copper alloy plate

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 with excellent 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 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 with the weight reduction, thinning, and miniaturization of electric and electronic devices, even 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 with 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 applications where current flows in a specific direction, such as busbars, electrical and electronic equipment components require particularly strong conductivity in the longitudinal direction. However, conventional Cu-Cr and Cu-Zr alloys have not been proposed with sufficient consideration given to the anisotropy of electrical conductivity. Furthermore, while Patent Document 1 aims to improve properties such as strength by suppressing the expansion of anisotropy in mechanical properties, it does not focus on the anisotropy of electrical conductivity.

[0006] The present invention has been made in view of the circumstances described above, and aims 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 equipment components used in applications where current flows in a specific direction. [Means for solving the problem]

[0007] To solve the above problems, the copper alloy plate of embodiment 1 of the present invention contains Cr in a range of 0.05% by mass or more and 1.0% by mass or less, and Zr in a range of 0.01% by mass or more and 0.5% by mass or less. The composition consists of the remainder being Cu and unavoidable impurities. When the TD surface was observed, the ratio Gr / Gn, which is the maximum crystal length Gr in the rolling direction to the maximum crystal length Gn in the thickness direction, was 5 or greater, and the conductivity I in the rolling direction was GW and the conductivity I in the width direction of the plate BW Both have an IACS of 70% or more, and the electrical conductivity in the rolling direction is I GW and the conductivity I in the width direction of the plate BW Difference I GW -I BW It is characterized by having a strength exceeding 0.1% IACS and a tensile strength of 500 MPa or more in the rolling direction.

[0008] According to the copper alloy sheet of embodiment 1 of the present invention, it contains Cr in the range of 0.05 mass% to 1.0 mass%, and Zr in the range of 0.01 mass% to 0.5 mass%, and has an electrical conductivity I in the rolling direction. GW and the conductivity I in the width direction of the plate BWSince both are 70% IACS or higher and the tensile strength in the rolling direction is 500 MPa or higher, they are excellent in strength and conductivity. Therefore, it is possible to reduce the amount of heat generated during energization, and to reduce the size and thickness of parts. 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 of electric and electronic devices for applications where current flows in a specific direction.

[0009] The copper alloy sheet of Embodiment 2 of the present invention is characterized in that, in the copper alloy sheet of Embodiment 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 sheet thickness direction is 4 μm or less. According to the copper alloy sheet of Embodiment 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 sheet 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 sheet of Embodiment 3 of the present invention is characterized in that, in the copper alloy sheet of Embodiment 1 or Embodiment 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 sheet of Embodiment 3 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, so it is particularly excellent in strength and heat resistance.

[0011] [[ID=The copper alloy sheet of embodiment 4 of the present invention is characterized in that, in any one of embodiments 1 to 3 of the present invention, it contains one or more additive elements 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 from Ti, Ag, Fe, Co, Ni, Mn, Zn, Mg, Si, P, Sn, and B, its strength can be further improved. Furthermore, since the total content of the additive elements is 0.1% by mass or less, a decrease in electrical conductivity can be suppressed.

[0012] The copper alloy plate of embodiment 5 of the present invention is a copper alloy plate in any one of embodiments 1 to 4 of the present invention, Of the total number of precipitates less than 100 nm, the proportion of precipitates containing Cr with an equivalent circle diameter of 50 nm or less is 60% or more, and of the total number of precipitates 100 nm or more, the proportion of precipitates containing Zr with an equivalent circle diameter of 1 μm or less is 60% or more. It is characterized by the following: According to the copper alloy plate of embodiment 5 of the present invention, since precipitates containing Cr with an equivalent circular diameter of 50 nm or less and precipitates containing Zr with an equivalent circular diameter of 1 μm or less are mainly present, the strength can be sufficiently improved by precipitation strengthening, and high conductivity can be obtained. [Effects of the Invention]

[0013] This makes it possible to provide copper alloy sheets that are excellent in strength and conductivity, and also possess anisotropic conductivity, making them particularly suitable as materials for electrical and electronic equipment components used in applications where current flows in a specific direction. [Brief explanation of the drawing]

[0014] [Figure 1] This is a flowchart of the manufacturing method for the copper alloy plate according to this embodiment. [Modes for carrying out the invention]

[0015] The following describes a copper alloy plate, which is one embodiment of the present invention. The copper alloy plate of this embodiment has a composition in which Cr is contained in a range of 0.05% to 1.0% by mass, Zr in a range of 0.01% to 0.5% by mass, and the remainder is Cu and unavoidable impurities. Furthermore, in the copper alloy sheet of this embodiment, when the TD surface is observed, the ratio Gr / Gn, which is the maximum crystal length Gr in the rolling direction to the maximum crystal length Gn in the thickness direction, is set to 5 or more. Here, the TD surface refers to the surface perpendicular to the rolling direction (RD surface) and the surface perpendicular to the rolling surface (ND surface).

