TWI432587B - Cu-Co-Si-Zr alloy and its manufacturing method - Google Patents

Description

Cu-Co-Si-Zr alloy material and manufacturing method thereof

The present invention relates to a material for electrical and electronic equipment which is excellent in bending workability and highly conductive, and particularly relates to a Cu-Co-Si-Zr copper alloy material which is suitable as a material for electrical and electronic equipment such as a movable connector.

The materials for electrical and electronic equipment are required to have characteristics of electrical conductivity, strength, and bending workability. In recent years, the demand for high current of electrical and electronic parts, especially movable connectors, has been increasing. In order to increase the size of the movable connector, it is necessary to have a good bendability even at a thickness of 0.2 mm or more, and at the same time, a material having high conductivity and strength can be secured.

In the case of a precipitation-strengthened copper alloy which can achieve high strength without deteriorating the conductivity, a Cu-Ni-Si-based copper alloy, a Cu-Co-Si system, and a Cu-Co-Si- are known. Zr-based or Cu-Ni-Co-Si-based copper alloy. In order to produce these copper alloys, the additive elements are solid-solved by solution treatment, and then Ni ₂ Si, Co ₂ Si, or the like as the second phase particles are precipitated or crystallized in the matrix by cold rolling and aging heat treatment. However, since the amount of solid solution of Ni ₂ Si is relatively large, it is difficult to achieve a conductivity of 60% IACS or more in a Cu-Ni-Si-based copper alloy. Therefore, a Cu-Co-Si system, a Cu-Co-Si-Zr system or a Cu-Ni-Co-Si alloy having a low solid solution amount of Co ₂ Si as a main precipitate and exhibiting high conductivity is used. research. When the copper alloy is sufficiently solid-solved and the fine precipitates are not precipitated, the target strength cannot be achieved. However, if it is solid-solved at a high temperature, problems such as coarsening of crystals and deterioration of bending workability occur, and various countermeasures have been examined.

In order to manufacture a precipitation-strengthened copper alloy for use in an electrical and electronic component material such as a lead frame, the use of the first aspect is disclosed in Japanese Laid-Open Patent Publication No. 2009-242814 (Patent Document 1). The two-phase particle suppresses the effect of grain growth, controls the crystal grain size, and improves the bending workability. In the above-mentioned literature, the second phase particles are precipitated during the cooling process of the hot working or the heating process of the solution heat treatment, and are also precipitated by the aging precipitation heat treatment after the surface grinding ("0025" of Patent Document 1). In addition, in the Cu-Co-Si (-Zr) alloy having a specific composition, it is described in the above-mentioned Japanese Patent Publication No. 2010/016429 (Patent Document 3) that precipitates having different compositions of two sizes can be suppressed. Grain growth and strength.

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2009-242814

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2008-266787

[Patent Document 3] International Publication No. 2010/016429

In general, a specific target value for not increasing the size of the movable connector is a conductivity of 60% IACS or more, a 0.2% of 600 MPa or more, a tensile stress YS of YS or 630 MPa or more, and no bending workability index. The ratio of the ultimate bending radius R to the plate thickness t (MBR/t) of the crack is 0.5 or less (0.3 mm thick plate, Bad Way). This bending workability changes depending on the crystal grain size and the size and number of the second phase particles, and is considered to be 0.3 mm thick in the Cu-Co-Si-based or Cu-Ni-Co-Si-based alloy. The crystal grain size of the MBR/t at which the plate is 0.5 or less is usually 10 μm or less. The crystal grains are grown in the solution treatment, and the size of the crystal grain size is determined by the temperature and time of the solution treatment, the size of the additive element, and the size or number of the second phase particles.

