Copper alloy sheet

Abstract

To provide a copper alloy sheet that exhibits superior strength and conductivity, has anisotropy in conductivity, and is particularly suitable as a material for components of electrical and electronic devices that are intended for current conduction in a specific direction.SOLUTION: This copper alloy sheet is characterized in that: Cr is contained in a range of 0.05 mass% or more and 1.0 mass% or less, Zr is contained in a range of 0.01 mass% or more and 0.5 mass% or less, and when the TD surface is observed, the ratio Gr / Gn of the maximum crystal length Gr in the rolling direction to the maximum crystal length Gn in the sheet thickness direction is 5 or more, the electrical conductivity IGW in the rolling direction and the electrical conductivity IBW in the sheet width direction are both 70% IACS or more, the difference IGW-IBW between the electrical conductivity IGW in the rolling direction and the electrical conductivity IBW in the sheet width direction exceeds 0.1% IACS, and the tensile strength in the rolling direction is 500 MPa or more.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a copper alloy plate suitable as a material for parts for electric and electronic devices such as terminals, connectors, relays, switches, sockets, bus bars, lead frames, heat sinks, etc.

Background Art

[0002] Conventionally, copper alloy plates excellent in conductivity have been used as materials for parts for electronic and electric devices such as terminals, connectors, relays, switches, sockets, bus bars, lead frames, heat sinks, etc. As copper alloy plates serving as materials for the above various applications, conventional Cu-Cr-based alloys and Cu-Zr-based alloys have been widely used. Cu-Cr-based alloys and Cu-Zr-based alloys are precipitation-strengthened alloys in which the strength is improved by precipitating intermetallic compounds containing Cr or intermetallic compounds containing Zr in the copper matrix phase, and are widely used in various applications because they are excellent in strength, conductivity, and thermal conductivity.

[0003] In recent years, with the expansion of the applications of Cu-Cr-based alloys and Cu-Zr-based alloys, and the weight reduction, thinning, and miniaturization of electric and electronic devices, further higher strength, higher conductivity, and good thermal conductivity have been demanded for Cu-Cr-based alloys and Cu-Zr-based alloys. For example, in Patent Document 1, the properties such as strength are improved by controlling the area ratio of particle groups having different crystal grain sizes.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, in electrical and electronic equipment components, in applications where current flows in a specific direction, such as bus bars, electrical conductivity is particularly required in the longitudinal direction. However, no conventional Cu-Cr alloys or Cu-Zr alloys have been proposed that have been thoroughly examined for their electrical conductivity anisotropy. Patent Document 1 aims to improve properties such as strength by suppressing the increase in the anisotropy of mechanical properties, but does not pay attention to the anisotropy of electrical conductivity.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and an object of the present invention is to provide a copper alloy sheet which is excellent in strength and electrical conductivity, has anisotropic electrical conductivity, and is particularly suitable as a material for parts of electric and electronic devices in which electric current flows in a specific direction. [Means for solving the problem]

[0007] In order to solve the above problems, the copper alloy sheet of the first aspect of the present invention contains Cr in the range of 0.05 mass% or more and 1.0 mass% or less, and Zr in the range of 0.01 mass% or more and 0.5 mass% or less, and when observing the TD surface, the ratio Gr / Gn of the maximum crystal length Gr in the rolling direction to the maximum crystal length Gn in the sheet thickness direction is 5 or more, and the electrical conductivity in the rolling direction I GW and the electrical conductivity I in the plate width direction BW Both are 70%IACS or more, and the electrical conductivity I GW and the electrical conductivity I in the plate width direction BW Difference I GW -I BW It is characterized by having a tensile strength of 500 MPa or more in the rolling direction and a hardness of 0.1% IACS or more.

