JP6736630B2 - Titanium copper, method for producing titanium copper, and electronic component - Google Patents

Description

The present invention relates to titanium copper, a method for producing titanium copper, and electronic parts, for example, titanium copper suitable for use in electronic parts such as connectors, battery terminals, jacks, relays, switches, autofocus camera modules, and lead frames, The present invention relates to a method for producing titanium copper and an electronic component using titanium copper.

2. Description of the Related Art In recent years, electronic components such as lead frames and connectors used in electric/electronic devices and in-vehicle components have been miniaturized, and there has been a remarkable tendency toward narrower pitch and lower profile of copper alloy members constituting the electronic components. The smaller the connector, the narrower the pin width, and the smaller the folded shape becomes. Therefore, the copper alloy member to be used is required to have high strength for obtaining the required spring property. In this respect, a copper alloy containing titanium (hereinafter referred to as “titanium copper”) has relatively high strength and is the most excellent in stress relaxation resistance among the copper alloys, so that strength is particularly required. It has been used for a long time as a member for signal system terminals.

Titanium copper is an age-hardening type copper alloy, and has excellent balance between strength and bending workability, and in addition, exhibits excellent stress relaxation resistance among various copper alloys. Therefore, development has been performed to improve the properties such as strength and bending workability while maintaining the stress relaxation property of titanium copper.

Japanese Unexamined Patent Application Publication No. 2014-185370 (Patent Document 1) discloses a Cu-Ti-based copper alloy having excellent bending workability while maintaining high strength and improved fatigue resistance while maintaining good stress relaxation resistance. % By mass, Ti: 2.0 to 5.0%, Ni: 0 to 1.5%, Co: 0 to 1.0%, Fe: 0 to 0.5%, Sn: 0 to 1.2. %, Zn:0 to 2.0%, Mg:0 to 1.0%, Zr:0 to 1.0%, Al:0 to 1.0%, Si:0 to 1.0%, P:0. .About.0.1%, B:0 to 0.05%, Cr:0 to 1.0%, Mn:0 to 1.0%, V:0 to 1.0%, and Sn of the above elements, A copper alloy sheet material having a total content of Zn, Mg, Zr, Al, Si, P, B, Cr, Mn, and V of 3.0% or less, and a composition of the balance Cu and inevitable impurities. A copper alloy sheet material having a metallographic structure in which the maximum width of grain boundary reactive precipitates is 500 nm or less and the density of granular precipitates having a diameter of 100 nm or more is 10 ⁵ pieces/mm ² or less in a cross section perpendicular to the plate thickness direction. Examples of are described.

Japanese Unexamined Patent Application Publication No. 2010-126777 (Patent Document 2) discloses a copper alloy sheet having excellent bending workability and stress relaxation resistance while maintaining high strength. Of the average value of the crystal grain size in each region of the plurality of regions having the same shape and size randomly selected on the plate surface, which has a composition containing Ti and the balance being Cu and unavoidable impurities The maximum value is the maximum grain size, the minimum value of the average grain sizes in each region is the minimum grain size, and the average value of the average grain sizes in each region is the average grain size. , Average crystal grain size of 5 to 25 μm, (maximum crystal grain size-minimum crystal grain size)/average crystal grain size of 0.20 or less, and X-ray diffraction of {420} crystal plane on the plate surface of the copper alloy plate material. When the intensity is I{420} and the X-ray diffraction intensity of the {420} crystal plane of the pure copper standard powder is I ₀ {420}, a crystal orientation satisfying I{420}/I ₀ {420}>1.0 is obtained. An example of a copper alloy sheet material characterized by having is described.

Japanese Unexamined Patent Application Publication No. 2008-308734 (Patent Document 3) discloses a copper alloy plate material having high strength, excellent bending workability, and stress relaxation resistance at the same time, and improved springback, in a mass% of Ti : 1.0 to 5.0%, the balance being Cu and unavoidable impurities, having a crystal orientation satisfying I{420}/I ₀ {420}>1.0, and having an average crystal grain size of An example of a copper alloy sheet material having a thickness of 10 to 60 μm is described.

