JP5411679B2 - Copper alloy material - Google Patents

Description

  The present invention relates to a copper alloy material suitably used as a material for electric / electronic parts, for example, and particularly relates to a copper alloy material having excellent stress relaxation resistance.

  Materials used for electrical and electronic parts such as connectors, relays and switches have sufficient strength to obtain a high contact pressure as a spring material, and stress resistance that can maintain the contact pressure even when used for a long time at high temperatures There are demands for characteristics such as relaxation and high conductivity to suppress the generation of Joule heat during energization and to easily dissipate the generated heat.

  In recent years, hybrid vehicles and electric vehicles have been put to practical use, and there is an increasing demand for materials having both higher electrical conductivity and better spring properties in parts such as terminals and connectors used in these vehicles. In addition, since the use environment of such components for in-vehicle use is high, there is an increasing demand for a material having higher stress relaxation resistance than ever so that sufficient reliability can be ensured even in a high temperature environment. Conventionally, brass or the like has been used as such a material, but it is not possible to obtain characteristics that satisfy the requirements of high conductivity and stress relaxation resistance.

  Cu—Zr-based and Cu—Cr-based alloys have been proposed as materials that can meet the above demands for high conductivity (see, for example, Patent Documents 1 to 4). Among these alloys, Cu—Zr-based alloys can secure an extremely high conductivity around 90% IACS and are considered to be promising alloys.

Japanese Patent Laid-Open No. 2-97632 JP 2008-248275 A JP-A-6-158201 JP-A-7-166270

  However, Cu—Zr alloys are unlikely to have high strength by precipitation hardening, like Cu—Ni—Si alloys, which are similar precipitation alloys. Also, the stress relaxation resistance is insufficient for the high level characteristics required for recent automotive parts.

  Therefore, the object of the present invention is to use a Cu-Zr-based alloy having a high conductivity as a raw material, and as an electric / electronic component material having both higher stress relaxation resistance and superior strength and springiness. The object is to provide a suitable copper alloy material.

In order to solve the above conventional problems, the present inventors have made various studies on Cu—Zr alloys. As a result, the following solutions (1) to (5) have been found and the present invention has been completed.
(1) The Cu—Zr alloy is based on a copper alloy containing 0.05 to 0.3% by mass of Zr.
(2) In addition to the above (1), the total amount of at least one selected from Mg, Ti, Zn, Ga, Y, Nb, Mo, Ag, In, and Sn is 0.01 to 0.3% by mass. A copper alloy containing Cu and the inevitable impurities is used as a raw material.
(3) The copper alloy in the composition range configured as in the above (1) and (2) further has a stress relaxation rate of 20% or less after holding the stress relaxation resistance at 150 ° C. for 1000 hours. It is prescribed as follows.
(4) The copper alloy having the stress relaxation resistance of (3) is further specified to have a tensile strength of 480 MPa or more while maintaining a conductivity of 90% IACS or more with respect to the characteristic value.
(5) In order to realize the characteristic (3) more stably, the average crystal grain size after the intermediate annealing is adjusted to 20 to 100 μm.

  That is, in order to achieve the above object, the present invention contains 0.05 to 0.3% by mass of Zr, and includes Mg, Ti, Zn, Ga, Y, Nb, Mo, Ag, In, and Sn. One or more selected from the group consisting of 0.01 to 0.3% by mass, the balance being Cu and inevitable impurities, and the stress relaxation rate after holding at 150 ° C. for 1000 hours is 20% or less Provided is a copper alloy material characterized by having relaxation properties.

  In order to achieve the above object, the present invention contains 0.05 to 0.3% by mass of Zr, and includes Mg, Ti, Zn, Ga, Y, Nb, Mo, Ag, In, and Sn. One or more selected from the group consisting of 0.01 to 0.3 mass% in total, the balance being made of Cu and inevitable impurities, and having a tensile strength of 480 MPa or more while maintaining a conductivity of 90% IACS or more And the copper alloy material characterized by having a stress relaxation resistance with a stress relaxation rate of 20% or less after holding at 150 ° C. for 1000 hours.