[0008] According to the copper alloy sheet of the first aspect of the present invention, Cr is contained in the range of 0.05 mass% or more and 1.0 mass% or less, Zr is contained in the range of 0.01 mass% or more and 0.5 mass% or less, and electrical conductivity in the rolling direction I GW and the electrical conductivity I in the plate width direction BWSince both are 70% IACS or more and the tensile strength in the rolling direction is 500 MPa or more, they are excellent in strength and conductivity. Therefore, it is possible to reduce the amount of heat generated during energization, and to make the parts smaller and thinner. And when observing the TD plane, the ratio Gr / Gn of the maximum crystal length Gr in the rolling direction to the maximum crystal length Gn in the plate thickness direction is 5 or more, and the conductivity I in the rolling direction GW and the conductivity I in the plate width direction BW the difference I GW -I BW exceeds 0.1% IACS, so it has anisotropy in conductivity, and since the conductivity in the rolling direction is particularly high, it is particularly suitable as a material for parts for electrical and electronic equipment for applications where current flows in a specific direction.

[0009] The copper alloy plate of Aspect 2 of the present invention is characterized in that, in the copper alloy plate of Aspect 1 of the present invention, when observing the TD plane, the maximum crystal length Gr in the rolling direction is 8 μm or more and the maximum crystal length Gn in the plate thickness direction is 4 μm or less. According to the copper alloy plate of Aspect 2 of the present invention, since the maximum crystal length Gr in the rolling direction is 8 μm or more and the maximum crystal length Gn in the plate thickness direction is 4 μm or less, it has a crystal structure extended in the rolling direction, and the anisotropy of conductivity can be further improved so that the conductivity in the rolling direction becomes higher.

[0010] The copper alloy plate of Aspect 3 of the present invention is characterized in that, in the copper alloy plate of Aspect 1 or Aspect 2 of the present invention, the Vickers hardness is 180 HV or more and the heat resistance temperature that becomes 80% of the initial Vickers hardness when heat-treated for 1 hour is 500 °C or more. According to the copper alloy plate of Aspect 3 of the present invention, since the Vickers hardness is 180 Hv or more and the heat resistance temperature that becomes 80% of the initial Vickers hardness when heat-treated for 1 hour is 500 °C or more, it is particularly excellent in strength and heat resistance.

[0011] The copper alloy sheet of Embodiment 4 of the present invention is one of the copper alloy sheets of any one of Embodiments 1 to 3 of the present invention, and contains one or more additive elements selected from Ti, Ag, Fe, Co, Ni, Mn, Zn, Mg, Si, P, Sn, and B, and the total content of the additive elements is 0.1% by mass or less. According to the copper alloy of Embodiment 4 of the present invention, since it contains one or more additive elements selected from Ti, Ag, Fe, Co, Ni, Mn, Zn, Mg, Si, P, Sn, and B, the strength can be further improved. Further, since the total content of the additive elements is 0.1% by mass or less, it is possible to suppress a decrease in conductivity.

[0012] The copper alloy sheet of Embodiment 5 of the present invention is characterized in that, in any one of the copper alloy sheets of Embodiments 1 to 4 of the present invention, precipitates having a circle equivalent diameter of 50 nm or less containing Cr and precipitates having a circle equivalent diameter of 1 μm or less containing Zr mainly exist. According to the copper alloy sheet of Embodiment 5 of the present invention, since precipitates having a circle equivalent diameter of 50 nm or less containing Cr and precipitates having a circle equivalent diameter of 1 μm or less containing Zr mainly exist, the strength can be sufficiently improved by precipitation strengthening, and a high conductivity can be obtained.

Effects of the Invention

[0013] It is possible to provide a copper alloy sheet that is excellent in strength and conductivity, has anisotropy in conductivity, and is particularly suitable as a material for electrical and electronic device parts for applications in which current flows in a specific direction.

Brief Description of the Drawings

[0014]

Figure 1

Modes for Carrying Out the Invention

[0015] Hereinafter, a copper alloy sheet according to an embodiment of the present invention will be described. The copper alloy sheet of the present embodiment contains Cr in the range of 0.05% by mass or more and 1.0% by mass or less, and Zr in the range of 0.01% by mass or more and 0.5% by mass or less, with the balance being Cu and inevitable impurities. Further, in the copper alloy sheet of the present embodiment, when observing the TD plane, the ratio Gr / Gn of the maximum crystal length Gr in the rolling direction to the maximum crystal length Gn in the sheet thickness direction is 5 or more. Here, the TD plane is a plane orthogonal to the rolling direction plane (RD plane) and the rolling plane (ND plane).