Japanese Unexamined Patent Publication No. 7-258803 (Patent Document 4) describes a weight ratio as a method for producing a high-strength copper alloy having improved strength and bending workability by adjusting the production process of solution treatment-cold rolling process. In a copper alloy containing Ti: 0.01 to 4.0% and the balance of Cu and unavoidable impurities, (1) at a temperature of 800° C. or higher, within 240 seconds and with an average crystal grain size exceeding 20 μm. The first solution heat treatment performed under no heat treatment condition, (2) the first cold rolling performed at a workability of less than 80%, (3) the temperature of 800° C. or higher within 240 seconds and the average grain size of 1 to 1. Second solution heat treatment performed under heat treatment conditions not exceeding 20 μm, (4) Second cold rolling performed at a workability of 50% or less, (5) At a temperature of 300 to 700° C. for 1 hour or more 15 There is described a method for producing a titanium-copper alloy having excellent bendability and stress relaxation characteristics, which is characterized by sequentially performing aging treatment for less than time.

JP, 2014-185370, A JP, 2010-126777, A JP 2008-308734 A JP, 7-258803, A

In recent years, electronic devices are required to have higher reliability in addition to higher functionality, and electronic components used in electronic devices are also required to have high reliability. Among them, heat resistance is one of the important indexes, and a higher level than before is required. It is known that titanium copper is relatively excellent in stress relaxation resistance, but it cannot be said that the titanium copper alloys of Patent Documents 1 to 4 have yet obtained sufficient stress relaxation resistance. Further improvement of relaxation characteristics is desired.

In view of the above problems, the present disclosure provides titanium copper having excellent stress relaxation resistance, a method for producing titanium copper, and an electronic component using the titanium copper.

The present inventor has conducted extensive studies in order to solve the above-mentioned problems, and as a result, the misorientation (GOS) in the crystal grains calculated in the EBSD measurement with respect to the rolled surface and the area ratio thereof, and the crystal grain where the Schmid factor has a predetermined value It was found that the titanium-copper having the area ratios in the respective ranges above are excellent in stress relaxation resistance.

In one aspect, the titanium-copper according to the embodiment of the present invention contains 2.0 to 4.5 mass% of Ti, and Fe, Co, Ni, Cr, Zn, Zr, P, B and Mo as the third element. , V, Nb, Mn, Mg, and Si are contained in a total amount of 0 to 0.5% by mass, and the balance is copper and inevitable impurities. In the crystal orientation analysis, the area ratio of the crystal grains having a GOS (Grain Orientation Spread) of 2 to 6° when the orientation difference of 5° or more is regarded as a crystal grain boundary is 60 to 90%, and the Schmid factor is 0. The area ratio of crystal grains of 35 or less is 5 to 20%, which is titanium copper.

In one aspect, the method for producing titanium copper according to the embodiment of the present invention contains Ti in an amount of 2.0 to 4.5% by mass, and Fe, Co, Ni, Cr, Zn, Zr, P, and A titanium-copper ingot containing 0 to 0.5 mass% in total of one or more selected from the group consisting of B, Mo, V, Nb, Mn, Mg, and Si, with the balance comprising copper and unavoidable impurities. A method for producing titanium copper, comprising casting, hot-rolling, and then performing a cold-rolling step and a final solution treatment step thereafter, wherein the hot-rolling step is performed for each ingot with respect to one pass. The compressive strain was set to 0.15 to 0.30, and the treatment was performed so that the maximum strain rate at 700 to 900° C. was 2.0 to 6.0/s. Mass%) is X, the heating temperature (° C.) is 52×X+610 to 52×X+680, and the holding time is 5 to 60 seconds.

According to the present invention, titanium copper having excellent stress relaxation resistance, a method for producing titanium copper, and an electronic component using titanium copper can be obtained.

It is a figure explaining the measurement principle of a stress relaxation rate. It is a figure explaining the measurement principle of a stress relaxation rate.

