JP2019157256A - Copper alloy plate excellent in strength and conductivity, electronic component for electrification, electronic component for heat release - Google Patents

Abstract

To provide a Cu-Cr-Zr-Ti-based alloy plate having high strength, high conductivity, and flexure processability, and of which stress relaxation rate and Young modulus are improved.SOLUTION: There is provided a copper alloy plate containing Cr of 0.1 to 0.6 mass%, one or two kind of Zr and Ti of total 0.01 to 0.30 mass% and the balance copper with inevitable impurities, and having area percentage of Cube orientation {001}<100> of 10% or less, area percentage of Brass orientation {110}<112> of 40% or less, and area percentage of Copper orientation {112}<111> of 20% or more, in which 100000/mmor less of second phase particles with size of 0.1 μm or more exist.SELECTED DRAWING: None

Description

  TECHNICAL FIELD The present invention relates to a copper alloy plate and an electronic component for energization or heat dissipation that can be suitably used for manufacturing electronic components such as electronic materials, and in particular, terminals, connectors, relays, and switches mounted on electric machines / electronic devices, automobiles, and the like. The present invention relates to a copper alloy plate used as a material for electronic components such as sockets, bus bars, lead frames, and heat sinks, and an electronic component using the copper alloy plate. Among them, a copper alloy plate suitable for use in energizing electronic components such as connectors and terminals used in electric vehicles, hybrid vehicles, etc., or in heat dissipating electronic components such as liquid crystal frames used in smartphones and tablet PCs, and the copper The present invention relates to an electronic component using an alloy plate.

  Copper alloy strips having excellent strength and conductivity are widely used as materials for transmitting electricity or heat, such as terminals, connectors, switches, sockets, relays, bus bars, lead frames, and heat sinks of electronic devices. Here, electrical conductivity and thermal conductivity are in a proportional relationship. By the way, in recent years, high currents have been developed in connectors of electronic devices, and it is considered necessary to have good bendability, conductivity of 80% IACS or more, and proof stress of 600 MPa or more.

  On the other hand, for example, a heat radiating component called a liquid crystal frame is used for a liquid crystal of a smartphone or a tablet PC. Even in such a copper alloy plate for heat dissipation, high thermal conductivity is progressing, and it is considered necessary to have good bendability and high strength. For this reason, it is considered that a copper alloy plate for heat dissipation needs to have a conductivity of 80% IACS or more and a proof stress of 600 MPa or more.

  However, since it is difficult to achieve a conductivity of 80% IACS or higher with a Corson alloy-based copper alloy, the development of Cu-Cr-based and Cu-Zr-based copper alloys has been promoted. For example, a copper alloy excellent in bending workability and stress relaxation rate by controlling I (220) is disclosed as a Cu—Cr—Zr copper alloy (Patent Document 1). Moreover, the copper alloy excellent in bending workability is disclosed by making I (200) high as a Cu-Cr-Zr-type copper alloy (patent document 2).

JP 2017-179503 A Japanese Patent No. 5834528

However, although the Cu-Cr-Zr-based copper alloy has relatively good stress relaxation characteristics, the level of the stress relaxation characteristics is not necessarily used as a part that conducts a large current or a part that dissipates a large amount of heat. In some cases, it was not enough. Further, there is a limit to increasing the proof stress while ensuring a high conductivity of 80% IACS or higher and good bending workability, and there are cases where sufficient contact pressure cannot always be secured when used as a connector. Further, even if I (220) / I ₀ (220) is controlled as in Patent Document 1 to improve the bending workability, wrinkles are generated in the bent portion, and it is not possible to cope with a high current. In addition, as in Patent Document 2, in order to improve the bending workability while maintaining the strength, there may be a concern about a decrease in Young's modulus.

  Therefore, the present invention is to provide a Cu—Cr—Zr—Ti alloy plate with improved stress relaxation rate and Young's modulus in a copper alloy plate having high strength, high conductivity, and bending workability. And Furthermore, another object of the present invention is to provide an electronic component suitable for energization or heat dissipation.

In one aspect, the copper alloy plate according to the present invention contains 0.1 to 0.6% by mass of Cr, 0.01 to 0.30% by mass in total of one or two of Zr and Ti, and the balance Is made of copper and inevitable impurities, and in the crystal orientation analysis in the EBSD measurement, the area ratio of the Cube orientation {0 0 1} <1 0 0> is 10% or less, and the Brass orientation {1 1 0} <1 1 2> area ratio of 40% or less, and the copper orientation {1 1 2} <1 1 1> area ratio of 20% or more, copper second phase particles of 0.1μm or more in size exist 100,000 / mm ² or less An alloy plate is provided.

