KR20060046273A - Titanium copper having excellent strength, electric conductivity and bendability and manufacturing method thereof - Google Patents

Abstract

(Problem) Titanium copper excellent in strength, electroconductivity, and bending workability.

(Solution) A copper alloy containing 1.5 to 2.3 mass% of Ti, balance Cu and unavoidable impurities, with 0.2% yield strength (YS) of 750 MPa or more, conductivity (EC) of 17% IACS or more, and perpendicular to the rolling direction. When the W bending test described in JIS H3130 was conducted in the direction, the ratio (MBR / t) of the minimum bending radius (MBR; mm) and the plate thickness (t; mm) where no crack was generated was 0.2% yield strength (YS; MPa). Titanium copper which is excellent in strength, electroconductivity, and bending workability which have a relationship of MBR / t <= 0.04 * YS-30 between and.

Description

Titanium copper excellent in strength, conductivity, and bending workability and its manufacturing method {TITANIUM COPPER HAVING EXCELLENT STRENGTH, ELECTRIC CONDUCTIVITY AND BENDABILITY AND MANUFACTURING METHOD THEREOF}

(Patent Document 1) Japanese Patent Application Laid-Open No. 7-258803

(Patent Document 2) Japanese Unexamined Patent Publication No. 2002-356726

(Patent Document 3) Japanese Patent Application No. 2003-78751

TECHNICAL FIELD This invention relates to the titanium copper excellent in strength, electroconductivity, and bending workability, and its manufacturing method.

BACKGROUND ART With the miniaturization and light weight of electronic devices, the miniaturization and lightening of electrical and electronic parts such as connectors (thinning and narrow pitch) are progressing. When the connector is thinned and narrowed, the cross-sectional area of the contact is reduced, and it is necessary to compensate for the reduction in contact pressure and conductivity due to the reduced cross-sectional area, and a higher strength and conductivity are required for the metal material used for the contact. In addition, since the parts are miniaturized, the metal material used is subjected to severe and severe bending, so that the metal material must have good bending workability.

As a high strength copper alloy, the usage-amount of an age hardening copper alloy is increasing recently. In the age hardening type copper alloy, by aging the solution-treated supersaturated solid solution, fine precipitates are uniformly dispersed in the alloy to increase the strength of the alloy.

Among the aging-curable copper alloys, Ti-containing copper alloys (hereinafter "titanium copper") have high mechanical strength and excellent bendability, and thus are widely used as various terminals and connectors of electronic equipment. At present, industrially used titanium copper is JIS C1990, and this alloy contains 2.9 to 3.5 mass% of Ti. This is because sufficient strength is not obtained when Ti is reduced, as also shown in Examples, such as patent document 1, patent document 2, and the like.

There is high beryllium copper (JIS C1720) as an aging hardening type high strength copper alloy like titanium copper. Since titanium copper has the same strength and bending workability as compared to high beryllium copper, and has excellent stress relaxation resistance, titanium copper is more suitable than high beryllium copper in applications requiring heat resistance such as, for example, burn-in sockets. On the other hand, when the conductivity is compared, titanium copper is 10 to 16% IACS, which is lower than 20% IACS of copper beryllium copper. Therefore, high beryllium copper is used for the use which requires electroconductivity. However, the high beryllium copper has a problem that a beryllium compound is toxic and the manufacturing process is complicated and expensive, and the demand for titanium copper is further increased.

If Ti is dissolved in copper, the conductivity decreases, so that the amount of solid solution Ti can be reduced by increasing Ti as a Cu-Ti intermetallic compound phase to increase the conductivity. In Patent Literature 3, the conductivity is improved by adjusting the amount of precipitation of the Cu-Ti intermetallic compound on titanium copper containing 2.5 to 4.5 mass% of Ti, but as a result of investigating the bending workability of the titanium copper disclosed in the specification, Bending workability was remarkably bad. It was confirmed that the coarse Cu-Ti intermetallic compound phase precipitated in a large amount was a starting point of cracking due to the deterioration of bending workability. In particular, when the Cu-Ti intermetallic compound phase whose diameter exceeds 2 micrometers exists, bending workability was remarkably bad. By optimizing the crystal grain size and the final rolling workability, the strength and bending workability of titanium copper can be made compatible (for example, Patent Document 2). However, a technique for balancing all of the strength, bending workability, and conductivity of titanium copper has not been achieved yet.

