JP2000169920A - Copper base alloy having shape memory characteristic and superelasticity, and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a copper base alloy having high shape memory characteristics and superelasticity wile maintaining excellent workability. SOLUTION: This copper base alloy, which has shape memory characteristics and superelasticity and whose crystal structure is the recrystallized texture in which the crystal orientation of βsingle phase is arranged, is produced by executing forming by cold working including annealing, solution heat treatment, quenching and aging treatment, and the cold working is executed at the total working ratio after the final annealing so as to control the abundance ratio in the specified crystal orientation of the βsingle phase in the working direction measured by an electron back scattering pattern method to >=2.0.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper alloy and a method for producing the same, and more particularly, to a copper alloy having excellent shape memory characteristics and superelasticity and a method for producing the same.

[0002]

2. Description of the Related Art It is well known that shape memory alloys such as TiNi alloys and copper-based alloys exhibit a remarkable shape memory effect and superelasticity accompanying the reverse transformation of martensitic transformation.
Above all, TiNi alloy has excellent functions in the vicinity of living environment temperature, so it is used in a wide range of fields such as microwave oven damper, air conditioner wind direction control, rice cooker steam pressure regulating valve, ventilator for construction, mobile phone antenna, eyeglass frame, etc. Has been put to practical use. TiNi is superior to copper-based alloys in many aspects such as repetition characteristics and corrosion resistance, but is less expensive than copper-based alloys.
There is a need for alloys that are 0 times or more, and in that respect lower cost.

[0003] In response to such a demand, research into practical use of a copper-based shape memory alloy which is advantageous in terms of cost has been made. However, many copper-based alloys have poor cold workability, which hinders practical application. Then, the present inventors have previously proposed a Cu-Al-Mn-based shape memory alloy having a β single phase structure excellent in cold workability (Japanese Patent Laid-Open No. 7-62472).
issue).

[0004]

However, the characteristics of the Cu-Al-Mn-based shape memory alloy produced by the conventional method, particularly the superelasticity is not sufficient, and the maximum applied strain showing a shape recovery of 90% or more is 2%. About 3%. The reason is that quenching after the solution treatment is performed at a temperature as high as 900 ° C., so that the growth of crystal grains cannot be avoided and a specific crystal orientation cannot be obtained.

Accordingly, it is an object of the present invention to solve these problems and to provide a copper-based alloy having high shape memory characteristics and superelasticity while maintaining excellent workability, and a method for producing the same. .

[0006]

Means for Solving the Problems In view of the above problems, as a result of intensive studies, the present inventors have found that the shape memory characteristics and superelasticity are greatly improved by aligning the crystal orientation of the β single phase in the crystal structure. The inventors have found that the working ratio and the solution treatment during the cold working are related to the degree of alignment of the crystal orientation of the β single phase, and have completed the present invention.

That is, the copper-based alloy of the present invention is a copper-based alloy having shape memory and superelasticity and substantially consisting of a β single phase, and has a crystal structure in which the β single phase has the same crystal orientation. It has a recrystallized texture.

In the method of the present invention for producing a copper-based alloy, a copper-based alloy substantially consisting of a single β phase is produced by cold working including annealing, solution treatment, quenching and aging treatment. The cold working is performed at a total working ratio after final annealing such that the frequency of existence of the specific crystal orientation of the β single phase in the working direction measured by an electron backscattering pattern method is 2.0 or more. And

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The copper-based alloy of the present invention has a substantially β
It is composed of a single phase, and has a recrystallized texture in which specific crystal orientations such as <110> and <100> of the β single phase are aligned with a cold working direction such as rolling or drawing. When expressed by the frequency of the crystal orientation of the alloy structure measured by the electron back scattering pattern method, the frequency of the specific crystal orientation in the working direction of the copper-based alloy of the present invention is 2.0.
Or more, preferably 2.5 or more. Hereinafter, the copper-based alloy of the present invention will be described in detail.

[1] Composition of Copper-Based Alloy The copper-based alloy of the present invention is an alloy having a two-phase structure of β phase (body-centered cubic) at a high temperature and β + α (face-centered cubic) at a low temperature.
It contains at least Cu and Al. As preferred specific examples of the copper-based alloy of the present invention, 3 to 10% by weight of Al,
And Mn in an amount of 5 to 20% by weight, the balance being Cu and inevitable impurities.

