JP4493083B2 - High-performance copper alloy for electronic equipment with excellent strength and conductivity and method for producing the same - Google Patents

Description

  The present invention relates to a high-strength, high-conductivity copper alloy for electronic device parts, particularly in a small-sized and highly integrated copper alloy for semiconductor device leads and terminal connectors, without particularly reducing bending workability. The present invention relates to a copper alloy for electronic parts having excellent strength and conductivity.

Copper and copper alloys are widely used materials for electronic parts such as connectors and lead terminals, and flexible circuit boards, and the rapid development of IT has led to higher functionality and smaller size of information equipment. There are demands for further improvements in properties (strength, bendability, conductivity) in response to the reduction in thickness and thickness.
Terminals and connectors used in electronic electrical components are required to have high strength, high conductivity, and good bending workability as electronic and electrical devices become smaller and lighter. In addition, with the high integration of ICs, many semiconductor elements with high power consumption are used, and the lead frame material of semiconductor devices has a good heat dissipation (conductivity) such as Cu-Ni-Si or Cu. Precipitation alloys such as -Fe-P, Cu-Cr-Sn, and Cu-Ni-P have come to be used. However, in general, in lead frame processing of an IC or the like, the lead terminal portion is bent at a right angle after forming the lead terminal portion and the conductive connection portion with the IC by stamping or etching the raw material. Therefore, the lead frame is required to have strength, in particular bending workability, in addition to conductivity, but strength and bending workability are generally incompatible.

  In the prior art, alloys having strength, conductivity, and stress relaxation resistance are known by adjusting the amounts of Ni, P, and Mg components in a Cu—Ni—P alloy. (For example, patent document 1). However, the invention described in Patent Document 1 is intended to be used for electrical connection terminals and connectors, and although it is an alloy having excellent stress relaxation resistance, it has sufficient strength to ensure bending workability. It wasn't.

JP 2000-273562 A

  Accordingly, the present invention provides a copper alloy that has sufficient strength as a lead material for a spring material and a semiconductor device, and also has bending workability, without impairing the excellent conductivity of the Cu—Ni—P—Mg alloy. Aimed.

  As a result of repeated studies to achieve the above object, the present inventors have adjusted the components of the Cu—Ni—P—Mg based alloy, and then the morphology of the precipitate (shape, size and area ratio). ) Was adjusted to a specified range, and it was found that a copper alloy having unprecedented high strength can be obtained without impairing high conductivity and bending workability.

That is, the present invention is as follows.
(1) By mass ratio, Ni: more than 1.0% and 2.0% or less, P: 0.1% or more and 0.5% or less, Mg: 0.01% or more and 0.20% or less In a Cu—Ni—P—Mg alloy in which the content ratio of Ni and P is Ni / P: 4.0 or more and 6.5 or less and the balance is Cu and inevitable impurities , the conductivity is 40% IACS or more. As for the size and shape of the Ni—P—Mg-based precipitates, when the major axis is a and the minor axis is b, at least the aspect ratio a / b is 2 to 50 and the minor axis b is 10 to 25 nm. The sum of the areas of the left deposit and the precipitate having an aspect ratio a / b of less than 2 and a minor axis b of 20 to 50 nm is the sum of the areas of all precipitates in the copper alloy. High strength for electronic parts with excellent strength, conductivity and bending workability characterized by occupying 80% or more Whenever highly conductive copper alloy.

( 2 ) The Cu—Ni—P—Mg alloy as described in ( 1 ) above, wherein one or more of Zn, Sn and In are contained in a total of 0.01% to 1.0%. High-strength, high-conductivity copper alloy for electronic parts that combines excellent strength, conductivity and bending workability.

(3) Tensile strength: The high-strength, high-conductivity copper alloy for electronic parts described in either (1) or (2) above, which is 700 MPa or more and 950 MPa or less.
( 4 ) Tensile strength: The high-strength, high-conductivity copper alloy for electronic components described in ( 2 ) above, which is 750 MPa or more and 1000 MPa or less.