(Ti concentration)
In the titanium copper according to the embodiment of the present invention, the Ti concentration is 2.0 to 4.5 mass %. Titanium-copper increases the strength and conductivity by solid-solutioning Ti in a Cu matrix by solution treatment and dispersing fine precipitates in the alloy by aging treatment.
If the Ti concentration is less than 2.0% by mass, the precipitation of precipitates will be insufficient and the desired strength cannot be obtained. If the Ti concentration exceeds 4.5 mass %, the workability deteriorates and the material is likely to crack during rolling. Considering the balance between strength and workability, the preferable Ti concentration is 2.5 to 3.5 mass %.

(Third element)
In the titanium copper according to the embodiment of the present invention, the third selected from the group consisting of Fe, Co, Ni, Cr, Zn, Zr, P, B, Mo, V, Nb, Mn, Mg, and Si. The strength can be further improved by containing at least one element. However, if the total concentration of the third element exceeds 0.5% by mass, the workability deteriorates and the material is easily cracked during rolling. Therefore, these third elements can be contained in a total amount of 0 to 0.5% by mass, and considering the balance of strength and workability, the total amount of one or more of the above elements is 0.1 to 0.4% by mass. It is preferable to contain it. For each additive element, Zr, P, B, V, Mg, and Si are 0.01 to 0.15 mass %, and Fe, Co, Ni, Cr, Mo, Nb, and Mn are 0.01 to 0. 3 mass% and Zn can be contained by 0.1-0.5 mass %.

(GOS)
The titanium copper according to the embodiment of the present invention is characterized in that the Grain Orientation Spread (GOS) that quantifies the average orientation difference in the crystal grains is controlled within a certain range. Specifically, the area ratio of the crystal grains where GOS is 2 to 6° is 60 to 90%. When the GOS is within the above range, it means that there is fine precipitation in the crystal grains, which can improve the stress relaxation resistance property.

When the area ratio of the crystal grains where GOS is 2 to 6° is smaller than 60%, fine precipitates are insufficient and the stress relaxation resistance property is not improved. On the other hand, if the area ratio of the crystal grains where GOS is 2 to 6° is larger than 90%, coarse precipitation increases, and the stress relaxation resistance property is not improved. The area ratio of the crystal grains in which GOS is 2 to 6° is preferably 65 to 85%, more preferably 70 to 80%.

In the present embodiment, “GOS” means analysis software attached to EBSD (for example, OIM Analysis manufactured by TSL Solutions, Inc.) in crystal orientation analysis in EBSD (Electron Back Scatter Diffraction) measurement on a rolled surface. ) Is used to show the average value of the orientation difference between all the pixels in each crystal grain when the orientation difference of 5° or more is regarded as a crystal grain boundary. This is an average value when the average value of the orientation difference between pixels is calculated and this is performed for all the crystal grains.

In this embodiment, the following are adopted as the measurement conditions in the EBSD measurement.
(A) SEM conditions ・Beam conditions: acceleration voltage 15 kV, irradiation current amount 5×10 ^-8 A
・Work distance: 25mm
・Observation field: 150 μm × 150 μm
・Observation surface: Rolled surface ・Preliminary treatment of observation surface: Electropolishing in a solution of phosphoric acid 67%+sulfuric acid 10%+water under conditions of 15 V×60 seconds to reveal the structure (b) EBSD condition ・measurement program : OIM Data Collection
・Data analysis program: OIM Analysis (Ver.5.3)
・Step width: 0.25 μm

(Schmidt factor)
In the titanium copper according to the present invention, the area ratio of crystal grains having a Schmid factor of 0.35 or less is controlled to 5 to 20%. When the area ratio of the crystal grains having a Schmid factor of 0.35 or less is 5 to 20%, the stress resistance of the titanium copper according to the present invention is combined with the area ratio of the crystal grains having the GOS of 2 to 6°. The relaxation characteristics can be improved.