When the content of the Al element is less than 3% by weight, β
A single phase cannot be formed, and if it exceeds 10% by weight, it becomes extremely brittle. Although the content of the Al element varies depending on the composition of the Mn element, the preferable content of the Al element is 6 to 10% by weight.

By containing the Mn element, the range of existence of the β phase is widened toward the low Al side, and the cold workability is remarkably improved, thereby facilitating the forming process. Mn element addition amount is 5
If the amount is less than about 30% by weight, satisfactory workability cannot be obtained, and a β single phase region cannot be formed. If the amount of the Mn element exceeds 20% by weight, sufficient shape recovery characteristics cannot be obtained. The preferred Mn content is 8 to 12% by weight.

[0013] The Cu-Al-Mn alloy having the above composition is rich in hot workability and cold workability, and enables a work ratio of 20% to 90% or more in a cold state, and has been difficult to achieve in the past. It can be easily formed into wire, foil, pipe, etc.

In addition to the above component elements, the copper alloy of the present invention further comprises Ni, Co, Fe, Ti, V, Cr, Si, N
b, Mo, W, Sn, Mg, P, Be, Sb, Cd, A
One or more selected from the group consisting of s, Zr, Zn, B, C, Ag and misch metal can be contained. Among them, Ni and / or Co are particularly preferable. These elements exhibit the effect of refining the crystal grains while maintaining the cold workability and improving the strength of the copper-based alloy. The total content of these additional elements is 0.001-1.
It is preferably 0% by weight, particularly preferably 0.001 to 5% by weight. When the content of these elements exceeds 10% by weight, the martensitic transformation temperature decreases and the β single phase structure becomes unstable.

Ni, Co, Fe and Sn are effective elements for strengthening the base structure. The preferred contents of Ni and Fe are 0.001 to 3% by weight, respectively. Co also refines the crystal grains by forming CoAl, but excessively decreases the toughness of the alloy. The preferred content of Co is 0.001 to 2
% By weight. The preferred content of Sn is 0.001 to 1% by weight.

[0016] Ti combines with the inhibitory elements N and O to form oxynitride. In addition, boron is formed by addition of B in combination to refine the crystal grains and improve the shape recovery rate. The preferred content of Ti is 0.001-2% by weight.

V, Nb, Mo, and Zr have the effect of increasing hardness and improve wear resistance. Further, since these elements hardly form a solid solution in the matrix, they precipitate as bcc crystals, and are effective in refining crystal grains. V, Nb, Mo, Z
The preferable content of r is 0.001 to 1% by weight.

Cr is an element effective for maintaining wear resistance and corrosion resistance. The preferred content of Cr is 0.001 to 2
% By weight.

Si has the effect of improving corrosion resistance.
The preferred content of Si is 0.001 to 2% by weight.

Since W hardly forms a solid solution in the matrix, it has the effect of strengthening precipitation. The preferred content of W is 0.001 to 1% by weight.

Mg removes the inhibitory elements N and O and fixes the inhibitory element S as a sulfide, which is effective in improving hot workability and toughness. And cause embrittlement. The preferred content of Mg is 0.001 to 0.5% by weight.

P acts as a deoxidizing agent and has an effect of improving toughness. The preferred content of P is 0.01-0.5% by weight.

Be, Sb, Cd, As have the effect of strengthening the base organization. The preferred contents of Be, Sb, Cd, and As are each 0.001 to 1% by weight.

Zn has the effect of increasing the shape memory processing temperature. The preferred content of Zn is 0.001 to 5% by weight.

B and C have the effect of refining the crystal structure. Particularly, a composite addition with Ti and Zr is preferable. The preferred content of B and C is 0.001 to 0.5% by weight.

Ag has the effect of improving cold workability.
The preferred content of Ag is 0.001 to 2% by weight.

Misch metal has an effect of making crystal grains fine. The preferred content of misch metal is 0.001 ~
5% by weight.

