JP2008266787A - Copper alloy material and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a copper alloy material for an electric-electronic equipment having a high electrical conductivity of ≥50% LACS which can be hardly realized in a Cu-Ni-Si system and having a high strength, stress relaxation resistance characteristic, and bending workability, and a manufacturing method for controlling the crystal grain size thereof. <P>SOLUTION: The copper alloy material contains, by mass, 0.1 to 4% X element (where the element X denotes one or two or more among transition metals Ni, Fe, Co, Cu) and 0.01 to 3% Y element (where the element Y denotes one or two or more among Si, Zt, Hf) and the balance copper and inevitable impurities. The copper alloy material has the electrical conductivity of ≥50% LACS and an yield strength of ≥600 MPa and the stress relaxation rate when the copper alloy material is held for 1,000 hours in the state of applying a stress of 80% of the yield strength thereto is ≤20%. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a copper alloy material applied to a lead frame, a connector, a terminal material, etc. for an electric / electronic device, for example, a connector, a terminal material, a relay, a switch, a socket, etc. for an automobile.

The characteristic items required for the copper alloy material used for these applications include conductivity, yield strength (yield stress), tensile strength, bending workability, and stress relaxation resistance. In recent years, the required characteristics have been increased with the downsizing, weight reduction, high functionality, high density mounting, and high usage environment of electric / electronic devices.
Conventionally, as materials for electric and electronic devices, copper-based materials such as phosphor bronze, red brass, brass and the like are widely used in addition to iron-based materials. These alloys have improved strength by a combination of solid solution strengthening of Sn and Zn and work hardening by cold working such as rolling and wire drawing. In this method, the electrical conductivity is insufficient, and high strength is obtained by adding a high cold work rate, so that bending workability and stress relaxation resistance are insufficient.

  An alternative strengthening method is precipitation strengthening in which a fine second phase of nanometer order is precipitated in the material. This strengthening method has a merit of improving the conductivity at the same time in addition to increasing the strength, and is therefore performed in many alloy systems. Among them, a Cu—Ni—Si alloy (for example, CDA 70250, which is a registered CDA [Copper Development Association] registered alloy) strengthened by finely depositing a compound of Ni and Si in Cu, has the ability to strengthen. Although there is a high merit, the electrical conductivity is insufficient, and there is a demand for further higher conductivity.

Further, generally, in the precipitation hardening type alloy, a solution heat treatment for dissolving solute atoms is introduced in an intermediate step before the aging precipitation heat treatment for obtaining a fine precipitation state. Although this temperature varies depending on the alloy system and solute concentration, it is as high as 750 ° C. to 1000 ° C. In order to obtain a sufficient amount of precipitation hardening, it is preferable to increase the concentration of solute atoms and increase the precipitation density by increasing the solution treatment temperature.
In order to achieve high conductivity, it is necessary to select a precipitation-type copper alloy system in which the solid solubility limit of the solute atoms in the copper matrix phase is small. The temperature rises. Since the solution treatment temperature becomes high, there is a problem that the crystal grain size of the material becomes coarse. If the crystal grain size is coarse, the problem of cracking by promoting local deformation during bending, and the wrinkle on the surface of the bent part will increase, so when using the bent part as a contact point, Problems such as cracking of the plating applied to the material surface occur. There is a need for a technique for controlling the crystal grain size to be small at a high temperature in the solution heat treatment.

Against this technical background, there is an invention example of a method for producing a high-strength copper alloy in which a compound of Ni and Ti is dispersed (for example, see Patent Document 1). In addition, there is an invention example of a method for producing a copper alloy in which a compound of Ti and Fe is dispersed (see, for example, Patent Document 2).
However, it is difficult to make the strength, electrical conductivity, stress relaxation resistance, and bending workability parallel to each other, and all these required characteristics have not been satisfied.
Japanese Patent Publication No. 04-53945 JP 07-258806 A

  In view of the above problems, the object of the present invention is excellent in conductivity, strength, stress relaxation resistance, bending workability, connectors for electrical and electronic devices, terminal materials, etc. To provide a copper alloy material suitable for use in connectors, terminal materials, relays, switches, sockets and the like. In particular, it is to provide a precipitation-type copper alloy material capable of realizing a high conductivity of 50% IACS or higher, which is difficult to realize with a Cu-Ni-Si system, and a technique for controlling the crystal grain size in the production thereof.