[0016] And, in the copper alloy sheet of the present embodiment, the conductivity I in the rolling direction GW and the conductivity I in the sheet width direction BW are both 70% IACS or more, and the difference I GW between the conductivity I in the rolling direction and the conductivity I in the sheet width direction BW exceeds 0.1% IACS. That is, the conductivity I in the rolling direction GW -I BW is higher than the conductivity I in the sheet width direction GW and has anisotropy in conductivity. BW Further, in the copper alloy sheet of the present embodiment, the tensile strength in the rolling direction is 500 MPa or more.

[0017] Here, the copper alloy sheet of the present embodiment contains one or more additive elements among Ti, Ag, Fe, Co, Ni, Mn, Zn, Mg, Si, P, Sn, and B, and the total content of these additive elements may be 0.1% by mass or less.

[0018] Also, in the copper alloy sheet of the present embodiment, when observing the TD plane, it is preferable that the maximum crystal length Gr in the rolling direction is 8 μm or more and the maximum crystal length Gn in the sheet thickness direction is 4 μm or less. Furthermore, in the copper alloy sheet of the present embodiment, it is preferable that precipitates having a circle equivalent diameter of 50 nm or less containing Cr and precipitates having a circle equivalent diameter of 1 μm or less containing Zr mainly exist. Also, in the copper alloy sheet of the present embodiment, the Vickers hardness is preferably 180 Hv or more. Further, when heat-treated for 1 hour, the temperature (heat-resistant temperature) at which it becomes 80% of the initial Vickers hardness is preferably 500 °C or more.

[0019] In the copper alloy sheet of the present embodiment, the reasons for defining the component composition, crystal structure, precipitate, conductivity, tensile strength, Vickers hardness, and heat-resistant temperature as described above will be explained below.

[0020] (Cr) Cr is an element that has the effect of improving strength without reducing conductivity by finely precipitating Cr-based precipitates (for example, Cu-Cr) in the crystal grains of the matrix phase by aging treatment. Here, when the content of Cr is less than 0.05% by mass, there is a possibility that the effects of improving strength and Vickers hardness cannot be sufficiently obtained. On the other hand, when the content of Cr exceeds 1.0% by mass, relatively coarse Cr precipitates are generated, which may cause defects. Therefore, in the present embodiment, the content of Cr is in the range of 0.05% by mass or more and 1.0% by mass or less. In addition, the content of Cr is preferably 0.10% by mass or more, more preferably 0.15% by mass or more, and even more preferably 0.20% by mass or more. Also, the content of Cr is preferably 0.80% by mass or less, more preferably 0.60% by mass or less, and even more preferably 0.40% by mass or less.

[0021] (Zr) Zr is an element that has the effect of improving strength without reducing conductivity by finely precipitating Zr-based precipitates (for example, Cu5Zr) in the crystal grains of the matrix phase by aging treatment. Here, when the content of Zr is less than 0.01% by mass, there is a possibility that the effects of improving strength and Vickers hardness cannot be sufficiently obtained. On the other hand, when the content of Zr exceeds 0.5% by mass, relatively coarse Zr precipitates are generated, which may cause defects. Therefore, in this embodiment, the content of Zr is in the range of 0.01% by mass or more and 0.5% by mass or less. In addition, the content of Zr is preferably 0.03% by mass or more, more preferably 0.06% by mass or more. Also, the content of Zr is preferably 0.4% by mass or less, more preferably 0.2% by mass or less.

[0022] (Additive element) One or more of the additive elements Ti, Ag, Fe, Co, Ni, Mn, Zn, Mg, Si, P, Sn, and B have the effect of improving the strength of the copper alloy sheet. Therefore, for further strength improvement, these additive elements may be included. However, since these additive elements decrease the conductivity, it is preferable to limit the total content of the additive elements to 0.1% by mass or less. In addition, the total content of one or more of the additive elements Ti, Ag, Fe, Co, Ni, Mn, Zn, Mg, Si, P, Sn, and B is more preferably 0.08% by mass or less, and even more preferably 0.05% by mass or less.