[0016] Furthermore, in the copper alloy sheet of this embodiment, the conductivity I in the rolling direction GW and the conductivity I in the width direction of the plate BW Both have an IACS of 70% or more, and the electrical conductivity in the rolling direction is I GW and the conductivity I in the width direction of the plate BW Difference I GW -I BW It exceeds 0.1% IACS. That is, the conductivity in the rolling direction I GW The conductivity I in the width direction of the plate BW It is higher than that and exhibits anisotropy in conductivity. Furthermore, in this embodiment of the copper alloy sheet, the tensile strength in the rolling direction is set to 500 MPa or more.

[0017] In this embodiment, the copper alloy plate contains one or more additive elements from 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] Furthermore, in the copper alloy sheet of this embodiment, when the TD surface is observed, 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 thickness direction is 4 μm or less. Furthermore, in the copper alloy plate of this embodiment, it is preferable that precipitates containing Cr with an equivalent circular diameter of 50 nm or less, and precipitates containing Zr with an equivalent circular diameter of 1 μm or less are mainly present. Furthermore, in the copper alloy plate of this embodiment, it is preferable that the Vickers hardness is 180 Hv or higher. In addition, it is preferable that the temperature at which the initial Vickers hardness becomes 80% after heat treatment held for 1 hour (heat resistance temperature) is 500°C or higher.

[0019] The reasons for specifying the component composition, crystal structure, precipitates, electrical conductivity, tensile strength, Vickers hardness, and heat resistance temperature in the copper alloy plate of this embodiment, as described above, are explained below.

[0020] (Cr) Cr is an element that improves strength without reducing conductivity by causing fine Cr-based precipitates (e.g., Cu-Cr) to precipitate within the crystal grains of the matrix phase through aging treatment. If the Cr content is less than 0.05 mass%, the improvement in strength and Vickers hardness may not be fully achieved. On the other hand, if the Cr content exceeds 1.0 mass%, relatively coarse Cr precipitates may form, which may cause defects. Therefore, in this embodiment, the Cr content is set to be within the range of 0.05% by mass or more and 1.0% by mass or less. Furthermore, the Cr content 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. In addition, the Cr content 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 improves strength without reducing conductivity by causing fine Zr-based precipitates (e.g., Cu5Zr) to precipitate within the crystal grains of the matrix phase through aging treatment. If the Zr content is less than 0.01% by mass, the improvement in strength and Vickers hardness may not be fully achieved. On the other hand, if the Zr content exceeds 0.5% by mass, relatively coarse Zr precipitates may form, which may cause defects. Therefore, in this embodiment, the Zr content is set to be within the range of 0.01% by mass or more and 0.5% by mass or less. Furthermore, the Zr content is preferably 0.03% by mass or more, and more preferably 0.06% by mass or more. In addition, the Zr content is preferably 0.4% by mass or less, and more preferably 0.2% by mass or less.

[0022] (Additional element) One or more additive elements from Ti, Ag, Fe, Co, Ni, Mn, Zn, Mg, Si, P, Sn, and B have the effect of improving the strength of copper alloy plates. For this reason, these additive elements may be included to further improve strength. However, since these additive elements reduce electrical conductivity, it is preferable to limit the total content of these additive elements to 0.1% by mass or less. Furthermore, the total content of one or more additive elements from 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 of maximum crystal length Gr in the rolling direction to maximum crystal length Gn in the thickness direction Gr / Gn) When observing the TD surface of the copper alloy plate in this embodiment, if the ratio Gr / Gn (the ratio of the maximum crystal length Gr in the rolling direction to the maximum crystal length Gn in the thickness direction) is large, the crystals will have a shape that extends in the rolling direction, and the precipitates will also be distributed along the rolling direction. This results in anisotropy in conductivity. Therefore, in this embodiment, the ratio Gr / Gn, which is the maximum crystal length Gr in the rolling direction to the maximum crystal length Gn in the thickness direction, is set to 5 or more. Furthermore, the ratio Gr / Gn, which is the ratio of the maximum crystal length Gr in the rolling direction to the maximum crystal length Gn in the thickness direction, is preferably 6 or greater, and more preferably 7 or greater.