[2] Production method of copper alloy (a) Molding of copper alloy A copper alloy having the above composition is melted and cast, and hot rolling, cold rolling,
It is molded into a desired shape by a molding method such as pressing,
In the present invention, the forming process immediately before the solution treatment is cold rolling,
Performed by cold working such as cold drawing. By performing cold working, the crystal orientation of the β single phase of the obtained copper-based alloy becomes uniform, and the shape memory characteristics and superelasticity are improved.

In order to increase the orientation of the alloy structure, the higher the total working ratio after the final annealing, the better, but the lower limit depends on the alloy composition. In the present invention, the value of the frequency of occurrence is determined from the relationship between the frequency of existence of a specific crystal orientation such as <110> or <100> of the β single phase measured by the electron backscattering pattern method and the shape memory property and the superelastic property. The total processing rate can be determined as a guide. For example, when the frequency of the specific crystal orientation of the β single phase in the processing direction is 2.0 or more, Cu 82.2% by weight, Al 8.1% by weight, Mn 9.7% by weight
Alloy having a composition of 50% or more, Cu8
0.4% by weight, Al 8.0% by weight, Mn 9.5% by weight, Ni2.1
For alloys having a composition of weight%, the total processing rate needs to be 30% or more. If the total working ratio after the final annealing is low, the crystal orientation of the alloy structure is not uniform, and the improvement in shape memory characteristics and superelasticity cannot be obtained.

The cold working needs to be performed on the crystal structure in which the α phase exists. The presence of the α phase having good workability can realize a high cold work rate, thereby making it easy to make the crystal orientation uniform. The preferred volume fraction of the α phase is 20% by volume or more.

(B) Solution treatment Next, a solution treatment for heating to a β single phase region temperature to transform the crystal structure into a β single phase is performed.

In a preferred embodiment of the present invention, after the solution treatment, the solution is cooled to the temperature of the two-phase region of β + α and the solution treatment is performed again. As described above, by performing the solution treatment twice or more than twice, remarkable improvements in shape memory characteristics and superelasticity can be seen. This is because the β phase formed once is cooled to form two phases β + α, and the precipitated α phase becomes a nucleus, and the β phase generated in the next solution treatment has priority over the crystal orientation in which slip deformation is unlikely to occur. It is thought to be due to growth.

Although the β single phase zone temperature and the β + α two phase zone temperature differ depending on the alloy components, the preferred β single phase zone temperature is 700
950 ° C., and the preferred β + α two-phase temperature is 400-
850 ° C. The holding time at the β single phase region temperature may be at least 0.1 minute, but if the holding time exceeds 15 minutes, no further improvement in the effect can be obtained, so the holding time should be 0.1 to 15 minutes. preferable.

Before the final solution treatment, a skin pass for giving a strain of about 5 to 20% at room temperature may be performed. The skin pass is preferable because the crystal orientation of the alloy structure can be more easily made uniform.

The solution treatment may be performed by so-called tension annealing in which heat treatment is performed while applying stress. By performing the tension annealing, the memory shape of the alloy can be precisely controlled.

(C) Quenching Finally, the solution-treated alloy is rapidly cooled to freeze the β single phase state. The quenching can be carried out by putting into a cooling medium such as water or by forced air cooling. If the cooling rate is low, precipitation of the α phase occurs, and the crystal structure of the β single phase cannot be maintained. The cooling rate is preferably at least 50 ° C./sec.

(D) Aging treatment The aging treatment is performed at a temperature of less than 300 ° C., preferably 100 to 250 ° C. If the heating temperature is too low, the β phase is unstable,
If left at room temperature, the martensitic transformation temperature may change. Conversely, if the heating temperature is higher than 300 ° C., precipitation of the α phase occurs, and the shape memory characteristics and superelasticity are significantly reduced.

The aging time varies depending on the composition of the copper-based alloy, but is preferably 1 to 300 minutes, particularly preferably 5 to 200 minutes. If the aging treatment time is less than 1 minute, the effect of aging cannot be obtained, and if the aging treatment time exceeds 300 minutes, the structure becomes coarse and the mechanical properties as a material become insufficient.