[0023] (Ratio Gr / Gn of the maximum crystal length Gr in the rolling direction to the maximum crystal length Gn in the sheet thickness direction) When observing the TD surface of the copper alloy sheet of this embodiment, if the ratio Gr / Gn of the maximum crystal length Gr in the rolling direction to the maximum crystal length Gn in the sheet thickness direction is large, the crystal has a shape extending in the rolling direction, and the precipitates are also distributed along the rolling direction. As a result, the conductivity has anisotropy. Therefore, in this embodiment, the ratio Gr / Gn of the maximum crystal length Gr in the rolling direction to the maximum crystal length Gn in the sheet thickness direction is defined to be 5 or more. In addition, the ratio Gr / Gn of the maximum crystal length Gr in the rolling direction to the maximum crystal length Gn in the sheet thickness direction is preferably 6 or more, more preferably 7 or more.

[0024] (Maximum crystal length Gr in the rolling direction, maximum crystal length Gn in the sheet thickness direction) When observing the TD plane of the copper alloy sheet of the present embodiment, when the maximum crystal length Gr in the rolling direction is 8 μm or more and the maximum crystal length Gn in the sheet thickness direction is 4 μm or less, the crystal has a relatively fine crystal structure extending in the rolling direction, so that the anisotropy of conductivity can be further improved and further strength improvement can be achieved. In addition, the maximum crystal length Gr in the rolling direction is more preferably 9 μm or more, and even more preferably 10 μm or more. Further, the maximum crystal length Gn in the sheet thickness direction is more preferably 3 μm or less, and even more preferably 2 μm or less.

[0025] (Precipitates containing Cr and precipitates containing Zr) In the copper alloy sheet of the present embodiment, when precipitates having a circle equivalent diameter of 50 nm or less containing Cr and precipitates having a circle equivalent diameter of 1 μm or less containing Zr mainly exist, the strength is further improved by precipitation strengthening by these precipitates. Note that "mainly existing" specifically means that, in the observation field of view, the number ratio occupied by precipitates having a circle equivalent diameter of 50 nm or less containing Cr and precipitates having a circle equivalent diameter of 1 μm or less containing Zr among the total number of observed precipitates is 60% or more.

[0026] (Conductivity I in the rolling direction GW , conductivity I in the sheet width direction BW ) In parts for electric and electronic equipment, in order to suppress heat generation during energization, it is required to have excellent conductivity. For this reason, in the copper alloy sheet of the present embodiment, the conductivity I in the rolling direction GW and the conductivity I in the sheet width direction BW are both specified to be 70% IACS or more. In addition, the conductivity I in the rolling direction GW , the conductivity I in the sheet width direction BW is preferably 73% IACS or more, and more preferably 76% IACS or more.

[0027] (The difference I between the conductivity I in the rolling direction GW and the conductivity I in the sheet width direction BW I GW -IBW ) In the copper alloy plate of this embodiment, the conductivity I in the rolling direction GW and the conductivity I in the plate width direction BW The difference I GW -I BW is made to have anisotropy in conductivity so that it exceeds 0.1% IACS. As a result, in parts for electric and electronic equipment that conduct electricity in a specific direction, it becomes possible to suppress heat generation during energization. Incidentally, the difference I GW between the conductivity I in the rolling direction BW and the conductivity I in the plate width direction GW -I BW is preferably 0.2% IACS or more, and more preferably 0.4% IACS or more.

[0028] (Tensile strength) In the copper alloy plate of this embodiment, by increasing the strength, it becomes possible to reduce the weight and thickness of parts for electric and electronic equipment. Therefore, in this embodiment, the tensile strength in the rolling direction of the copper alloy plate is defined to be 500 MPa or more. Incidentally, the tensile strength in the rolling direction is preferably 550 MPa or more, and more preferably 600 MPa or more.

[0029] (Vickers hardness) In the copper alloy plate of this embodiment, when the Vickers hardness becomes sufficiently high, it does not easily deform during use or handling, and it becomes possible to further reduce the weight and thickness of parts for electric and electronic equipment. Therefore, in this embodiment, the Vickers hardness of the copper alloy plate is preferably 180 HV or more. Incidentally, the Vickers hardness of the copper alloy plate of this embodiment is more preferably 190 HV or more, and even more preferably 200 HV or more.