  In another embodiment, the copper alloy sheet according to the present invention has a stress relaxation rate of 10% or less.

  In yet another embodiment of the copper alloy plate according to the present invention, the Young's modulus of the copper alloy plate is 120 GPa or more.

  In yet another embodiment, the copper alloy plate according to the present invention is at least one selected from the group consisting of Ag, B, Co, Fe, Mg, Mn, Ni, P, Si, Sn and Zn. Are contained in a total of 1.0% by mass or less.

  In another aspect, the present invention is an electronic component for energization using the copper alloy plate.

  In another aspect of the present invention, there is provided a heat dissipating electronic component using the copper alloy plate.

  According to the present invention, a Cu-Cr-Zr-Ti alloy plate having excellent bending workability and having improved stress relaxation rate and Young's modulus while maintaining conductivity and strength, as well as energization use or heat dissipation use. It is possible to provide a suitable electronic component. This copper alloy plate can be suitably used as a material for electronic parts such as terminals, connectors, switches, sockets, relays, bus bars, lead frames, etc., and particularly dissipates the material or large amount of heat of electronic parts that carry a large current. It is useful as a material for electronic parts.

It is a figure explaining the measurement principle of a stress relaxation rate. It is a figure explaining the measurement principle of a stress relaxation rate.

  Hereinafter, a copper alloy plate (Cu—Cr—Zr—Ti alloy plate) according to an embodiment of the present invention will be described. In the present invention, “%” means mass% unless otherwise specified.

(Ingredient concentration)
The copper alloy plate according to the embodiment of the present invention includes Cr in an amount of 0.1 to 0.6%, one or two of Zr and Ti in a total of 0.01 to 0.30%, and the balance being copper. And inevitable impurities. In one embodiment, it is preferable to contain 0.15 to 0.3% of Cr and 0.05 to 0.20% in total of one or two of Zr and Ti. If Cr exceeds 0.6%, the bending workability decreases, and if it is less than 0.1%, it becomes difficult to obtain a 0.2% yield strength of 600 MPa or more. If the total of one or two of Zr and Ti exceeds 0.30%, the bending workability decreases, and if it is less than 0.01%, it becomes difficult to obtain a 0.2% proof stress of 600 MPa or more.

  Furthermore, the copper alloy plate according to the embodiment of the present invention includes a total of at least one selected from the group consisting of Ag, B, Co, Fe, Mg, Mn, Ni, P, Si, Sn, and Zn. It is preferable to contain 0% or less. These elements contribute to an increase in strength by solid solution strengthening or precipitation strengthening. If the total amount of these elements exceeds 1.0%, the electrical conductivity may decrease, or may be cracked by hot rolling.

  In addition, it is understandable by those skilled in the art that in a copper alloy plate having high strength and high conductivity, the amount of each additive is changed depending on the combination of additive elements to be added. In one exemplary embodiment, for example, Ag is 1.0% or less, B is 0.05% or less, Co is 0.1% or less, Fe is 0.1% or less, and Mg is 0.1% or less. , Mn is 0.1% or less, Ni is 0.2% or less, P is 0.05% or less, Si is 0.1% or less, Sn is 0.1% or less, and Zn is 0.5% or less. However, the copper alloy sheet of the present invention is not necessarily limited to these upper limit values as long as the combination and addition amount of additive elements whose conductivity does not fall below 80% IACS.

  Although the thickness of the copper alloy plate which concerns on embodiment of this invention is not specifically limited, For example, it can be 0.03-0.6 mm.

(Crystal orientation)
For various Cu-Cr-Zr-Ti alloy plates, the crystal orientation distribution is measured by the EBSD method (Electron Back Scatter Diffraction) and the developed orientation component is obtained using the crystal orientation distribution function. As a result, three orientations were detected: Cube orientation {0 0 1} <1 0 0>, Brass orientation {1 1 0} <1 1 2> and Copper orientation {1 1 2} <1 1 1>. Here, for example, the {0 0 1} <1 0 0> orientation means that the (0 0 1) plane is oriented in the rolling surface normal direction (ND) and the (1 0 0) plane is oriented in the rolling direction (RD). Indicates the state.
As a result of experimentally examining the relationship between the degree of development of each orientation and the bending workability, the Cube orientation {0 0 1} <1 0 0> and the Copper orientation {1 1 2} <1 1 1> are very effective. there were. On the other hand, the Brass orientation {1 1 0} <1 1 2> was a component harmful to bending workability.
Moreover, as a result of experimentally examining the relationship between the degree of development of each orientation and the Young's modulus, the Copper orientation {1 1 2} <1 1 1> was very effective. On the other hand, the Cube orientation {0 0 1} <1 0 0> was a harmful component for Young's modulus.
Therefore, the present inventor has an area ratio of Cube orientation of 10% or less, an area ratio of Copper orientation of 20% or more, and an area ratio of Brass orientation of 40% or less. It has been found that a Cu—Cr—Zr—Ti alloy having a balanced Young's modulus can be obtained.
Measurement conditions by the EBSD method will be described later.

