JP2009242814A - Copper alloy material and producing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a for electric or electronic equipment which has high electric conductivity of ≥50% IACS hardly achieved in a Cu-Ni-Si series and is excellent in strength, stress-relaxation resistance and bendability, and to provide a producing method by which the crystal grain diameter of the copper alloy material can be controlled. <P>SOLUTION: The copper alloy material contains, composed by mass%, 0.1-4% X elements (wherein, the X elements are one or two or more elements in transition elements of Ni, Fe, Co and Cr) and 0.01-3% Y elements (wherein, the Y elements are one or two or more elements of Ti, Si, Zr and Hf) and the balance copper with inevitable impurities. The alloy material has ≥50% IACS electric conductivity and ≥600 MPa proof strength and the stress-relaxation ratio at the time of holding 1,000 hours under state of giving the stress having 80% proof strength, is ≤20%. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a copper alloy material applied to lead frames, connectors, terminal materials, relays, switches, sockets, and the like for electric and electronic devices, and a method for manufacturing the same.

  Characteristic items required for copper alloy materials used for electrical and electronic equipment 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 based alloy (for example, CDA 70250 which is a registered CDA [Copper Development Association] registered alloy) strengthened by fine precipitation of 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 (see, for example, Patent Document 1). Further, there is an invention example of a method for producing a copper alloy in which a compound of Ti and Fe is dispersed (for example, see Patent Document 2).

Japanese Patent Publication No. 04-053945 JP 07-258806 A

  However, with only the techniques described in the above-mentioned patent documents, it is difficult to align strength, electrical conductivity, stress relaxation resistance, and bending workability, and all these required characteristics have not been satisfied.

  In view of the above problems, an object of the present invention is to provide a copper alloy material that is excellent in electrical conductivity, strength, stress relaxation resistance, and bending workability, and is suitable for electrical and electronic equipment applications. In particular, to provide a precipitation-type copper alloy material that can stably realize a high conductivity of 50% IACS or higher, which is difficult to achieve with a Cu-Ni-Si system, and a technique for controlling the crystal grain size in the production thereof. is there.

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 to 4% by mass of X element (where X element is one or more of transition elements of Ni, Fe, Co and Cr) and Y element is 0.01 to 3% by mass (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, 50% IACS or more And a stress relaxation rate of 30% or less when held for 1000 hours in a state where a stress of 80% of the proof stress is applied and a second phase existing on the grain boundary. A copper alloy material characterized in that particles exist at a density of 10 ⁴ to 10 ⁸ particles / mm ² and an average crystal grain size is 10 μm or less;
(2) 0.1 to 4% by mass of X element (where X element is one or more of transition elements of Ni, Fe, Co and Cr) and 0.01 to 0.01% of Y element 3% by mass (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, 50% IACS or more And a stress relaxation rate when held for 1000 hours in a state where a stress of 80% of the proof stress is applied and having a proof stress of 500 MPa or more, the particle diameter r (unit: second phase particle) : Μm), the ratio of the volume fraction f of the particles, the value of r / f is 1 to 100, and the average crystal grain size is 10 μm or less,
(3) 0.01 to 3% by mass 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) or (2),
(4) The copper alloy material according to any one of (1) to (3), wherein the second phase is a compound containing Si, Co, Ni, Fe, Ti, Zr or Cr,
(5) Casting [1], homogenization heat treatment [2], hot working [3], water cooling [4], surface cutting [5], cold working [7], solution heat treatment [8] ], Cold working [9], aging precipitation heat treatment [10], cold working [11] and temper annealing [12] in this order, and hot working [3] is 500 ° C. The solution heat treatment is performed as described above, and the solution heat treatment is performed in a temperature range of 400 ° C. to 700 ° C. at a temperature increase rate of 10 ° C. to 400 ° C./second, and the processing rate R1 (%) in the cold working [9]. The copper alloy material according to any one of claims 1 to 4, wherein the sum of the machining rate R2 (%) in cold working [11] is 5 to 65%. Production method,
(6) In the method for producing a copper alloy material according to the above (5), aging precipitation heat treatment [6] is performed at 400 to 800 ° C. for 5 seconds to 20 hours after chamfering [5], and cold working [7 A method for producing a copper alloy material,
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.