[0024] (Maximum crystal length Gr in the rolling direction, maximum crystal length Gn in the thickness direction) When observing the TD surface of the copper alloy plate of this embodiment, if 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, the crystal structure becomes relatively fine with the crystals extending in the rolling direction. This allows for improved anisotropy of conductivity and further improvement of strength. Furthermore, the maximum crystal length Gr in the rolling direction is more preferably 9 μm or more, and even more preferably 10 μm or more. Also, the maximum crystal length Gn in the 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 plate of this embodiment, if precipitates containing Cr with an equivalent circular diameter of 50 nm or less and precipitates containing Zr with an equivalent circular diameter of 1 μm or less are mainly present, the strength will be further improved by precipitation strengthening due to these precipitates. Specifically, "mainly present" means that, in the observation field, the proportion of precipitates containing Cr with an equivalent circular diameter of 50 nm or less and precipitates containing Zr with an equivalent circular diameter of 1 μm or less among the total number of precipitates observed is 60% or more.

[0026] (Electrical conductivity in the rolling direction I GW , conductivity I in the plate width direction BW ) In electrical and electronic equipment components, excellent conductivity is required to suppress heat generation during current flow. Therefore, in the copper alloy sheet of this embodiment, the conductivity in the rolling direction is I GW and the conductivity I in the width direction of the plate BW Both stipulate that IACS should be 70% or higher. Note that the conductivity I in the rolling direction GW , conductivity I in the plate width direction BW It is preferable that the IACS ratio be 73% or higher, and more preferably 76% or higher.

[0027] (Electrical conductivity in the rolling direction I GW and the conductivity I in the width direction of the plate BW Difference I GW -IBW ) In the copper alloy sheet of this embodiment, the conductivity I in the rolling direction GW and the conductivity I in the width direction of the plate BW Difference I GW -I BW The material is designed to have anisotropic conductivity such that the IACS ratio exceeds 0.1%. This makes it possible to suppress heat generation during current flow in electrical and electronic equipment components that conduct electricity in a specific direction. Note that the conductivity I in the rolling direction GW and the conductivity I in the width direction of the plate BW Difference I GW -I BW It is preferable that the concentration is 0.2% or higher, and more preferably 0.4% or higher.

[0028] (Tensile strength) In this embodiment, by increasing the strength of the copper alloy sheet, it becomes possible to reduce the weight and thickness of electrical and electronic equipment components. For this reason, in this embodiment, the tensile strength of the copper alloy sheet in the rolling direction is specified to be 500 MPa or higher. Furthermore, the tensile strength in the rolling direction is preferably 550 MPa or higher, and more preferably 600 MPa or higher.

[0029] (Vickers hardness) In this embodiment, when the Vickers hardness of the copper alloy sheet is sufficiently high, it does not easily deform during use or handling, making it possible to further reduce the weight and thickness of electrical and electronic equipment components. For this reason, in this embodiment, the Vickers hardness of the copper alloy sheet is preferably 180 HV or higher. Furthermore, the Vickers hardness of the copper alloy plate in this embodiment is more preferably 190 HV or higher, and even more preferably 200 HV or higher.

[0030] (Heat-resistant temperature) Depending on the intended use of electrical and electronic equipment components, heat resistance may be required. Therefore, in the copper alloy plate of this embodiment, it is preferable that the heat resistance temperature at which the initial Vickers hardness is reduced to 80% after heat treatment held at a specific temperature for one hour is 500°C or higher. Furthermore, the heat resistance temperature of the copper alloy plate in this 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 plate according to this embodiment will be described with reference to the flowchart shown in Figure 1.

[0032] (Melting and casting process S01) First, the molten copper obtained by dissolving copper raw materials is modified by adding the aforementioned elements to adjust its composition and produce a molten copper alloy. Individual elements or the master alloy can be used for adding the various elements. Alternatively, raw materials containing the aforementioned elements may be dissolved together with the copper raw materials. Furthermore, recycled and scrap materials of this alloy may be used. Here, the molten copper is preferably so-called 4NCu with a purity of 99.99% by mass or higher, or so-called 5NCu with a purity of 99.999% by mass or higher. Then, the molten copper alloy with adjusted composition is poured into a mold to produce an ingot. When considering mass production, it is preferable to use a continuous casting method or a semi-continuous casting method.