However, in the methods of controlling the crystal grain size by the second phase particle precipitate described in Patent Document 1, the patent documents 1 and 2 are based on a wide range of second phase particles, and are not necessarily Co. The crystal grain size can be controlled, but the conductivity is deteriorated, and high current cannot be achieved. In Patent Document 2, the second phase particles having a diameter of 50 to 1000 nm which have an effect of suppressing the growth of recrystallized grains during the solution treatment are focused on. However, the Co-based second phase particles of this size may disappear due to solid solution. . Therefore, it is necessary to adjust the solid solution temperature or time so that the precipitate does not solidify, and only a Cu-Co-Si-Zr alloy which is inferior in either conductivity or bendability can be obtained. Further, the second phase particle precipitates of this range may precipitate after solid solution, and do not directly exhibit the effect of controlling the crystal grain size. Further, in the same literature, the density of the second phase particles on the grain boundary and the diameter or bulk density of the second phase particles are evaluated by observation through a transmission electron microscope (TEM), but the second phase is precipitated until the second phase is precipitated. When the crystal grain size is controlled to 10 μm or less, accurate numerical values may not be grasped due to overlapping of particles or the like.

Further, Patent Document 3 also focuses on Co-based second phase particles having an effect of controlling the growth of crystal grain size, but the particle size is 0.005 to 0.05 μm and 0.05 to 0.5 μm in diameter, and the Cu-Co-Si- The bendability of the Zr alloy deteriorates.

As described above, the precipitation-strengthened copper alloy has been mainly used for a thin plate of an electronic component such as a lead frame. Therefore, the excellent bending workability of a thick plate of about 0.3 mm has not been studied.

The inventors of the present invention have completed the following inventions in order to solve the above problems.

(1) A copper alloy material which has good bending workability and contains 1.0 to 2.5% by weight of Co, 0.2 to 0.7% by weight of Si, 0.001 to 0.5% by weight of Zr and an element ratio of Co/Si of 3.5. The Cu-Co-Si-Zr alloy material of ～5.0 contains 2-3 to 500,000 pieces/mm ² of the second phase particles having a diameter of 0.20 μm or more and less than 1.00 μm, and the conductivity EC is 60% IACS or more, and the crystal grain size is 10 μm or less.

(2) The copper alloy material according to (1), which contains 10 to 2,000 pieces/mm ² of the second phase particles having a diameter of 1.00 μm or more and 10.00 μm or less.

(3) The copper alloy material of (1) or (2) has a 0.2% proof stress YS of 600 MPa or more.

(4) A method for producing a copper alloy material according to (1) or (2), wherein the temperature at which the high temperature is heated after the casting and before the solution treatment is higher than the solution treatment temperature selected below by 45 ° C or higher. Temperature, and the cooling rate from the start of hot rolling to 600 ° C is 100 ° C / min or less; the solution treatment temperature is above (50 × Cowt% + 775) ° C, (50 × Cowt% + 825) ° C below Choose within the range.

(5) The method for producing a copper alloy material according to (4), wherein the aging treatment after the solution treatment is carried out at 450 to 650 ° C for 1 to 20 hours.

In the production of a Cu-Co-Si-Zr alloy material having a specific composition, the solution treatment temperature is adjusted to avoid coarsening of the crystal, and the high-temperature heating temperature before the solution treatment is also adjusted to be suitable for solid solution. The treatment temperature is also adjusted, and the cooling rate after high-temperature heating is also adjusted to precipitate a specific amount of the second phase particles having a specific particle diameter. By adjusting the second phase particles, a crystal grain size of 10 μm or less can be obtained, and the bending workability suitable for the movable connector and the conductivity which can be increased in current can be obtained, and the practical strength can be achieved.

(Cu-Co-Si-Zr alloy material)

The alloy material of the present invention contains 1.0 to 2.5% by weight (hereinafter, unless otherwise specified, in %), preferably 1.5 to 2.2% of Co, and contains 0.2 to 0.7%, preferably 0.3 to 0.55% of Si. . It is preferable that the remainder other than the following Zr is composed of Cu and unavoidable impurities, but it may also be included in the range of effects constituting the invention of the invention, and further contains a component which is generally used as a component added to the copper alloy by those skilled in the art. Various elements such as Cr, Mg, Mn, Ni, Sn, Zn, P, Ag, and the like.