An object of the present invention is to provide a titanium copper excellent in strength, conductivity, and bending workability.

MEANS TO SOLVE THE PROBLEM The present inventors earnestly researched for the purpose of providing the titanium copper which is high strength, is excellent in bending workability, and has a conductivity equivalent to copper beryllium copper, As a result, Ti concentration, the size and area ratio of a Cu-Ti intermetallic compound phase, By adjusting the average grain size to the optimum range, titanium copper having desired strength, bending workability and electrical conductivity could be obtained.

The cause which worsened the bending workability of the titanium copper shown by the above-mentioned patent document 3 was a coarse Cu-Ti intermetallic compound phase precipitated in large quantities. In the present invention, by reducing the Ti concentration, the coarse Cu-Ti intermetallic compound phase is reduced, and the structure and manufacturing conditions are optimized to obtain desired strength and bending workability at low Ti concentration.

(1) The present invention is a copper alloy containing 1.5 to 2.3 mass% of Ti, consisting of residual Cu and unavoidable impurities, with 0.2% yield strength (YS) of 750 MPa or more, and conductivity (EC) of 17% IACS or more, and further rolling. When the W bending test described in JIS H3130 was carried out in the direction perpendicular to the direction, the ratio (MBR / t) of the minimum bending radius (MBR; mm) and the plate thickness (t; mm) at which cracking did not occur was 0.2% yield strength (YS It has a relationship of MBR / t <= 0.04 * YS-30 between MPa), It is related with the titanium copper excellent in intensity | strength, electroconductivity, and bending workability.

(2) The said titanium copper is a copper alloy containing 1.5-2.3 mass% of Ti, and remainder Cu and an unavoidable impurity, and the diameter of the Cu-Ti intermetallic compound phase observed in the cross section orthogonal to a rolling direction is 2.0 micrometers or less And Ti content ([Ti]; mass%) and area ratio (S;%) and Ti content ([Ti]; mass%) of the Cu-Ti intermetallic compound having a diameter of 0.02 to 2.0 µm observed in a cross section perpendicular to the rolling direction. It is characterized by having an average crystal grain size (measured by JIS H0501 cutting method) of a cross section perpendicular to the rolling direction and having a relationship of -11.5?

(3) In the manufacturing process of the titanium copper which performs the hot rolling, cold rolling, solution treatment, cold rolling, and aging treatment of the ingot sequentially, the titanium copper has a cold rolling process degree before the solution treatment. % Or more and the range of the heating temperature (T (° C.)) in the solution treatment is [6580 / {7.35-ln [Ti]}]-333≤T≤ [6580 / {7.35-ln [Ti]}]-273 , The average cooling rate in the solution treatment is 300 ° C./s or more, the cold rolling workability before the aging treatment is 10 to 70%, the heating temperature in the aging treatment is 350 to 450 ° C., and the heating holding time is 5 to 20 h. It can manufacture by making average cooling rate from a heating temperature into 10-50 degreeC / h in a process.

Best Mode for Carrying Out the Invention

The present invention will be described in detail below.

(1) conductivity

Increasing the electrical conductivity reduces the amount of heat generated when the material is used as various terminals and connectors. To achieve low calorific value, such as copper beryllium copper, a conductivity of 17% IACS or higher is required. More preferred conductivity is 20% IACS or more.

(2) 0.2% yield strength

When the 0.2% yield strength is less than 750 MPa, when the material is used as a connector, the contact pressure at the contact decreases, so that the contact resistance increases, and even if the conductivity is adjusted to 17% or more IACS, a low contact resistance at the same level as that of copper beryllium is obtained. I do not lose. Therefore, 0.2% yield strength is made into 750 Mpa or more. More preferable 0.2% yield strength is 800 Mpa or more.