[0033] (Homogenization step S02) Next, the resulting ingot is subjected to heat treatment to homogenize it. It is preferable to hold the ingot at 850°C to 1050°C for at least one hour. Here, there is no upper limit on the holding time in the homogenization process S02, but considering cost and manufacturing efficiency, it is preferable to keep it to 24 hours or less. Also, there is no particular limit on the cooling rate in the homogenization process S02, and air cooling or water cooling may be used.

[0034] (Hot working process S03) Next, hot working is performed. Alternatively, this hot working process S03 may also serve as the homogenization process S02. After maintaining a temperature between 850°C and 1050°C for at least one hour, hot working is performed at a temperature between 600°C and 1050°C. When the temperature drops below 600°C, it is heated again, and when it reaches 800°C, hot working is performed again. This process is repeated multiple times until a processing rate of 90% or more is achieved, at which point the material temperature is rapidly reduced by water cooling.

[0035] (Cold working process S04) Cold working is performed after the hot working process S03. There are no particular limitations on the processing rate at this stage, but it is preferable that the total processing rate of cold working performed after hot working be 90% or more.

[0036] (Heat treatment process S05) After the hot working process S03, a heat treatment is performed in which the material is held at a temperature of 200°C to 600°C for at least one minute. This heat treatment process S05 serves to relieve strain and induce age precipitation. Heat treatment at temperatures exceeding 600°C is undesirable because it destroys the desired crystalline structure through recrystallization. In the case of aging treatment, it is preferable to hold the material at 400°C to 600°C for at least one hour. Note that the heat treatment step S05 and the cold working step S04 can be freely combined without any problems.

[0037] The copper alloy plate of this embodiment is manufactured through the processes described above. In this embodiment, the heating and processing steps S03 are repeated multiple times, and the resulting structure is maintained until the final step, thereby improving conductivity in a specific direction and achieving high strength. By repeatedly increasing the temperature and processing during hot rolling, crystalline materials and precipitates that could not be dissolved during homogenization are refined by elongation or shearing in the rolling direction, forming a metal structure in which crystalline materials and precipitates are easily arranged continuously, resulting in anisotropic conductivity. Furthermore, some of the crystalline substances and precipitates that could not be dissolved in the homogenization process S02 were redissolved, and the subsequent heat treatment process S05 promoted precipitation, thereby also promoting increased strength due to the fine precipitates.

[0038] According to the copper alloy sheet of this embodiment, which has the above configuration, it contains Cr in the range of 0.05 mass% to 1.0 mass%, and Zr in the range of 0.01 mass% to 0.5 mass%, and the electrical conductivity in the rolling direction is I GW and the conductivity I in the width direction of the plate BW Both materials have an IACS of 70% or higher, and their tensile strength in the rolling direction is 500 MPa or higher, indicating excellent strength and conductivity. Therefore, it is possible to reduce the amount of heat generated when energized, and to miniaturize and thin components for electrical and electronic equipment.

[0039] Furthermore, when the TD surface was observed, the ratio Gr / Gn, which is the maximum crystal length Gr in the rolling direction to the maximum crystal length Gn in the thickness direction, was 5 or more, and the conductivity I in the rolling direction was GW and the conductivity I in the width direction of the plate BW Difference I GW -I BW Since it exceeds 0.1% IACS, it exhibits anisotropy in conductivity, and its conductivity is particularly high in the rolling direction, making it especially suitable as a material for electrical and electronic equipment components used in applications where current flows in a specific direction.

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

[0041] In this embodiment, when the copper alloy plate has a Vickers hardness of 180 Hv or higher, it does not easily deform during use or handling, making it possible to further reduce the weight and thickness of electrical and electronic equipment components. Furthermore, in the copper alloy plate of this embodiment, if the heat resistance temperature at which the initial Vickers hardness is reduced to 80% after a heat treatment held for one hour is 500°C or higher, then it has sufficient heat resistance and can be used as a material for electrical and electronic equipment components used in high-temperature environments.

[0042] In the copper alloy plate of this embodiment, if it contains one or more additive elements 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, the strength can be further improved while maintaining high conductivity.

[0043] In the copper alloy plate of this embodiment, when precipitates containing Cr with an equivalent circular diameter of 50 nm or less and precipitates containing Zr with an equivalent circular diameter of 1 μm or less are mainly present, the strength can be sufficiently improved by precipitation strengthening, and high conductivity can be obtained.