The shear stress τ required when the material undergoes slip deformation can be expressed as τ=σcosφcosλ. Here, σ is the tensile stress, φ is the angle between the tensile axis and the normal to the slip surface, λ is the angle between the tensile axis and the slip direction, and the cosφcosλ portion is the Schmid factor. The Schmid factor takes a value of 0 to 0.5 and represents the easiness of deformation. That is, when the Schmid factor is small, it is difficult to deform, and when the Schmit factor is large, it is easy to deform. If the area ratio of the crystal grains with the Schmitt factor of 0.35 or less exceeds 20%, the resistance when stress is applied increases, and the strain easily accumulates. As a result, the stress relaxation resistance does not improve. The smaller the area ratio of the crystal grains with a Schmid factor of 0.35 or less, the more the stress relaxation resistance is improved, but the area ratio of the crystal grains with a Schmit factor of 0.35 or less when completely recrystallized is 5 or less. It is practically difficult to control it to be less than %. From this viewpoint, the area ratio of the crystal grains having a Schmid factor of 0.35 or less is preferably 6 to 18%, more preferably 7 to 16%.

In the present embodiment, the “Schmid factor” means the analysis software attached to the EBSD (for example, manufactured by TSL Solutions Inc.) in the crystal orientation analysis in the EBSD (Electron Back Scatter Diffraction: Electron Backscatter Diffraction) measurement on the rolled surface. OIM Analysis) is used to mean the result calculated for each crystal grain when the misorientation of 5° or more is regarded as a crystal grain boundary, and the following is adopted as the measurement condition in the EBSD measurement.
(A) SEM conditions ・Beam conditions: acceleration voltage 15 kV, irradiation current amount 5×10 ^-8 A
・Work distance: 25mm
・Observation field: 150 μm × 150 μm
・Observation surface: Rolled surface ・Pre-treatment of observation surface: Electrolytic polishing in a solution of phosphoric acid 67%+sulfuric acid 10%+water under conditions of 15V×60 seconds to reveal the structure

(Stress relaxation property)
The titanium copper according to the embodiment of the present invention can have excellent stress relaxation resistance. One embodiment is characterized in that the stress relaxation rate after holding titanium copper at 300° C. for 10 hours is 10% or less.

(Average grain size)
From the viewpoint of enhancing the strength, bending workability, and fatigue characteristics in a well-balanced manner, in one embodiment of the titanium-copper according to the present invention, it is preferable to control the average crystal grain size on the rolled surface to a range of 2 to 30 μm, It is more preferable to control in the range of 15 μm, and it is even more preferable to control in the range of 2 to 10 μm.

The average crystal grain size is the same as the average crystal grain size used for calculating the coefficient of variation of the crystal grain size described above, and the EBSD (Electron Back Scatter Diffraction) measurement on the rolling surface is performed by the crystal orientation analysis to determine the EBSD. The average crystal grain size when the orientation difference of 5° or more is regarded as a crystal grain boundary using the analysis software (eg, OIM Analysis manufactured by TSL Solutions) attached to the above.

(0.2% proof stress)
In the titanium copper according to the embodiment of the present invention, in one embodiment, 0.2% proof stress in a direction parallel to the rolling direction can achieve 800 MPa or more. The 0.2% proof stress of titanium copper according to the present invention is 850 MPa or more in a preferred embodiment, 900 MPa or more in a more preferred embodiment, and 950 MPa or more in a more preferred embodiment.

The upper limit of the 0.2% proof stress is not particularly limited in terms of the strength intended by the present invention, but since it takes time and cost, the 0.2% proof stress of the titanium copper according to the present invention is generally 1300 MPa. Or less, typically 1200 MPa or less, and more typically 1100 MPa or less.

In the present invention, the 0.2% proof stress in the direction parallel to the rolling direction of titanium copper is measured according to JIS-Z2241 (2011) (metal material tensile test method).

(Thickness of titanium copper)
In one embodiment of the titanium-copper according to the present invention, the thickness can be 1.0 mm or less, and in a typical embodiment, the thickness can be 0.02-0.8 mm, and more typically. In another embodiment, the thickness can be 0.05-0.5 mm.