(3) bending workability

When the material is used as various terminals and connectors, the balance of 0.2% yield strength and bending workability is important. MEANS TO SOLVE THE PROBLEM As a result of quantitatively analyzing the relationship of the 0.2% yield strength and bending workability which are required for recent electronic components with respect to titanium copper which has a Ti concentration of 1.5-2.3 mass% and having a conductivity of 17% IACS or more, We have found some measure to meet the demand for. That is, between the 0.2% yield strength (YS) and the ratio of the minimum bending radius and plate thickness (MBR / t) that can be bent without generating cracks when the material is bent in a direction perpendicular to the rolling direction (JIS H3130). The titanium copper which can satisfy | fill the relationship of MBR / t <= 0.04 * YS-30 can balance the strength and bending workability, and can respond to the recent request.

(4) Ti content

Aging of the titanium copper causes spinod decomposition to produce a modulated structure of titanium concentration in the base material, whereby very high strength is obtained. If the titanium content is less than 1.5 mass%, it is difficult to obtain a 0.2% yield strength of 750 MPa or more. On the other hand, when the titanium content exceeds 2.3 mass%, coarse Cu-Ti intermetallic compound phases having a diameter of more than 2 µm are precipitated when manufactured under the conditions of obtaining a conductivity of 17% IACS or higher, which will be described later. This gets worse. Therefore, titanium content of the titanium copper of this invention is 1.5-2.3 mass%, Preferably it is 1.6-2.0 mass%. Moreover, titanium copper of this Ti concentration range has not been put to practical use until now. Although it is reported in the patent document, there is no example which balanced all the strength, bendability, and electrical conductivity. For example, in the 1st Example of patent document 2, the alloy whose Ti is 1.7 mass% is reported, The electrical conductivity of this alloy is 20.3% IACS, equivalent to the alloy of this invention, but the 0.2% yield strength is low as 710 MPa. . In addition, in Example 2 of Patent Document 2, alloys having Ti of 1.5 mass% and 2.3 mass% have been reported, but their 0.2% yield strengths are 720 MPa and 1180 MPa, and the conductivity is 26.4% IACS and 10.2% IACS, respectively. However, strength and conductivity are not compatible.

(5) the diameter of the Cu-Ti intermetallic compound phase

By depositing Ti as a Cu-Ti intermetallic compound phase, the amount of solid solution Ti can be reduced to increase the electrical conductivity. However, when the diameter of the minimum circle (maximum diameter of the Cu-Ti intermetallic compound phase) containing one Cu-Ti intermetallic compound phase observed in the cross section perpendicular to the rolling direction exceeds 2.0 µm, the material may be bent. At this time, it becomes a starting point of a crack, and bending workability falls. Therefore, the diameter of a Cu-Ti intermetallic compound phase shall be 2 micrometers or less.

(6) Area ratio of Cu-Ti intermetallic compound phase

In order to raise the electrical conductivity of copper, it is important to precipitate Ti sufficiently and to reduce the amount of solid solution Ti as much as possible. In other words, the conductivity increases when the amount of the Cu-Ti intermetallic compound phase is increased. In addition, by depositing a fine Cu-Ti intermetallic compound phase, the strength of the material can be increased. MEANS TO SOLVE THE PROBLEM In this titanium copper containing 1.5-2.3 mass% of Ti, the area ratio of the Cu-Ti intermetallic compound phase whose diameter observed in the cross section orthogonal to a rolling direction is 0.02-2.0 micrometers is S (%), Ti When the content was made [Ti] (mass%), it was found that an electric conductivity of 17% IACS or more was obtained when the relationship of S ≧ 8.1 × [Ti] -11.5 was satisfied. On the other hand, even if the diameter of the precipitated Cu-Ti intermetallic compound phase is 2.0 μm or less, when S exceeds 7.5%, the bending workability of the material is lowered, and it is difficult to maintain the balance between the 0.2% yield strength and the bending workability prescribed in the present invention. It became difficult. Therefore, the area ratio S of the Cu-Ti intermetallic compound phase is set to 8.1x [Ti] -11.5≤S≤7.5. Further, in Ti = 1.5 to 2.0 mass%, if the relationship of 8.1 × [Ti] -9.5 ≦ S ≦ 7.5 can be satisfied, 20% IACS while satisfying the relationship of 0.2% yield strength and bending workability prescribed in the present invention. It was also found that the above conductivity can be obtained.