The inventors of the present invention can improve these characteristics by examining the composition of the copper alloy material and its average crystal grain size, conductivity, proof stress, stress relaxation, and bending workability, and appropriately defining these. This has been found and the present invention has been made.
That is, the present invention
(1) 0.1-4% by mass of X element (where X element is one or more of transition elements of Ni, Fe, Co, Cr) and Y element is 0.1%. Containing 0.1 to 3% (where Y element is one or more of Ti, Si, Zr, and Hf), the balance being a copper alloy material consisting of copper and inevitable impurities,
A copper alloy having a conductivity of 50% IACS or more, a proof stress of 600 MPa or more, and a stress relaxation rate of 20% or less when held for 1000 hours with a stress of 80% of the proof stress applied Material,
(2) The element further contains 0.01 to 3% of the Z element (wherein the Z element is one or more of Sn, Mg, Zn, Ag, Mn, B, and P). The copper alloy material according to (1),
(3) The copper alloy material according to (1) or (2), wherein the average crystal grain size is 10 μm or less and the bending workability is excellent,
(4) The copper alloy material according to any one of (1) to (3), wherein the second phase having a particle size of 50 to 1000 nm is present at a distribution density of 10 ⁴ pieces / mm ² or more,
(5) The copper alloy material according to (4), wherein the second phase is a compound containing Si, Co, Ni, Fe, Ti, Zr or Cr,
(6) The copper alloy material according to (4) or (5), wherein the second phase is a ternary compound,
(7) For copper alloy material, casting [1], homogenization heat treatment [2], hot working [3], facing [4], cold working [6], solution heat treatment [7], cold The processing composed of the processing [9], the aging precipitation heat treatment [10], the cold processing [11] and the temper annealing [12] is performed in this order, and the processing rate R1 (%) in the cold processing [9] ) And the processing rate R2 (%) in cold working [11] is 5 to 65%, and the copper alloy material according to any one of (1) to (6) is obtained. Copper alloy material manufacturing method,
(8) Casting [1], homogenization heat treatment [2], hot working [3], face milling [4], cold working [6], solution heat treatment [7], aging precipitation on copper alloy material A process comprising a heat treatment [8], a cold work [9], an aging precipitation heat treatment [10], a cold work [11] and a temper annealing [12] is performed in this order, and the cold work [9]. The sum of the processing rate R1 (%) in the cold working and the processing rate R2 (%) in the cold working [11] is 5 to 65%, the processing temperature of the aging precipitation heat treatment [8] is 400 to 700 ° C., and the aging precipitation heat treatment. The copper alloy material according to any one of (1) to (6), wherein the processing temperature of [10] is lower than the processing temperature of aging precipitation heat treatment [8]. In the manufacturing method of the alloy material and (9) the manufacturing method of the above (7) or (8), 400 to 800 ° C. after the chamfering [4]. Performing a aging precipitation heat treatment [5] for 5 seconds to 20 hours and performing a cold working [6], a method for producing a copper alloy material for electronic and electrical equipment,
Is to provide.

  According to the present invention, it is possible to provide a copper alloy material that is excellent in electrical conductivity, strength, stress relaxation resistance and bending workability, and is optimal for use in electrical and electronic equipment, and a method for producing the same. The stress relaxation characteristics are evaluated at 150 ° C. in the standard specification, but the effect of the copper alloy material of the present invention is exhibited at 150 ° C. or less.

A preferred embodiment of the copper alloy material of the present invention will be described in detail.
First, the reason for addition of the component elements constituting the copper alloy material suitable for the electric / electronic device of the present invention and the content thereof will be described.
In the present invention, the X element indicates a transition element having 3d electrons of Ni, Fe, Co, and Cr in the outer shell, and the Y element indicates 2 valence electrons of Ti, Si, Zr, and Hf. Indicates an element that is four or four. X element and Y element are NiSiTi, NiSiZr, CoSiTi, Co ₂ Si, CuSiTi, CoHfSi, CuHfSi, Fe ₅ Si ₃ , Ti ₅ Si ₃ , Ni ₃ Ti ₂ Si, Co ₃ Ti ₂ Si, Cr ₃ Ti ₂ Si , Fe ₂ Ti, Ni ₃ Zr ₂ Si, CoSiZr, Cr ₂ Ti, CrMnTi, Ni ₂ Si, Ni ₃ Si, Ni ₉ Ti ₂ Zr, etc., and constituent elements of these compounds are replaced with other elements When the compound is precipitated in copper with a fine size of mainly 50 nm or less in conformity with the parent phase, the strength, conductivity, and stress relaxation resistance are improved.