The stoichiometric ratio of Co/Si in the case where the second phase particles are Co ₂ Si is theoretically 4.2, but in the present invention, it is 3.5 to 5.0, preferably 3.8 to 4.6, and if it is within this range, it is formed. The second phase particles Co ₂ Si and Co-Si-Zr compounds are suitable for precipitation strengthening and crystal grain size adjustment. When the amount of Co and/or Si is too small, the precipitation strengthening effect is small, and if it is too large, it is not solid solution and the conductivity is also poor. When the second phase particles Co ₂ Si are precipitated, the precipitation strengthening effect is exhibited, and the purity of the matrix after precipitation increases, so that the conductivity is improved. Further, when a specific amount of the second phase particles having a specific size is present, the crystal grain growth is inhibited, and the crystal grain size can be made 10 μm or less.

The alloy material of the present invention contains 0.001 to 0.5% by weight, preferably 0.01 to 0.4% by weight, of Zr, and the strength and electrical conductivity are increased. This effect is more than the extent predicted by the system of only Cu-Co-Si. When Zr is less than 0.001% by weight, the effect of increasing the strength or conductivity is not obtained. When Zr exceeds 0.5% by weight, coarse telluride is generated, and strength or bending workability is lowered.

The alloy material of the present invention has a crystal grain size of 10 μm or less. When the crystal grain size is 10 μm or less, good bending workability can be achieved.

The copper alloy material of the present invention may have various shapes such as a plate material, a strip material, a wire material, a rod material, and a foil, and may be a plate material or a strip material for a movable connector, and is not particularly limited.

(2nd phase particle)

The second phase particles of the present invention are those which are formed when other elements are contained in copper, and which form particles different from the copper matrix (matrix). The number of second phase particles having a diameter of 50 nm or more can be obtained by calendering a parallel section of a copper plate subjected to electrolytic polishing or pickling etching after mirror polishing by mechanical polishing (parallel to the calendering surface and parallel to Five sites were selected arbitrarily in the thickness direction, and the number of particles in the diameter range was measured from the scanning electron microscope photograph of the field of view obtained thereby. Here, the diameter is determined by measuring the short diameter (L1) and the long diameter (L2) of the particles as shown in Fig. 1, and means the average value of L1 and L2.

Most of the second phase particles of the present invention are Co ₂ Si or Co-Si-Zr compounds, but other intermetallic compounds such as Ni ₂ Si may be used as long as the diameter is within the range. The element constituting the second phase particles can be confirmed, for example, by using EDX attached to FE-SEM (Japan FEI Co., Ltd., model: XL30SFEG).

The copper alloy material of the present invention contains 3,000 to 500,000 pieces/mm ² , preferably 10,000 to 200,000 pieces/mm ² , more preferably 13,000 to 100,000 pieces/mm ² of 0.20 μm or more and less than 1.00 μm. The two-phase particles, which are mainly precipitated after hot rolling and before solution treatment, may be precipitated by solution treatment. The second phase particles precipitated before the solution treatment can suppress the growth of the crystal grain size during the solution treatment, but there is also a tendency to cause solid solution. Therefore, it is preferable to adjust the solution treatment conditions to suppress the fluctuation of the number of the second phase particles as much as possible.

Further, the second phase particles having a diameter of 1.00 μm or more and 10.00 μm or less are preferably 10 to 2,000 pieces/mm ² , more preferably 20 to 1,000 pieces/mm ² , and most preferably 30 to 500 pieces/mm. ² . The second phase particles in the diameter range can be precipitated by slowing down the cooling rate after the high temperature heating, and if necessary, the first aging treatment can be performed to adjust the particle diameter. The preferred range of the number of second phase particles of the above diameter is also in conjunction with the number of second phase particles of 0.20 μm or more and less than 1.00 μm. When it is this range, it can be solid-solved at a high temperature, and can suppress the growth of the crystal grain size in the solution treatment, and on the other hand, Co, Si, and Zr which are sufficiently solid-solved are treated by the (second) aging treatment in the latter stage. Finely deposited, high strength, high electrical conductivity, and good bending workability can be achieved. However, if it exceeds 2,000 pieces/mm ² , the bendability is lowered and it is not preferable.