(7) average crystal grain size

When the average grain size (measured by JIS H0501 cutting method) of the cross section perpendicular to the rolling direction exceeds 10 µm, the strength of the material due to grain refinement cannot be increased, and it is difficult to obtain a 0.2% yield strength of 750 MPa or more. In addition, if the average crystal grain size is adjusted to less than 2 µm, the unrecrystallized portion may remain, and if the unrecrystallized portion remains, the bending workability deteriorates. Therefore, the average crystal grain diameter of the cross section perpendicular | vertical to the rolling direction of the titanium copper of this invention shall be 2-10 micrometers.

(8) manufacturing method

MEANS TO SOLVE THE PROBLEM In this manufacturing process of the titanium copper performed sequentially by melt-casting of a raw material, hot rolling of a ingot, cold rolling, solution treatment, cold rolling, and an aging treatment, it cold-rolled before solution treatment, solution treatment, It was found that titanium copper satisfying the characteristics of the present invention was obtained by setting the cold rolling after the solution treatment and the aging treatment to appropriate conditions, respectively. Below, the manufacturing conditions of each process are demonstrated.

(Cold rolled drawing before solution treatment)

When the material is recrystallized, the strain introduced by rolling becomes the nucleus of the recrystallized grain. Since the higher the cold rolling workability before the solution treatment, the larger the amount of deformation is introduced, the recrystallized grains are remarkably produced, the growth of the grains is suppressed, and a fine grain size is obtained. By making the cold rolling workability before a solution treatment into 89% or more, the average grain size of 10 micrometers or less can be obtained.

(Solubilization)

In general, the solution treatment of titanium copper is carried out at a temperature at which the solubility of Ti in Cu is equal to the concentration of Ti contained. However, when the solution treatment is carried out in this temperature range, the crystal grain size exceeds 10 µm. MEANS TO SOLVE THE PROBLEM This inventor calculated | required the solution treatment temperature range for obtaining the crystal grain diameter of 2-10 micrometers stably by experiment. That is, under the conditions of the solution treatment temperature (T (° C.)) of T> [6580 / {7.35-ln [Ti]}]-273, the grain size exceeds 10 µm, and it is difficult to obtain a 0.2% yield strength of 750 MPa or more. Lose. Moreover, on the conditions of solution treatment temperature T of T <[6580 / {7.35-ln [Ti]}]-333, a crystal grain size becomes less than 2 micrometers, and bending property of a material deteriorates. When the solution treatment temperature (T) is set to [6580 / {7.35-ln [Ti]}]-333≤T≤ [6580 / {7.35-ln [Ti]}]-273, the crystal grain size of 2 to 10 mu m is obtained. Obtained. Moreover, when the average cooling rate of the material from the heating temperature in solution treatment to 25 degreeC is less than 300 degreeC / s, the Cu-Ti intermetallic compound phase whose diameter exceeds 2.0 micrometers precipitates at a grain boundary during material cooling, When bending stress is applied to the material, cracks are likely to occur at grain boundaries. Therefore, the average cooling rate in the solution treatment is made into 300 degreeC / s or more. Moreover, although the cooling method at this time is not specifically limited, Usually, it is water-cooled in many cases.

(Cold rolled drawing after solution treatment)

If the cold rolling workability after the solution treatment is less than 10%, high strength due to work hardening cannot be expected, and it is difficult to obtain a 0.2% yield strength of 750 MPa or more, and the aging treatment which is the next step because there is little deformation introduced by rolling. The deposition rate on the Cu-Ti intermetallic compound is slow, and it is difficult to obtain a conductivity of 17% IACS or more. In addition, when the workability exceeds 70%, the ductility decreases and the bending workability significantly deteriorates. Therefore, it is difficult to obtain the relationship between the 0.2% yield strength and the bending workability specified in the present invention. Therefore, the cold rolling workability after solution treatment is made into 10 to 70%. In order to obtain a better relationship between the 0.2% yield strength and the bending workability, the cold rolling workability after the solution treatment is preferably 40 to 65%.