[0044] Although embodiments of the present invention, namely copper alloys and components for electronic and electrical equipment, have been described above, the present invention is not limited thereto and can be modified as appropriate without departing from the technical spirit of the invention. In the embodiments described above, an example of a method for manufacturing copper alloys was described, but the method for manufacturing copper alloys is not limited to that described in the embodiments, and existing manufacturing methods may be appropriately selected and used. [Examples]

[0045] The results of the verification experiments conducted to confirm the effects of the present invention are described below.

[0046] A copper raw material consisting of oxygen-free copper with a purity of 99.99 mass% was prepared and charged into a high-purity graphite crucible, where it was high-frequency melted in an atmospheric furnace under an Ar gas atmosphere. Various additive elements were added to the resulting molten copper to adjust the composition shown in Table 1, and the molten copper was poured into a water-cooled copper mold to produce an ingot. The size of the ingot was approximately 50 mm thick x 80 mm wide x 150 mm long.

[0047] The obtained ingots underwent a heat treatment process in which they were heated at 1000-1050°C for 4 hours in an Ar gas atmosphere for homogenization and solution treatment, followed by hot rolling. During hot rolling, the material temperature was measured after each roll to ensure that the rolling was performed at a temperature between 600°C and 1050°C. When the temperature fell below 600°C, it was raised again, and rolling was repeated once the material temperature reached 800°C or higher. This process was repeated multiple times until a processing rate of 90% or more was achieved. After that, the material temperature was rapidly reduced by water cooling to complete the hot rolling process and produce plates with a thickness of 2-4 mm. Table 1 shows the number of times the hot working process was repeated.

[0048] As an intermediate processing step, 90-95% cold rolling was performed, followed by an intermediate heat treatment at 400-600°C for 2-8 hours. Table 1 shows the heat treatment temperatures at that time. Next, cold rolling was performed as a finishing process to produce strips with a thickness of approximately 0.1 mm. Then, the obtained strips were heat-treated at 200°C for 1 minute to produce strips for characterization.

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

[0050] (Alloy composition) A sample was taken from the obtained ingot and its components were analyzed. Cr and Zr were measured using inductively coupled plasma atomic emission spectrometry (ICPAES). Other elements were measured using glow discharge mass spectrometry (GD-MS).

[0051] (Maximum crystal length Gr in the rolling direction and maximum crystal length Gn in the thickness direction) A 20mm wide x 20mm long test piece was cut from the obtained copper alloy plate, and the plane perpendicular to the width direction of rolling, i.e., the TD plane (Tranverse Direction), was embedded in resin as the observation surface to create an observation sample. The grain size was measured using a SEM-EBSD (Electron Backscatter Diffraction Patterns) measuring device as described below. Mechanical polishing was performed using waterproof abrasive paper and diamond abrasive grains on the surface perpendicular to the width direction of the rolled material, i.e., the TD surface (Transverse direction), which was used as the observation surface. Next, finish polishing was performed using a colloidal silica solution to obtain a sample for measurement. Subsequently, an EBSD measuring device (Hitachi High-Tech Corporation SU7000, EDAX / TSL Corporation (now AMETEK Corporation) APEX) and analysis software (EDAX / TSL Corporation (now AMETEK Corporation) OIM Data Analysis ver.8.6.109) were used to measure 1000 μm. 2 The observation surface was measured using the EBSD method at a measurement interval of 0.07 μm over the above measurement area. The measurement results were analyzed using the data analysis software OIM to obtain the CI value for each measurement point. Excluding measurement points with a CI value of 0.1 or less, the orientation difference of each crystal grain was analyzed using the data analysis software OIM. The boundary between measurement points where the orientation difference between adjacent measurement points was 5° or more was defined as the grain boundary. A crystal grain boundary map was created from the obtained orientation analysis results. In accordance with the sectioning method of JIS H 0501, at least 10 line segments of predetermined length were drawn vertically and horizontally on the crystal grain boundary map, and the section length of the crystal grain with the maximum length was determined and defined as the maximum crystal length Gr in the rolling direction and the maximum crystal length Gn in the plate thickness direction.

