plates shown in the upper part of Table 3 were overlapped so as to be on the laser irradiation side.
The results are shown in Table 3.

According to Examples 27 to 28, in the joining of two plates made of pure Cu and having different component compositions, a first laser beam having a wavelength of 400 to 500 nm is irradiated with a spot diameter of 100 to 500 μm, and 800. A second laser beam having a wavelength of about 1200 nm is irradiated with a spot diameter of 10 to 300 μm, and an inert gas containing 1 to 50 ppm of oxygen is injected into the molten portion at a flow rate of 10 to 50 L / min at 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 the irradiation time of.

(Examples 29 to 31) Joining of two plates made of Cu alloy and having different composition compositions In Examples 29 to 31, the plates made of Cu alloy having the composition shown in Table 4 are used and are shown in Table 4. The same as in Example 1 was carried out except that the welding was performed under the welding conditions. The results are shown in Table 4.

According to Examples 29 to 31, in the joining of two plates made of Cu alloy and having different component compositions, a first laser beam having a wavelength of 400 to 500 nm is irradiated with a spot diameter of 100 to 500 μm, and 800. A second laser beam having a wavelength of about 1200 nm is irradiated with a spot diameter of 10 to 300 μm, and an inert gas containing 1 to 50 ppm of oxygen is injected into the molten portion at a flow rate of 10 to 50 L / min at 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 the irradiation time of.

(Examples 32 to 33) Welding of a plate material made of pure Cu and a plate material made of Cu alloy In Example 32, a plate material made of pure Cu having the component composition shown in Table 5 and a plate material made of Cu alloy are used. The same as in Example 1 (butting) except that the welding was performed under the welding conditions described in 5.
In Example 33, a plate material made of pure Cu having the component composition shown in Table 5 and a plate material made of a Cu alloy were used and welded under the welding conditions shown in Table 5, but in Example 6 (superimposition). I did the same. The first plate materials shown in the upper part of Table 5 were 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 joining of the plate material made of pure Cu and the plate material made of Cu alloy, the first laser beam having a wavelength of 400 to 500 nm is irradiated with a spot diameter of 100 to 500 μm, and 800. A second laser beam having a wavelength of about 1200 nm is irradiated with a spot diameter of 10 to 300 μm, and an inert gas containing 1 to 50 ppm of oxygen is injected into the molten portion at a flow rate of 10 to 50 L / min at 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 the irradiation time of. It was

As described above, by increasing the area ratio in which the GAM value is 0.5 ° or more and less than 2.0 ° by these Examples and Comparative Examples, the hardness of the welded portion can be controlled to 60 or more, and in addition, the welded portion and the non-welded portion are not welded. When the hardness inclination ratio of the portion is 0.2 / μm or less, it becomes more resistant to deformation, and it can be seen that there is no practical problem. Therefore, according to the present invention, in an electric / electronic device component having a welded portion such as a vapor chamber or a bus bar, the hardness of the welded portion / non-welded portion is controlled to have rigidity and locality at the welded portion. It can be seen that parts for electrical and electronic equipment that are resistant to deformation can be obtained.

1, 2 Plate material 3, 3A, 3B, 3C Welded part 10, 10A, 10B, 10C Joined body 10D Cu member 101, 102 Cu plate material 20 Laser welding device 21 Laser control unit 24 Processing table 25 Glass fiber 26 Condensing lens 28 Focusing Lens 29 Laser head 30 Gas supply nozzle 221,222 Laser oscillator 231 1st laser beam 232 2nd laser beam 261 1st condensing lens 262 2nd condensing lens 271 1st mirror 272 2nd mirror

Claims (7)

1. It is composed of a plurality of plate materials containing 90% by mass or more of Cu.
   It has a welded portion in which the plurality of plate materials are joined to each other in a linear or dot shape by welding in a state of being abutted against each other or in a state of being overlapped with each other.
   The weld extends over the entire thickness of the plate.
   In the cross section when the welded portion is cut in the direction in which the plurality of joined plates extend.
   The welded portion is a component for electrical and electronic equipment having a Vickers hardness HV1 of 60 or more when measured at a position corresponding to half the thickness of the plate material at the center of the weld width, which is the width of the weld mark. ..
2. In the cross section, when the GAM value obtained from the crystal orientation analysis data of the SEM-EBSD method is measured in the rectangular region partitioned by the welding width of the welded portion and the thickness of the plate material, the GAM value is 0. The component for electrical / electronic equipment according to claim 1, wherein the crystal grains having a temperature of 5.5 ° or more and less than 2.0 ° have an area ratio of 25% or more to all the crystal grains existing in the measurement area.
3. It is composed of a plurality of plate materials containing 90% by mass or more of Cu.
   It has a welded portion in which the plurality of plate materials are joined to each other in a linear or dot shape by welding in a state of being abutted against each other or in a state of being overlapped with each other.
   The weld extends over the entire thickness of the plate.
   In the cross section when the welded portion is cut in the direction in which the plurality of joined plates extend.
   The Vickers hardness at the welded portion when measured at a position corresponding to half the thickness of the plate material at the center of the weld width, which is the width of the weld mark on the surface of the plate material, is defined as HV1.
   When the Vickers hardness in the non-welded portion when measured at a position separated along the direction of the weld width by a distance corresponding to 1.5 times the weld half width from the center position of the welded portion is HV2.
   The Vickers hardness HV2 in the non-welded portion is 75 or more, and the Vickers hardness is 75 or more.
   Hardness when the difference between the Vickers hardness HV2 in the non-welded portion and the Vickers hardness HV1 in the welded portion is divided by the indentation distance X (μm) between the positions where the Vickers hardness HV1 and HV2 are measured. The component for electrical / electronic equipment according to claim 1 or 2, wherein the slope ratio ((HV2-HV1) / X) is 0.2 / μm or less.
4. The invention according to any one of claims 1 to 3, wherein 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 equipment.
5. The component for electrical / electronic equipment according to any one of claims 1 to 3, wherein the plate material is 99.96% by mass or more of Cu and unavoidable impurities.
6. The component for electrical / electronic equipment according to any one of claims 1 to 5, wherein the component for electrical / electronic equipment is a vapor chamber.
7. The component for electrical / electronic equipment according to any one of claims 1 to 5, wherein the component for electrical / electronic equipment is a bus bar.

Images