[3] Properties of Copper-Based Alloy (1) Crystal Structure The crystal structure of the copper-based alloy of the present invention substantially consists of a β single phase, and the β single phase has a <110> or <100> direction or the like. It is a recrystallized texture with a specific crystal orientation. In the method of the present invention, the crystal orientation is given by cold working, and the β single phase <
The <110> or <100> direction is aligned with a cold working direction such as rolling or drawing. The crystal orientation of the alloy structure can be measured by the electron backscattering pattern method, and the frequency of occurrence indicating the degree of alignment of the crystal orientation can be obtained. For example, the frequency of occurrence of <110> in the processing direction is the rate of occurrence when assuming that the frequency of occurrence of <110> oriented in the processing direction is 1 when the crystal orientation is theoretically completely random, The larger the value, the more uniform the crystal orientation. The existence frequency of the specific crystal orientation in the processing direction of the copper-based alloy of the present invention is 2.0 or more, preferably 2.
5 or more.

(2) Superelasticity The copper-based alloy of the present invention having such a uniform crystal orientation has superelasticity which is remarkably superior to that of a conventional copper-based alloy. The applied strain having a shape recovery rate of 90% or more after deformation release is at least 3%. In particular, when the solution treatment is performed twice or more, the applied strain at which the shape recovery rate after deformation release is 90% or more is at least 5%.

(3) Shape Memory Characteristics The copper-based alloy of the present invention has excellent shape memory characteristics, and the shape recovery rate is 95% or more, substantially 100%.

[0042]

Examples 1 to 3 and Comparative Example 1 Cu 80.4% by weight, Al 8.0% by weight, Mn 9.5% by weight, N
i2.1 Dissolve a copper alloy having a composition by weight of 14% by weight
After solidifying at a cooling rate of 0 ° C./min to produce a billet having a diameter of 20 mm, hot rolling was performed at 850 ° C., and further cold rolling was performed while performing intermediate annealing to obtain a length of 100 mm and a width of 1 mm.
A plate material having a thickness of 0 mm and a thickness of 0.2 mm was obtained. Table 1 shows the total working ratio after the final annealing. The final annealing was both at 600 ° C. for 10 minutes, and the α-phase volume fraction at the time of final processing was 70%.
After the obtained plate material was subjected to a solution treatment at 900 ° C. for 15 minutes, it was put into ice water and rapidly cooled, and then subjected to an aging treatment at 200 ° C. for 15 minutes to obtain a plate material made of a copper-based alloy.

With respect to the obtained plate material, the measurement of the electron backscattering pattern and the stress-strain correlation diagram were obtained according to the following methods.

(1) Electron backscattering pattern Electron backscattering pattern measuring device (trade name: Orientation
Using an Imaging Microscope (manufactured by TSL), the frequency of the β-phase crystal orientation in the rolling direction of the obtained sheet material was measured. FIG. 1 is an inverse pole figure showing the frequency of each crystal orientation in the rolling direction of the sheet material obtained in Example 2 and FIG. 2 by contour lines in FIG. In FIG. 1 of Example 2, the contour lines are gathered in the <110> direction, which indicates that the <110> direction is aligned with the rolling direction. The existence frequency of <110> in the rolling direction was 5.0. On the other hand, in FIG. 2 of Comparative Example 1, the crystal orientations were almost randomly dispersed, and the frequency of <110> presence in the rolling direction was 1.5. Table 1 also shows the frequencies of <110> present in the rolling directions of the sheet materials of Examples 1 to 3 and Comparative Example 1.

(2) Shape recovery rate in superelasticity A stress-strain correlation diagram of the obtained sheet material was prepared. FIG. 3 shows the stress at a given strain of 6% of the sheet material of Example 2.
FIG. 4 shows a stress-strain correlation diagram of Comparative Example 1 at an applied strain of 6%. The shape recovery rate in superelasticity was calculated from the stress-strain relationship diagram by the following equation: shape recovery rate (%) = 100 × (grant-residual strain)
/ Strain The shape recovery ratio at a strain of 4% is shown in Table 1.