[0030] (Heat resistance temperature) Depending on the intended use of the components for electrical and electronic equipment, heat resistance may be required. Therefore, in the copper alloy sheet of the present embodiment, it is preferable that the heat resistance temperature, which becomes 80% of the initial Vickers hardness when heat-treated at a specific temperature for 1 hour, is 500°C or higher. In addition, the heat resistance temperature of the copper alloy sheet of the present embodiment is more preferably 520°C or higher, and even more preferably 540°C or higher.

[0031] Next, an example of a method for manufacturing the copper alloy sheet of the present embodiment will be described with reference to the flowchart shown in FIG. 1.

[0032] (Melting and casting process S01) First, the above-mentioned elements are added to the copper melt obtained by melting the copper raw material to adjust the composition, and a copper alloy melt is produced. For the addition of various elements, elemental substances, master alloys, etc. can be used. Also, a raw material containing the above-mentioned elements may be melted together with the copper raw material. Further, recycled materials and scrap materials of this alloy may be used. Here, the copper melt is preferably so-called 4N Cu with a purity of 99.99 mass% or more, or so-called 5N Cu with a purity of 99.999 mass% or more. Then, the composition-adjusted copper alloy melt is poured into a mold to produce an ingot. When considering mass production, it is preferable to use the continuous casting method or the semi-continuous casting method.

[0033] (Homogenization process S02) Next, heat treatment is performed to homogenize the obtained ingot. It is preferable to hold the ingot at 850°C or higher and 1050°C or lower for 1 hour or more. Here, there is no limit to the upper limit of the holding time in the homogenization process S02, but considering costs and manufacturing efficiency, it is preferably 24 hours or less. Also, there is no particular limitation on the cooling rate in the homogenization process S02, and air cooling or water cooling may be performed.

[0034] (Hot working process S03) Next, hot working is performed. Also, in this hot working process S03, the homogenization process S02 may be combined. After holding at 850 °C or higher and 1050 °C or lower for 1 hour or longer, hot working is carried out at 600 °C or higher and 1050 °C or lower. When the temperature drops below 600 °C, the temperature is raised again, and when it reaches 800 °C, hot working is carried out again. This is repeated a plurality of times, and after the working rate reaches 90% or higher, the material temperature is rapidly lowered by water cooling.

[0035] (Cold working process S04) Cold working is carried out after the hot working process S03. Although there is no particular limitation on the working rate at this time, the total working rate of the cold working carried out after the hot working is preferably 90% or higher.

[0036] (Heat treatment process S05) After the hot working process S03, a heat treatment of holding at 200 °C or higher and 600 °C or lower for 1 minute or longer is carried out. This heat treatment process S05 serves to relieve strain and cause age precipitation. Heat treatment at a high temperature exceeding 600 °C is not desirable because the target crystal structure is destroyed by recrystallization. In the case of age treatment, it is preferably held at 400 °C or higher and 600 °C or lower for 1 hour or longer. Note that the heat treatment process S05 and the cold working process S04 can be freely combined without problems.

[0037] By the above-described respective processes, the copper alloy sheet according to the present embodiment is manufactured. In the present embodiment, the temperature increase and working are repeated a plurality of times in the hot working process S03, and the working structure is continued to the final process, thereby improving the conductivity in a specific direction and achieving high strength. By repeating the temperature increase and working a plurality of times during hot rolling, crystalline substances and precipitates that could not be dissolved during homogenization are refined by elongation or shearing in the rolling direction, and a metal structure in which the crystalline substances and precipitates are likely to be continuously arranged is formed, so that the conductivity has anisotropy. Furthermore, a part of the crystalline substances and precipitates that could not be dissolved in the homogenization process S02 is re-dissolved, and precipitation is promoted by the subsequent heat treatment process S05, thereby also promoting high strength by fine precipitates.

[0038] According to the copper alloy plate of the present embodiment configured as described above, it contains Cr in the range of 0.05% by mass or more and 1.0% by mass or less, and Zr in the range of 0.01% by mass or more and 0.5% by mass or less, and the conductivity I in the rolling direction GW and the conductivity I in the sheet width direction BW are both 70% IACS or more, and the tensile strength in the rolling direction is 500 MPa or more, so it is excellent in strength and conductivity. Therefore, it is possible to reduce the amount of heat generated during energization, and to make the parts for electric and electronic equipment smaller and thinner.