( 5 ) By mass ratio, Ni: more than 1.0% and 2.0% or less, P: 0.1% or more and 0.5% or less, Mg: 0.01% or more and 0.20% or less , Ni / P content ratio Ni / P: 4.0 to 6.5, the remainder of the Cu-Ni-P-Mg alloy ingot consisting of Cu and inevitable impurities is hot-rolled, after performing the water cooling from the material temperature 600 to 850 ° C. at the end of rolling the solution treatment, and aging treatment of 0.1 to 24 hours at 300 to 550 ° C., the size and shape of the Ni-P-Mg-based precipitates When the major axis is a and the minor axis is b, the total area of the precipitates having an aspect ratio a / b of 2 to 50 and a minor axis b of 10 to 25 nm is the total precipitate area in the copper alloy. to produce an intermediate material, which accounts for 80% or more based on the sum, either the intermediate material according to claim 1-4 you cold rolling The manufacturing method of the high intensity | strength highly electroconductive copper alloy for electronic components described in (2).

  In the present specification, a precipitate having an aspect ratio a / b of 2 to 50 and a minor axis b of 10 to 25 nm and an aspect ratio a / b of less than 2 and a minor axis b of 20 to 50 nm. The ratio of the total area with precipitates to the total area of all precipitates in the copper alloy is expressed as “area ratio C”. A precipitate having an aspect ratio a / b of 2 to 50 is expressed as a “fibrous precipitate”, and a “spherical precipitate” having an aspect ratio a / b of less than 2.

  The copper alloy of the present invention has excellent strength and unprecedented strength as a conventional Cu—Ni—P—Mg based copper alloy, and has excellent bending workability. . Therefore, it can be provided as an appropriate material for various electric and electronic parts such as lead frames, terminals, connectors and the like that are compatible with rapidly developing IT and are particularly small and highly integrated.

Next, the reason why the numerical range of the composition of the copper alloy, the form of the precipitates (shape, size, area ratio) and the like are limited in the present invention will be described together with the operation thereof.
[Ni]
Ni has the effect of ensuring the strength and heat resistance of the alloy and precipitates a compound with P and Mg, which will be described later, and contributes to an increase in the strength of the alloy. However, if the content is 1.0% or less, the desired strength cannot be obtained. On the other hand, if Ni is contained in excess of 2.0%, the workability during hot rolling deteriorates and the product is bent. A decrease in workability and electrical conductivity is significant. Further, coarse precipitates are generated, and there are many precipitates whose sizes are out of the scope of claims, and the area ratio C is lowered. Therefore, the Ni content of the alloy of the present invention is more than 1.0% and not more than 2.0%, preferably not less than 1.1% and not more than 1.8%.

[P]
P precipitates a compound with Ni and Mg to improve the strength and heat resistance of the alloy. If the P content is less than 0.1%, precipitation of the compound is insufficient, so that the desired strength cannot be obtained. On the other hand, when the P content exceeds 0.5%, the workability during hot rolling is lowered and the conductivity is significantly lowered. In addition, coarse precipitates are generated, and the number of precipitates whose size is out of the scope of claims increases, and the area ratio C decreases, which is not preferable. Therefore, the P content of the alloy of the present invention is 0.1% to 0.5%, preferably 0.2% to 0.4%.

[Mg]
Mg precipitates a compound with Ni and P to improve the strength and heat resistance of the alloy.
Further, when a Cu—Ni—P-based alloy is produced by the production method of the present invention described later, precipitates having an aspect ratio a / b close to 1 to 5 are obtained. In the production method of the present invention, a fibrous precipitate having an aspect ratio a / b of 2 to 50 is obtained. In this case, higher strength can be obtained as compared with Cu-Ni-P alloys having the same amount of Ni and P. Furthermore, the effect is greater than the increase in strength obtained when Mg is dissolved.
However, when the Mg content is less than 0.01%, desired strength and heat resistance cannot be obtained. On the other hand, if the Mg content exceeds 0.20%, the workability during hot rolling is remarkably lowered and the conductivity is significantly lowered. Moreover, the amount of precipitates whose size is out of the scope of claims increases so that coarse precipitates are generated, which is not preferable.
Therefore, the Mg content of the alloy of the present invention is 0.01% or more and 0.20% or less, preferably 0.02% or more and 0.15% or less.