This effect is not preferable when the X element content is less than 0.1% by mass or the Y element content is less than 0.01% by mass because the precipitation hardening amount is insufficient. In addition, when the X element exceeds 4 mass% or the Y element exceeds 3 mass%, coarse crystallized matter is generated in the alloy material structure to deteriorate the plating property or cause cracks during bending. Therefore, it is not preferable.
Therefore, the range of the X element is 0.1 to 4% by mass, preferably 0.3 to 3.0% by mass, and more preferably 0.3 to 2.5% by mass. The content range of Y element is 0.01-3 mass%, Preferably it is 0.03-2.0 mass%, More preferably, it is 0.04-1.5 mass%.

In the present invention, the Z element represents Sn, Mg, Zn, Ag, Mn, B, and P.
Sn, Mg, Zn, Ag, and Mn form a compound with X and Y elements and have a synergistic effect, and partly dissolve in copper alone, thereby improving strength and stress relaxation resistance. is there. B and P exhibit an effect of improving strength and stress relaxation resistance by improving the density of fine precipitates composed of X and Y elements or X, Y and Z elements. In addition, the Z element may be a constituent element of the second phase that is effective for controlling the crystal grain size, which will be described later.
When the element Z is less than 0.01% by mass, this effect cannot be obtained sufficiently. Moreover, when exceeding 3 mass%, since the fall of electroconductivity and the deterioration of castability are caused, it is unpreferable. Therefore, the content range of the Z element is 0.01 to 3% by mass, preferably 0.03 to 2% by mass, and more preferably 0.05 to 1.0% by mass.

Further, the crystal grain size can be controlled by high-temperature solution heat treatment, and the bending workability can be improved when the average crystal grain size is 10 μm or less. There is an effect of improving the strength by reducing the crystal grains. By setting the preferable average crystal grain size to 6 μm or less, more preferably 4 μm or less, good bending workability and strength can be obtained.
The average crystal grain size can be measured based on the cutting method of JISH0501 described later.

Moreover, in controlling the crystal grain size, the present inventors have also found that it is effective to disperse the second phase of 50 to 1000 nm at a density of 10 ⁴ / mm ² or more. Here, the second phase mainly refers to precipitates and some crystallized substances. In the solution heat treatment at a high temperature such as 750 ° C. or more, when this second phase is present, it has an effect of suppressing the growth of recrystallized grains, and as a result, by keeping the crystal grain size smaller, high strength and Bending workability can be further improved. The particle size of the second phase is preferably 60 nm to 800 nm, more preferably 70 nm to 700 nm, and the distribution density is preferably 10 ⁵ particles / mm ² or more.
When the particle size of the second phase is less than 50 nm, the effect of suppressing the grain growth is low, which is not preferable, and when larger than 1000 nm, the bending workability and the density of the second phase are reduced. It is not preferable.
The particle size and distribution density of the second phase can be measured based on the method described later.

This second phase is composed of elements having a melting point of 1400 ° C. or higher, such as Si, Co, Ni, Fe, Ti, Zr, and Cr, and thus stably exists without being dissolved in copper even at higher temperatures. Therefore, the action and effect of suppressing the coarsening of the crystal grain size can be increased.
Specifically, the configuration of this second phase is (a) when these elements are simple substances, (b) when these elements are compounds containing Si, Co, Ni, Fe, Ti, Zr, Cr, (C) The case where these elements form a compound with copper such as Cu—Zr and Cu—Hf is included.
In the case of (b), for example, Ni—Co—Cr—Si, Co—Si, Ni—Co—Si, Cr—Ni—Si, Co—Cr—Si, Ni—Zr, Mn—Zr, Ni— Mn-Zr, Fe-Zr, Mn-Zr, Fe-Mn-Zr, Ni-Ti, Co-Ti, Ni-Co-Ti, Fe-Ni-Si, Fe-Si, Mn-Si, Ni-Mn- P, Fe-P, Ni-P, Fe-Ni-P, Mn-B, Fe-B, Mn-Fe-B, Ni-B, Cr-B, Ni-Cr-B, Ni-Co-B, Forming compounds such as Ni-Co-Hf-Si, Ni-Co-Al, Ni-Ca, Ni-Co-Mn-Sn, Co-Ni-P, Al-Hf, Al-Zr, Al-Cr This is the case.
The second phase is preferably a ternary compound such as Cr—Ni—Si, Co—Cr—Si, or Fe—Ni—Si.