(Density of second phase particles having a size of 0.1 μm or more)
By adjusting the density of the second phase particles having a size of 0.1 μm or more to 100000 particles / mm ² or less, the bending workability of the copper alloy plate is improved. Here, the second phase particles refer to particles different from the Cu matrix such as Cr and Cu—Zr compounds, and when the number density exceeds 100,000 / mm ² , the bending workability decreases.
The measurement conditions of the density of the second phase particles having a size of 0.1 μm or more will be described later.

(Use)
The copper alloy plate according to the embodiment of the present invention can be suitably used for applications of electronic components such as terminals, connectors, relays, switches, sockets, bus bars, lead frames, heat sinks, in particular, electric vehicles, This is useful for energizing applications such as connectors and terminals used in hybrid vehicles and the like, or for heat-dissipating electronic components such as liquid crystal frames used in smartphones and tablet PCs.

(Production method)
The copper alloy plate according to the embodiment of the present invention can be manufactured by the following manufacturing process. First, after dissolving electrolytic copper or the like as a pure copper raw material and reducing the oxygen concentration by carbon deoxidation or the like, Cr, one or two of Zr and Ti, and other alloy elements as necessary are added. And cast into an ingot having a thickness of about 30 to 300 mm. After this ingot is made into a plate having a thickness of about 3 to 30 mm by hot rolling at 800 to 1000 ° C., for example, the first cold rolling, solution treatment, first aging treatment, second cold rolling, second The aging process is performed in this order. If necessary, surface grinding and pickling are performed after hot rolling and after heat treatment such as aging treatment and solution treatment in order to remove the oxide film and the like.

  The first cold rolling is processed to a target plate thickness that is set in consideration of a reduction in plate thickness due to surface grinding or pickling so that the second cold rolling degree is within a predetermined range.

  In the solution treatment, the average temperature rising rate of the material up to 300 ° C. to 600 ° C. is set to 5 to 30 ° C./min, the average temperature rising rate of the material of 600 ° C. or higher is set to 300 ° C./min or higher, and 850 to 900 ° C. After holding for 5 seconds to 2 minutes, it is performed by water cooling.

When the average rate of temperature increase from 300 ° C. to 600 ° C. is less than 5 ° C./min, the number of second phase particles having a size of 0.1 μm or more exceeds 100000 particles / mm ² and the bending workability is lowered.

  When the solution temperature is lower than 850 ° C., the amount of additive element dissolved in copper decreases, and the 0.2% yield strength (YS) of the product may be lowered. If it exceeds 900 ° C., the Cube orientation develops. Therefore, the solution temperature is preferably 850 to 900 ° C.

  The first aging treatment is preferably performed at a low temperature for a long time, and preferably at 300 to 400 ° C. for 15 to 25 hours. In an aging treatment of less than 300 ° C. or less than 15 hours, the conductivity after the first aging treatment is less than 75% IACS, and the Brass orientation develops in the subsequent cold rolling. In addition, in the aging treatment exceeding 400 ° C. or exceeding 25 h, the conductivity after the first aging treatment exceeds 90% IACS, the Cube orientation develops, and the Young's modulus decreases.

  The second cold rolling preferably has a workability of 85% or more. If it is less than 85%, the development of Copper orientation is insufficient.

  The second aging treatment is preferably carried out at a low temperature for a long time, and preferably at 200 to 300 ° C. for 15 to 30 hours. Long-term aging treatment in a low temperature range that does not recrystallize to maintain Copper orientation grains after the second cold rolling, restore the conductivity decreased by the second cold rolling, and improve the stress relaxation rate Can be achieved.