[Ni / P]
If the Ni / P content ratio Ni / P is less than 4.0 and more than 6.5, even if the Ni and P contents are within the above-mentioned limited range, the precipitates deviate from an appropriate composition ratio. If it is less than 0.0, P is exceeded, and if it exceeds 6.5, the amount of Ni dissolved increases, and the decrease in conductivity becomes remarkable, which is not preferable. Also, in both cases of less than 4.0 and more than 6.5, the amount of Mg dissolved in the alloy increases, so that the workability during hot rolling is significantly reduced and the decrease in conductivity is remarkable. Become.
Therefore, the Ni / P ratio of the alloy of the present invention is 4.0 or more and 6.5 or less, preferably 4.5 or more and 6.0 or less.

[O]
O easily reacts with P and Mg in the alloy, and when present in the alloy in an oxide state, the precipitation of Ni-P-Mg compounds is hindered, resulting in a decrease in strength and bending workability. Therefore, the O content of the alloy of the present invention is 0.0050% or less, preferably 0.0030% or less.

[Zn, Sn, In]
Zn, Sn and In all have the effect of improving the strength mainly by solid solution strengthening without greatly reducing the conductivity of the alloy. Accordingly, if necessary, one or more of these metals are added, but if the total content is less than 0.01%, the effect of improving the strength by solid solution strengthening cannot be obtained, while the total amount is 1.0% or more. When adding, the conductivity and bending workability of the alloy are significantly reduced. For this reason, the amount of Zn, Sn and In added individually or in combination of two or more types is 0.01% or more and 1.0% or less, preferably 0.05% or more and 0.8% or less in total. In the present invention, these elements are intentionally added elements, and when the total amount is 0.01% or more, they are not regarded as inevitable impurities.

[Form of precipitates (shape, size, area ratio)]
In precipitation hardening type copper alloys, it is generally known to increase the strength by dispersing more small precipitates and reducing the dispersion interval of each precipitate.
In the present invention, the inventors pay attention to the form of precipitates in the Cu-Ni-P-Mg alloy, and in order to increase the strength, fibrous precipitates having an aspect ratio a / b of 2 or more are obtained. It has been found that the presence of the presence of spherical precipitates having an aspect ratio a / b of less than 2 has a greater effect of increasing the strength than the presence of a single precipitate. That is, in the Cu—Ni—P—Mg based alloy, it was found that the presence of precipitates having an aspect ratio a / b of 2 to 50 and a minor axis b of 10 to 25 nm greatly contributes to the increase in strength. .

A Cu—Ni—P—Mg alloy satisfying the above requirements is a manufacturing process performed in the order of ingot casting, hot rolling, solution treatment, intermediate cold rolling, solution treatment, aging treatment, and final cold rolling. In the above, it is obtained after the final cold rolling by forming the form of the precipitate described below by the solution treatment and the aging treatment before the final cold rolling.
Furthermore, what was obtained by heat-processing what was obtained by said manufacturing process, and what was obtained by the last cold rolling using this invention for intermediate | middle cold rolling are also contained in this invention.
Below, the form of the precipitate of each manufacturing process is demonstrated in detail.

(A) Form of the precipitate after the final cold rolling The form of the precipitate obtained after the solution treatment and the aging treatment in the present invention and after the final cold rolling is a fiber having an aspect ratio a / b of 2 or more. Although there is almost no minor axis b less than 10 nm. In the Cu—Ni—P—Mg-based alloy of the present invention, precipitates having a minor axis b of 10 nm or more are hardly changed before and after the cold rolling, but are cold having a minor axis b of less than 10 nm. This is because the precipitate before rolling is dissolved again by cold rolling and disappears.