Next, a preferable processing step will be exemplified for a method for producing a copper alloy material that is most effective in extracting the characteristics of the alloy material system of the present invention and is suitable for use in electrical and electronic equipment.
For copper alloy material, casting [1], homogenization heat treatment [2], hot working [3], face milling [4], cold working [6], solution heat treatment [7], cold working [9] ], An aging precipitation heat treatment [10], a cold working [11] and a temper annealing [12] are performed in this order.
Cold work [6] has the function of making fine precipitates denser and finer by controlling the precipitation state of fine precipitates in solution heat treatment [7], and can improve strength, conductivity, and stress relaxation resistance. I can do it. Cold work [9] can improve strength by work hardening. The sum of the processing rate R1 (%) in the cold processing [9] and the processing rate R2 (%) in the cold processing [11] is preferably 5 to 65%.
If the total of the cold working ratios is less than 5%, the above effect cannot be obtained sufficiently, and if it exceeds 65%, the bending workability is remarkably lowered. By setting the total of the two processing rates to 5 to 65%, all characteristics can be improved. Preferably, the processing rate is 10 to 60%, more preferably 15 to 55%.

In the method for producing a copper alloy material of the present invention, it is preferable to add an aging precipitation heat treatment [8] after the solution heat treatment [7] in the above treatment step. The aging precipitation heat treatment [8] has the function of making the precipitation state denser and finer in the aging precipitation heat treatment [8] by providing precipitation nuclei and increasing the dislocation density in the cold working [7]. , Strength, electrical conductivity and stress relaxation resistance can be improved. The temperature of the aging precipitation heat treatment [8] is 400 to 700 ° C, preferably 425 to 675 ° C, more preferably 450 to 650 ° C. When the temperature is lower than 400 ° C., the amount of precipitation is small, and when the temperature exceeds 700 ° C., the precipitate becomes coarse, and thus the above effect cannot be obtained sufficiently. The best characteristics are obtained at 400-700 ° C. for 5 seconds to 20 hours.
Since the precipitates contributing to precipitation hardening need to be kept dense and fine, the treatment temperature of the aging precipitation heat treatment [10] is preferably lower than the treatment temperature of the aging precipitation heat treatment [8].

Further, as a method for controlling the dispersion state of the second phase of 50 to 1000 nm, it is preferable to perform aging precipitation heat treatment [5] at 400 to 800 ° C. for 5 seconds to 20 hours after the chamfering [4].
The second phase for controlling the crystal grain size precipitates during the cooling process of hot working [3] and the temperature increasing process of solution heat treatment [7], and contributes to controlling the crystal grain size small. The aging precipitation heat treatment [5] has a function of further increasing the density of the second phase. When this temperature is less than 400 ° C. or over 800 ° C. or when the treatment time is less than 5 seconds, the effect is small. When it exceeds 20 hours, the density of the second phase becomes coarse, so the effect is small. The temperature of the aging precipitation heat treatment [5] is preferably in the temperature range of 425 to 675 ° C, more preferably 450 to 650 ° C.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited thereto.
In addition, about the test material of the copper alloy material obtained in the Example, the following characteristic investigation was conducted.
A. Yield strength [YS]:
Three test pieces of JIS Z2201-13B cut out from the rolling parallel direction were measured according to JIS Z2241, and the average value was obtained.
B. Conductivity [EC]:
The specific resistance was measured by a four-terminal method in a thermostat kept at 20 ° C. (± 0.5 ° C.) to calculate the conductivity. In addition, the distance between terminals was 100 mm.
C. Stress relaxation rate [SR]:
The measurement was performed under the conditions of 150 ° C. × 1000 hours in accordance with Japan Electronic Material Industries Association Standard EMAS-3003. An initial stress of 80% of the proof stress was applied by the cantilever method.
FIG. 1 is an explanatory diagram of a stress relaxation characteristic test method, in which (a) shows a state before heat treatment and (b) shows a state after heat treatment. As shown in FIG. 1A, the position of the test piece 1 when an initial stress of 80% of the proof stress is applied to the test piece 1 held in a cantilever manner on the test stand 4 is a distance of δ ₀ from the reference. is there. This was held for 1000 hours in a thermostat at 0.99 ° C., the position of the test piece 2 after removing the load, the distance from the reference H _t as shown in FIG. 1 (b). 3 is a test piece when no stress is applied, and its position is a distance H ₁ from the reference.
From this relationship, the stress relaxation rate (%) was calculated as (H _t −H ₁ ) / (δ ₀ −H ₁ ) × 100.