(Use)
The titanium-copper according to the present invention can be processed into various copper products such as plates, strips, tubes, rods and wires. The titanium copper according to the present invention is preferably used as a conductive material or a spring material in electronic parts such as, but not limited to, switches, connectors, autofocus camera modules, jacks, terminals (particularly battery terminals) and relays. You can These electronic components can be used as, for example, in-vehicle components or components for electric/electronic devices.

(Production method)
Hereinafter, the manufacturing method of titanium copper according to the embodiment of the present invention contains 2.0 to 4.5 mass% of Ti, and Fe, Co, Ni, Cr, Zn, Zr, P, B as the third element. A titanium-copper ingot containing at least one selected from the group consisting of Mo, V, Nb, Mn, Mg, and Si in a total amount of 0 to 0.5% by mass, with the balance being copper and inevitable impurities. After casting and hot rolling, it includes performing a cold rolling step and a subsequent final solution treatment step. Hereinafter, a preferable example of manufacturing titanium copper according to the present embodiment will be described step by step.

<Ingot manufacturing>
The production of ingots by melting and casting is basically carried out in vacuum or in an inert gas atmosphere. If there is an undissolved portion of the additional element in the dissolution, it will not work effectively for improving the strength. Therefore, in order to eliminate the undissolved residue, it is necessary to add a high melting point third element such as Fe or Cr, sufficiently stir it, and then hold it for a certain period of time. On the other hand, Ti is relatively easily dissolved in Cu, so it may be added after the third element is dissolved. Therefore, in Cu, one or more kinds selected from the group consisting of Fe, Co, Ni, Cr, Zn, Zr, P, B, Mo, V, Nb, Mn, Mg, and Si in total of 0 to 0. It is desirable to add 5 mass% and then add Ti to 2.0 to 4.5 mass% to produce an ingot.

<Homogenized annealing and hot rolling>
Since the solidification segregation and crystallized substances generated during the production of ingots are coarse, it is desirable to make them as small as possible by forming a solid solution in the matrix phase by homogenizing annealing so as to eliminate them. This is because it is effective in preventing bending cracks. Specifically, it is preferable that after the ingot manufacturing step, hot rolling is performed after heating at 900 to 970° C. for homogenization annealing for 3 to 24 hours. In order to prevent liquid metal brittleness, it is preferable that the temperature is 960° C. or lower before and during hot rolling, and 800° C. or higher in the pass from the original thickness to 80% in the overall reduction workability.

In this embodiment, the compressive strain per pass is 0.15 to 0.30, the maximum strain rate at 700 to 900° C. is 2.0 to 6.0/s, and in one preferred embodiment, 3.0 to 5 .0. This makes it possible to control the GOS and Schmitt factor within the above range. The compressive strain per pass is the compressive strain η=ln{(cross-sectional area before hot rolling)/(cross-sectional area after hot rolling)} divided by the total number of passes in hot rolling. It can be calculated by Further, the strain rate ε(/s) is calculated by the following equation (1).

ここで、Ｈ₀：入側での板厚（ｍｍ）、ｎ：圧延ロールの回転速度（ｒｐｍ）、Ｒ：圧延ロールの半径（ｍｍ）、ｒ’：加工度（（入側での板厚）−（出側での板厚）／入側での板厚）である。

Here, H ₀ : plate thickness on the entry side (mm), n: rotational speed of the rolling roll (rpm), R: radius of the rolling roll (mm), r′: working ratio ((plate thickness on the entry side )-(Thickness at exit side)/(thickness at entrance side).

<Cold rolling and annealing>
After hot rolling, cold rolling is performed. The workability of cold rolling is typically 60% or more. The workability per pass is calculated by the equation (2), where T _{0 is} the thickness of the ingot before rolling in the pass and T is the thickness of the ingot when rolling in the pass is completed.
Workability (%)={(T ₀ −T)/T ₀ }×100 (2)
Annealing can then be performed. The annealing condition is typically 900° C. for 1 to 5 minutes. This cold rolling and annealing can be appropriately repeated if necessary.