On the other hand, a precipitate having a minor axis “b” exceeding 25 nm has an excessively large dispersion interval, resulting in a decrease in strength as compared to 25 nm or less.
Further, when the aspect ratio a / b exceeds 50, the minor axis b often exceeds 25 nm, and the minor axis b rarely exceeds 50 at 10 to 25 nm. However, if the aspect ratio a / b exceeds 50, the dispersion interval of the precipitates becomes large, and the strength is lowered.
Therefore, the short diameter b of a preferable fibrous precipitate (aspect ratio a / b is 2 or more) contributing to high strength is 10 to 25 nm, and the aspect ratio a / b is 50 or less.

  On the other hand, since it is difficult to control all of the precipitates within the range of the above-specified minor axis b and aspect ratio a / b, the ratio of the precipitates within the above-specified range to the total precipitates is important. Therefore, the ratio of the total area of the precipitates in the above-mentioned limited range to the total area of all precipitates in the alloy is defined as area ratio C, and the area ratio C is defined in the present invention. For example, precipitates exceeding 200 nm and crystallized substances generated during melt casting are not sufficiently re-solidified by hot rolling or solution treatment, and the minor axis b exceeds 25 nm after cold rolling and the aspect ratio a / b There are cases where there are many precipitates exceeding 2 and the area ratio C is less than 80%. In this case, the dispersion interval of the precipitates becomes large and the desired strength cannot be obtained. Therefore, the area ratio C is 80% or more.

(B) Form of precipitate when heat-treated after final cold rolling Although the fibrous precipitate (aspect ratio a / b is 2 to 50) of the present invention is effective for increasing the strength, For example, when rolling with a rolling strain of 2 or more is performed, a part of the fibrous precipitate is re-dissolved, and a decrease in conductivity is caused. Here, the rolling strain, the plate thickness before rolling t _0, when the plate thickness after rolling was t, is expressed by the rolling strain _{= ln (t 0 / t)} .

Therefore, in the present invention, by conducting a heat treatment after the final cold rolling, the element in which the precipitate is re-dissolved can be precipitated, and the conductivity can be improved. In this case, the element in which the precipitate is re-dissolved is spherical (aspect ratio a / b is less than 2) and forms the precipitate. On the other hand, the fibrous deposits (aspect ratio a / b is 2 to 50) that have already been deposited and the minor axis b is 10 to 25 nm are almost unchanged. As a result, high conductivity is obtained while maintaining high strength. However, if the spherical precipitates having a minor axis b exceeding 50 nm are precipitated in this heat treatment, the strength is lowered. Therefore, when the aspect ratio a / b is less than 2, the minor axis b of the precipitate is 50 nm or less. Furthermore, when the present invention described later is used for intermediate cold rolling, when the aspect ratio a / b of the precipitates precipitated by the heat treatment after rolling is less than 2 and the minor axis b is less than 20 nm, the final cold rolling In consideration of re-dissolving in, the short diameter b is preferably 20 nm or more.
Even in this state, the area ratio C was set to 80% or more for the reason described in (a).

When heat treatment is performed after the final cold rolling, preferable precipitates contributing to high strength and high conductivity are precipitates having an aspect ratio a / b of 2 to 50 and a minor axis b of 10 to 25 nm, and an aspect ratio a This is a precipitate in which / b is 2 or less and the minor axis b is 20 to 50 nm.
Therefore, by subjecting the final cold rolling to heat treatment on the precipitate having an aspect ratio a / b of 2 to 50 and a minor axis b of 10 to 25 nm and an area ratio C of 80% or more, a / b Having a precipitate with a short diameter b of 10 to 25 nm and a deposit with the aspect ratio a / b of 2 or less and a short diameter b of 20 to 50 nm. It is also the present invention that the total sum is 80% or more with respect to the total sum of the areas of all precipitates in the copper alloy.