Table 1 Working Conditions and Properties in Examples 1 to 3 and Comparative Example 1 Example No. Total Working Rate (%) at 110 % Strain in Rolling Direction after Final Annealing Recovery of Presence Frequency Shape of <110> Rate (%) Example 1 30 2.8 90 Example 2 50 5.0 97 Example 3 75 5.2 97 Comparative Example 1 20 1.0 82

As can be seen from Table 1, in Examples 1 to 3 in which the total working ratio after the final annealing was 30% or more, the frequency of <110> in the rolling direction was 2.0 or more, and <110> was It shows that they are complete. Further, the shape recovery rates are all 90% or more. However, in Comparative Example 1 in which the total working ratio after the final annealing was 20%, the <110> frequency in the rolling direction was 1.5, indicating that the <110> direction was almost random. The shape recovery rate was 82%, which was less than 90%. These results demonstrate that the high total post-annealing work ratio aligned the crystallographic orientation in the copper-based alloy and thus improved the superelasticity.

Example 4 and Comparative Example 2 A copper alloy having a composition of 82.2% by weight of Cu, 8.1% by weight of Al and 9.7% by weight of Mn was melted and solidified at an average cooling rate of 140 ° C./min. After making a billet with a diameter of 20 mm,
Hot rolling is performed at 850 ° C., and further cold rolling is performed while performing intermediate annealing to obtain a length of 100 mm, a width of 10 mm, and a thickness of 0.1 mm.
A 2 mm plate was obtained. The final annealing temperature was 600 ° C., and the α-phase volume fraction at the time of final processing was 70%. Table 2 shows the total working ratio after the final annealing. 900 obtained plate material
After a solution treatment at 15 ° C. for 15 minutes, the mixture was put into ice water and rapidly cooled, and then subjected to an aging treatment at 200 ° C. for 15 minutes to obtain a plate material made of a copper-based alloy.

An electron backscattering pattern and a stress-strain correlation diagram were obtained for the obtained sheet material in the same manner as in Example 1, and the frequency of <110> existing in the rolling direction and the shape recovery rate at 3% applied strain were determined. Are shown in Table 2.

[0050] Table 2 Example 4 and processing conditions in Comparative Example 2 and Example No. Total working ratio at given strain of 3% in the rolling direction after the properties final annealing (%) occurrence frequency shape recovery ratio of <110> ( %) Example 4 50 2.3 90 Comparative Example 2 30 1.3 81

As can be seen from Table 2, in Example 2 in which the total working ratio after the final annealing was 50%, <11 in the rolling direction.
0> existence frequency was 2 or more, <110> was aligned in the rolling direction, and the shape recovery rate was 90%. However, in Comparative Example 2 in which the total working ratio after the final annealing was 30%, the frequency of <110> existing in the rolling direction was 1.3, and <11>
0> direction is almost random. The shape recovery rate was 81%.

Examples 5 to 8 and Comparative Example 3 Using the same copper alloy as in Example 3, hot rolling was performed in the same manner as in Example 3, and further cold rolling was performed while performing intermediate annealing to obtain a length of 100 mm. A plate material having a width of 10 mm and a thickness of 0.2 mm was obtained. However, in the final annealing, quenching was performed after heating to the temperature shown in Table 3, and α in the alloy structure as shown in Table 3
The phase volume fraction was adjusted. The total working ratio after the final annealing was 75% in all cases. After the obtained plate material was subjected to a solution treatment at 900 ° C. for 15 minutes, it was put into ice water and rapidly cooled, and then subjected to an aging treatment at 200 ° C. for 15 minutes to obtain a plate material made of a copper-based alloy. The frequency of existence of the β single phase in the <110> direction in the rolling direction of the obtained copper-based alloy and the shape recovery rate (%) at 4% applied strain were measured in the same manner as in Example 3.
It is shown along with.

Table 3 Processing conditions and characteristics in Examples 5 to 8 and Comparative example 3 Final annealing Final processing Example with 4% applied strain in rolling direction No. Temperature (° C.) α-phase volume fraction (%) < occurrence frequency shape recovery ratio of 110> (%) example 5 550 80 4.4 95 example 6 600 70 3.9 97 example 7 700 45 4.3 95 example 8 800 18 3.0 95 Comparative example 3 900 0 1.5 82

As can be seen from Table 3, the content of the α phase at the time of forming after the final annealing affects the superelasticity of the obtained copper-based alloy. In Examples 5 to 8 in which the α phase volume fraction was 18% or more, the frequency of <110> in the rolling direction was 2
As described above, <110> is aligned in the rolling direction, and the shape recovery rates are all 90% or more. However, in Comparative Example 3 where substantially no α phase was present, <11 in the rolling direction
0> Existence frequency is 1.5, almost random,
The shape recovery rate was as low as 82%.