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 two valence electrons of Ti, Si, Zr, and Hf or It shows four elements. 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, Ni ₂ Si, Ni ₃ Si, Ni ₉ Ti ₂ Zr, Ni ₃ Ti, NiCoSi, and other constituent elements of these compounds The compound substituted with the element precipitates in copper with a fine size of mainly 50 nm or less in conformity with the parent phase, thereby improving strength, conductivity, and stress relaxation resistance.

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. This 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. Here, the second phase mainly refers to precipitates and some crystallized substances.
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.

  Further, in controlling the crystal grain size, it is effective to disperse the second phase, which deteriorates the bending processability, and the coarsening of the crystal grain size during solution heat treatment at a high temperature such as 750 ° C. or higher. It is particularly effective to disperse the second phase appropriately. This is because, during grain growth, energy gain is generated at the interface between the dispersed grain and the grain boundary when passing through the second phase grain in which the grain boundary is dispersed, and the grain boundary movement is delayed. It is assumed that there is. As a result of the effect of suppressing the crystal grain growth by the series of second phase particles, bending workability can be improved by keeping the crystal grain size small.

In the present invention, the appropriate second phase dispersion state for sufficiently obtaining the effect of controlling the crystal grain size is defined by the following two methods. The particle size and distribution density of the second phase can be measured based on the method described later.
The first is that the second phase particles present on the grain boundaries are present at a density of 10 ⁴ to 10 ⁸ particles / mm ² . In this case, it is more preferably 5 × 10 ^{5 to} 5 × 10 ⁷ pieces / mm ² . When the density is lower than 10 ⁴ pieces / mm ^2, the effect of suppressing the growth of crystal grains is insufficient, and when the density exceeds 10 ⁸ pieces / mm ² , the grain boundaries become brittle and bending work is performed. This is not preferable because it lowers the properties.
Second, the ratio of the particle diameter r (unit: μm) of all second phase particles including the inside of the crystal grains and the crystal grain boundaries to the volume fraction f of the particles, and the value of r / f is 1-100. That is. Here, the display of the volume fraction f is that f = 0.005 represents 0.5 vol%. More preferably, the value of r / f is 5 to 90. When the value of r / f is smaller than 1, the particle diameter is too small with respect to the volume fraction, so that the effect of suppressing grain growth cannot be sufficiently obtained at the high temperature of the solution heat treatment, and the value of r / f Is larger than 100, the particle diameter is too large with respect to the volume fraction, which causes stress concentration at the time of bending deformation and deteriorates bending workability, which is not preferable.

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 , Ni-Co-Hf-Si, Ni-Co-Al, Ni-Ca, Ni-Co-Mn-Sn, Co-Ni-P, Al-Hf, Al-Zr, Al-Cr, etc. It is a case.
The second phase is preferably a ternary compound such as Cr—Ni—Si, Co—Cr—Si, or Fe—Ni—Si.

  Next, the preferable processing steps will be exemplified with respect to a method for producing a copper alloy material suitable for use in electrical and electronic equipment, which is most effective in extracting the characteristics of the alloy system of the present invention. Here, “copper alloy material” means a copper alloy (plate, strip, wire, bar, foil, etc.) having a specific shape, but in the following example, an example applied to a plate or strip is shown.

  First, the basic steps of the method for producing a copper alloy material of the present invention will be described. This step is performed on a copper alloy material by casting [1], homogenizing heat treatment [2], hot working [3], water cooling [4], face cutting [5], cold working [7], solution heat treatment [ 8], cold working [9], aging precipitation heat treatment [10], cold working [11], and temper annealing [12].