The number of the second phase particles having a diameter of 0.20 μm or more and less than 1.00 μm and 1.00 μm or more and 10.00 μm or less is not changed before and after the solution treatment and after the second aging treatment, and thus the final calendering may be utilized or The final processed test piece was evaluated.

When the second phase particles having a diameter of more than 10.00 μm are present, the precipitation of the fine second phase particles is inhibited, and the precipitation strengthening effect cannot be obtained. Therefore, in the alloy material of the present invention, the second phase particles having a diameter of more than 10.00 μm are preferably used. It is contained in only 1 / mm ² or less, more preferably 0.01 / mm ² or less.

The second phase particles of 0.05 μm or more and less than 0.20 μm are precipitated by hot rolling, subsequent cooling, and first aging treatment, but most of them are solid-solved in the solution treatment, and are cooled by the following ( 2) Precipitation by aging treatment. The second phase particles of less than 0.05 μm were solid-solved in the solution treatment, and were largely precipitated by the (second) aging treatment. Therefore, these second phase particles have no effect of adjusting the crystal grain size, but contribute to the improvement of strength.

(physical properties of alloy materials)

The electrical conductivity EC of the alloy material of the present invention is 60% IACS or more, preferably 65% IACS or more. If it is within this range, it is possible to manufacture a component that can be made high in current.

The term "good bending workability" as used in the present invention means that the minimum bending radius MBR/t of a 0.3 mm thick plate is 0.5 or less (Bad Way). If the MBR/t is 0.5 or less on a 0.3 mm thick plate, the characteristics required for manufacturing and using electronic parts, particularly movable connectors, can be satisfied. Further, when the thickness of the alloy material of the present invention is thinner than 0.3 mm, better bending workability can be obtained.

The 0.2% proof stress YS of the alloy material of the present invention is preferably 600 MPa or more, more preferably 650 MPa or more, and the tensile strength TS is preferably 630 MPa or more, more preferably 660 MPa or more. In the above range, it is sufficient as a material for an electronic component such as a plate material for a movable connector.

(Production method)

The steps of the method for producing the alloy material of the present invention are the same as those of the usual precipitation-strengthened copper alloy, namely: melt casting → (homogeneous heat treatment) → hot rolling → cooling → (first aging treatment) → surface grinding → cold rolling → Solution treatment → cooling → (cold rolling) → second aging treatment → final cold rolling → (tempering relaxation annealing). Furthermore, the steps in the brackets can be omitted, and the final cold rolling can also be performed before the aging heat treatment.

In the present invention, the homogenization heat treatment and the hot calendering are carried out after casting, but the homogenization heat treatment may also be the heating in the hot calendering (further, in the present specification, the heating will be performed by homogenization heating and hot pressing delay). It is "high temperature heating").

The temperature at which the high temperature is heated may be a temperature at which the additive element is substantially solid-dissolved. Specifically, it is higher than the solution treatment temperature selected below by 40 ° C or higher, preferably at a temperature higher than 45 ° C. The upper temperature limit for high-temperature heating is specified by the metal composition and equipment individually, but is usually 1,000 ° C or less. The heating time also varies depending on the thickness of the sheet, and is preferably from 30 to 500 minutes, more preferably from 60 to 240 minutes. When heating at a high temperature, it is preferred that most of the additive elements such as Co or Si are melted.

The cooling rate after high-temperature heating is 100 ° C / min or less, preferably 5 to 50 ° C / min. At this cooling rate, the second phase particles having a final diameter of 0.20 μm or more and less than 10.00 μm are precipitated in the target range. However, in the past, in order to suppress the coarsening of the second phase particles, the particles are quenched by water-cooling or the like, so that only the fine second phase particles are precipitated.

After the cooling, the material is subjected to surface grinding, and if the first aging treatment is performed arbitrarily, the size and number of the second phase particles of the target can be adjusted, which is preferable. The conditions of the first aging treatment are preferably carried out at 600 to 800 ° C for 30 s to 30 h.