<First solution treatment>
It is preferable to perform the first solution treatment after appropriately repeating cold rolling and annealing. The reason why the solution treatment is performed in advance here is to reduce the load in the final solution treatment. That is, in the final solution treatment, it is not a heat treatment for solid-solving the second phase particles, but since it has already been solutionized, it is sufficient to cause only recrystallization while maintaining that state. Heat treatment is enough. Specifically, the first solution heat treatment may be performed at a heating temperature of 850 to 900° C. for 2 to 10 minutes. It is preferable that the temperature rising rate and the cooling rate at that time are as fast as possible so that the second phase particles are not precipitated here. The first solution treatment may not be performed.

<Intermediate rolling>
Then, intermediate rolling is performed. The workability of the intermediate rolling is typically 60% or more.

<Final solution treatment>
In the final solution treatment, it is desirable to completely dissolve the precipitate, but if heated to a high temperature until it completely disappears, the crystal grains tend to coarsen, so the heating temperature is near the solid solution limit of the second phase particle composition. Temperature. Specifically, when the amount of Ti added (% by mass) is X, the heating temperature (° C.) is in the range of 52×X+610 to 52×X+680.

When the heating temperature is lower than 52×X+610° C., it is not recrystallized, and when the heating temperature is higher than 52×X+680, the crystal grain size becomes coarse and the strength of finally obtained titanium copper decreases.

The GOS and Schmid factor can be controlled by adjusting the heating time in the final solution treatment. The heating time can be, for example, 5 to 60 seconds, and typically 20 to 45 seconds.

<Final cold rolling>
After the final solution heat treatment, final cold rolling is performed. Although the strength can be increased by the final cold working, the working ratio is preferably 5 to 50%, and more preferably 20 to 40% in order to obtain good stress relaxation resistance.

<Aging treatment>
Following the final cold rolling, an aging treatment is performed. Heating at a material temperature of 300 to 500° C. for 1 to 50 hours is preferable, and heating at a material temperature of 350 to 450° C. for 10 to 30 hours is more preferable. The aging treatment is preferably performed in an inert atmosphere of Ar, N ₂ , H ₂ or the like in order to suppress the generation of an oxide film.

Summarizing the above, the method for producing titanium copper according to the embodiment of the present invention,
From the group consisting of Fe, Co, Ni, Cr, Zn, Zr, P, B, Mo, V, Nb, Mn, Mg, and Si as the third element, containing 2.0 to 4.5 mass% of Ti. A step of casting an ingot of titanium copper containing the selected one or more kinds in a total amount of 0 to 0.5 mass% and the balance copper and unavoidable impurities;
A hot rolling step of treating the ingot so that the compression strain per pass is 0.15 to 0.30 and the maximum strain rate at 700 to 900° C. is 2.0 to 6.0/s. When,
When the addition amount (% by mass) of Ti is X, the heating temperature (° C.) is 52×X+610 to 52×X+680, and the final solution treatment step is a treatment time of 5 to 60 seconds.

It will be understood by those skilled in the art that steps such as grinding, polishing, and shot blast pickling for removing oxide scale on the surface can be appropriately performed between the above steps.

Hereinafter, the invention examples of the present invention will be shown together with comparative examples, but these are provided for better understanding of the present invention and its advantages, and are not intended to limit the invention.

An alloy containing the alloy components shown in Table 1 and the balance consisting of copper and unavoidable impurities was used as an experimental material. The alloy components, hot rolling, and final solution heat treatment conditions were 0.2% proof stress and average crystal grain size. , GOS, the Schmid factor and the effect on stress relaxation resistance were investigated.

First, 2.5 kg of electrolytic copper was melted in a vacuum melting furnace, and the third element was added at the mixing ratio shown in Table 1, and then Ti was added at the mixing ratio shown in the same table. After paying sufficient attention to the holding time after addition so as not to leave undissolved additive elements, these were injected into a mold in an Ar atmosphere to produce ingots of about 2 kg each.