In the hot working [3], it is preferable to perform hot working at 500 ° C. to 1000 ° C. to cause dynamic recrystallization in the cast structure to obtain an equiaxed structure. When the temperature is 500 ° C. or lower, coarse precipitates are generated, and it is difficult to realize dispersed particles of second phase particles effective in suppressing the coarsening of crystal grains found in the present invention, which is not preferable. More preferably, it is 650-950 degreeC.
The solution heat treatment [8] is preferably performed in a temperature range of 400 ° C. to 700 ° C. at a rate of temperature increase of 10 ° C. to 400 ° C./second. If it is slower than 10 ° C./second, recovery occurs during the temperature rise, and the crystal grain size becomes coarse due to a decrease in the frequency of recrystallization nucleation. Also, the temperature rise rate is faster than 400 ° C./second. In this case, the amount of the second phase particles precipitated during the temperature rise is decreased, and it is difficult to realize the dispersed particles of the second phase particles effective in suppressing the coarsening of the crystal grains found in the present invention, which is not preferable. More preferably, it is 20 degreeC-300 degreeC / second.
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%. Cold working [9] has the effect of obtaining a dense, uniform and fine precipitation state in the aging precipitation heat treatment [10] and improving strength, conductivity and stress relaxation resistance. In particular, in the present invention, since the dispersed particles of the second phase are actively left at the time of solution treatment, the solute atoms that are solutionized work not as the growth of the particles but as fine precipitates in the crystal grains. ,is important. Moreover, the cold work [11] realizes excellent strength by work hardening. When the total of the cold working ratios is 5% or less, the above effect cannot be obtained sufficiently, and when it is 65% or more, 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%.

Furthermore, as a method for realizing a dispersed state of the second phase effective for crystal grain growth, 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 parallel to the rolling direction, and the bending axis is W-bent parallel to the perpendicular to the rolling direction, and the presence or absence of cracks in the bent portion is checked with an optical microscope and a scanning electron microscope (SEM). 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 [r], volume fraction [f] and distribution density [ρ] on the grain boundary 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. Photographic images with a magnification of 300 kV were arbitrarily taken at 10 fields of view with a transmission electron microscope (TEM) at an acceleration voltage of 300 kV, and the particle diameter and density of the second phase were measured on the photographs. The thickness of the observation specimen was measured from the equal thickness interference fringes, and the volume fraction of the second phase particles in the total volume in the observation field was taken as the volume fraction.
G. Identification of constituent atoms of the second phase [C]
The energy dispersive X-ray elemental analyzer (EDX) attached to the 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 is subjected to homogenization heat treatment at 900 to 1050 ° C. for 0.5 to 10 hours, and after hot working with a cross-section reduction rate of 50% or more and a processing temperature of 500 ° C. or more, water quenching is performed 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 working of 5 to 50% was performed, and temper annealing was performed at 200 to 550 ° 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. For each test material, yield strength [YS], conductivity [EC], stress relaxation rate [SR], bending workability [R / t], The average crystal grain size [GS], the density [ρ] of the second phase particles on the grain boundary, and the constituent atoms [C] of the second phase were investigated, and the obtained results are shown in Table 1-1 and Table 1- It was shown in 2. In the table, “10 ^ n represents 10 ⁿ ” (the same applies to the following tables).

  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 inferior 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 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 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. In Comparative Example 1-5, since the density of the second phase on the grain boundary was low, the crystal grain size was coarse and bending workability was poor. In Comparative Example 1-6, since the density of the second phase on the grain boundary was large, grain boundary cracking was caused, the crystal grain size was coarsened, and bending workability was inferior.