The temperature of the solution treatment performed after any of the above first aging treatments is selected within a range of (50 × Cowt% + 775) ° C or more and (50 × Cowt % + 825) ° C or less. The preferred treatment time is from 30 to 500 s, more preferably from 60 to 200 s. When it is in this range, the adjusted second phase particles may remain and the crystal grain size may be prevented from increasing. On the other hand, Co, Si, and Zr which are finely precipitated are sufficiently solid-solved, and the second stage of the latter stage The aging treatment is formed into fine second phase particles and precipitated.

The preferred cooling rate after solution treatment is 10 ° C / s or more. When the cooling rate is lower than this, the second phase particles are precipitated during cooling, and the amount of solid solution is lowered. There is no particularly preferable upper limit for the cooling rate, and if it is a commonly used device, for example, it may be about 100 ° C / s.

According to the present invention, when the content of Co, Si, and Zr is low, or is not slowly cooled after hot rolling, and the second aging treatment is not performed, the second phase particles precipitated before the solution treatment are less. When the alloy having a small amount of precipitated second phase particles is subjected to a solution treatment, the crystal grain size is coarsened at a solution temperature exceeding 850 ° C for more than 1 minute, so that only a short time of about 30 seconds can be performed. In the heat treatment, the amount of solid solution can be practically small, so that a sufficient precipitation strengthening effect cannot be obtained.

The temperature of the second aging treatment after the solution treatment is preferably from 450 ° C to 650 ° C for 1 to 20 hours. When it is in this range, the diameter of the second phase particles remaining in the solution treatment can be maintained within the range of the present invention, and the solid solution-added element is formed into fine second phase particles and precipitates, which contributes to Strength enhancement.

The final calendering degree is preferably from 5 to 40%, more preferably from 10 to 20%. If it is less than 5%, the strength improvement by work hardening is inadequate, and if it exceeds 40%, bending workability will fall.

Further, in the case where the final cold rolling is performed before the second aging heat treatment, the second aging heat treatment may be carried out at 450 ° C to 600 ° C for 1 to 20 hours.

The relaxation annealing temperature is preferably from 250 to 600 ° C, and the annealing time is preferably from 10 s to 1 hour. If it is in this range, the size and number of the second phase particles do not change, and the crystal grain size does not change.

[Examples]

(manufacturing)

In the molten metal containing electrolytic copper, Si, Co, and Zr as raw materials, the amount and type of the additive element were changed and added, and an ingot having a thickness of 30 mm was cast. The ingot was heated at a temperature of the table for 3 hours (high temperature), and was formed into a plate having a thickness of 10 mm by hot rolling. Then, the scale of the surface is removed by grinding, and the aging heat treatment is performed for 15 hours, and then the solution treatment is carried out by appropriately changing the temperature and time, and the cooling is performed at the cooling temperature in the table, and the temperature in the table is performed for 1 to 15 hours. The aging heat treatment finishes the final thickness to 0.3 mm by final cold rolling. The relaxation annealing time is 1 minute.

(Evaluation)

The concentration of the additive element in the copper alloy matrix was analyzed by ICP-mass spectrometry using the sample after the surface grinding step.

The diameter and the number of the second phase particles can be measured by mechanically grinding the parallel section of the sample before the final cold rolling and polishing it into a mirror surface, followed by electrolytic polishing or pickling etching using a scanning electron microscope. Five micrographs of each magnification were obtained, and the diameter and number of the second phase particles were measured from the microscope photograph. The observation magnification is as follows: (a) 0.05 μm or more and less than 0.20 μm is 5 × 10 ⁴ times, (b) 0.20 μm or more and less than 1.00 μm is 1 × 10 ⁴ times, (c) 1.00 μm or more and 10.00 μm or less. It is 1 × 10 ³ times (in the table, it is expressed as "50-200 nm", "200-1000 nm", and "1000-10000 nm", respectively).

The crystal grain size is determined by a cutting method in accordance with JIS H0501.

The conductivity EC was measured in a thermostat kept at 20 ° C (± 0.5 ° C), and the specific resistance (the distance between the terminals was 50 mm) was measured by a four-terminal method.