(Aging treatment)

In aging treatment, in order to precipitate the Cu-Ti intermetallic compound phase prescribed | regulated by this invention, aging conditions are adjusted as follows, for example.

(1) heating temperature

When heating temperature is less than 350 degreeC, precipitation of Cu-Ti intermetallic compound phase is not enough and the 0.2% yield strength of 750 Mpa or more and the electrical conductivity of 17% IACS or more cannot be obtained. Moreover, when heating temperature exceeds 450 degreeC, since a Cu-Ti intermetallic compound phase will coarsen, strength and bending workability will fall. Therefore, heating temperature is made into 350-450 degreeC. Here, heating temperature is the temperature of the furnace which heats a material.

(2) holding time at heating temperature

If the holding time at the heating temperature is less than 5 h, the precipitation of the Cu-Ti intermetallic compound phase is not sufficient, and it is difficult to obtain a conductivity of 17% IACS or more. When the holding time at the heating temperature exceeds 20 h, the Cu-Ti intermetallic compound phase is coarsened, so that the strength and the bending workability decrease. Thus, the holding time at the heating temperature is set to 5 to 20 h. The holding time here is a time from when the temperature of the material reaches the furnace temperature to the start of cooling.

(3) average cooling rate

In the aging treatment, if the average cooling rate from the heating temperature to 200 ° C. is faster than 50 ° C./h, the precipitation of Cu-Ti intermetallic compounds sufficient to obtain a conductivity of 17% IACS or more does not occur. In addition, when the average cooling rate is less than 10 ° C / h, precipitation of the Cu-Ti intermetallic compound phase becomes remarkable, and the bending workability is increased because the area ratio of the Cu-Ti intermetallic compound phase having a diameter of 0.02 to 2.0 µm exceeds 7.5%. Deteriorates. Therefore, the average cooling rate from the heating temperature in the aging treatment to 200 ° C. is set to 10 to 50 ° C./h.

Example

After electrolytic copper was used as a raw material, ingots (60 mm in width x 30 mm in thickness) of various compositions shown in Table 1 were melt-cast in a high frequency vacuum melting furnace, and then hot-rolled to 900 mm at 8 mm. Thereafter, the cold rolling before the solution treatment, the cold treatment after the solution treatment, and the cold rolling and aging treatment after the solution treatment were performed under the conditions shown in Table 1 to change the average grain size and the size and area ratio of the Cu-Ti intermetallic compound phase. I was. In addition, in the solution treatment, after the temperature of the specimen reached the temperature shown in Table 1, the mixture was held for 1 minute and then cooled. In this cooling, in order to change a cooling rate, a cooling method was performed by air cooling, injection of Ar gas, injection of water, and immersion in a water tank, and the injection amount of Ar gas and water was changed. The thermocouple was welded to the specimen and the average cooling rate until the temperature of the specimen became 25 ° C (room temperature) was measured. In the aging treatment, the cooling rate was changed by controlling the temperature of the furnace, and the average cooling rate from the heating temperature to 200 ° C. was measured.

The alloys thus obtained were evaluated for 0.2% yield strength, electrical conductivity, bending workability (MBR / t), average grain size of the cross section perpendicular to the rolling direction, and size and area ratio of the Cu-Ti intermetallic compound phase.

The 0.2% yield strength was measured in accordance with JIS Z2241 using a tensile tester. The electrical conductivity was measured by the four-terminal method in accordance with JIS H0505. Regarding the evaluation of the bending workability, thin and long samples having a width of 10 mm and a length of 50 mm were taken in a direction in which the longitudinal direction of the sample was orthogonal to the rolling direction, and the W bend test (JIS H3130) was conducted for various bending radii. The ratio of the minimum bending radius (mm) and the plate thickness (mm) where cracking does not occur is compared with the evaluation criteria according to the technical standard JBMA T307: 1999 of the Japan Shinto Society (JBMA T307: 1999). MBR / t) was obtained.