(C) Form of precipitate before final cold rolling and manufacturing method As described above, the size of the fibrous precipitate aspect ratio a / b of 10 nm or more of the minor axis b of 10 nm or more before cold rolling in the present invention is 2 or more) Since it hardly changes even when cold-rolled, the area ratio C of precipitates having an aspect ratio a / b of 2 to 50 and a minor axis b of 10 to 25 nm after the final cold rolling is 80% or more. Therefore, it can be seen that the area ratio C of the precipitate having an aspect ratio a / b of 2 to 50 and a minor axis b of 10 to 25 nm may be 80% or more before the final cold rolling.
Specifically, prior to the final cold rolling, an aging treatment is performed subsequent to the solution treatment, and the Ni—P—Mg-based precipitate has an aspect ratio a / b of 2 to 50 and a short diameter b of 10 to 25 nm. After the area ratio C of the object occupies 80% or more, it can be manufactured by final cold rolling.

(D) Form of precipitates after final rolling when the present invention is used for intermediate cold rolling Aging treatment is performed subsequent to solution treatment before intermediate cold rolling, and the aspect ratio a in Ni-P-Mg based precipitates / B is 2 to 50 and the minor axis b is 10 to 25 nm, and after the intermediate cold rolling is performed after the area ratio C is 80% or more, the precipitate after the intermediate cold rolling Can be obtained in a state where the area ratio C of the precipitate having an aspect ratio a / b of 2 to 50 and a minor axis b of 10 to 25 nm is 80% or more. When this is subjected to a heat treatment such as aging treatment and strain removal, and then subjected to final cold rolling, the precipitate has an aspect ratio a / b of 2 to 50 and a minor axis b of 10 to 25 nm and an aspect ratio a / b. A copper alloy having high strength and high conductivity can be obtained while the area ratio C with a precipitate having a length of less than 2 and a short diameter of b of 50 nm or less is 80% or more.

  Prior to intermediate cold rolling, solution treatment is followed by aging treatment, and the area ratio C of Ni—P—Mg based precipitates having an aspect ratio a / b of 2 to 50 and a minor axis b of 10 to 25 nm. 80% or more, and after intermediate cold rolling, heat treatment, and final rolling, the precipitate has an a / b of 2 to 50 and a minor axis b of 10 to 25 nm. It is also the present invention that the total area of precipitates with a / b of 2 or less and the minor axis b of 20 to 50 nm is 80% or more with respect to the total area of all precipitates in the copper alloy. .

  From the above, the alloy of the present invention has excellent electrical and thermal conductivity, strength, springiness, and bending workability, and preferably has a tensile strength of 700 to 950 MPa, more preferably 750 to 1000 MPa, and preferably conductivity. The characteristic value of 45-65% IACS is shown.

Sample preparation Electro-copper or oxygen-free copper as the main raw material, nickel, Cu-P master alloy, copper-magnesium master alloy, zinc, tin, and indium as auxiliary raw materials, dissolved in vacuum or argon atmosphere in a high-frequency melting furnace And then cast into a 25 × 50 × 150 mm ingot. Next, the ingot was subjected to hot rolling, solution treatment, aging treatment, and final cold rolling in this order to obtain a flat plate having a thickness of 0.15 mm.
Various test pieces of the obtained plate material were collected and tested, and “strength”, “conductivity”, and “bending workability” were evaluated.

Method for producing target precipitate An example of a method for producing the target precipitate is shown as follows.
(A) When the size of the precipitate is within the scope of the claims The ingot was heated to 650 to 950 ° C. for 0.5 to 24 hours to dissolve the Ni—P—Mg-based crystallized material generated during casting. Thereafter, hot rolling is performed. Water cooling is performed at a material temperature of 600 to 850 ° C, preferably 700 to 850 ° C at the end of hot rolling. When a material temperature of 600 ° C. or higher cannot be obtained at the end of hot rolling, after heating again to 700 to 950 ° C. for 0.5 hour or longer, water cooling is performed sufficiently. Thereafter, an aging treatment is performed at 300 to 550 ° C. for 0.1 to 24 hours.
(B) When the minor axis b of the precipitate is smaller than the claims, hot rolling is performed in the same manner as in the above (a), and an aging treatment is performed at 250 to 400 ° C. for 0.1 to 24 hours.
(C) When the minor axis b of the precipitate is larger than the claims, the ingot before hot rolling is heated in the same manner as in the above (a), and the positive cooling after hot rolling is not performed, and it is allowed to cool. (Air cooling). Thereafter, an aging treatment is performed at 500 to 700 ° C. for 0.1 to 24 hours.