Regarding the bending workability MBR/t, a 90° W bending test (JIS) of a rectangular test piece (width 10 mm × length 30 mm × thickness 0.3 mm) cut by TD (Transverse Direction) is performed at a right angle to the bending direction. H3130, Bad Way), the minimum bending radius (mm) which does not cause cracks is MBR (Minimum Bend Radius), and the bending workability is evaluated based on the ratio MBR/t of the MBR to the thickness t (mm).

With respect to the 0.2% proof stress YS and the tensile strength TS, a sample of JIS Z2201-13B cut in the parallel direction of rolling was measured three times in accordance with JIS Z 2241, and an average value was obtained.

The addition of Zr is required to set the elemental ratio of Co and Si, the element ratio of Co/Si, the number of second phase particles having a diameter of 0.20 μm or more and less than 1.00 μm, the conductivity EC and the crystal grain size within the scope of the present invention. The results of the amounts are shown in Tables 1A to C.

According to Tables 1A and B, in Example 1 or 2 in which 0.01% or 0.3% of Zr was added, the strength, electrical conductivity, or electrical conductivity increased as compared with Comparative Example 3 in which Zr was not added at all. Further, it was confirmed that the electrical conductivity increased in proportion to the amount of Zr added. However, in Comparative Example 4 in which 1.0% of Zr was added, the strength and bending workability were lowered (described in Table 1C to be described later).

According to the above results, the results obtained by changing the component composition and the production conditions by setting the amount of Zr to 0.1% are shown in Tables 2A to C (described in Table 2C to be described later).

Since the examples 1 to 11 satisfy the requirements of the present invention, they are excellent in electrical conductivity, strength, and bending workability under a thick plate, and are suitable as a material for a high-current movable connector.

Reference Example 22 was the same as the conditions of Example 6, after the solution treatment, and was cooled at the cooling temperature in the table, and the final thickness was finished to 0.3 mm by final cold rolling before the aging treatment, at the temperature in the table. The aging treatment was carried out for 3 hours, and the material obtained by quenching and tempering annealing was similarly obtained, and the strength was slightly deteriorated compared with the physical properties of Example 6, but the flexibility was improved.

In Comparative Example 12, since the solid solution temperature is too high, the second phase particles having a diameter of 0.20 μm or more and less than 1.00 μm disappear in the solution heat treatment, and the effect of suppressing crystal growth cannot be exhibited, and the crystal grain size becomes large and the flexibility is high. Poor.

In Comparative Example 13, the Co/Si ratio was low, and in Comparative Example 14, the Co/Si ratio was high, and the precipitation strengthening effect by the fine second phase particles could not be obtained, and the strength was lowered, and the solid solution concentration of Co or Si was increased. The conductivity also deteriorates.

In Comparative Example 15, since the cooling rate after the hot working was excessively slow, the second phase particles having a diameter of 1.00 μm or more and less than 10.00 μm were increased, and the flexibility was inferior.

In Comparative Example 16, the cooling rate after hot working was fast, and the number of second phase particles having a diameter of 0.20 μm or more and less than 1.00 μm was small, and the effect of suppressing crystal growth was not exhibited, and the flexibility was inferior. In Comparative Example 17, the first aging treatment was performed at a high temperature in order to compensate for the fact that the cooling rate after hot working was fast and the number of second phase particles having a diameter of 0.20 μm or more and less than 1.00 μm was small. The second phase particles having a diameter of 0.20 μm or more and less than 1.00 μm are precipitated. However, when heated, the crystal grain size is increased, so that the flexibility is poor.

In Comparative Example 18, since the high-temperature heating temperature and the solution treatment temperature were higher than those in Example 8, the effect of suppressing crystal growth was not exhibited, the crystal grain size was increased, the bendability was poor, and the conductivity was also lower than that of Example 8.

In Comparative Example 19, the solution treatment temperature was lower than that of Example 11, and the amount of solid solution of the added element in the solution treatment was small, and the strength was low.

In Comparative Example 20, the Co concentration was high, the solution treatment temperature was high, and the time was also long. Therefore, the number of second phase particles having a diameter of 0.20 μm or more and less than 1.00 μm was large, and the flexibility was poor.