D. Bending workability [R / t]:
Cut to a width of 10 mm and a length of 25 mm in parallel to the rolling direction, and the bending axis is W-bent parallel to the rolling direction at right angles to the rolling direction. R / t was calculated by observing the presence or absence of cracks in the bent part and adopting the ratio of the bending radius R and the plate thickness t, at which no cracks were generated. The measurement is performed such that a sample with a plate width w = 10 (mm) of each plate thickness is lightly rubbed on the surface with a metal polishing powder to remove the oxide film, and then the inner angle of bending becomes 90 °. Bending was performed in two types: bending for a sample parallel to the rolling direction (GOOD WAY: hereinafter GW) and bending for a sample perpendicular to the rolling direction (BAD WAY: hereinafter BW).
E. Average crystal grain size [GS]:
After the cross section perpendicular to the rolling direction of the test material is mirror-polished by wet polishing and buffing, the polished surface is corroded for several seconds with a solution of chromic acid: water = 1: 1, and then subjected to scanning electron microscope (SEM). A photograph was taken at a magnification of 400 to 1000 times using the backscattered electron image, and the cross-sectional particle size was measured by the cross cut method of JIS H0501.
F. Particle size and distribution density of the second phase:
The specimen was punched into a diameter of 3 mm, and thin film polishing was performed using a twin jet polishing method to produce an observation test piece. Images of 2000 and 40,000 times were arbitrarily taken with a transmission electron microscope (TEM) at an acceleration voltage of 300 kV for 10 fields of view, and the particle size and distribution density of the second phase were measured. The number of 50 to 1000 nm in the field of view was measured, and the number was calculated per unit area (/ mm ² ). For identification of the compound, an EDX analyzer attached to TEM was used.

Example 1
The X element and the Y element are blended so as to have the components and composition (mass%) shown in Table 1-1 and Table 1-2 below, and an alloy consisting of Cu and inevitable impurities is melted in a high frequency melting furnace, This was cast at a cooling rate of 0.1 to 100 ° C./second to obtain an ingot. This was subjected to a homogenization heat treatment at 900 to 1050 ° C. for 0.5 to 10 hours, followed by hot working with a cross-section reduction rate of 50% or more and a processing temperature of 650 ° C. or more, followed by water quenching to remove oxide scale. Carved for.
In the subsequent process, a copper alloy material was manufactured by performing (displaying) any one of the processes A to D described below.
Step A: Cold work with a cross-section reduction rate of 50 to 98%, solution heat treatment at 800 to 1000 ° C., cold work with a cross-section reduction rate of 5 to 50%, and aging at 400 to 650 ° C. Precipitation heat treatment was performed, finish cold work of 5 to 50% was performed, and temper annealing was performed at 200 to 450 ° C. for 5 seconds to 10 hours.
Step B: Cold work with a cross-section reduction rate of 50 to 98%, solution heat treatment at 800 to 1000 ° C, aging precipitation heat treatment at 400 to 650 ° C, and cold reduction with a cross-section reduction rate of 5 to 50% An aging precipitation heat treatment at 400 to 650 ° C. was performed, a finish cold work at 5 to 50% was performed, and temper annealing was performed at 200 to 550 ° C. for 5 seconds to 10 hours.
Step C: Aging precipitation heat treatment at 400 to 650 ° C., cold working with a cross-section reduction rate of 50 to 98%, solution heat treatment at 800 to 1000 ° C., and a cross-section reduction rate of 5 to 50% An aging precipitation heat treatment at 400 to 650 ° C. was performed, a finish cold work at 5 to 50% was performed, and temper annealing was performed at 200 to 550 ° C. for 5 seconds to 10 hours.
Step D: Aging precipitation heat treatment at 400 to 650 ° C., cold working with a cross-sectional reduction rate of 50 to 98%, solution heat treatment at 800 to 1000 ° C., and aging precipitation heat treatment at 400 to 550 ° C. In addition, a cold working with a cross-sectional reduction rate of 5 to 50% is performed, an aging precipitation heat treatment at 400 to 650 ° C. is performed, a finish cold working at 5 to 50% is performed, and a temperature of 200 to 550 ° C. is applied for 5 seconds to 10 hours. Temper annealing was performed.