  Furthermore, in order to achieve the above-mentioned object, the present invention contains 0.05 to 0.3% by mass of Zr, and includes Mg, Ti, Zn, Ga, Y, Nb, Mo, Ag, In, and Sn. The total amount of one or more selected from the group consisting of 0.01 to 0.3% by mass, the balance being made of Cu and inevitable impurities, the average crystal grain size after intermediate annealing being adjusted to 20 to 100 μm, and 150 It is a copper alloy material characterized by having a stress relaxation resistance of 20% or less after holding at 1000C for 1000 hours.

  Furthermore, in order to achieve the above object, the present invention contains 0.05 to 0.3% by mass of Zr, and at least one of Ga and Mo in a total amount of 0.01 to 0.3% by mass. The copper alloy material is characterized by having a stress relaxation resistance consisting of Cu and inevitable impurities.

  According to the present invention, it is possible to effectively obtain a copper alloy material which has high stress relaxation resistance and has both good conductivity and excellent strength as compared with conventional materials characterized by high conductivity.

[Summary of embodiment]
The Cu-Zr-based copper alloy material contains 0.05 to 0.3% by mass of Zr and is selected from Mg, Ti, Zn, Ga, Y, Nb, Mo, Ag, In, and Sn. One or more kinds are contained in a total amount of 0.01 to 0.3% by mass, the balance is made of Cu and inevitable impurities, and the stress relaxation resistance after holding at 150 ° C. for 1000 hours is 20% or less. A copper alloy material characterized by having is provided.

[Embodiment]
Hereinafter, preferred embodiments of the present invention will be specifically described.

(Composition of Cu-Zr alloy)
The Cu—Zr-based alloy in this embodiment contains Zr (zirconium) and, as subcomponents, Mg (magnesium), Ti (titanium), Zn (zinc), Ga (gallium), Y (yttrium), Basic composition component comprising at least one selected from Nb (niobium), Mo (molybdenum), Ag (silver), In (indium) and Sn (tin), with the balance being Cu and inevitable impurities It is said. This Zr affects the amount and size of the formed precipitated particles and changes the balance between conductivity and tensile strength (strength). The Zr content is 0.05 to 0. A range of .3% by mass is preferred.

  As a subcomponent, it is preferable to contain 0.01 to 0.3 mass% in total of any one or more of Mg, Ti, Zn, Ga, Y, Nb, Mo, Ag, In, and Sn. is there. Among these components, those containing one or more of Ga and Mo in a total amount of 0.01 to 0.3% by mass are particularly preferable. By adding these components together with Zr, further improvement in strength can be expected.

  The Cu—Zr-based alloy according to this embodiment can be effectively used as a material for electric / electronic parts used in hybrid vehicles and electric vehicles. The technology in this field supports and contributes greatly to the development of high-quality materials.

  The reasons for adding and limiting the alloy components of the copper alloy material configured as described above will be described below.

(Zr)
Zr is an element added to improve conductivity and tensile strength by precipitating in the parent phase of Cu. By including this Zr within a specified range of 0.05 to 0.3% by mass, good characteristics are easily realized. When the content of Zr is less than the specified range of 0.05% by mass, the tensile strength becomes insufficient and the stress relaxation resistance cannot be obtained with sufficient characteristics. When the content of Zr is larger than the specified range of 0.3% by mass, the amount of Zr remaining in a solid solution state without being precipitated in the parent phase of Cu increases, and the conductivity decreases.