After homogenizing annealing in which the ingot was heated at 950° C. for 3 hours, hot rolling was performed at 900 to 950° C. to obtain a hot-rolled sheet having a sheet thickness of 10 mm. After descaling by chamfering, cold rolling and annealing were repeated to obtain a strip thickness (2.0 mm), and the first solution treatment was performed on the strip. The conditions of the first solution heat treatment were heating at 850° C. for 10 minutes and then water cooling. Next, after intermediate cold rolling, final solution treatment was performed, and then water cooling was performed. Then, after descaling by pickling, final cold rolling with a workability of 25% was performed to a plate thickness of 0.1 mm, and finally an aging treatment was performed under the conditions of 400° C.×15 hours to obtain test pieces of the invention examples and comparative examples. And

The following evaluation was performed about the produced test piece.
(0.2% proof stress)
A JIS 13B test piece was prepared, and 0.2% proof stress in a direction parallel to the rolling direction was measured by using a tensile tester according to the above-described measuring method.

(Average grain size)
The plate surface (rolled surface) of each test piece was polished and then etched, and the crystal orientation analysis in EBSD (Electron Back Scatter Diffraction) measurement was performed to analyze the software attached to the EBSD (Example: Using OIM Analysis manufactured by TSL Solutions, Inc., the average crystal grain size when the orientation difference of 5° or more was regarded as the crystal grain boundary was measured.

(GOS)
The plate surface (rolled surface) of each test piece was polished and then etched, and crystal orientation analysis in EBSD measurement was performed on this. Using the analysis software (eg: OIM Analysis manufactured by TSL Solutions Inc.), the average value of the orientation difference between all pixels in each crystal grain when the orientation difference of 5° or more is regarded as a crystal grain boundary is shown. The average value of the orientation difference between a certain pixel and all the remaining pixels was calculated, and this was performed for all the crystal grains to calculate the average value.

(Schmidt factor)
The plate surface (rolled surface) of each test piece was polished and then etched, and crystal orientation analysis in EBSD measurement was performed on this. The Schmid factor of each crystal grain when the orientation difference of 5° or more was regarded as a crystal grain boundary was calculated using analysis software (eg, OIM Analysis manufactured by TSL Solutions).

(Stress relaxation property)
The stress relaxation rate after the test piece was kept at 300° C. for 10 hours was measured. A strip-shaped test piece having a width of 10 mm and a length of 100 mm was sampled so that the longitudinal direction of the test piece was parallel to the rolling direction. As shown in FIG. 1, the deflection of y ₀ was given to the test piece with the position of l=50 mm as the point of action, and the stress (s) corresponding to 80% of the 0.2% proof stress in the rolling direction was applied. y ₀ was calculated by the following equation.
y ₀ =(2/3)·l ² ·s / (E·t)
Here, E is Young's modulus in the rolling direction, and t is the thickness of the sample. After heating at 300° C. for 10 hours, the load is removed, the permanent deformation amount (height) y is measured as shown in FIG. 2, and the stress relaxation rate {[y (mm)/y ₀ (mm)]×100(%) } Was calculated.
When the stress relaxation rate was 10% or less, the stress relaxation resistance was considered good (◯).

In each of Inventive Examples 1 to 18, the stress relaxation rate after holding at 300° C. for 10 hours was 10% or less, and excellent stress relaxation resistance properties were exhibited.

On the other hand, in Comparative Example 1, since the compression strain per pass was too low, fine precipitates were not sufficiently obtained, and the area ratio of the crystal ratio at which GOS was 2 to 6° was lower than 60%. Therefore, the stress relaxation resistance superior to those of Invention Examples 1 to 18 was not obtained.

Comparative Example 2 could not be manufactured because the compression strain per pass was too high and the shape during rolling deteriorated. In Comparative Examples 3 and 4, the maximum strain rate of 700 to 900° C. was not appropriate, so that the area ratio of the crystal grains where the Schmid factor was 0.35 or less was large, and the stress relaxation resistance superior to that of Invention Examples 1 to 18 was obtained. The characteristics could not be obtained.