  Each part of the obtained copper alloy material was used as a test material, and the characteristics of the yield strength [YS], conductivity [EC], and stress relaxation rate [SR] were examined for each test material, and the results obtained Are shown in Table 1-1 and Table 1-2.

  As is clear from Table 1, Invention Example 1-1 to Invention Example 1-32 were excellent in yield strength, conductivity, and stress relaxation resistance. However, as shown in Table 1-2, the characteristics were not excellent when the provisions of the present invention were not satisfied. That is, since Comparative Example 1-1 had a small amount of X element, the density of precipitates was low, and the strength, conductivity, and stress relaxation resistance were inferior. In Comparative Example 1-2, since the amount of X element was large, the amount of solid solution atoms was increased and the conductivity was inferior. Since Comparative Example 1-3 had a small amount of Y element, the density of precipitates was low, and the strength, conductivity, and stress relaxation resistance were inferior. Since Comparative Example 1-4 had a large amount of Y element, the amount of solid solution atoms increased and the conductivity was inferior.

(Example 2)
The copper alloy which mix | blends X element, Y element, and Z element so that it may become a component and composition shown in the following Table 2-1 and Table 2-2, and the remainder consists of Cu and an unavoidable impurity was described in the said Example 1. An alloy material was prepared according to the same manufacturing method as above, and a part of each was used as a test material. The characteristics of each test material were investigated in the same manner as in Example 1, and the obtained results are shown in Tables 2-1 and 2-2.

  As is apparent from Table 2-1, Invention Example 2-1 to Invention Example 2-32 were excellent in yield strength, conductivity, and stress relaxation resistance. However, as shown in Table 2-2, the characteristics were not excellent when the prescribed values of the component amounts of the present invention were not satisfied. That is, Comparative Example 2-1 to Comparative Example 2-3 had very poor conductivity because the amount of Z element was too large.

(Example 3)
The copper alloy which mix | blended X element, Y element, and Z element so that it might become a component and composition shown in the following Table 3-1 and Table 3-2, and the remainder consists of Cu and an unavoidable impurity was described in the said Example 1. An alloy material was prepared according to the same manufacturing method as above, and a part of each was used as a test material. However, Comparative Example 3-1 to Comparative Example 3-3 performed solution heat treatment at a temperature higher by about 20 to 30 ° C. than the respective manufacturing steps of Invention Example 3-1 to Invention Example 3-3.
In addition to the yield strength [YS], the electrical conductivity [EC], and the stress relaxation rate [SR], for each of these test materials, the average crystal grain size [GS] and the bending workability [R / t] Characteristic investigation was performed and the obtained results are shown in Tables 3-1 and 3-2.

  As is apparent from Table 3-1, Invention Example 3-1 to Invention Example 3-32 were excellent in yield strength, conductivity, stress relaxation resistance, and bending workability. However, as shown in Table 3-2, in Comparative Examples 3-1 to 3-3 having a high solution heat treatment temperature, the crystal grain size was larger than 10 μm and the bending workability was inferior.

Example 4
The copper alloy which mix | blends X element, Y element, and Z element so that it may become a component and composition shown in the following Table 4-1 and Table 4-2, and the remainder consists of Cu and an unavoidable impurity was described in the said Example 1. An alloy material was prepared according to the same manufacturing method as above, and a part of each was used as a test material. However, Comparative Examples 4-1 to 4-3 were subjected to solution heat treatment at 1200 ° C. for 10 minutes.
For each of the test materials, as in Example 3, the characteristics of the yield strength [YS], conductivity [EC], stress relaxation rate [SR], average grain size [GS] and bending workability [R / t] were investigated. In addition, the constituent elements of the 50-1000 nm particles constituting the second phase and the particle density thereof were investigated, and the results obtained are shown in Tables 4-1 and 4-2. In the table, “10 ^ n represents 10 ⁿ ” (the same applies to the following tables).