In the measurement of the average crystal grain size (mu m), a cross section perpendicular to the rolling direction was etched (water (100 mL) -FeCl ₃ (5 g) -HCl (10 mL)) to exhibit crystal grains, and a scanning electron microscope was used. It observed and the crystal grain size was computed by the cutting method (JIS H0501).

The Cu-Ti intermetallic compound phase precipitated in the alloy was observed using FE-SEM (manufactured by Nippon F. K., XL30SFEG). After polishing the cross-section perpendicular to the rolling direction of the material with a # 150 waterproof abrasive paper, mirror polishing the colloidal silica having a particle diameter of 40 nm was performed with a turbid polishing agent, and the obtained sample was carbon-deposited. Reflective electron images of the µm ² field of view were observed at five locations with altered field of view for each alloy. Then, the diameter and area ratio of the minimum circle | round | yen containing the Cu-Ti intermetallic compound phase in an observation visual field were calculated | required using the image analysis apparatus. In the size evaluation of a Cu-Ti intermetallic compound phase, evaluation x was made about the alloy in which the diameter exceeds 2.0 micrometers, and evaluation (circle) was set about the alloy in which the diameter exceeding 2.0 micrometers does not exist. In the evaluation of the area ratio, the Cu-Ti intermetallic compound phase to be measured should have a diameter of 0.02 to 2.0 µm, and a value of Cu-Ti intermetallic compound phase as the total area of the observation field is measured. It was set as the area ratio of Ti intermetallic compound phase.

Table 2 shows the evaluation results of each alloy. Inventive Examples 1 to 10 all satisfy the Ti content, crystal grain size, size and area ratio of the Cu-Ti intermetallic compound phase defined in the present invention, and thus exhibit a conductivity of 17% IACS or higher and 0.2% yield strength of 750 MPa or higher. , 0.2% yield strength (YS) and MBR / t also satisfy the scope of the present invention. In particular, the invention examples 2, 4, 7, and Ti content which exist in the range of 1.5-2.0 mass%, and the area ratio S of Cu-Ti intermetallic compound phase satisfy 8.1x [Ti] -11.5 <= S <7.5. 10 the conductivity exceeded 20% IACS. Moreover, when the Ti content is in the range of 1.6 to 2.0 mass% and the rolling workability after the solution treatment is in the range of 40 to 65%, 0.2% yield strength is the same as in the other examples. Shows good bending workability (MBR / t), and high bending strength when the bending workability is equivalent.

On the other hand, in Comparative Example 11, since the Ti concentration is too low, 0.2% yield strength of 750 MPa or more cannot be obtained.

In Comparative Example 12, the coarse Cu-Ti intermetallic compound phase having a size of 2.0 µm or more was precipitated because the Ti concentration was too high, and the area ratio of the Cu-Ti intermetallic compound phase exceeded the scope of the present invention. Bending workability cannot be obtained.

In Comparative Example 13, since the workability before the solution treatment was low, the average grain size after the solution treatment exceeded 10 μm, and the 0.2% yield strength did not reach 750 MPa.

In Comparative Example 14, since the solution treatment temperature was lower than the range of the present invention, the unrecrystallized portion remained, and both the size and the area ratio of the Cu-Ti intermetallic compound phase exceed the range of the present invention, the bending workability prescribed in the present invention was defined. Can't get it.

In Comparative Example 15, since the solution treatment temperature is higher than the range of the present invention, 0.2% yield strength of 750 MPa or more cannot be obtained when the aging treatment is performed under conditions in which the average grain size exceeds 10 µm and a conductivity of 17% IACS or more is obtained.

In Comparative Example 16, the coarse Cu-Ti intermetallic compound phase having a size of 2.0 µm or more was precipitated because the average cooling rate after the solution was slow, and thus the bending workability specified in the present invention could not be obtained.