[0039] And when observing the TD plane, the ratio Gr / Gn of the maximum crystal length Gr in the rolling direction to the maximum crystal length Gn in the sheet thickness direction is 5 or more, and the conductivity I in the rolling direction GW and the conductivity I in the sheet width direction BW The difference I GW -I BW exceeds 0.1% IACS, so it has anisotropy in conductivity, and the conductivity in the rolling direction is particularly high. Therefore, it is particularly suitable as a material for parts for electric and electronic equipment for applications where current flows in a specific direction.

[0040] In the copper alloy plate of the present embodiment, when observing the TD plane, if the maximum crystal length Gr in the rolling direction is 8 μm or more and the maximum crystal length Gn in the sheet thickness direction is 4 μm or less, the crystal structure extends in the rolling direction, and the anisotropy of conductivity can be further improved so that the conductivity in the rolling direction becomes even higher.

[0041] In the copper alloy plate of the present embodiment, when the Vickers hardness is 180 Hv or more, it does not easily deform during use or handling, and it is possible to further reduce the weight and thickness of the parts for electric and electronic equipment. Also, in the copper alloy plate of the present embodiment, when the heat resistance temperature, which becomes 80% of the initial Vickers hardness when heat-treated for 1 hour, is 500 °C or more, it has sufficient heat resistance and can be used as a material for parts for electric and electronic equipment used in a high-temperature environment.

[0042] In the copper alloy sheet of the present embodiment, when it contains one or more additive elements among Ti, Ag, Fe, Co, Ni, Mn, Zn, Mg, Si, P, Sn, and B, and the total content of the additive elements is 0.1% by mass or less, the strength can be further improved while maintaining a high conductivity.

[0043] In the copper alloy sheet of the present embodiment, when precipitates having a circle equivalent diameter of 50 nm or less containing Cr and precipitates having a circle equivalent diameter of 1 μm or less containing Zr mainly exist, the strength can be sufficiently improved by precipitation strengthening, and a high conductivity can be obtained.

[0044] As described above, the copper alloy and the parts for electronic and electrical equipment according to the embodiments of the present invention have been described. However, the present invention is not limited thereto, and can be appropriately changed without departing from the technical idea of the invention. In the above-described embodiments, an example of the manufacturing method of the copper alloy has been described. However, the manufacturing method of the copper alloy is not limited to that described in the embodiments, and an existing manufacturing method may be appropriately selected for manufacturing.

Examples

[0045] The results of the confirmation experiments conducted to confirm the effects of the present invention will be described below.

[0046] A copper raw material made of oxygen-free copper with a purity of 99.99 mass% was prepared, loaded into a high-purity graphite crucible, and melted by high-frequency in an atmosphere furnace with an Ar gas atmosphere. Various additive elements were added to the obtained copper melt to prepare the component compositions shown in Table 1, and the melt was poured into a water-cooled copper mold to produce an ingot. The size of the ingot was about 50 mm in thickness × about 80 mm in width × about 150 mm in length.

[0047] For the obtained ingot, a heat treatment process was carried out in an Ar gas atmosphere at 1000 - 1050 °C for 4 hours for homogenization and solution treatment, and then hot rolling was performed. In hot rolling, in order to perform rolling at 600 °C or higher and 1050 °C or lower, the material temperature was measured each time rolling was performed. When the temperature dropped below 600 °C, the temperature was raised again. After the material temperature reached 800 °C or higher, rolling was performed again. This was repeated multiple times. After the processing rate reached 90% or higher, the material temperature was rapidly decreased by water cooling to complete the hot rolling process, and a plate material with a thickness of 2 - 4 mm was produced. The number of times of repeating the hot working is described in Table 1.