[0052] (Precipitates containing Cr with an equivalent circle diameter of 50 nm or less, and precipitates containing Zr with an equivalent circle diameter of 1 μm or less are mainly present.) Using the aforementioned measurement samples, precipitates were observed as follows. For precipitates smaller than 100 nm, observation was performed using a high-resolution scanning transmission electron microscope (S / TEM), and the precipitate composition was confirmed using an energy-dispersive X-ray spectrometer (EDS (EDX)). For precipitates larger than 100 nm, observation was performed using a scanning electron microscope (SEM), and the precipitate composition was confirmed by EDS. S / TEM is 10000nm 2 The above field of view, magnification of ×376k, and SEM with a 100μm field of view. 2Under the above field of view and magnification ×10k conditions, observations were made for at least 5 fields of view, and the longest shear length of the precipitate was defined as the particle size of the precipitate. Furthermore, samples with a precipitate count of 60% or more were rated "○", and those with a count of less than 60% were rated "×".

[0053] (conductivity) A 10 mm wide x 100 mm long test specimen was taken from the obtained copper alloy sheet, and its electrical resistance was determined using the four-terminal method. Additionally, a 100 mm long specimen in the rolling direction and a 100 mm long specimen in the sheet width direction were taken, and the electrical resistance in the rolling direction and the sheet width direction were measured, respectively. Furthermore, the dimensions of the test specimen were measured using a micrometer, and the volume of the test specimen was calculated. Then, from the measured electrical resistivity and the calculated volume, the conductivity in the rolling direction I was determined. GW and the conductivity I in the width direction of the plate BW We measured it.

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

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

[0056] (Heat resistance evaluation) The heat resistance temperature was measured in accordance with the Japan Copper Association's JCBA T325:2013 standard. The Vickers hardness of the sample before the heat resistance test was defined as HvRT. For the heat resistance test, heat treatment was performed for 1 hour at 10°C increments between 450°C and 650°C, followed by rapid cooling. 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 in the rolling direction is I GW and the conductivity I in the width direction of the plate BW Difference I GW -I BW The IACS was low at 0.1%, and it did not have sufficient anisotropy for conductivity. Furthermore, the strength was low at 492 MPa. In Comparative Example 2, the ratio Gr / Gn, which is the ratio of the maximum crystal length Gr in the rolling direction to the maximum crystal length Gn in the thickness direction, is small at 2.2, and the conductivity I in the rolling direction is small. GW and the conductivity I in the width direction of the plate BW Difference I GW -I BW No anisotropy was observed in the conductivity, and it did not exhibit anisotropy.

[0061] In Comparative Example 3, the conductivity I in the rolling direction GW and the conductivity I in the width direction of the plate BW Difference I GW -I BW The IACS was small at 0.1%, and did not have sufficient anisotropy for conductivity. In Comparative Example 4, the conductivity I in the rolling direction GW and the conductivity I in the width direction of the plate BW Difference I GW -I BW The IACS was small at 0.1%, and did not have sufficient anisotropy for conductivity.

[0062] In contrast, in Examples 1 to 11 of the present invention, the conductivity I in the rolling direction GW and the conductivity I in the width direction of the plate BW Difference I GW -I BWThe material exhibits an anisotropy exceeding 0.1% IACS, indicating sufficient conductivity and confirming its particular suitability as a material for electrical and electronic equipment components used in applications where current flows in a specific direction.

Claims

1. The composition contains Cr in an amount of 0.05% to 1.0% by mass, Zr in an amount of 0.01% to 0.5% by mass, with the remainder being Cu and unavoidable impurities. When the TD surface was observed, the ratio of the maximum crystal length Gr in the rolling direction to the maximum crystal length Gn in the thickness direction, Gr / Gn, was 5 or greater. Electrical conductivity I in the rolling direction ＧＷ and the conductivity I in the width direction of the plate ＢＷ Both have an IACS of 70% or higher, and the electrical conductivity in the rolling direction is I ＧＷ and the conductivity I in the width direction of the plate ＢＷ Difference I ＧＷ -I ＢＷ This is 0.1% above IACS, A copper alloy sheet characterized by having a tensile strength of 500 MPa or more in the rolling direction.

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

3. A copper alloy sheet according to claim 1 or 2, characterized in that it has a Vickers hardness of 180 HV or higher, and a heat resistance temperature of 500°C or higher at which the Vickers hardness becomes 80% of the initial Vickers hardness after heat treatment held for 1 hour.

4. A copper alloy plate according to claim 1 or 2, characterized in that it contains one or more additive elements 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.

5. The copper alloy plate according to Claim 1 or Claim 2, characterized in that of the total number of precipitates less than 100 nm in size, the proportion of precipitates containing Cr with an equivalent circle diameter of 50 nm or less is 60% or more, and of the total number of precipitates 100 nm or larger in size, the proportion of precipitates containing Zr with an equivalent circle diameter of 1 μm or less is 60% or more.

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