In Comparative Example 17, since the rolling workability after the solution treatment was too low, 0.2% yield strength of 750 MPa or more was not obtained, and the precipitation rate of Ti in aging was slow and the area ratio of the Cu-Ti intermetallic compound phase was within the scope of the present invention. As a result, the conductivity of 17% IACS or more is not obtained.

Since the comparative example 18 has too high the rolling workability after solution treatment, the bending workability prescribed | regulated by this invention cannot be obtained.

In Comparative Example 19, since the heating temperature in the aging treatment was too low, 0.2% yield strength of 750 MPa or more was not obtained due to insufficient aging, and the area ratio of the Cu-Ti intermetallic compound was less than the scope of the present invention. No conductivity above% IACS is obtained.

In Comparative Example 20, since the heating temperature in the aging treatment is too high, coarsening of the Cu-Ti intermetallic compound occurs due to overaging, and the relationship between 0.2% yield strength and bending workability prescribed in the present invention is not satisfied.

In Comparative Example 21, since the heat holding time in the aging treatment was short, and the area ratio of the Cu-Ti intermetallic compound phase was less than the scope of the present invention, a conductivity of 17% IACS or more was not obtained.

In Comparative Example 22, since the heat holding time in the aging treatment is too long, coarsening of the Cu-Ti intermetallic compound occurs due to overaging, and the relationship between 0.2% yield strength and bending workability prescribed in the present invention is not satisfied. .

In Comparative Example 23, the average cooling rate in the aging treatment was high, and the area ratio of the Cu-Ti intermetallic compound phase was less than the scope of the present invention, so that a conductivity of 17% IACS or more was not obtained.

In Comparative Example 24, the average cooling rate in the aging treatment was slow, and the area ratio of the Cu-Ti intermetallic compound phase exceeded the scope of the present invention, and hence the bending workability specified in the present invention cannot be obtained.

According to the present invention, it is possible to supply a titanium copper alloy excellent in strength, bending workability and conductivity, which can cope with the recent miniaturization and thinning of electronic equipment.

Claims (3)

A copper alloy containing 1.5 to 2.3 mass% of Ti and consisting of residual Cu and unavoidable impurities. JIS H3130 with 0.2% yield strength (YS) of 750 MPa or more, conductivity (EC) of 17% IACS or more, and perpendicular to the rolling direction. When the W bending test described in the above is conducted, the ratio (MBR / t) of the minimum bending radius (MBR; mm) and the plate thickness (t; mm) where no cracking occurs is between the 0.2% yield strength (YS; MPa). Titanium copper excellent in strength, electroconductivity, and bending workability, which has a relationship of MBR / t ≦ 0.04 × YS-30. The Cu-Ti intermetallic compound phase according to claim 1, which is a copper alloy containing 1.5 to 2.3 mass% of Ti, consisting of residual Cu and unavoidable impurities, and observed in a cross section perpendicular to the rolling direction. The area ratio (S;%) and Ti content ([Ti]; mass%) of Cu-Ti intermetallic compounds having a diameter of 0.02 to 2.0 µm or less observed in a cross section perpendicular to the rolling direction were 8.1 × [ Ti] -11.5 ≤ S ≤ 7.5, and the average grain size (measured by JIS H0501 cutting method) of the cross section perpendicular to the rolling direction is 2 to 10 µm, characterized in that the strength, conductivity, and bending workability This excellent titanium copper. In the manufacturing process of titanium copper which performs the hot rolling, cold rolling, solution treatment, cold rolling, and aging treatment of ingots sequentially, the cold rolling workability before solution treatment is 89% or more, and the heating temperature in solution treatment. The range of (T (° C.)) is [6580 / {7.35-ln [Ti]}]-333≤T≤ [6580 / {7.35-ln [Ti]}]-273, and the average cooling rate in the solution treatment. 300-C / s or more, 10-70% of cold-rolling workability before an aging treatment, 350-450 degreeC of heating temperature in an aging treatment, 5-20 h of heating holding time, and average cooling rate from a heating temperature in an aging treatment It is set to 10-50 degreeC / h, The manufacturing method of the titanium copper of Claim 1 or 2 characterized by the above-mentioned.