[0048] As an intermediate processing step, after performing cold rolling at 90 - 95%, as an intermediate heat treatment, heat treatment was carried out at 400 - 600 °C for 2 - 8 hours. The heat treatment temperature at that time is described in Table 1. Next, as a finishing processing step, cold rolling was performed to produce a strip material with a thickness of about 0.1 mm. Then, the obtained strip material was heat treated at 200 °C for 1 minute to produce a strip material for property evaluation.

[0049] The copper alloy plates of the present invention examples and comparative examples obtained as described above were evaluated as follows.

[0050] (Alloy composition) Measurement samples were taken from the obtained ingot and component analysis was carried out. Cr and Zr were measured using an inductively coupled plasma atomic emission spectrometer (ICPAES). Other elements were measured using a glow discharge mass spectrometer (GD - MS).

[0051] (The maximum crystal length Gr in the rolling direction and the maximum crystal length Gn in the plate thickness direction) A test piece with a width of 20 mm × a length of 20 mm was cut out from the obtained copper alloy plate, embedded in resin with the surface perpendicular to the width direction of rolling, that is, the TD surface (Transverse Direction) as the observation surface, and used as an observation sample. The crystal grain size was measured as follows by an SEM - EBSD (Electron Backscatter Diffraction Patterns) measuring device. A surface orthogonal to the width direction of rolling, that is, the TD surface (Transverse direction), was used as the observation surface, and mechanical polishing was performed using a water-resistant abrasive paper and diamond abrasive grains. Subsequently, finish polishing was performed using a colloidal silica solution to obtain a measurement sample. Then, using an EBSD measurement device (SU7000 manufactured by Hitachi High-Tech Corporation, APEX manufactured by EDAX / TSL Corporation (currently AMETEK Corporation)) and analysis software (OIM Data Analysis ver. 8.6.109 manufactured by EDAX / TSL Corporation (currently AMETEK Corporation)), the observation surface was measured by the EBSD method in steps with a measurement interval of 0.07 μm over a measurement area of 1000 μm 2 or more. The CI value of each measurement point was obtained by analyzing the measurement results using the data analysis software OIM. Excluding the measurement points where the CI value was 0.1 or less, the analysis of the orientation difference of each crystal grain was performed using the data analysis software OIM. Then, the boundary between the measurement points where the orientation difference between adjacent measurement points was 5° or more was defined as the grain boundary. A grain boundary map was created from the obtained orientation analysis results. In accordance with the cutting method of JIS H 0501, for the grain boundary map, more than 10 line segments of a predetermined length in the vertical and horizontal directions were drawn, and the one with the maximum cutting length of the crystal grains was determined as the maximum crystal length Gr in the rolling direction and the maximum crystal length Gn in the plate thickness direction.

[0052] (Precipitates with a circular equivalent diameter of 50 nm or less containing Cr and precipitates with a circular equivalent diameter of 1 μm or less containing Zr mainly exist) Using the above measurement sample, precipitates were observed as follows. Regarding precipitates less than 100 nm, they were observed using a high-resolution scanning transmission electron microscope (S / TEM), and the precipitate composition was confirmed by an energy dispersive X-ray spectroscope (EDS (EDX: Energy Dispersive X-ray Spectroscope)). Regarding precipitates 100 nm or more, they were observed using a scanning electron microscope (SEM: Scanning Electron Microscope), and the precipitate composition was confirmed by EDS. The S / TEM has a field of view of 10000 nm 2 or more, magnification ×376k, and the SEM has a field of view of 100 μm 2Under the above-mentioned visual field and magnification ×10k conditions, more than 5 visual fields were observed, and the longest shear length of the precipitate was taken as the particle size of the precipitate. In addition, when the number ratio of the precipitates was 60% or more, it was evaluated as "〇", and when it was less than 60%, it was evaluated as "×".

[0053] (Conductivity) A test piece with a width of 10 mm and a length of 100 mm was taken from the obtained copper alloy plate, and the electrical resistance was determined by the four-terminal method. In addition, a test piece with a length of 100 mm in the rolling direction and a test piece with a length of 100 mm in the plate width direction were taken, and the electrical resistance in the rolling direction and the electrical resistance in the plate width direction were measured respectively. In addition, the dimensions of the test piece were measured using a micrometer, and the volume of the test piece was calculated. Then, from the measured electrical resistivity and the calculated volume, the conductivity I in the rolling direction GW and the conductivity I in the plate width direction BW were measured.