(Mg, Ti, Zn, Ga, Y, Nb, Mo, Ag, In, Sn)
These Mg, Ti, Zn, Ga, Y, Nb, Mo, Ag, In, and Sn are elements added to improve the stress relaxation resistance of the Cu—Zr alloy. These components also have an effect of improving the strength of the material, and in particular, have an effect of realizing a high level of stress relaxation resistance required as an in-vehicle electric / electronic component material. When the addition amount of these components is less than the specified range of 0.01% by mass, the effect of adding cannot be sufficiently obtained. When the added amount of these components is larger than the specified range of 0.3% by mass, adverse effects such as a decrease in conductivity increase.

  These components have a common feature that their atomic radii are larger than those of Cu atoms as the parent phase. The reason why the stress relaxation resistance is improved by adding a component having a large atomic radius is considered as follows. Stress relaxation is a phenomenon in which elastic strain changes to plastic strain over time and stress decreases in a constant strain state. These changes are considered to proceed by both atomic diffusion and dislocation movement at the atomic level. The diffusion of atoms proceeds as the atoms move by jumps mediated by holes. Here, the additive component having a large atomic radius is likely to be combined with a vacancy in order to reduce lattice distortion generated around the crystal lattice. The volume of the connected holes is reduced. Since vacancies with a small volume are unlikely to act as a medium for movement of atoms, the addition of a component with a large atomic radius has the effect of hindering the diffusion of atoms.

  The influence of dislocations on the movement is considered as follows. Additive components having a large atomic radius gather around the dislocations to reduce the distortion of the crystal lattice, creating a state called a Cottrell atmosphere. Since the dislocation must move while dragging this state, the resistance of movement increases. As a result, the addition of a component having a large atomic radius has an effect of preventing the movement of dislocations. With these effects, it can be said that the stress relaxation resistance can be improved by adding a component having a large atomic radius.

(Stress relaxation resistance)
The copper alloy material according to this embodiment is preferably specified so that the stress relaxation rate after holding for 1000 hours at 150 ° C. is 20% or less as an index showing good stress relaxation resistance. Conventional Cu—Zr alloys generally have a stress relaxation rate of about 40% after holding at 150 ° C. for 1000 hours. On the other hand, by containing at least the basic composition component, a Cu—Zr-based alloy capable of suppressing the stress relaxation rate characteristic to be significantly low can be obtained.

  The method of this stress relaxation test is prescribed in the standard EAMAS-1011 of the Japan Electronic Materials Industry Association and the technical standard JCBA-T309 of the Japan Copper and Brass Association. In that method, the sample is put in a cantilever state, bent so that the initial maximum surface stress is 80% of the 0.2% proof stress, and heated to 150 ° C. for about 1000 hours. Hold. Then, the bending stress is unloaded after the end of holding, and the amount of deflection due to the permanent deformation that occurs is measured.

  This stress relaxation rate is calculated based on the ratio of the amount of permanent deformation after heating and holding with respect to the amount of bending added initially. If the stress relaxation rate is 20% or less, it is possible to secure sufficient characteristics for the stress relaxation resistance required as an initial vehicle-mounted electrical / electronic component material.

  Further, this copper alloy material has a conductivity of 90% IACS or more and a tensile strength of 480 MPa or more with respect to the characteristic value. Conventional Cu—Zr alloys are generally made of a material having a tensile strength of about 400 to 450 MPa. On the other hand, the characteristics of the copper alloy material according to this embodiment have superior strength and springiness compared to conventional high-conductivity materials, which is sufficient as a target automotive electric / electronic component material. It can have the characteristic.

  The copper alloy material is further preferably adjusted to have an average crystal grain size after intermediate annealing of 20 to 100 μm. The reason why the average crystal grain size is adjusted to 20 to 100 μm is to realize the initial objective high stress relaxation resistance and good strength even more stably. The crystal grain size greatly affects the material characteristics. If the crystal grain size is too small, the stress relaxation resistance is deteriorated. An excessively large crystal grain size is not preferable because sufficient strength cannot be secured.