In Comparative Example 21, the Co concentration was high, and the solution treatment temperature and the hot working temperature were both high, so that the effect of suppressing the growth of the crystal grain size could not be exhibited, and the second phase particles having a diameter of 0.20 μm or more and less than 1.00 μm were not produced. The number of second phase particles having a diameter of 1.00 μm or more and 10.00 μm or less is large, and the flexibility is poor.

In the present invention, although there is no limitation in theory, it is considered that the relationship between the steps of the production method and the disappearance and precipitation of the second phase particles is as follows. In high temperature heating, the added elements are solid-solubilized in copper. The second phase particles of 0.05 μm or more are precipitated in the cooling stage in which the temperature is adjusted during hot rolling and after hot rolling. In the first aging treatment after the hot rolling, the second phase particles of 0.05 μm or more were not precipitated, and the second phase particles of less than 0.05 μm were precipitated in a large amount. In the solution treatment in which the temperature was adjusted, the second phase particles which did not reach 0.20 μm solid solution disappeared. In the cooling stage in which the rate after the solution treatment is adjusted, mainly the second phase particles of 0.05 μm or more and less than 0.2 μm are precipitated in a small amount. In the second aging treatment after the solution treatment, a large amount of the second phase particles of less than 0.05 μm were precipitated.

Table 1C and Table 2C show the measurement of (a) the second phase particles having a diameter range of 50 nm or more and less than 200 nm, (b) 200 nm or more and less than 1000 nm, and (c) 1,000 nm or more and 10,000 nm or less in the production steps. How to change the results. Further, in the entire measurement, the second phase particles having a diameter exceeding 10,000 nm (10.00 μm) could not be confirmed. Since the number is reduced logarithmically as the diameter becomes larger, the number of expressed bits is changed.

(a), in the case of the solution treatment conditions of the present invention, the number of solid solution is about 1/5 to 1/10, and the number does not change after the second aging treatment. Regarding (b), in the case of the solution treatment conditions and the second aging treatment conditions of the present invention, the number is hardly increased or decreased. Regarding (c), in the case of the high-temperature heating and cooling conditions of the present invention, the number before the solution treatment and before the final cold rolling does not change at all.

Further, when the first aging treatment temperature is high, the number of (b) is increased (Comparative Example 17), and if the solution treatment temperature is high or the treatment time is long, the number of (b) is decreased. Further, there was a tendency that the lower limit of the present invention was not reached (Comparative Examples 18 and 21).

[Industrial availability]

According to the copper alloy material of the present invention, the bending workability suitable for the movable connector and the conductivity capable of high current can be achieved, and the practical strength can be achieved.

L1. . . Short diameter of particles

L2. . . Long diameter of particles

Fig. 1 is a reference view showing the diameter of the second phase particles.

Claims (5)

A copper alloy material having good bending workability, comprising 1.0 to 2.5 wt% of Co, 0.2 to 0.7 wt% of Si, 0.001 to 0.5 wt% of Zr, and an element ratio of Co/Si of 3.5 to 5.0. The Cu-Co-Si-Zr alloy material contains 3,000 to 500,000 pieces/mm ² of the second phase particles having a diameter of 0.20 μm or more and less than 1.00 μm, a conductivity EC of 60% IACS or more, and a crystal grain size of 10 μm or less. The copper alloy material according to the first aspect of the invention includes 10 to 2,000 particles/mm ² of the second phase particles having a diameter of 1.00 μm or more and 10.00 μm or less. For the copper alloy material of the first or second patent application, the 0.2% guaranteed stress YS is 600 MPa or more. A method for producing a copper alloy material according to claim 1 or 2, wherein a temperature at which high temperature is heated after casting and before solution treatment is higher than a temperature at which a solution treatment temperature selected below is 45 ° C or higher. And the cooling rate from the start of the hot rolling to 600 ° C is 100 ° C / min or less; the solution treatment temperature is in the range of (50 × Cowt% + 775) ° C ~ ~ (50 × Cowt% + 825) ° C below Internal selection. The method for producing a copper alloy material according to claim 4, wherein the aging treatment after the solution treatment is performed at 450 to 650 ° C for 1 to 20 hours.