As mentioned above, the manufacturing method of the copper alloy plate which concerns on this invention contains 0.1-0.6 mass% of Cr, 0.01 to 0.30 mass% in total of 1 type or 2 types of Zr and Ti Then, after hot-rolling a copper alloy ingot whose balance is made of copper and inevitable impurities, the first cold rolling process, the solution treatment process, the first aging treatment process, the second cold rolling process, A method for producing a copper alloy plate including an aging treatment step of 2,
In the solution treatment, an average rate of temperature increase from 300 ° C. to 600 ° C. is 5 to 30 ° C./min,
The first aging treatment is performed at 300 to 400 ° C. for 15 to 25 hours,
The second cold rolling has a workability of 85% or more,
The second aging treatment is performed at 200 ° C. to 300 ° C. for 15 to 30 hours, and is a method for producing a copper alloy plate.

  Examples of the present invention will be described below together with comparative examples, but these examples are provided for better understanding of the present invention and its advantages, and are not intended to limit the invention.

  After adding the alloy element to the molten copper, it was cast into an ingot having a thickness of 200 mm. The ingot was heated at 950 ° C. for 3 hours and formed into a plate having a thickness of 15 mm by hot rolling. After grinding and removing the oxide scale on the surface of the hot-rolled sheet with a grinder, the sheet was made into a 1.5 mm thick sheet by cold rolling, and then subjected to a solution treatment with an average heating rate of the material from 300 ° C to 600 ° C. 5 to 30 ° C./min (specific average temperature rising rate is shown in the column of “temperature rising rate” in Table 1), and the average temperature rising rate of materials of 600 ° C. or higher is 300 ° C./min or higher. After holding at 900 ° C. for 5 seconds to 2 minutes, it was performed by cooling with water. Thereafter, the first aging treatment is carried out at 300 ° C. to 400 ° C. for 15 to 25 hours, the second cold rolling is performed to form a 0.1 mm plate, and the second aging treatment is carried out at 200 ° C. to 300 ° C. for 15 to 30 hours. Carried out.

Each sample was evaluated as follows.
<Tensile strength (TS)>
The tensile strength (TS) in a direction parallel to the rolling direction was measured with a tensile tester according to JIS-Z2241.

<0.2% yield strength (YS)>
A 0.2% proof stress (YS) in a direction parallel to the rolling direction was measured with a tensile tester in accordance with JIS-Z2241. 0.2% yield strength (YS) was taken as the yield strength.

<Conductivity (EC, unit:% IACS)>
The test piece was sampled so that the longitudinal direction of the test piece was parallel to the rolling direction, and the conductivity at 20 ° C. was measured by a four-terminal method in accordance with JIS-H0505.

<EBSD>
The area ratio of each direction of {0 0 1} <1 0 0>, {1 1 0} <1 1 2> and {1 1 2} <1 1 1> was measured using EBSD measurement.
As a sample for analyzing the crystal orientation of the surface layer, the sample surface was mechanically polished and then finished to a mirror surface by electrolytic polishing.
In the EBSD measurement, a 500 μm square sample area containing 200 or more crystal grains was scanned in 0.5 μm steps to measure the crystal orientation distribution. Then, a crystal orientation distribution function analysis is performed, and within 10 degrees from each orientation of {0 0 1} <1 0 0>, {1 1 0} <1 1 2>, and {1 1 2} <1 1 1> The area ratio of the region having the difference in orientation was obtained. For the above analysis, OIM Analysis 5.3 manufactured by TSL was used.

<Young's modulus>
A No. 13B test piece defined in JIS-Z2201 was taken so that the tensile direction was parallel to the rolling direction, and a tensile test was performed. From the obtained stress-strain curve, the slope of the straight line portion in the elastic range was obtained, and this value was taken as the Young's modulus.

<Bending workability>
A sample cut into a width of 10 mm and a length of 200 mm was used as a bending test piece. Bending workability was evaluated based on rough skin at the bent part. In accordance with JIS-H3130, a Badway (bending axis is in the same direction as the rolling direction) W-bending test was performed, and it was magnified 50 times with an optical microscope and in accordance with the evaluation criteria of Japan Technical Standard JCBA T307 (2007). There were no wrinkles, B: small wrinkles, C: large wrinkles, D: small cracks, and E: large cracks.

<Density of second phase particles having a size of 0.1 μm or more>
The density of the second phase particles having a size of 0.1 μm or more is 2000 μm ² using a scanning electron microscope after mechanical polishing of the sample surface after final aging to finish it into a mirror surface, and then performing electrolytic polishing and pickling etching. The evaluation area was observed at 1000 to 10000 times, the number of second phase particles having a major axis of 0.1 μm or more was counted, and the numerical value divided by the evaluation area was taken as the density.