(Effect of embodiment)
According to the copper alloy material which is the said embodiment, there can exist the following effects.
(1) A material that combines an excellent balance between stress relaxation resistance and strength higher than conventional ones can be obtained without impairing the excellent conductivity of the Cu-Zr alloy.
(2) Such materials are particularly suitable for application to electrical and electronic parts used in high-temperature environments such as in-vehicle connectors and the like, and have a great effect on miniaturization and high functionality of these parts. I can expect.

  In addition, this invention is not limited to the said embodiment, Of course, the technical range which can be easily changed by those skilled in the art from the embodiment is also included.

  Hereinafter, examples and comparative examples will be described in detail as more specific embodiments of the present invention. In this example, a typical example of the copper alloy material according to the above-described embodiment is given, and the present invention is of course not limited to these examples and comparative examples.

  Table 1 shows a sample No. as an example. 1 to 10 compositions, sample No. The compositions of Nos. 11 to 15 are shown together. The evaluation result of the electrical conductivity of 1-15, tensile strength, and stress relaxation rate is shown collectively. Table 3 shows a sample No. as an example. 1, 16, 17 and sample No. which is a comparative example. The intermediate annealing conditions of 18 to 20 and the evaluation results of average crystal grain size, stress relaxation rate, and tensile strength are collectively shown.

[Sample No. 1]
A copper alloy containing oxygen free copper as a base material and containing Zr: 0.15 mass% and Mg: 0.05 mass% was melted and cast into an ingot having a thickness of 70 mm, a width of 200 mm, and a length of 500 mm. This was heated to 950 ° C. and hot-rolled to a thickness of 10 mm, then cold-rolled to a thickness of 1 mm and subjected to intermediate annealing in which heating was performed at 700 ° C. for 1 minute. After taking a small amount of sample from the copper alloy material after the intermediate annealing, the remainder was cold-rolled to a thickness of 0.3 mm and further subjected to strain relief annealing that was heated at 450 ° C for 1 minute to produce a prototype. .

  Sample No. For one prototype, the electrical conductivity and tensile strength were measured. Furthermore, sample no. About 1 prototype, the stress relaxation test was done and the stress relaxation rate after 1000-hour holding | maintenance was measured at 150 degreeC.

  As is clear from Tables 1 and 2, the properties of conductivity 92% IACS and tensile strength 508MPa are obtained, and the initial target conductivity (90% IACS or more) and strength (480MPa or more) can be realized. Was confirmed. The stress relaxation rate was 17.6%, and it was confirmed that the initial specified range (20% or less) was satisfied.

  Sample No. after intermediate annealing The average crystal grain size was measured by observing the metal structure of the sample collected from the prototype material of 1. The crystal grain size was measured using an Olympus metal microscope PMG3.

  As is apparent from Table 3, the average crystal grain size was 55 μm, and it was confirmed that the initial specified range (20 to 100 μm) was satisfied.

  From these results, sample no. It was found that the prototype No. 1 was a material having both good strength and excellent conductivity while having good stress relaxation resistance as an initial purpose.

[Sample No. 2-10]
Sample No. As for the prototype No. 2, the above sample No. 2 was used except that 0.05% by mass of Ti was added instead of Mg. Produced under the same manufacturing method and conditions as the first prototype. Sample No. Samples Nos. 3 to 10 were replaced with Mg except that 0.05% by mass of each selected Zn, Ga, Y, Nb, Mo, Ag, In, and Sn was added. Produced under the same manufacturing method and conditions as the first prototype.

  As is clear from Tables 1 and 2, sample no. All of the prototypes 2 to 10 have good stress relaxation resistance with a stress relaxation rate of 20% or less after holding at 150 ° C. for 1000 hours, conductivity of 90% IACS or more, and tensile strength of 480 MPa. The above characteristics were obtained, and it was found that excellent initial conductivity and good strength could be ensured.

[Comparative example]
In Tables 1 and 2, Sample No. 11 exemplifies an example of a Cu—Zr-based alloy that does not contain an auxiliary component such as Mg. This sample No. In the comparative product No. 11, the above sample No. 1 was used except that no subcomponent was added. Produced under the same manufacturing method and conditions as the first prototype.