(Example 2)
The X element and Y element are blended so as to have the components and compositions shown in Table 2-1 and Table 2-2 below, and the copper alloy consisting of Cu and inevitable impurities is the same as described in Example 1 above. It produced according to the manufacturing method, and each one part was made into the test material.
For each of the test materials, the yield strength [YS], the electrical conductivity [EC], the stress relaxation rate [SR], the bending workability [R / t], the average crystal grain size [GS], the particle size of the second phase particles and The ratio [r / f] to the volume fraction and the constituent atoms [C] of the second phase were investigated, 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 inferior when the prescribed values of the component amounts of the present invention were not satisfied. That is, Comparative Example 2-1 was inferior in strength, electrical conductivity, and stress relaxation resistance due to the small amount of X element. In Comparative Example 2-2, since the amount of X element was large, the amount of solid solution atoms increased and the conductivity was inferior. Since Comparative Example 2-3 had a small amount of Y element, the strength, conductivity, and stress relaxation resistance were inferior. In Comparative Example 2-4, since the amount of the Y element was large, the amount of solid solution atoms increased and the conductivity was inferior. Since Comparative Example 2-5 has a small r / f value and crystal grains are coarse, Comparative Example 2-6 has a large r / f value and a coarse second phase, and cracks are generated during bending deformation. Bending workability deteriorated.

(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. For each of these test materials, yield strength [YS], conductivity [EC], stress relaxation rate [SR], bending workability [R / t], average crystal grain size [GS], second phase on grain boundaries The density [ρ] of the particles and the constituent atoms [C] of the second phase were investigated, 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, the characteristics were inferior when the provisions of the present invention were not satisfied. That is, in Comparative Examples 3-1 to 3-3, since the amount of the Z element was large, the amount of dissolved atoms was increased and the conductivity was inferior. In Comparative Example 3-4, since the density of the second phase on the grain boundary was low, the crystal grain size was coarse and bending workability was poor. In Comparative Example 3-5, since the density of the second phase on the grain boundary was large, grain boundary cracking was caused, the crystal grain size was coarsened, and 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. For each of the test materials, the yield strength [YS], the electrical conductivity [EC], the stress relaxation rate [SR], the bending workability [R / t], the average crystal grain size [GS], the particle size of the second phase particles and The ratio [r / f] to the volume fraction and the constituent atom [C] of the second phase were investigated, and the obtained results are shown in Tables 4-1 and 4-2.

  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 Table 4-2, the characteristics were inferior when the provisions of the present invention were not satisfied. That is, in Comparative Examples 4-1 to 4-3, since the amount of the Z element was large, the amount of solid solution atoms was increased and the conductivity was inferior. Since Comparative Example 4-4 had a small r / f value and crystal grains were coarse, Comparative Example 4-5 had a large r / f value and a coarse second phase, and cracks occurred during bending deformation. Bending workability deteriorated.

(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 subjected to a homogenization treatment at 900 to 1050 ° C. for 0.5 to 10 hours, and then subjected to hot quenching after hot rolling at a cross-section reduction rate of 50% or more and a lower limit of the treatment temperature of TL [° C.] in the table. And chamfered to remove oxide scale. 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, cold working with a cross-section reduction rate of 2 to 40% is performed, and aging at 400 to 650 ° C. Precipitation heat treatment is performed, finish cold working with a cross-section reduction rate of 2 to 30% is performed, temper annealing is performed at 200 to 450 ° C. for 5 seconds to 10 hours, a copper alloy is manufactured, and each part thereof is provided. Samples were used.
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 The characteristics such as density were investigated, and the obtained 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 Table 5-3, in Comparative Examples 5-1 and 5-2, the hot working temperature was less than 500 ° C., and a large amount of coarse precipitation occurred. As a result of deterioration of the crystal grain size, bending workability deteriorated.

(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, a solution heat treatment was performed at S (° C./sec) shown in Table 6 at a temperature increase rate in the temperature range of 400 ° C. to 700 ° C., a holding temperature of 800 to 1000 ° C., and a holding time of 5 seconds to 2 hours. And cold work with a cross-section reduction rate of 2 to 40%, aging precipitation heat treatment at 400 to 650 ° C., finish cold work with a cross-section reduction rate of 2 to 30%, and 5 to 200 to 450 ° C. A temper annealing for 2 to 10 hours was performed to produce a copper alloy, 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 6-1 and Table 6-2.