[0054] (Tensile strength) In accordance with JIS Z 2241, a No. 13 B test piece was taken from the obtained copper alloy plate, and the tensile strength was measured. The test piece was taken such that the tensile direction was parallel to the rolling direction.

[0055] (Vickers hardness) In accordance with the micro-Vickers hardness test method specified in JIS Z 2244, the Vickers hardness was measured with a test load of 0.98 N.

[0056] (Heat resistance evaluation) In accordance with JCBA T325:2013 of the Japan Copper Development Association, the heat resistance temperature was measured. The Vickers hardness of the sample before the heat resistance test was designated as HvRT. As the heat resistance test, heat treatment was carried out at 10 °C intervals between 450 and 650 °C for 1 hour each and then rapidly cooled, and the temperature at which the measured Vickers hardness became 80% of the Vickers hardness of HvRT was determined as the heat resistance temperature.

[0057]

Table 1

[0058] [Table 2]

[0059] [Table 3]

[0060] In Comparative Example 1, the electrical conductivity I GW and the electrical conductivity I in the plate width direction BW Difference I GW -I BW The electrical conductivity was not sufficiently anisotropic, with a small electrical conductivity of 0.1% IACS. In addition, the strength was low at 492 MPa. In Comparative Example 2, the ratio Gr / Gn of the maximum crystal length Gr in the rolling direction to the maximum crystal length Gn in the sheet thickness direction was small at 2.2, and the electrical conductivity I GW and the electrical conductivity I in the plate width direction BW Difference I GW -I BW No anisotropy was observed in the electrical conductivity.

[0061] In Comparative Example 3, the electrical conductivity I GW and the electrical conductivity I in the plate width direction BW Difference I GW -I BW The anisotropy was small, at 0.1% IACS, and the electrical conductivity was not sufficiently anisotropic. In Comparative Example 4, the electrical conductivity I GW and the electrical conductivity I in the plate width direction BW Difference I GW -I BW The anisotropy was small, at 0.1% IACS, and the electrical conductivity was not sufficiently anisotropic.

[0062] In contrast, in Examples 1 to 11 of the present invention, the electrical conductivity I GW and the electrical conductivity I in the plate width direction BW Difference I GW -I BWexceeds 0.1% IACS, has sufficient anisotropy in conductivity, and has been confirmed to be particularly suitable as a material for parts of electrical and electronic equipment for applications where current flows in a specific direction.

Claims

1. It contains Cr in the range of 0.05% by mass or more and 1.0% by mass or less, and Zr in the range of 0.01% by mass or more and 0.5% by mass or less. When observing the TD plane, the ratio Gr / Gn of the maximum crystal length Gr in the rolling direction to the maximum crystal length Gn in the plate thickness direction is 5 or more. The conductivity I in the rolling direction ＧＷ and the conductivity I in the plate width direction ＢＷ are both 70% IACS or more, and the conductivity I in the rolling direction ＧＷ and the conductivity I in the plate width direction ＢＷ The difference I ＧＷ - I ＢＷ exceeds 0.1% IACS, A copper alloy plate characterized in that the tensile strength in the rolling direction is 500 MPa or more.

2. The copper alloy plate according to claim 1, characterized in that when observing the TD plane, the maximum crystal length Gr in the rolling direction is 8 μm or more and the maximum crystal length Gn in the plate thickness direction is 4 μm or less.

3. The copper alloy plate according to claim 1 or claim 2, characterized in that the Vickers hardness is 180 HV or more and the heat resistance temperature that becomes 80% of the initial Vickers hardness when heat-treated for 1 hour is 500 °C or more.

4. It contains one or more additive elements among Ti, Ag, Fe, Co, Ni, Mn, Zn, Mg, Si, P, Sn and B, and the total content of the additive elements is 0.1% by mass or less. The copper alloy plate according to claim 1 or claim 2.

5. The copper alloy plate according to claim 1 or claim 2, characterized in that precipitates with a circle equivalent diameter of 50 nm or less containing Cr and precipitates with a circle equivalent diameter of 1 μm or less containing Zr mainly exist.

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