  As is clear from Tables 1 and 2, in the Cu-Zr alloy with no additive added, the stress relaxation rate after holding for 1000 hours at 150 ° C exceeds 30%, and the stress relaxation resistance is not good. It turns out that it is enough. The electrical conductivity of 90% IACS or higher is maintained, but the tensile strength is less than 480 MPa. Sample No. above. It was found that the tensile strength was low compared to the prototype 1 and sufficient springiness could not be expected.

[Sample No. 12]
Sample numbers in Tables 1 and 2 No. 12 exemplifies an example of a Cu—Zr-based alloy having a Zr content less than the specified range of the above examples. This sample No. In the comparative product No. 12, the sample No. 1 was changed except that the Zr content was changed. Produced under the same manufacturing method and conditions as the first prototype.

  As is clear from Tables 1 and 2, sample no. The comparison product of No. 12 has a stress relaxation resistance after holding at 150 ° C. for 1000 hours exceeding 20%, and it was found that the stress relaxation resistance is insufficient. The electrical conductivity of 90% IACS or higher is maintained, but the tensile strength is less than 480 MPa. Sample No. above. It was found that the tensile strength was low compared to the prototype 1 and sufficient springiness could not be expected.

[Sample No. 13]
Sample numbers in Tables 1 and 2 No. 13 exemplifies an example of a Cu—Zr-based alloy having a Zr content greater than the specified range of the above-described example. This sample No. In the comparative product No. 13, the sample No. 1 was changed except that the Zr content was changed. Produced under the same manufacturing method and conditions as the first prototype.

  As is clear from Tables 1 and 2, sample no. The comparative product No. 13 has a stress relaxation resistance after holding at 150 ° C. for 1000 hours of 20% or less, a tensile strength of 480 MPa or more, and maintains stress relaxation resistance and tensile strength. It has been found that a conductivity of 90% IACS or higher cannot be ensured.

[Sample No. 14]
In Tables 1 and 2, Sample No. No. 14 shows that the content of Mg as an accessory component is the above-mentioned sample No. An example of a Cu-Zr alloy less than the specified range in one prototype is illustrated. This sample No. In the comparative product No. 14, the above sample No. 4 was changed except that the content of Mg was changed. Produced under the same manufacturing method and conditions as the first prototype.

  As is clear from Tables 1 and 2, sample no. The comparative product No. 14 has a stress relaxation rate after holding at 150 ° C. for 1000 hours exceeding 26%, and the stress relaxation resistance is insufficient as in the case of not containing Mg as a subcomponent. I understood. It was also found that although the electrical conductivity of 90% IACS or higher is maintained, the tensile strength is less than 480 MPa, the tensile strength is low, and sufficient springiness cannot be expected.

[Sample No. 15]
Sample numbers in Tables 1 and 2 No. 15 has a content of Mg as an accessory component of the above sample No. An example of a Cu-Zr alloy that is larger than the specified range in one prototype is illustrated. This sample No. In the comparative product No. 15, except for changing the content of Mg, the above sample No. Produced under the same manufacturing method and conditions as the first prototype.

  As is clear from Tables 1 and 2, sample no. The comparative product of No. 15 has a stress relaxation resistance after holding for 1000 hours at 150 ° C. of 20% or less, a tensile strength of 480 MPa or more, Maintains relaxation and tensile strength. However, the decrease in conductivity is large, and a conductivity of 90% IACS or more cannot be secured.

  Next, the reason for limiting the range of the crystal grain size will be described in detail by giving more specific examples and comparative examples of the present invention. In Table 3, Sample No. Nos. 16 and 17 are examples and sample nos. Reference numerals 18 to 20 respectively illustrate comparative examples.