In Comparative Example 5, the temperature of the final solution treatment was too low, so that the stress relaxation resistance characteristics superior to those of Invention Examples 1 to 18 were not obtained. In Comparative Example 6, since the temperature of the final solution treatment was too high, the area ratio of the crystallization rate at which GOS was 2 to 6° was higher than 90%, and the stress relaxation resistance characteristics superior to those of Inventive Examples 1 to 18 were obtained. Was not obtained.

In Comparative Example 7, since the holding time of the final solution treatment was too short, the crystal grain size became a mixed grain, the area ratio of the crystal ratio where GOS was 2 to 6° was lower than 60%, and the Schmid factor was The area ratio of the crystal grains of 0.35 or less was small, and the stress relaxation resistance characteristics superior to those of Inventive Examples 1 to 18 were not obtained. In Comparative Example 8, since the holding time of the final solution treatment was too long, the crystal grain size was coarsened, and the area ratio of the crystal ratio where GOS was 2 to 6° was higher than 90%. Better stress relaxation resistance could not be obtained.

Comparative Examples 9 to 11 show cases where the amount of titanium or the third element added was not appropriate. Comparative Example 9 could not be manufactured because the amount of the additional element was too large and cracking occurred during hot rolling. In Comparative Example 10, since the addition amount of Ti was too small, the area ratio of crystal grains having a Schmid factor of 0.35 or less was large, and the stress relaxation resistance characteristics superior to those of Inventive Examples 1 to 18 were not obtained. .. Comparative Example 11 could not be manufactured because the additive element of Ti was too much and cracking occurred in the hot rolling.

Claims (6)

From 2.0 to 4.5 mass% of Ti, and Fe, Co, Ni, Cr, Zn, Zr, P, B, Mo, V, Nb, Mn, Mg, and Si as the third element. When one or more selected ones are contained in a total amount of 0 to 0.5% by mass, the balance consists of copper and unavoidable impurities, and an orientation difference of 5° or more is regarded as a grain boundary in EBSD measurement on the rolled surface. The area ratio of crystal grains having a GOS (Grain Orientation Spread) of 2 to 6° is 60 to 90%, and the area ratio of crystal grains having a Schmid factor of 0.35 or less is 5 to 20%. Titanium copper. The titanium-copper according to claim 1, which has a stress relaxation rate of 10% or less after being kept at 300°C for 10 hours. The titanium-copper according to claim 1 or 2, which has an average crystal grain size of 2 to 30 µm when the orientation difference of 5° or more is regarded as a crystal grain boundary in the crystal orientation analysis in the EBSD measurement with respect to the rolled surface. The titanium-copper according to any one of claims 1 to 3, which has a 0.2% proof stress of 800 MPa or more in a direction parallel to the rolling direction when a tensile test is performed according to JIS-Z2241 (2011). An electronic component comprising the titanium-copper according to claim 1. From the group consisting of Fe, Co, Ni, Cr, Zn, Zr, P, B, Mo, V, Nb, Mn, Mg, and Si as the third element, containing 2.0 to 4.5 mass% of Ti. After casting the ingot of titanium copper containing the selected one or more kinds in total in an amount of 0 to 0.5 mass% and the balance consisting of copper and unavoidable impurities, hot-rolling, cold-rolling step and subsequent final The method for producing titanium copper according to any one of claims 1 to 4, which comprises performing a solution treatment step,
In the hot rolling process, the compressive strain per pass for the ingot is set to 0.15 to 0.30, and the maximum strain rate at 700 to 900° C. is set to 2.0 to 6.0/s. Process and
In the final solution treatment step, when the addition amount (% by mass) of Ti is X, the heating temperature (° C.) is 52×X+610 to 52×X+680, and the holding time is 5 to 60 seconds. A method for producing titanium-copper characterized.

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