Evaluation of Precipitates Using a scanning electron microscope and a transmission electron microscope, the alloy strips before the final cold rolling were cut parallel to the rolling direction at right angles to the thickness, and the precipitates in the cross section were observed in 10 fields. When the size of the precipitate (major axis b) is 5 to 50 nm, the field of view (approximately 1.4 × 10 ^{10 to} 2.0 × 10 ¹⁰ nm ² ) at a magnification of 500,000 to 700,000 times, 100 to 2000 nm In this case, the image was taken with a field of view of about 5 to 100,000 times (about 1.0 × 10 ^{13 to} 2.0 × 10 ¹³ nm ² ). The image of the photograph taken was measured for the major axis a, the minor axis b, and the area of each of the precipitates having a size of 5 nm or more using an image analysis apparatus (trade name Luzex, manufactured by Nireco Corporation). 100 of these precipitates are taken out randomly, and the area of the precipitate having an aspect ratio a / b of 2 to 50 and a minor axis b of 10 to 25 nm with respect to the total area of all precipitates having a major axis a of 5 nm or more. The ratio of the total area of precipitates having an aspect ratio a / b of less than 2 and a minor axis b of 50 nm or less was calculated as an area ratio C (%).
In addition, although Ni-P-Mg based precipitates in which the minor axis b of the precipitate before cold rolling is smaller than 10 nm are dissolved by final cold rolling (usually rolling strain = 2 or more), the minor axis It was confirmed that the precipitate having b of 10 nm or more maintains its major axis, minor axis b and aspect ratio a / b even after the final cold rolling. Similarly, the area ratio C of the precipitates hardly changes even after the final cold rolling.

About physical property evaluation "strength" of a test piece, it carried out using the No. 13 B test piece according to the tensile test prescribed | regulated to JISZ2241, and measured the tensile strength.
“Conductivity” was measured by measuring the electric resistance of a test piece using a four-terminal method, and the electric conductivity ratio with standard annealed copper (having a volume resistivity of 1.7241 μΩcm) was expressed as a percentage and expressed in% IACS.
Regarding “bending workability”, the surface of a bending part obtained by bending a test piece having a width of 10 mm with a W bending tester using a die having a bending radius of 0.15 mm and a load of 50 kN was observed with an optical microscope (100 times). The presence / absence of cracks was investigated and evaluated. The case where no cracks occurred was indicated by ○, and the case where cracks occurred was indicated by ×.

The Example of the high intensity | strength highly conductive copper alloy which concerns on this invention is described with a comparative example about the copper alloy of the component composition shown in Table 1. FIG.
Examples 1-7 and Comparative Examples 8-12 compare the range of the alloy composition of the present invention, and Comparative Examples 8-12 are alloys with components outside the range of the alloy composition of the present invention. . Thus, after cold rolling, the claims for the minor axis b and the aspect ratio a / b were satisfied, and the area ratio C was 80% or more in both Examples 1 to 7 and Comparative Examples 8 to 12.

Table 2 shows the results of the strength, conductivity, and bending workability of the examples and comparative examples.
Since Examples 1 to 7 were within the range of the alloy composition of the present invention, they had excellent strength, electrical conductivity, and bending workability. On the other hand, when the results of Comparative Examples 8 to 12 are examined, in Comparative Example 8, the amount of Ni—P—Mg-based precipitates decreases because the amount of Ni added is less than 1.0%. Therefore, sufficient strength cannot be obtained. In Comparative Example 9, since the addition amount of P exceeds 0.5%, the solid solution amount of P increases, resulting in a decrease in electrical conductivity and poor bending workability. In Comparative Example 10, since the Ni / P ratio deviates from the appropriate composition ratio of the precipitates, the amount of Ni dissolved increases, resulting in a decrease in conductivity, and the precipitation of Ni—P—Mg based precipitates. Since the amount is small, sufficient strength cannot be obtained. In Comparative Example 11, the added amount of Zn, Sn, and In as subcomponents generally exceeds 1.0%. Therefore, although the strength is high due to these solid solutions, the conductivity is lowered due to the solid solutions, and bending work is also performed. Inferior. In addition, since Zn, Sn, and In in Comparative Example 11 are not inevitable impurities, Comparative Example 11 does not fall under the invention example. In Comparative Example 12, since the added amount of Mg exceeds 0.2%, the solid solution amount of Mg increases, resulting in a decrease in electrical conductivity and poor bending workability.