[Sample No. 16]
Except for performing the intermediate annealing which is heated at 650 ° C. for 1 minute, the above sample No. Sample No. 1 with the same composition, manufacturing method, and conditions as the prototype No. 1. 16 prototypes were produced.

[Sample No. 17]
Sample No. 1 was used except that intermediate annealing was performed at 750 ° C. for 1 minute. 16 with the same components, production method and conditions as in No. 16. 17 prototypes were produced.

[Sample No. 18-20]
Except for performing the intermediate annealing in which heating is performed for 1 minute at three temperatures of 600 ° C., 800 ° C., and 850 ° C., the above-described sample No. Sample No. 16 with the same components, production method and conditions as the 16 prototypes. 18 to 20 comparative products were produced.

(Evaluation results of crystal grain size, stress relaxation rate, and tensile strength)
These sample Nos. 1, no. While measuring the tensile strength about 16-20, the stress relaxation test was done and the stress relaxation rate after 1000-hour holding | maintenance was measured at 150 degreeC. Each sample No. 1, no. Table 3 shows the evaluation results of the intermediate annealing conditions of 16 to 20, the average crystal grain size after the intermediate annealing, and the stress relaxation rate and tensile strength of the final material.

  As is apparent from Table 3, sample No. In the prototypes 16 and 17, the average crystal grain size after the intermediate annealing is within the specified range of 20 to 100 μm, which is the initial target. The stress relaxation rate after holding at 150 ° C. for 1000 hours also has excellent stress relaxation resistance of 20% or less. A tensile strength of 480 MPa or more is obtained. From the above, it was found that both high stress relaxation resistance and good strength and springiness can be achieved.

  As apparent from Table 3, the sample No. In the 18 comparative products, the initial target tensile strength of 480 MPa or more was obtained. However, the average crystal grain size after the intermediate annealing was smaller than the specified range of 20 μm, and the stress relaxation rate exceeded 20%, and the stress relaxation resistance was insufficient.

  As apparent from Table 3, the sample No. The comparative products 19 and 20 have an initial target stress relaxation resistance of 20% or less. However, the average crystal grain size after the intermediate annealing is larger than the initial target range of 100 μm. Moreover, it can be understood that the tensile strength is lower than the initial target range of 480 MPa, and the spring property may be insufficient.

Claims (4)

While containing 0.05 to 0.3% by mass of Zr, the total amount of at least one selected from Mg, Ti, Zn, Ga, Y, Nb, Mo, Ag, In, and Sn is 0.01 to Containing 0.3% by weight, the balance consisting of Cu and inevitable impurities,
A copper alloy material characterized by having a stress relaxation resistance with a stress relaxation rate of 20% or less after holding at 150 ° C for 1000 hours. While containing 0.05 to 0.3% by mass of Zr, the total amount of at least one selected from Mg, Ti, Zn, Ga, Y, Nb, Mo, Ag, In, and Sn is 0.01 to Containing 0.3% by weight, the balance consisting of Cu and inevitable impurities,
It has a tensile strength of 480 MPa or more while maintaining a conductivity of 90% IACS or more, and has a stress relaxation resistance of 20% or less after holding for 1000 hours at 150 ° C. Copper alloy material. While containing 0.05 to 0.3% by mass of Zr, the total amount of at least one selected from Mg, Ti, Zn, Ga, Y, Nb, Mo, Ag, In, and Sn is 0.01 to Containing 0.3% by weight, the balance consisting of Cu and inevitable impurities,
A copper alloy material characterized in that the average crystal grain size after intermediate annealing is adjusted to 20 to 100 μm, and the stress relaxation rate after holding at 150 ° C. for 1000 hours is 20% or less. With containing 0.05-0.3 wt% of Zr, Ga, containing 0.01 to 0.3 wt% in total of one or more one of Mo, Ri Do the balance is Cu and unavoidable impurities A copper alloy material characterized by having a stress relaxation resistance with a stress relaxation rate of 20% or less after holding at 150 ° C. for 1000 hours .