<Stress relaxation rate>
A strip-shaped test piece having a width of 10 mm and a length of 100 mm was collected so that the longitudinal direction of the test piece was parallel to the rolling direction. As shown in FIG. 1, with the position of l = 50 mm as the working point, the test piece is given a deflection of y ₀ , which corresponds to 80% of the 0.2% yield strength (measured in accordance with JIS-Z2241) in the rolling direction. Stress (s) was applied. y ₀ was determined by the following equation.
y ₀ = (2/3) · I ² · s / (E · t)
Here, E is the Young's modulus in the rolling direction, and t is the thickness of the sample. Unloading after heating at 150 ° C. for 1000 hours, and measuring the amount of permanent deformation (height) y as shown in FIG. 2, stress relaxation rate {[y (mm) / y ₀ (mm)] × 100 (%) } Was calculated.

  The composition and production conditions of each test piece are shown in Table 1, and the results obtained for each Example and Comparative Example are shown in Table 2. In addition, about the comparative example, it manufactured on the conditions similar to an Example except the manufacturing conditions of Table 1.

  As is clear from Table 1 and Table 2, the first aging treatment is performed at 300 ° C. to 400 ° C. for 15 to 25 hours, the workability of the second cold rolling is set to 85% or more, and the second aging treatment is performed. In each example carried out at 200 ° C. to 300 ° C. for 15 to 30 hours, YS is 600 MPa or more, conductivity is 80% IACS or more, bending workability evaluation is B or more, stress relaxation rate is 10% or less, (partially A good characteristic with a Young's modulus of 120 GPa or more was obtained.

  On the other hand, in the case of Comparative Examples 1 and 2 with high Cr and Zr component concentrations, the bending workability was inferior. In the case of Comparative Examples 3 and 4 where the component concentrations of Cr and Ti were low, the 0.2% yield strength was inferior.

  In Comparative Example 5 where the first aging treatment time is short and Comparative Examples 6, 8, and 9 where the first aging treatment temperature is low, the conductivity after aging treatment is low and the area ratio of the Copper orientation is reduced, and bending workability is reduced. The Young's modulus was inferior.

  In Comparative Example 13 with a long first aging treatment time and Comparative Example 7 with a high first aging treatment temperature, the conductivity after aging treatment is high, the area ratio of the Cube orientation is increased, and the yield strength and Young's modulus are inferior. .

  In Comparative Example 8 in which the second aging treatment temperature was low and in Comparative Example 9 in which the second aging treatment time was short, the area ratio of the Copper orientation was reduced and bending workability, Young's modulus, and stress relaxation rate were inferior.

  In the case of Comparative Example 10 where the second aging treatment temperature is high, the area ratio of the Cube orientation was increased and the yield strength and Young's modulus were inferior.

  In Comparative Examples 11 and 12 having a low second cold rolling work degree, the area ratio of the Copper orientation was reduced, and the bending workability and Young's modulus were inferior.

In Comparative Example 14 in which the heating rate at 300 to 600 ° C. during solution treatment was less than 5 ° C./s, the density of second phase particles of 0.1 μm or more exceeded 100,000 particles / mm ² , and the bending workability was poor. It was.

Claims (6)

0.1 to 0.6% by mass of Cr, one or two of Zr and Ti are contained in a total of 0.01 to 0.30% by mass, and the balance is made of copper and inevitable impurities. In the crystal orientation analysis, the area ratio of the Cube orientation {0 0 1} <1 0 0> is 10% or less, the area ratio of the Brass orientation {1 1 0} <1 1 2> is 40% or less, and the Copper orientation {1 1 2} A copper alloy plate in which the area ratio of <1 1 1> is 20% or more and the number of second phase particles having a size of 0.1 μm or more is 100000 pieces / mm ² or less.   The copper alloy sheet according to claim 1, wherein the stress relaxation rate is 10% or less.   The copper alloy sheet according to claim 1 or 2, wherein Young's modulus is 120 GPa or more.   Any one of Claims 1-3 which contain 1.0 mass% or less in total of at least 1 sort (s) chosen from the group which consists of Ag, B, Co, Fe, Mg, Mn, Ni, P, Si, Sn, and Zn. The copper alloy sheet according to item.   The electronic component for electricity_supply using the copper alloy plate of any one of Claims 1-4.   The electronic component for thermal radiation using the copper alloy plate of any one of Claims 1-4.

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