  Examples 1-7 and Comparative Examples 13-17 are the examples which compare the area ratio C by the state (the minor axis b of a precipitate, and aspect ratio a / b) differing, and Comparative Examples 13-17 Is an example that deviates from the area ratio C of the present invention. The alloy compositions of the invention examples are within the scope of the claims as shown in Table 1, and the alloy compositions of the comparative examples are shown in Table 3.

The results are shown in Table 4 for the examples and Table 5 for the comparative examples. In addition, about the comparative example, since the state of precipitates is difficult to understand only by the area ratio C, the average minor axis and the average aspect ratio are shown for reference. Here, the average minor axis is the average value of the minor axis of each precipitate, and the average aspect ratio is a value obtained by dividing the sum of the major axis of each precipitate by the sum of the minor axes.
Since the area ratio C is 80% or more, the examples have excellent strength, conductivity, and bending workability.

In Comparative Example 13, since the minor axis b of the precipitate before cold rolling is smaller than the specified range and the area ratio C of the precipitate satisfying the specification is 0%, the precipitate is dissolved in the cold rolling. Thus, no precipitate was observed after cold rolling. Therefore, the strength after cold rolling is high due to solid solution strengthening, but the conductivity is remarkably lowered and the bending workability is inferior.
In Comparative Example 14, before cold rolling, the minor axis b is 25 nm or less, but the precipitate has an aspect ratio a / b exceeding 50, and the aspect ratio a / b is 50 or less, but the minor axis b is 25 nm. The area ratio C in which a large number of precipitates with a minor axis b exceeding 25 nm and an aspect ratio a / b exceeding 50 is present is less than 80%. After cold rolling, the size of the precipitate (minor axis b and aspect ratio a / b) hardly changes, no solid solution of the precipitate is observed, and the area ratio C hardly changes from that before cold rolling. . For this reason, the electrical conductivity is sufficient, but with the size of the precipitate, work hardening due to the precipitate is small, and a desired strength cannot be obtained.

In comparative example 15, the aspect ratio a / b before cold rolling is 2 to 50, but many coarse precipitates having a minor axis b exceeding 25 nm are observed, and the area ratio C is extremely low. After cold rolling, the size of the precipitates hardly changes, no solid solution is seen, and the conductivity is high, but the area ratio C is extremely low, so the work hardening is very small and the strength is extremely low. It was.
In Comparative Example 16, a large precipitate having a minor axis b of 10 to 25 nm and an aspect ratio a / b exceeding 50 is observed, and the area ratio C is extremely low. As in Comparative Example 15, no solid solution is observed and the electrical conductivity is high, but the work hardening is small and the strength is not sufficient.
From Comparative Examples 14, 15, and 16, it can be seen that the upper limit of the fibrous precipitate constituting the present invention is a minor axis b of 25 nm or less and an aspect ratio a / b of 50 or less.
In Comparative Example 17, many fine precipitates having a minor axis b of 5 to 15 nm and an aspect ratio a / b of 4 to 6 are observed, and the area ratio C is low. Precipitates of less than 10 nm are solid-dissolved during cold rolling. In this case, since the deposits of 10 nm or more remain as they are, the area ratio C becomes 100%. However, although the strength is sufficient by the solid solution strengthening, the conductivity is remarkably lowered. Further, like the comparative example 13, bending workability is poor.