  As is clear from Table 4-1, Invention Example 4-1 to Invention Example 4-32 were excellent in yield strength, conductivity, stress relaxation resistance, and bending workability. However, as shown in Comparative Example 4-1 to Comparative Example 4-3 in Table 4-2, when the particle density of the second phase was low, the crystal grain size was larger than 10 μm and the bending workability was inferior.

(Example 5)
The elements are blended so as to have the components and compositions shown in Table 5-1 below, and an alloy composed of Cu and inevitable impurities is melted in a high-frequency melting furnace, and this is cooled at a rate of 0.1 to 100 ° C./second. The ingot was obtained by casting. This was homogenized at 900 to 1050 ° C for 0.5 to 10 hours, then hot-worked with a cross-section reduction rate of 50% or more and a processing temperature of 650 ° C or more, and then water quenching to remove oxide scale. Carved for. Thereafter, cold working with a cross-sectional reduction rate of 50 to 98% is performed, solution heat treatment at 800 to 1000 ° C. is performed, and cold working with a cross-sectional reduction rate of R1 [%] in the table is performed, and 400 to 650 ° C. Aging precipitation heat treatment, finish cold working with a cross-sectional reduction rate of R2 [%] in the table, temper annealing at 200-450 ° C. for 5 seconds to 10 hours to produce a copper alloy material, Each part was used as a test material. The results are shown in Tables 5-2 and 5-3.

  As apparent from Table 5-2, Invention Example 5-1 to Invention Example 5-3 were excellent in yield strength, conductivity, stress relaxation resistance, and bending workability. However, as shown in Comparative Example 5-1, when the sum of R1 and R2 is less than 5%, the strength is low, which is not preferable. As shown in Comparative Example 5-2, when the sum of R1 and R2 exceeds 65%, the stress relaxation resistance and bending workability are inferior, which is not preferable.

(Example 6)
In the same manner as in Example 5, the elements were blended so as to have the components and compositions shown in Table 5-1, and an alloy composed of Cu and unavoidable impurities in the remainder was melted in a high-frequency melting furnace. An ingot was obtained by casting at a cooling rate of / sec. This was homogenized at 900 to 1050 ° C for 0.5 to 10 hours, then hot-worked with a cross-section reduction rate of 50% or more and a processing temperature of 650 ° C or more, and then water quenching to remove oxide scale. Carved for. Thereafter, cold working with a cross-section reduction rate of 50 to 98% is performed, solution heat treatment at 800 to 1000 ° C. is performed, and the temperature indicated by T8 [° C.] in Table 6-1 and Table 6-2 is 4 hours. The aging precipitation heat treatment was applied, cold working was performed with a cross-sectional reduction rate of 5 to 50%, and aging precipitation heat treatment was performed at a temperature indicated by T10 [° C.] in the table for 4 hours. Subsequently, 5 to 50% finish cold work was performed, and temper annealing was performed at 200 to 450 ° C. for 5 seconds to 10 hours to produce a copper alloy material, each of which was used as a test material.
For each specimen, the yield strength [YS], conductivity [EC], stress relaxation rate [SR], average grain size [GS], bending workability [R / t], and constituent elements of the second phase And the characteristics such as density were investigated, and the obtained results are shown in Table 6-1 and Table 6-2.

  As apparent from Table 6-1, Invention Example 6-1 to Invention Example 6-2 were excellent in yield strength, conductivity, stress relaxation resistance, and bending workability. However, as shown in Comparative Example 6-1 and Comparative Example 6-2 in Table 6-2, if T10 is higher than the temperature T8 of the aging precipitation heat treatment, the precipitation hardening ability is insufficient, and the strength is low, which is not preferable. I understand that.