  As apparent from Table 6-1, Invention Example 6-1 to Invention Example 6-3 were excellent in yield strength, conductivity, stress relaxation resistance, and bending workability. However, as shown in Comparative Example 6-1 in Table 6-2, when the rate of temperature rise is too fast, the second phase that precipitates during the temperature rise is insufficient, the crystal grains become coarse, and the bending workability deteriorates. did. Further, as shown in Comparative Example 6-2, when the rate of temperature increase is too slow, recovery occurs during the temperature increase, the frequency of recrystallization nucleation decreases, the crystal grains become coarse, and the bending workability increases. Deteriorated.

(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, 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 to 450 ° C. for 5 seconds to 10 hours to produce a copper alloy, A part 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 Tables 7-1 and 7-2.

  As is apparent from Table 7-1, Invention Example 7-1 to Invention Example 7-3 were excellent in yield strength, conductivity, stress relaxation resistance, and bending workability. However, as shown in Comparative Example 7-1, when the sum of R1 and R2 is 5% or less, the strength is low, which is not preferable. As shown in Comparative Example 7-2, when the sum of R1 and R2 is 65% or more, the stress relaxation resistance and bending workability are inferior, which is not preferable.

(Example 8)
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 at a temperature indicated by TA [° C.] in Table 8 is performed for 4 hours, a cold working with a cross-sectional 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, 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 Table 8 shows the obtained results.

  As shown in Table 8, since the aging precipitation heat treatment [5] was performed at 400 to 800 ° C., the dispersion state of the second phase could be controlled well and the crystal grain size could be reduced. Workability was good.

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 (6)

0.1 to 4% by mass of X element (where X element is one or more of transition elements of Ni, Fe, Co and Cr) and 0.01 to 3% by mass of Y element (Wherein the Y element is one or more of Ti, Si, Zr, and Hf), and the balance is a copper alloy material consisting of copper and inevitable impurities,
It has a conductivity of 50% IACS or higher, a proof stress of 500 MPa or higher, and a stress relaxation rate of 30% or lower when held for 1000 hours in a state where a stress of 80% of the proof stress is applied.
A copper alloy material, wherein the second phase particles present on the grain boundaries are present at a density of 10 ⁴ to 10 ⁸ particles / mm ² , and the average crystal grain size is 10 μm or less. 0.1 to 4% by mass of X element (where X element is one or more of transition elements of Ni, Fe, Co and Cr) and 0.01 to 3% by mass of Y element (Wherein the Y element is one or more of Ti, Si, Zr, and Hf), and the balance is a copper alloy material consisting of copper and inevitable impurities,
It has a conductivity of 50% IACS or higher, a proof stress of 500 MPa or higher, and a stress relaxation rate of 30% or lower when held for 1000 hours in a state where a stress of 80% of the proof stress is applied.
The ratio of the particle size r (unit: μm) of the second phase particles to the volume fraction f of the particles, the value of r / f is 1 to 100, and the average crystal particle size is 10 μm or less. Copper alloy material to be used.   Further, it is characterized by further containing 0.01 to 3% by mass of Z element (wherein Z element is one or more of Sn, Mg, Zn, Ag, Mn, B, and P). The copper alloy material according to claim 1 or 2.   The copper alloy material according to claim 1, wherein the second phase is a compound containing Si, Co, Ni, Fe, Ti, Zr, or Cr.   For copper alloy material, casting [1], homogenization heat treatment [2], hot working [3], water cooling [4], face cutting [5], cold working [7], solution heat treatment [8], cold working A process composed of hot working [9], aging precipitation heat treatment [10], cold working [11] and temper annealing [12] is performed in this order, and hot working [3] is performed at 500 ° C. or higher. The solution heat treatment is performed in a temperature range of 400 ° C. to 700 ° C. at a rate of temperature increase of 10 ° C. to 400 ° C./second, and the processing rate R1 (%) in the cold processing [9] and cold The method for producing a copper alloy material according to any one of claims 1 to 4, wherein the sum of the processing rates R2 (%) in the processing [11] is 5 to 65%.   6. The method for producing a copper alloy material according to claim 5, wherein after the chamfering [5], an aging precipitation heat treatment [6] is performed at 400 to 800 ° C. for 5 seconds to 20 hours, and a cold working [7] is performed. A method for producing a copper alloy material.

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