Examples 9 and 10 A copper alloy having the composition shown in Table 4 was obtained in the same manner as in Example 2 to obtain a plate material having a length of 100 mm, a width of 10 mm and a thickness of 0.2 mm. However, the final annealing temperature was 600 ° C., and the total working ratio after the final annealing was 50% in each case. The obtained plate material was subjected to a solution treatment at 900 ° C. for 5 minutes, air-cooled to 800 ° C. or less, further subjected to a solution treatment at 900 ° C. for 15 minutes, rapidly poured into ice water, and then rapidly cooled at 200 ° C. for 15 minutes. Was performed to obtain a plate material made of a copper-based alloy.

Table 4 Composition (% by weight) of the copper-based alloys of Examples 9 and 10 Example No. Cu Al Mn Co Ni Cr Example 9 81.2 8.1 10.2 0.5 Example 10 79.0 7.8 9.3 2.1 1.8

The frequency of the crystal orientation in the rolling direction of the obtained copper alloy was measured in the same manner as in Example 2. FIG.
19 shows an inverse pole figure which is a measurement result of an electron backscattering pattern of the plate material obtained in Example 9. As can be seen from FIG. 5, the contour lines are gathered in the <100> direction, indicating that the <100> direction is aligned with the rolling direction. The frequency of <100> present in the rolling direction was 4.5.

With respect to the obtained plate material, the shape recovery rate after the deformation was released was measured in the same manner as in Example 2, and the results are shown in Table 5. The shape recovery rate of a plate manufactured by performing the solution treatment only once is also shown for comparison.

Table 5 Shape recovery rate of copper-based alloys obtained in Examples 9 and 10 Example of only one solution heat treatment in double solution heat No. Strain (%) Shape recovery rate (%) Shape recovery rate (%) Example 9 7 98 83 Example 10 6 90 52

As can be seen from Table 5, the superelasticity of each of the obtained sheet materials was significantly improved by performing the solution treatment twice.

Example 10 A copper alloy having the composition of Sample Nos. 1 to 4 shown in Table 6 was melted and solidified at an average cooling rate of 140 ° C./min.
After producing a 0-mm billet, it was hot-rolled at 850 ° C., and further cold-rolled while performing intermediate annealing to obtain a plate material having a length of 100 mm, a width of 10 mm, and a thickness of 0.2 mm. However, the condition of the final annealing was 600 ° C. × 10 minutes, and the total working ratio after the final annealing was 50% in each case. The obtained sheet material was heat-treated at 900 ° C. for 15 minutes, poured into ice water and rapidly cooled, and then subjected to aging treatment at 200 ° C. for 15 minutes to obtain a sheet material made of a copper-based alloy.

The obtained plate was placed in liquid nitrogen with a diameter of 2
After wrapped around a 0 mm round bar and taken out of liquid nitrogen,
The radius of curvature R ₀ of the bending was measured. Next, the bent plate was heated to 200 ° C. to recover the shape, and then the radius of curvature R ₁ of the plate was measured. Formula: Shape recovery rate (%) = 100
× (R ₁ −R ₀ ) / R ₁ was used to calculate the shape recovery rate due to shape memory. The shape recovery rate is also shown in Table 6.

Table 6 Composition of copper-based alloy and shape recovery rate by shape memory Composition (% by weight) Sample No. Cu Al Mn by shape memory Other shape recovery rate (%) 1 82.2 8.1 9.7 95 2 79.0 7.8 9.3 Ni: 2.1 Cr: 1.8 100 3 81.2 8.1 10.2 Co: 0.5 100 4 80.4 8.0 9.5 Ni: 2.1 100

As can be seen from Table 6, the copper-based alloy of the present invention has a shape recovery ratio of 95% or more and has excellent shape memory characteristics.