The lower column of Table 4 and Table 5 shows an example in which heat treatment was applied to Example 7 and Comparative Example 13 after cold rolling, and an example in which cold rolling was further performed after heat treatment. When the heat treatment is performed after cold rolling, the solid solution element is precipitated as a spherical precipitate and the electrical conductivity can be increased, but the electrical conductivity after rolling is 47.1%. Example No. 7 was heat-treated. 18, the conductivity is improved to 55.2%. In this case, elements that are partly dissolved in cold rolling are deposited as spherical precipitates having a minor axis b of 20 to 50 nm and an aspect ratio a / b of less than 2. And the area ratio C of the sum total with the precipitate whose minor axis b10-25nm and aspect ratio a / b is 2-50 is 95%, and is 80% or more.

  On the other hand, Comparative Example No. in which all precipitates were dissolved. Comparative Example No. 13 was heat-treated. In No. 19, spherical precipitates (aspect ratio a / b is less than 2) are precipitated, and those having a minor axis b of 20 to 50 nm are 80% or more. However, Comparative Example No. No. 19 has no fibrous precipitate (aspect ratio a / b of 2 to 50), so Example No. 19 having a fibrous precipitate (aspect ratio a / b of 2 to 50). Compared with 18, the strength is inferior. Further, in Comparative Example 20 where there are many precipitates exceeding 50 nm, it is apparent that sufficient strength is not obtained.

Furthermore, Example No. which heat-processed after cold rolling. No. 18 was further cold-rolled in Example 21, while having high conductivity, Example No. A strength higher than 18 can be obtained.
On the other hand, in the comparative example in which the comparative example 22 is rolled, the precipitates exceeding 50 nm hardly change even when rolled, and a sufficient strength cannot be obtained because the precipitates exist in a spherical shape exceeding 50 nm.

Claims (5)

Ni: more than 1.0% and 2.0% or less, P: 0.1% or more and 0.5% or less, Mg: 0.01% or more and 0.20% or less, In a Cu-Ni-P-Mg alloy in which the P content ratio Ni / P is 4.0 or more and 6.5 or less, and the balance is Cu and inevitable impurities , the conductivity is 40% IACS or more, With regard to the size and shape of the Ni-P-Mg based precipitate, when the major axis is a and the minor axis is b, the precipitate has an aspect ratio a / b of 2 to 50 and a minor axis b of 10 to 25 nm. The sum of the areas of the precipitates on the left and those having an aspect ratio a / b of less than 2 and a minor axis b of 20 to 50 nm is 80% of the total area of all precipitates in the copper alloy. High strength and high strength for electronic parts with excellent strength, conductivity and bending workability Conductive copper alloy. The Cu-Ni-P-Mg-based alloy according to claim 1 , wherein the Cu-Ni-P-Mg-based alloy includes at least one of Zn, Sn, and In in a total content of 0.01% to 1.0%, High-strength, high-conductivity copper alloy for electronic parts that has both conductivity and bending workability. Tensile strength: 700 MPa or more and 950 MPa or less, The high-strength high-conductivity copper alloy for electronic components described in any one of Claim 1 or 2. Tensile strength: 750 MPa or more and 1000 MPa or less, The high-strength, high-conductivity copper alloy for electronic components described in Claim 2 . Ni: more than 1.0% and 2.0% or less, P: 0.1% or more and 0.5% or less, Mg: 0.01% or more and 0.20% or less, P content ratio Ni / P: 4.0 or more and 6.5 or less, hot-rolling a Cu—Ni—P—Mg-based alloy ingot consisting of Cu and inevitable impurities, and at the end of hot rolling After cooling to water from a material temperature of 600 to 850 ° C. and solution treatment, aging treatment is performed at 300 to 550 ° C. for 0.1 to 24 hours, and the size and shape of the Ni—P—Mg-based precipitates are determined as follows : a, when the minor axis is b, the sum of the areas of the precipitates having an aspect ratio a / b of 2-50 and a minor axis b of 10-25 nm is the sum of the areas of all the precipitates in the copper alloy. an intermediate member which accounts for 80% or more to produce Te, serial this intermediate material to one of the claims 1-4 you cold rolling Process for the preparation of an electronic component for high strength and high conductivity copper alloy.