(Example 7)
In the same manner as in Example 5, the elements were blended so as to have the components and compositions shown in Table 5-1, and an alloy composed of Cu and unavoidable impurities in the remainder was melted in a high-frequency melting furnace. An ingot was obtained by casting at a cooling rate of / sec. This was homogenized at 900 to 1050 ° C for 0.5 to 10 hours, then hot-worked with a cross-section reduction rate of 50% or more and a processing temperature of 650 ° C or more, and then water quenching to remove oxide scale. Carved for. Thereafter, an aging precipitation heat treatment is performed for 4 hours at a temperature indicated by T5 [° C.] in Table 7, a cold working with a cross-section reduction rate of 50 to 98% is performed, and a solution heat treatment at 800 to 1000 ° C. is performed. Perform cold working with a cross-section reduction rate of 5 to 50%, perform aging precipitation heat treatment at 400 to 650 ° C, perform finish cold working at 5 to 50%, and adjust for 5 seconds to 10 hours at 200 to 550 ° C. Quality annealing was performed to produce a copper alloy material, and a part of each was used as a test material.
For each specimen, the yield strength [YS], conductivity [EC], stress relaxation rate [SR], average grain size [GS], bending workability [R / t], and constituent elements of the second phase And the characteristics such as density were investigated, and the obtained results are shown in Table 7.

  As shown in Table 7, when the aging precipitation heat treatment [5] is performed at 400 to 800 ° C., the density of the second phase can be increased, the crystal grain size can be reduced, and the bending workability can be improved. It was.

It is a schematic explanatory drawing of a stress relaxation test method.

Explanation of symbols

1 Test piece to which 80% of the proof stress was given 2 Test piece heat-treated and unloaded in the state of 1 3 Test piece when not loaded 4 Test stand δ ₀ Standard of test piece when deflected Distance from position
H ₁ Distance from the reference position of the specimen when not bent
H _t Distance from the reference position of the specimen after bending, heat treatment and unloading

Claims (9)

0.1-4% by mass of X element (where X element is one or more of transition elements of Ni, Fe, Co, Cr) and Y element is 0.01-3% % (Where Y element is one or more of Ti, Si, Zr, and Hf), the balance being a copper alloy material consisting of copper and inevitable impurities,
A copper alloy having a conductivity of 50% IACS or more, a proof stress of 600 MPa or more, and a stress relaxation rate of 20% or less when held for 1000 hours with a stress of 80% of the proof stress applied Wood.   The element further contains 0.01 to 3% by mass of Z element (wherein the Z element is one or more of Sn, Mg, Zn, Ag, Mn, B, and P). The copper alloy material according to claim 1.   The copper alloy material according to claim 1 or 2, wherein an average crystal grain size is 10 µm or less. The copper alloy material according to any one of claims 1 to 3, wherein a second phase having a particle diameter of 50 to 1000 nm is present at a distribution density of 10 ⁴ pieces / mm ² or more.   The copper alloy material according to claim 4, wherein the second phase is a compound containing Si, Co, Ni, Fe, Ti, Zr, or Cr.   The copper alloy material according to claim 5, wherein the second phase is a ternary compound.   For copper alloy material, casting [1], homogenization heat treatment [2], hot working [3], face cutting [4], cold working [6], solution heat treatment [7], cold working [9] ], Aging precipitation heat treatment [10], cold working [11], and temper annealing [12] are performed in this order, and the processing rate R1 (%) and cold processing in the cold working [9] are performed. The copper alloy material according to any one of claims 1 to 6, wherein the sum of the processing rates R2 (%) in the inter-working [11] is 5 to 65%. .   For copper alloy material, casting [1], homogenization heat treatment [2], hot working [3], facing [4], cold working [6], solution heat treatment [7], aging precipitation heat treatment [8] ], Cold working [9], aging precipitation heat treatment [10], cold working [11] and temper annealing [12] in this order, and processing in the cold working [9] The sum of the rate R1 (%) and the processing rate R2 (%) in the cold work [11] is 5 to 65%, the treatment temperature of the aging precipitation heat treatment [8] is 400 to 700 ° C., and the aging precipitation heat treatment [10]. A method for producing a copper alloy material for electronic equipment, comprising obtaining the copper alloy material according to any one of claims 1 to 6, wherein the treatment temperature is lower than the treatment temperature of the aging precipitation heat treatment [8].   The manufacturing method according to claim 7 or 8, characterized in that after the chamfering [4], an aging precipitation heat treatment [5] is performed at 400 to 800 ° C for 5 seconds to 20 hours, and a cold working [6] is performed. A method for producing a copper alloy material for electronic and electrical equipment.

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