[0065]

As described in detail above, the copper-based alloy of the present invention has a β single phase in which the specific crystal orientation is aligned, and has significantly improved shape memory characteristics and superelasticity as compared with conventional ones. . Further, the copper-based alloy can be easily manufactured by the method of the present invention. Further, since the copper-based alloy of the present invention has excellent workability, it can be formed in various shapes at low cost.

[Brief description of the drawings]

FIG. 1 is an inverse pole figure showing, with contour lines, the frequency of the presence of a β single phase crystal orientation in the rolling direction of the copper alloy sheet material of Example 2.

FIG. 2 is an inverse pole figure showing, with contour lines, the frequency of existence of a β single phase crystal orientation in the rolling direction of the copper alloy sheet material of Comparative Example 1.

FIG. 3 is a stress-strain correlation diagram of the copper alloy sheet material of Example 2.

FIG. 4 is a stress-strain correlation diagram of the copper alloy sheet material of Comparative Example 1.

FIG. 5 is an inverse pole figure showing the frequency of the β single phase crystal orientation in the rolling direction of the copper alloy sheet material of Example 9 by contour lines.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C22F 1/00 630 C22F 1/00 630L 686 686B 693 693A 694 694A

Claims (13)

[Claims] 1. A copper alloy having shape memory characteristics and superelasticity and substantially consisting of a β single phase, wherein the crystal structure is
A copper-based alloy having a recrystallized texture in which the crystal orientation of a single phase is uniform. 2. The copper-based alloy according to claim 1, which is formed by cold working, and wherein the specific crystal orientation of the β single phase is aligned with the working direction of the cold working. Copper alloy. 3. The copper-based alloy according to claim 2, wherein the frequency of the specific crystal orientation of the β single phase in the processing direction measured by an electron backscattering pattern method is 2.0 or more. Copper alloy. 4. The copper-based alloy according to claim 2, wherein the specific crystal orientation is a <110> or <100> direction. 5. The copper alloy according to claim 1, wherein 3 to 10% by weight of Al and 5 to 20% by weight.
A copper-based alloy characterized by having a composition consisting of Mn, the balance being Cu and unavoidable impurities. 6. The copper-based alloy according to claim 5, further comprising Ni, Co, Fe, Ti, V, Cr, Si, Nb,
Mo, W, Sn, Mg, P, Be, Sb, Cd, As,
A copper-based alloy comprising 0.001 to 10% by weight in total of one or more selected from the group consisting of Zr, Zn, B, C, Ag and misch metal. 7. A method for producing a copper-based alloy consisting essentially of β single phase by forming by cold working including annealing, performing solution treatment, quenching, and aging treatment, and measuring by an electron backscattering pattern method. The method of manufacturing a copper-based alloy, wherein the cold working is performed at a total working ratio after final annealing such that the frequency of the specific crystal orientation of the β single phase in the working direction is 2.0 or more. 8. The method for producing a copper-based alloy according to claim 7, wherein after the solution treatment, the solution is cooled to a two-phase temperature range of β + α and the solution treatment is performed again. Production method. 9. The method for producing a copper-based alloy according to claim 8, wherein the solution treatment is performed twice or more. 10. The method for producing a copper-based alloy according to claim 7, wherein the volume fraction of the α phase in the crystal structure at the time of cold working is set to 20% or more. Production method of base alloy. 11. The method for producing a copper-based alloy according to claim 7, wherein the copper-based alloy is 3 to 10% by weight.
Of a copper-based alloy having a composition comprising Al, 5 to 20% by weight of Mn, a balance of Cu and inevitable impurities, and a total working ratio after the final annealing is 50% or more. Method. 12. The method for producing a copper-based alloy according to claim 11, wherein the copper-based alloy further contains Ni and / or Co, and a total working ratio after the final annealing is 30% or more. Characteristic copper-based alloy production method. 13. The method for producing a copper-based alloy according to claim 11 or 12, further comprising: Fe, Ti, V, Cr, Si, and N.
b, Mo, W, Sn, Mg, P, Be, Sb, Cd, A
at least one selected from the group consisting of s, Zr, Zn, B, C, Ag and misch metal in a total of 0.001 to 10
What is claimed is: 1. A method for producing a copper-based alloy, comprising: