JP3344946B2 - Functionally graded alloy and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a functionally graded alloy and a method for producing the same, and more particularly, to a method for continuously or stepwise changing the properties such as hardness and elastic elongation of a copper-based alloy compact having a uniform composition and diameter. The present invention relates to a functionally graded alloy that can be formed and a method for producing the same.

[0002]

2. Description of the Related Art Functionally graded materials are characterized by continuous functional properties such as hardness, elasticity, thermal conductivity, and electrical conductivity without imparting a gradient to the dimensions by machining such as cutting or chemical treatment such as etching. It is a material that has been changed (graded) in a targeted or stepwise manner. As functionally graded materials developed to date, SiC / C-based, ZrO /
There are W system, TiC / Ni system, ZrO / Ni system, etc., but most of them are those in which the composition ratio of the binary system is gradually changed.

A conventional functionally graded material in which the composition ratio of two components is gradually changed is prepared by preparing a plurality of mixed powders having different mixing ratios by using powders of the respective components, and laminating them in order. And sintering. For example, Japanese Patent Application Laid-Open No. 5-278158 discloses a metal-metal functionally gradient material obtained by laminating and sintering W and Mo powders.

[0004]

However, the functionally graded material manufactured by such a method cannot be formed by rolling and drawing, but can be formed only by cutting, so that the manufacturing cost is high and the shape is complicated. There is a problem that molding is not possible. Therefore, conventional functionally graded materials are mainly used in high value-added fields such as the space industry and nuclear power generation, and at present, there is a strong demand for functionally graded materials that can be manufactured at low cost and that can be easily formed. is there.

[0005] It is an object of the present invention to solve these problems,
An object of the present invention is to provide an inexpensive functionally graded alloy having excellent workability and a method for producing the same.

[0006]

The present inventors previously proposed a Cu-Al-Mn based shape memory alloy having a β single-phase structure (Japanese Patent Laid-Open No. 7-62472). -Completed the present invention by discovering that partially heating the Al-Mn-based copper alloy at a specific temperature or providing a gradient in the heating temperature results in a partial change in the crystal structure and a large change in the functional characteristics. did.

That is, the functionally graded alloy of the present invention comprises
A first portion having a composition of 10 % by mass of Al, 5 to 20 % by mass of Mn, the balance of Cu and unavoidable impurities, and having a crystal structure substantially consisting of β single phase , and substantially α phase and a second portion having a crystal structure consisting of Heusler phase and the first
Between the first part and the second part.
Crystal structure changing from the crystal structure to the crystal structure of the second part
And a third portion having:

[0008] The functionally graded alloy of the present invention further comprises Ni, Co, F
e, Ti, V, Cr, Si, Nb, Mo, W, Sn, Mg, P, Zr, Z
1 selected from the group consisting of n, B and misch metal
Species or two or more species can be contained in a total of 0.001 to 10 % by mass .

The method of the present invention for producing a functionally graded alloy comprises the steps of: (a) forming a copper alloy having the above composition into a desired shape; (b) quenching after holding at a temperature of 500 ° C. or more; (C) using a heating device having a temperature gradient, setting the heating temperature of the first part to less than 250 ° C., and setting the heating temperature of the second part to 2
The aging treatment is performed at 50 to 350 ° C., and a temperature gradient is provided in the third portion from the heating temperature of the first portion to the heating temperature of the second portion.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [1] Composition of Functionally Gradient Alloy The functionally graded alloy of the present invention contains 3 to 10 % by mass of Al,
It contains 20 % by mass of Mn, with the balance being Cu and unavoidable impurities. This alloy has a β (bcc structure) single phase at high temperatures, but undergoes martensitic (non-diffusion) transformation at low temperatures. Specifically, the structure of β single phase changes to a two phase structure of α phase (fcc structure) and Heusler phase (regular bcc structure) by heat treatment at about 300 ° C.

When the content of the Al element is less than 3 % by mass , a β single phase cannot be formed, and when it exceeds 10 % by mass , 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 mass .

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. 5 % by mass of Mn element added
If it is less than 30, satisfactory workability cannot be obtained, and a β single phase region cannot be formed. In addition, the addition amount of Mn element is 20 mass
% , Sufficient shape recovery characteristics cannot be obtained. The preferred Mn content is 8 to 12 % by mass .

[0013] The Cu-Al-Mn alloy having the above composition is excellent in hot workability and cold workability, and can have a work ratio of 20% to 90% or more in a cold state. Therefore, it can be easily formed into a very fine wire, foil, pipe, or the like, which is difficult to obtain with the conventional functionally graded material.

In addition to the above component elements, the functionally graded alloy of the present invention further comprises Ni, Co, Fe, Ti, V, Cr, Si, Nb, Mo,
One, two or more selected from the group consisting of W, Sn, Mg, P, Zr, Zn, B and misch metal can be contained. These elements exhibit the effect of refining the crystal grains while maintaining the cold workability and improving the strength of the functionally graded alloy. The total content of these additional elements is 0.001 to 10
It is preferably from wt%, especially 0.001 to 5% by mass. If the content of these elements exceeds 10 % by mass , 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 each.
３3 % by mass . Co also refines the crystal grains by forming CoAl, but excessively reduces the toughness of the alloy.
The preferred content of Co is 0.001 to 2 % by mass . The preferred content of Sn is 0.001 to 1 % by mass .

[0016] Ti combines with N and O, which are inhibitory elements, 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 preferable content of Ti is 0.001 to 2 % by mass .

V, Nb, Mo, and Zr have the effect of increasing hardness and improve wear resistance. In addition, since these elements hardly form a solid solution in the matrix, they precipitate as bcc crystals, and are effective in refining crystal grains. The preferred contents of V, Nb, Mo and Zr are each 0.001 to 1 % by mass .

[0018] Cr is an element effective for maintaining wear resistance and corrosion resistance. The preferable content of Cr is 0.001 to 2 mass.
% .

Si has an effect of improving corrosion resistance. Si
Is preferably 0.001 to 2 % by mass .

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

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

P acts as a deoxidizing agent and has an effect of improving toughness. The preferable content of P is 0.01 to 0.5 % by mass .

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

B has the effect of refining the crystal structure. In particular, complex addition with Ti and Zr is preferable. The preferable content of B is 0.01 to 0.5 % by mass .

The misch metal has an effect of making crystal grains fine. The preferred content of misch metal is 0.001 ~
2 % by mass .

[2] Production method of functionally graded alloy (a) Forming of copper alloy A copper alloy having the above composition is melt-cast, and hot-rolled, cold-rolled,
It is formed into a desired shape by a forming method such as pressing. The copper alloy having the composition of the present invention is rich in hot workability and cold workability, and can be worked at a cold working rate of 20% to 90% or more. It can be easily formed into ultrafine wires, foils, pipes and the like.

In hot working, copper alloy is 8 to 10 % by mass
When Al is contained, the average cooling rate after hot working is 200
C./min or less, α + β2 which is rich in processability
It becomes possible to have a phase organization. In particular, it is desirable to cool at this cooling rate in a temperature range of 800 to 400 ° C. If the cooling rate is higher than the above cooling rate, it becomes β single phase and may be inferior to the workability of the α + β two-phase structure. 3-8 mass
% In the case of a copper alloy containing Al, the structure after hot working is β
It may be a single phase, and there is no limitation on the cooling rate after hot working.

(B) Heating treatment (solution treatment) Next, heating is performed at a temperature of 500 ° C. or more, preferably 600 to 800 ° C., to transform the crystal structure into a β single phase. 50 ℃ / after heat treatment
Rapid cooling at a rate of at least 2 seconds freezes 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 less than 50 ° C./sec, precipitation of α phase occurs, so that it is impossible to maintain the crystal structure of β single phase, and the gradient of function becomes small. The preferred cooling rate is at least 200 ° C./sec.

(C) Aging treatment In the present invention, the aging treatment is performed at a temperature lower than 250 ° C. on the portion (first part) for maintaining the crystal structure in a β single phase, and the crystal structure is changed to a two-phase structure of α phase and Heusler phase. Aging treatment is performed at a temperature of 250 to 350 ° C. for the part (second part) to be transformed. The third part located between the first part and the second part is subjected to aging with a temperature gradient (temperature distribution) that changes continuously or stepwise from the heating temperature of the first part to the heating temperature of the second part.

In order to satisfy the above conditions, the aging treatment is preferably performed by a heating device having a temperature gradient. FIG. 1 shows an example of a heating device having a temperature gradient. The heating device 1 is for aging the rod-shaped functionally graded alloy, and includes a furnace tube 2 and
It comprises a nichrome wire 3 wound around the furnace tube 2, a heat insulating material 4, a plurality of temperature sensors 51, 52,..., A power supply connected to the temperature sensor and the nichrome wire, and a temperature control device 6. In this example, a temperature gradient in the furnace is formed by the winding density of the nichrome wire 3. When the one end 71 of the functionally graded alloy rod 7 is the first part of the single β phase, the nichrome linear density at the end 21 of the core tube 2 where the end 71 is located is reduced, and the other end 72 is divided into the α phase and the Heusler phase. In the case of the second portion having a crystal structure composed of phases, the nichrome linear density at the end 22 of the core tube 2 at the end 72 is increased. Thus, a temperature gradient in the furnace is formed, and the temperature in the furnace is controlled by the power supply and the temperature control device 6.

The heating temperature of the first part is less than 250 ° C.
Preferably it is 100-200 ° C. If the heating temperature of the first part is too low, the β phase is unstable, and if left at room temperature, the martensitic transformation temperature may change. Conversely, if the heating temperature is 250 ° C or higher, precipitation of the α phase occurs,
The difference in the functional characteristics from the second part is small.

The heating temperature of the second part is 250-350 ° C.,
Preferably it is 280-320 degreeC. The heating temperature of the second part is 25
When the temperature is lower than 0 ° C., the crystal structure of the second part cannot be sufficiently transformed into the two phases of the α phase and the Heusler phase, and the difference in the functional properties between the first part and the first part is small. On the other hand, when the heating temperature exceeds 350 ° C., the structure becomes coarse, and the functional properties such as yield strength and hardness are reduced.

The difference between the heating temperature of the first part and the heating temperature of the second part is preferably at least 50 ° C., particularly preferably at least 80 ° C. When the difference between the heating temperature of the first part and the heating temperature of the second part is less than 50 ° C., the difference in the functional characteristics between the two parts is small.

The aging time varies depending on the composition of the functionally graded 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 Functionally Graded Alloy (1) Crystal Structure The functionally graded alloy of the present invention has a first portion having a crystal structure substantially consisting of a β single phase, and a substantially two phases of α phase and Heusler phase. There is a third portion in which the crystal structure changes continuously or stepwise between the second portion having a crystal structure composed of phases.

In the present invention, “consisting essentially of a single β phase ” means not only that the crystal structure consists of only the β phase, but also a small amount of the α phase and Heusler phase, and a small amount of TiB and Zr.
This includes the case where V, Mo, Nb and W in the B and bcc phases and intermetallic compounds such as NiAl and CoAl are contained. The total of the α phase and the Heusler phase is preferably 5% by volume or less. If the total of the α phase and the Heusler phase exceeds 5% by volume, the superelasticity and shape recovery of the first portion are significantly reduced, and the slope of the functional characteristics is undesirably reduced.

On the other hand, "the crystal structure substantially consists of two phases of the α phase and the Heusler phase" means not only the case where the crystal structure consists of only the α phase and the Heusler phase but also a small amount of the β phase and the Heusler phase.
And a small amount of TiB, ZrB, V, Mo, Nb and W, NiA in bcc phase
l, including the case of containing an intermetallic compound such as CoAl. β
The proportion of the phase is preferably not more than 10% by volume.

" Changing the crystal structure" means that the ratio of the β phase and the ratio of the α phase and the Heusler phase in the structure change . Due to the aging treatment, the α phase and the Heusler phase are gradually precipitated from the β phase, and the higher the temperature of the aging treatment, the longer the aging treatment time,
The precipitation amount of the α phase and the Heusler phase increases. Change in the crystal structure in the third portion either continuously or stepwise
good. If aging treatment is performed in a short time with a stepwise temperature distribution,
The crystal structure changes stepwise. Note that when the crystal structure of the third part is continuously changing, the boundaries between the first part and the third part and between the second part and the third part are not always clear, but the change in the functional characteristics in the third part is In general, it is relatively sharp and remarkable, so that it is relatively easy to determine the three parts from the distribution of the functional characteristics.

As described in JP-A-7-62472, the first portion having a β-phase crystal structure has shape memory characteristics and superelasticity. On the other hand, the second part is a hard material that is difficult to bend and has completely different functional characteristics from the first part. In the third part, the functional characteristic of the first part changes continuously or stepwise from the functional characteristic of the second part.
The distance between the first part and the second part, that is, the length of the third part can be arbitrarily set.
It is preferably set to cm or more. It is difficult to provide an aging temperature gradient within a distance of less than 2 cm. Specific differences between the first and second parts of some functional characteristics will be described in detail below.

(2) Hardness The hardness varies depending on the alloy composition.
v, and the difference in hardness between the first portion and the second portion can be 20 Hv or more.

(3) Yield stress The first portion having a crystal structure composed of β single phase has superelasticity, and its yield stress (0.2% proof stress) varies depending on the alloy composition, but is less than 400 MPa. The difference in yield stress between the first part and the second part can be set to 50 MPa or more.

(4) Shape recovery rate The first part has excellent shape memory, and the shape recovery rate is 80%.
That is all. On the other hand, the shape recovery rate of the second portion is less than 15%, and there is almost no shape memory property. The difference between the shape recovery rates of the first portion and the second portion can be 70% or more.

[0043]

EXAMPLES Example 1, Comparative Example 1 Sample Nos. 1 to 7 (Example 1) and Sample No. 8 shown in Table 1
A copper alloy having the composition of (Comparative Example 1) was melted and the average was 140
After solidifying at a cooling rate of ° C./min to produce a billet having a diameter of 20 mm, cold drawing was performed while performing intermediate annealing to obtain a wire rod having a diameter of 0.5 mm and a length of 200 mm. 900 obtained wire
After heat treatment at 15 ° C. for 15 minutes, the mixture was put into ice water and rapidly cooled, and then subjected to aging treatment for 15 minutes by a heating device shown in FIG. 1 to obtain a wire made of a functionally graded alloy. As shown in FIG. 2, the temperature distribution of the heating device during the aging treatment is as follows.
The temperature was 140 ° C and the high temperature side was 300 ° C.

Table 1 Composition of functionally graded alloy (unit: mass% ) Sample No. Cu Al Mn Other 1 Remaining 8.1 9.7 2 Remaining 8.7 10.6 3 Remaining 8.7 10.8 Ti: 0.1 B: 0.05 4 Remaining 8.4 10.5 V: 0.26 5 Remaining 7.6 9.7 V: 0.45 6 balance 8.0 9.6 Ni: 1.0 7 balance 8.1 9.7 Co: 0.5 8 balance 8.0 9.5 Co: 2.4

The low-temperature end and the high-temperature end of the wire thus aged were subjected to the following tests to measure the functional characteristics.

(1) Hardness The hardness at the low-temperature end and the high-temperature end of the wire was measured using a Micro Vickers hardness tester. Table 2 shows the measurement results.

(2) Shape recovery rate The wire is wound around a round bar having a diameter of 25 mm in liquid nitrogen,
After removal from the liquid nitrogen, the radius of curvature R ₀ of the bending was measured. Next, the bent wire was heated to 200 ° C. to cause shape recovery, and then the radius of curvature R ₁ of the wire was measured. The shape recovery ratio was calculated by the following formula: shape recovery ratio (%) = 100 × (R ₁ −R ₀ ) / R ₁ . Table 2 shows the shape recovery ratio.

(3) Tensile test A wire rod was subjected to a tensile test according to JIS Z 2241, and the tensile strength and
Elongation at break and 0.2% proof stress were determined. Table 3 shows the measurement results.

[0049]

Table 3 Results of tensile test of functionally graded alloy Tensile strength (MPa) Elongation at break (%) 0.2% proof stress (MPa) Sample No. Low temperature end High temperature end Low temperature end High temperature end Low temperature end High temperature end 1 432 1129 15.4 3.2 50 807 2 699 1074 17.2 3.3 310 774 3 639 728 15.7 3.2 315 544 4 749 1147 18.2 4.6 240 745 5 272 947 13.7 7.2 63 539 6 245 1032 18.2 2.7 212 783 7 529 894 17.3 3.6 237 717 8 594 650 2.4 0 370 Break

As can be seen from Tables 2 and 3, the functional characteristics at the low temperature end and the high temperature end are significantly different. For example, sample N
In o.1, the yield stress (0.2% proof stress) at the low temperature end is extremely low at 50 MPa, but the yield stress at the high temperature end is 16 times or more. On the other hand, sample No. 8 to which excessive Co was added
In (Comparative Example 1), the toughness at the high temperature end was significantly impaired by the influence of the precipitated CoAl, and the sample was broken in the tensile test.

The wire rod of sample No. 3 was divided into ten equal parts, and the hardness at the midpoint of each section was measured and plotted according to FIG.
As can be seen from FIG. 2, the hardness increases continuously as the aging temperature increases from the low temperature end to the high temperature end. In particular, when the aging temperature was around 250 ° C, a sharp change in hardness was observed. Judging from the change in hardness, the crystal structure from the low temperature end to about 7 cm is substantially a single phase β, and about 7 cm from the high temperature end.
Up to substantially two phases, the α phase and the Heusler phase. It is considered that the crystal structure is gradually changing at the middle 6 cm.

The microstructure at the low temperature end and the high temperature end of the wire rod of Sample No. 1 was observed with an optical microscope. FIG. 3 is an optical micrograph of the microstructure at the low temperature end. As a result of electron diffraction analysis, β
The single phase was confirmed. FIG. 4 is an optical micrograph of the microstructure at the high-temperature end, and it was confirmed by electron diffraction that it had a two-phase structure of an α phase and a Heusler phase. As a result of measuring the structure of the wire rod of Sample No. 1 by X-ray diffraction, the ratio of the β phase at the low temperature end was 100% by volume, and the ratio of the α phase and the Heusler phase was 0% by volume. On the other hand, the ratio of the β phase at the high temperature end was 0% by volume, the ratio of the α phase was 65% by volume, and the ratio of the Heusler phase was 35% by volume.

Example 2 A copper alloy having the composition of Samples Nos. 2 and 3 shown in Table 1 was formed into a wire having a diameter of 0.5 mm in the same manner as in Example 1, and quenched under the same conditions as in Example 1. 150, 200, 250, 3 respectively
The aging treatment was performed at temperatures of 00, 350 and 400 ° C. for 15 minutes. The hardness of the obtained copper alloy was measured in the same manner as in Example 1, and plotted in FIG.

As can be seen from FIG. 5, the aging temperature is 250 ° C.
Above, the hardness of the copper alloy sharply increased. However, when the aging temperature exceeded 350 ° C., the hardness decreased significantly.

Example 3 A copper alloy having the composition of Samples Nos. 5 and 6 shown in Table 1 was formed into a diameter of 0.5 mm in the same manner as in Example 1, quenched under the same conditions as in Example 1, and then cooled to 300 ° C. 5, 15, 60, 20 respectively
Aging treatment was performed for 0, 700, 4500, and 10,000 minutes. The hardness of the obtained copper alloy was measured in the same manner as in Example 1, and plotted in FIG.

As can be seen from FIG. 6, the sample to which V was added was used.
In No. 5 and Sample No. 6 to which Ni was added, the aging time was 5 to 5.
It shows the highest hardness in the range of 700 minutes.

[0058]

As described in detail above, the functionally gradient alloy of the present invention is obtained by aging a copper alloy having a substantially single-phase structure with a heating device having a specific temperature gradient. Shape memory, super-elasticity,
Functions such as strength are remarkably inclined. Since the functionally graded alloy of the present invention can be easily manufactured and has excellent workability, it can be formed in various shapes at low cost.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an example of a heating device having a temperature gradient.

FIG. 2 is a graph showing a hardness distribution and a temperature distribution of an aging treatment of a functionally graded alloy wire rod of Sample No. 3 of Example 1.

FIG. 3 is an optical microscope photograph showing a microstructure of a low-temperature end of a functionally graded alloy wire rod of Sample No. 1 of Example 1.

FIG. 4 is an optical microscope photograph showing a microstructure of a high-temperature end of a functionally graded alloy wire rod of Sample No. 1 of Example 1.

FIG. 5 is a graph showing the relationship between aging treatment temperature and hardness in Example 2.

FIG. 6 is a graph showing the relationship between aging time and hardness in Example 3.

[Explanation of symbols]

 2 ・ ・ ・ Core tube 3 ・ ・ ・ Nichrome wire 4 ・ ・ ・ Insulation material 6 ・ ・ ・ Temperature control device 7 ・ ・ ・ Functional gradient alloy rod 51, 52 ・ ・ ・ Temperature sensor

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI // C22F 1/00 601 C22F 1/00 601 630 630A 630K 630L 691 691B 691Z

Claims (10)

(57) [Claims] 1 to 3 % by mass of Al and 5 to 20 % by mass of Mn
When, having a composition comprising the balance Cu and unavoidable impurities, a first portion having a crystal structure consisting essentially of β single phase, <br/> first having a crystal structure consisting essentially of α-phase and a Heusler phase Between the two parts and the first and second parts.
From the crystal structure of the first portion to the crystal structure of the second portion.
A functionally graded alloy comprising: a third portion having a crystal structure that changes in structure . 2. The functionally graded alloy according to claim 1, further comprising Ni, Co, Fe, Ti, V, Cr, Si, Nb, Mo, W,
A functionally graded alloy containing at least one selected from the group consisting of Sn, Mg, P, Zr, Zn, B and misch metal in a total amount of 0.001 to 10 % by mass . 3. The functionally graded alloy according to claim 1, wherein the copper alloy having a crystal structure substantially consisting of a β single phase has a heating temperature of the first portion less than 250 ° C. The heating temperature of the second part from the heating temperature of the first part to the third part.
A functionally graded alloy obtained by aging treatment with a temperature gradient varying up to 4. The functionally graded alloy according to claim 1, wherein the hardness of the first portion is 350 Hv or less, and the hardness of the second portion is 20 Hv less than the hardness of the first portion.
The functionally graded alloy according to claim 1, wherein the hardness of the third portion is higher than the hardness of the first portion and the hardness of the second portion. 5. The functionally graded alloy according to claim 1, wherein the yield stress of the first portion is 400 MPa or less, and the yield stress of the second portion is 50 MPa or more than the yield stress of the first portion. high yield stress of the third part to the yield stress of the second portion from the yield stress of the first portion
Functionally graded alloy characterized by changes . 6. The functionally graded alloy according to claim 1, wherein the shape recovery ratio of the first portion is 80% or more, and the shape recovery ratio of the second portion is 15% or less,
A functionally graded alloy, wherein the shape recovery ratio of the third portion changes from the shape recovery ratio of the first portion to the shape recovery ratio of the second portion. 7. The tilting machine according to claim 1,
In the active alloy, the α phase in the crystal structure of the first portion and
The sum of the Heusler phases is not more than 5% by volume,
The ratio of β phase in the crystal structure of the minute should be 10% by volume or less
Functionally graded alloy characterized by the following. 8. It has a crystal structure substantially consisting of a β single phase.
Consisting essentially of an α phase and a Heusler phase
A second part having a crystal structure , the first part and the second part
Between the first portion and the crystal structure of the first portion,
The third part having a crystal structure that changes to the crystal structure of the second part
A method of manufacturing a gradient function alloy having a minute, and (a) 3 to 10 wt% Al, and 5 to 20 wt% Mn, balance Cu
And forming a copper alloy having a composition comprising unavoidable impurities into a desired shape, (b) holding at a temperature of 500 ° C. or more and then quenching to substantially change the crystal structure to a β single phase, and (c) temperature Using a heating device having a gradient, the heating temperature of the first portion is less than 250 ° C., and the heating temperature of the second portion is 2
A method for producing a functionally graded alloy, wherein the aging treatment is performed at 50 to 350 ° C. and a temperature gradient is formed in the third part from the heating temperature of the first part to the heating temperature of the second part. 9. The method of claim 8 , wherein the copper alloy further comprises Ni, Co, Fe, Ti, V,
One or more selected from the group consisting of Cr, Si, Nb, Mo, W, Sn, Mg, P, Zr, Zn, B and misch metal in a total of 0.
A method for producing a functionally graded alloy, comprising 001 to 10 % by mass . 10. The functionally gradient alloy according to claim 8 or 9.
Wherein the α phase in the crystal structure of the first part is
And the total of the Heusler phase is 5% by volume or less,
The proportion of β-phase in the two-part crystal structure is less than 10% by volume
A method for producing a functionally graded alloy, comprising: