Cu alloy and manufacturing method of Cu alloy

Abstract

The strength and thermal conductivity of the Cu alloy containing Y and Zr composite oxide particles are stably ensured. [Solution] A method for producing a Cu alloy includes the steps of: subjecting a mixed powder of CuZr powder, Y2O3 powder, and WO3 powder, or a mixed powder of Cu powder, Zr powder, Y2O3 powder, and WO3 powder, to mechanical alloying to produce an alloy powder; and sintering the alloy powder. The Cu alloy is formed by dispersing and precipitating Y-Zr composite oxide particles and W particles in a Cu matrix.

Description

[Technical Field]

[0001] The present invention relates to a Cu alloy containing Y and Zr composite oxide particles, and a method for producing the Cu alloy. [Background technology]

[0002] Copper (Cu) alloys are materials that combine excellent strength and thermal conductivity, and are used in a variety of fields for a variety of applications, such as heat sinks (heat transfer materials), electrodes such as welding electrodes, and contacts for high-current equipment. Furthermore, in fusion reactors, which are expected to provide fusion energy, copper alloys are used as the material for the divertor heat sink. However, Cu alloys for divertor heat sinks are required to have high strength and thermal conductivity in order to withstand the harsh environment inside a fusion reactor.

[0003] In response to this, oxide dispersion strengthened (ODS) Cu alloys (ODS-Cu) have attracted attention as Cu alloys that can achieve high strength and thermal conductivity. ODS-Cu alloys are Cu alloys in which oxide particles are dispersed, and the oxide particles, which have excellent stability at high temperatures, are finely and densely dispersed. By dispersing yttrium (Y) oxide particles, such as yttrium (Y2O3) particles, in a Cu alloy, the strength and thermal conductivity of the Cu alloy can be improved. Furthermore, a Cu alloy containing composite oxide particles of Y and zirconium (Zr) has been known as such an oxide dispersion strengthened Cu alloy (see Non-Patent Document 1).

[0004] In the conventional Cu alloy described in Non-Patent Document 1, Cu powder, Zr powder, and Y2O3 powder are mechanically alloyed, and then the powder is subjected to spark plasma sintering to produce the Cu alloy. Dispersing a composite oxide of Y and Zr in the Cu alloy improves the mechanical strength of the Cu alloy. However, when mechanically alloying a powder primarily composed of Cu powder, the powder tends to aggregate and become coarse due to the high ductility of Cu. As a result, not only does the yield of the powder after mechanical alloying decrease, but there are also concerns about the alloying of the powder by mechanical alloying, the sinterability of the powder, and the properties of the Cu alloy. Therefore, conventional Cu alloys still need improvement in terms of ensuring stable strength and thermal conductivity. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] Yong-qiang QIN etal., ' Effect of alloying element Zr on microstructure and properties of Cu-Y2O3composites ' Transactions of Nonferrous Metals Society of China Volume 33, Issue 11, November 2023, Pages 3418-3426. Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in view of the above-mentioned conventional problems, and its object is to stably ensure the strength and thermal conductivity of a Cu alloy containing composite oxide particles of Y and Zr. [Means for solving the problem]

[0007] The present invention is a Cu alloy in which Y-Zr composite oxide particles and W particles are dispersed and precipitated in a Cu matrix. The present invention also provides a method for producing a Cu alloy, comprising the steps of: subjecting a mixed powder of CuZr powder, Y2O3 powder, and WO3 powder, or a mixed powder of Cu powder, Zr powder, Y2O3 powder, and WO3 powder, to mechanical alloying to produce an alloy powder; and sintering the alloy powder. [Effects of the Invention]

[0008] According to the present invention, the strength and thermal conductivity of a Cu alloy containing composite oxide particles of Y and Zr can be stably ensured. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a flowchart showing a manufacturing procedure of a Cu alloy according to the present embodiment. [Figure 2] FIG. 2 is a diagram showing an SEM image of the alloy powder of the first example. [Figure 3] FIG. 10 is a diagram showing an SEM image of the alloy powder of the second example. [Figure 4] FIG. 10 is a diagram showing an SEM image of the alloy powder of the third example. [Figure 5] 3 is a graph showing the particle size distribution of the alloy powders produced by mechanical alloying in each of the first to third examples and the comparative example. [Figure 6] 1 is a graph showing the recovery rates of alloy powders produced by mechanical alloying in each of the first to third examples and the comparative example. [Figure 7] FIG. 3 is a diagram showing X-ray diffraction spectra of the alloy powders produced by mechanical alloying in each of the first to third examples. [Figure 8] FIG. 3 is a diagram showing X-ray diffraction spectra of Cu alloys of sintered bodies produced by sintering the alloy powders of the first to third examples. [Figure 9] FIG. 2 is a diagram showing an element map image of the Cu alloy of the first example. [Figure 10] FIG. 10 is a diagram showing an element map image of the Cu alloy of the second example. [Figure 11]FIG. 10 is a diagram showing an element map image of the Cu alloy of the third example. [Figure 12] 10A and 10B are diagrams showing a STEM-HAADF image and an element map image of the Cu alloy of the second example. [Figure 13] 1 is a graph showing the Vickers hardness of sintered bodies obtained by sintering the alloy powders of the first to third examples and the comparative example. [Figure 14] 1 is a graph showing the thermal diffusivities of sintered bodies obtained by sintering the alloy powders of the first to third examples and the comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of a Cu (copper) alloy and a method for manufacturing the Cu alloy of the present invention will be described with reference to the drawings. The Cu alloy of this embodiment is an oxide dispersion strengthened Cu alloy (ODS-Cu) that contains Cu as the main component and composite oxide particles of Y (yttrium) and Zr (zirconium). The composite oxide particles of Y and Zr are particles of an oxide (composite oxide) composed of two types of metal components (Y, Zr). The Cu alloy is manufactured by mechanical alloying and sintering of powder.

[0011] FIG. 1 is a flowchart showing the procedure for producing a Cu alloy according to this embodiment. As shown in the figure, when manufacturing a Cu alloy, multiple types of powders (raw material powders) that serve as raw materials for the Cu alloy are blended to obtain a mixed powder (blended powder) consisting of the blended multiple types of raw material powders (S101). At this time, CuZr powder, Y2O3 (yttrium oxide) powder, and WO3 (tungsten oxide) powder are blended as the raw material powders to obtain a mixed powder of CuZr powder, Y2O3 powder, and WO3 powder. Alternatively, Cu powder, Zr powder, Y2O3 powder, and WO3 powder are blended as the raw material powders to obtain a mixed powder of Cu powder, Zr powder, Y2O3 powder, and WO3 powder.

[0012] CuZr powder is a CuZr alloy powder in which Zr is added to the main component Cu, and is manufactured, for example, by atomization. To generate a composite oxide of Y and Zr in the Cu alloy, CuZr powder and Y2O3 powder, or Zr powder and Y2O3 powder, are mixed into the mixed powder. WO3 powder functions as an inorganic auxiliary agent that assists alloying by mechanical alloying of the mixed powder, and as an additive that improves the properties of the Cu alloy.

[0013] The proportion (content) of WO3 powder in the mixed powder is 1.3 to 5 wt% (mass%). The wt% of WO3 powder is the proportion (percentage: %) of the mass of WO3 powder to the total mass of the mixed powder. The mixed powder contains WO3 powder in the range of 1.3 to 5 wt% (1.3 wt% or more and 5 wt% or less). The respective proportions of Cu, Zr, and Y2O3 in the mixed powder are set according to the properties to be imparted to the Cu alloy to be manufactured.

[0014] Next, an alloy powder is obtained from the mixed powder by mechanical alloying (S102). In mechanical alloying, the mixed powder is placed in a container together with a large number of balls, and the mixed powder and balls are stirred in the container to mechanically alloy the mixed powder. During mechanical alloying, the mixed powder is pressed by the balls, causing the powder particles in the mixed powder to be repeatedly folded and rolled. This causes the powder particles in the mixed powder to be finely mixed and kneaded together, and the powder becomes an alloy, producing an alloyed alloy powder. The mixed powder is mechanically alloyed using a mechanical alloying device (e.g., a rotary ball mill, a vibrating ball mill, a planetary ball mill, an agitating ball mill, or an attritor).

[0015] A mixed powder of CuZr powder, YO powder, and WO powder, or a mixed powder of Cu powder, Zr powder, YO powder, and WO powder, is subjected to mechanical alloying to mechanically alloy the mixed powder. In this way, the mixed powder is alloyed by the mechanical alloying method to produce an alloy powder by alloying the mixed powder. The alloy powder contains Cu, Zr, and YO contained in the mixed powder, as well as W (tungsten) and O (oxygen) produced by decomposition of WO in the WO powder.

[0016] During the mechanical alloying of the mixed powder, the WO powder is difficult to dissolve in Cu and functions stably as a mechanical alloying aid. The presence of the WO powder between the Cu-containing powders during mechanical alloying prevents excessive aggregation of the powders, and the WO powder controls the aggregation and coarsening of the powders. Therefore, the alloy powder produced by mechanical alloying is refined, and the recovery rate of the alloy powder is improved.

[0017] Compared to W, WO3 has a lower melting point and is more easily chemically decomposed. Therefore, during mechanical alloying of the mixed powder, WO3 decomposes, generating W and O from WO3, and the generated W and O are contained in the alloy powder. Note that, depending on the wt% of WO3 powder in the mixed powder, some of the WO3 in the WO3 powder may not decompose and remain in the alloy powder. In this case, the alloy powder contains WO3 in addition to W and O.

[0018] Next, the alloy powder is sintered (S103) to bond the alloy powder particles together. A sintering method is used to produce a sintered body of Cu alloy by sintering the alloy powder, thereby manufacturing the Cu alloy. The alloy powder is sintered by, for example, pressure sintering, in which the alloy powder is heated and pressurized. Pressure sintering can be, for example, gas pressure sintering, hot press sintering, hot isostatic sintering, or spark plasma sintering (SPS). However, the alloy powder may also be sintered by a method other than pressure sintering (for example, atmospheric pressure sintering).

[0019] The alloy powder contains O resulting from the decomposition of WO3, which serves as an oxygen source for the oxidation of Zr. During sintering of the alloy powder, the O contained in the alloy powder supplies the O necessary for the oxidation of Zr, causing the Zr to oxidize. Furthermore, in the alloy powder and sintered compact during sintering, a Y-Zr composite oxide is formed from Zr, O, and Y2O3 in the alloy powder, and Y-Zr composite oxide particles are dispersed and precipitated in the sintered compact and Cu alloy of the sintered compact. During this process, Zr prevents excessive oxide aggregation, resulting in the Y-Zr composite oxide being refined, resulting in the fine and dense precipitation of the Y-Zr composite oxide. At the same time, W in the alloy powder precipitates during sintering, and simple W particles are dispersed and precipitated in the sintered compact and Cu alloy of the sintered compact, separate from the Y-Zr composite oxide particles.

[0020] In the Cu alloy manufactured through mechanical alloying and sintering as described above, Y-Zr composite oxide particles and W particles are dispersed and precipitated in the Cu matrix (parent phase). The Cu matrix is ​​the parent phase (Cu-based matrix) of the Cu alloy, with Cu as the main component, and the Y-Zr composite oxide particles and W particles are precipitate phases in the Cu alloy. The Y-Zr composite oxide particles and W particles are particles made of precipitates (precipitate particles), and are finely and densely dispersed.

[0021] Y-Zr composite oxide particles have excellent stability at high temperatures and function to provide both excellent strength and thermal conductivity in Cu alloys. Furthermore, W particles have high hardness and thermal conductivity, and function to improve the strength and thermal conductivity of Cu alloys. Therefore, by dispersing Y-Zr composite oxide particles and W particles in a Cu alloy, the strength and thermal conductivity of Cu alloys containing Y-Zr composite oxide particles can be stably ensured. In the divertor of a fusion reactor, W material is used as the divertor arm material. When a Cu alloy is used as the divertor heat sink material, the W particles in the Cu alloy are expected to improve the bonding of the heat sink material to the W material, which is the divertor arm material.

[0022] Cu alloys can be used for a variety of purposes in various fields, not limited to the field of nuclear fusion reactors, and can be used as materials that require strength and high thermal conductivity when exposed to high temperatures, such as electrodes, contacts for high-current equipment, and heat sinks for applications other than nuclear fusion reactors. Specifically, Cu alloys can be used as materials for, for example, resistance welding electrodes, MIG (Metal Inert Gas) welding electrodes, pantograph contact rods, medical electric scalpels, electrical contacts, lead frames, lead wires, and X-ray tubes, and are expected to replace existing commercially available Cu alloys in terms of performance.

[0023] In the mechanical alloying of the mixed powder, the WO powder reduces the particle size of the alloy powder produced by mechanical alloying, thereby increasing the recovery rate and amount of alloy powder usable for sintering, thereby improving the production efficiency of alloy powder, which is the raw material for Cu alloys.

[0024] If the proportion of WO3 powder in the mixed powder is less than 1.3 wt%, the amount of WO3 powder required as a mechanical alloying aid cannot be secured sufficiently, and the particle size of the alloy powder produced by mechanical alloying may become large. Also, the amount of O produced by decomposition of WO3 during mechanical alloying may decrease, resulting in a risk of an insufficient amount of O in the alloy powder, which serves as an oxygen source for the oxidation of Zr. If the proportion of WO3 powder in the mixed powder is more than 5 wt%, the amount of WO3 remaining in the alloy powder without decomposition during mechanical alloying may increase, which may affect the properties of the Cu alloy.

[0025] In contrast, when the proportion of WO3 powder in the mixed powder is 1.3 to 5 wt%, the amount of WO3 powder necessary as a mechanical alloying aid is ensured, ensuring a small particle size for the alloy powder produced by mechanical alloying. It is also possible to ensure the amount of O produced by the decomposition of WO3 during mechanical alloying and the amount of O in the alloy powder that serves as an oxygen source for the oxidation of Zr. Furthermore, by preventing the amount of WO3 powder from becoming too large, the increase in WO3 remaining in the alloy powder is suppressed, ensuring the properties of the Cu alloy. Therefore, the strength and thermal conductivity of the Cu alloy can be ensured while improving the production efficiency of the alloy powder.

[0026] (Example) The following describes examples of Cu alloys and methods for producing Cu alloys, but the conditions in the examples are merely examples adopted to confirm the feasibility and effects of the present invention. Therefore, the present invention is not limited to the conditions in the examples, and various conditions may be adopted as long as they do not deviate from the spirit of the present invention and achieve the object of the present invention.

[0027] Three examples (Example 1, Example 2, and Example 3) were tested here. In each of Examples 1 to 3, a mixed powder consisting of CuZr powder, Y2O3 powder, and WO3 powder was prepared as the raw powder for the Cu alloy. In all of Examples 1 to 3, the proportion of Y2O3 powder in the mixed powder was 1 wt%, and the proportion of Zr in the mixed powder was 0.8 wt%. In Example 1, the proportion of WO3 powder in the mixed powder was 1.3 wt%, in Example 2, the proportion of WO3 powder in the mixed powder was 2.5 wt%, and in Example 3, the proportion of WO3 powder in the mixed powder was 5 wt%. In each of Examples 1 to 3, the proportion remaining after subtracting the respective proportions of Y2O3 powder, Zr, and WO3 powder represents the proportion of Cu in the mixed powder. Therefore, the proportion of Cu in the mixed powder of the first example is 96.9 wt%, the proportion of Cu in the mixed powder of the second example is 95.7 wt%, and the proportion of Cu in the mixed powder of the third example is 93.2 wt%.

[0028] Examples 1 to 3 are distinguished by symbols including numerical values ​​(1.3, 2.5, 5) indicating the proportion (wt%) of WO3 powder in each mixed powder. Example 1 is represented as CuYZr-1.3WO3 based on the proportion (1.3 wt%) of WO3 powder. Example 2 is represented as CuYZr-2.5WO3 based on the proportion (2.5 wt%) of WO3 powder. Example 3 is represented as CuYZr-5WO3 based on the proportion (5 wt%) of WO3 powder. In each of Examples 1 to 3, the mixed powder was subjected to mechanical alloying to produce alloy powder. The alloy powder was then sintered to produce a sintered Cu alloy body.

[0029] The mixed powder was mechanically alloyed using a planetary ball mill in an Ar (argon) gas atmosphere. The balls of the planetary ball mill were stainless steel balls (diameter 10 mm), and the rotation speed of the planetary ball mill was 500 rpm. To prevent the temperature of the mixed powder from rising, the mixed powder was mechanically alloyed for 15 minutes and then stopped for 5 minutes. In this way, a 5-minute cooling period was provided after every 15 minutes of mechanical alloying, and the mixed powder was mechanically alloyed for a total of 24 hours.

[0030] Alloy powders were produced from the mixed powders of Examples 1 to 3 by mechanical alloying, and then the alloy powders were classified and sieved. By sieving, alloy powders with particle sizes unsuitable for sintering were separated from the produced alloy powders, and alloy powders with particle sizes suitable for sintering were collected. Each of the collected alloy powders of Examples 1 to 3 was sintered by spark plasma sintering. The sintering temperature was 880°C, the sintering time was 15 minutes, and the sintering pressure was 50 MPa. Cu alloys were produced from the alloy powders of Examples 1 to 3 by sintering.

[0031] In a comparative example for comparison with Examples 1 to 3, Cu powder, Zr powder, and Y2O3 powder were mixed without adding WO3 powder. In the comparative example, the Y2O3 powder in the mixed powder was 1 wt% and the Zr powder in the mixed powder was 0.8 wt%. As in Examples 1 to 3, the mixed powder of the comparative example was subjected to a mechanical alloying process to produce the alloy powder of the comparative example. In addition, alloy powder with a particle size unsuitable for sintering was separated from the produced alloy powder of the comparative example by sieving, and alloy powder with a particle size suitable for sintering was recovered. The recovered alloy powder of the comparative example was sintered to produce the Cu alloy of the comparative example. The comparative example is represented as Cu-Y2O3-Zr.

[0032] Fig. 2 is a diagram showing an SEM image of the alloy powder of Example 1. Fig. 3 is a diagram showing an SEM image of the alloy powder of Example 2. Fig. 4 is a diagram showing an SEM image of the alloy powder of Example 3. Figs. 2 to 4 show images (photographs substitute for drawings) taken by observing the alloy powder at various magnifications using a scanning electron microscope (SEM). Fig. 5 is a graph showing the particle size distribution of the alloy powders produced by mechanical alloying in Examples 1 to 3 and a comparative example.

[0033] As shown in the figure, in each of the first example (CuYZr-1.3WO), second example (CuYZr-2.5WO), and third example (CuYZr-5WO), mechanical alloying progressed in the mixed powder, resulting in the production of alloy powder. The particle size of the alloy powders in the first to third examples was smaller than that of the comparative example (Cu-YO-Zr), and the alloy powders in the first to third examples were finer than the alloy powder in the comparative example. Furthermore, the particle size of the alloy powders decreased in the order of the comparative example, first example, second example, and third example, and the alloy powders were finer in the order of the comparative example, first example, second example, and third example. Thus, the addition of WO powder to the mixed powder reduced the particle size of the alloy powder, resulting in the finer alloy powder. Furthermore, as the proportion of WO powder in the mixed powder increased, the particle size of the alloy powders decreased, resulting in the finer alloy powder.

[0034] 6 is a graph showing the recovery rates of alloy powders produced by mechanical alloying in Examples 1 to 3 and the Comparative Example. In Examples 1 to 3 and the Comparative Example, the alloy powders were sieved according to the same criteria, recovered, and the recovery rates of the alloy powders were measured. As shown in the figure, the recovery rate of the alloy powder in the comparative example (Cu-Y2O3-Zr) was about 65%. In contrast, the recovery rates of the alloy powder in the first example (CuYZr-1.3WO3), second example (CuYZr-2.5WO3), and third example (CuYZr-5WO3) were all nearly 100%, which was significantly higher than the recovery rate of the alloy powder in the comparative example.

[0035] Figure 7 shows X-ray diffraction spectra of the alloy powders produced by mechanical alloying in each of Examples 1 to 3. Figure 8 shows X-ray diffraction spectra of the Cu alloy sintered bodies produced by sintering the alloy powders in each of Examples 1 to 3. In Figures 7 and 8, the X-ray diffraction spectra of Example 1 (CuYZr-1.3WO3) are A1 and B1, the X-ray diffraction spectra of Example 2 (CuYZr-2.5WO3) are A2 and B2, and the X-ray diffraction spectra of Example 3 (CuYZr-5WO3) are A3 and B3.

[0036] As shown in the figure, for the alloy powder of Example 3, a WO3 peak was present in the X-ray diffraction spectrum (A3), indicating that WO3 was contained in the alloy powder. This is thought to be because the proportion of WO3 powder in the mixed powder was high, and the WO3 in the WO3 powder did not completely decompose during mechanical alloying, resulting in the WO3 remaining in the alloy powder. In contrast, for the alloy powders of Examples 1 and 2, no WO3 peak was present in the X-ray diffraction spectra (A1, A2), indicating that the WO3 in the WO3 powder decomposed during mechanical alloying.

[0037] In the Cu alloys of Examples 1 to 3, W peaks appeared in the X-ray diffraction spectra (B1, B2, B3), indicating that W precipitated due to sintering of the alloy powder. Furthermore, Y and Zr composite oxide (YZrO) peaks appeared in the X-ray diffraction spectra (B1, B2, B3), indicating that Y and Zr composite oxide precipitated due to sintering of the alloy powder. This suggests that O produced by the decomposition of WO3 precipitated as a Y and Zr composite oxide together with Zr.

[0038] Fig. 9 is a diagram showing an element map image of the Cu alloy of Example 1. Fig. 10 is a diagram showing an element map image of the Cu alloy of Example 2. Fig. 11 is a diagram showing an element map image of the Cu alloy of Example 3. Figs. 9 to 11 show images (photographs substitute for drawings) in which the distribution of six elements (C (carbon), Cu, Y, Zr, O, and W) contained in the Cu alloy is mapped using a scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS).

[0039] As shown in the figures, in the Cu alloys of Examples 1 to 3, particles of a composite oxide of Y and Zr were dispersed and precipitated in the Cu matrix, and W particles were dispersed and precipitated. Furthermore, in the Cu alloy of Example 1 (see FIG. 9), precipitates thought to be intermetallic compounds of Y and Zr were present. In Example 1, the proportion of WO powder in the mixed powder was small, and the O produced by the decomposition of WO was insufficient, which is thought to have caused some of the Y and Zr to form intermetallic compounds without forming composite oxides. In the Cu alloy of Example 3 (see FIG. 11), W particles were present that were larger than the W particles in the Cu alloy of Example 2 (see FIG. 10).

[0040] Fig. 12 shows a STEM-HAADF image and element map image of the Cu alloy of Example 2. Fig. 12 shows an image (photograph substitute for drawing) of the Cu alloy observed and taken using a scanning transmission electron microscope-high angle annular dark field (STEM-HAADF), and an image (photograph substitute for drawing) of the distribution of five elements (W, Cu, Y, Zr, and O) contained in the Cu alloy, which was mapped using a STEM.

[0041] As shown in the figure, in the Cu alloy of Example 2, particles of a composite oxide of Y and Zr were dispersed and precipitated in the Cu matrix, and particles of W were dispersed and precipitated. The size of the W particles was several tens of nanometers. As for the particles of the composite oxide of Y and Zr, most were 20 nm or less in size, but particles of about 100 nm in size were also present.

[0042] FIG. 13 is a graph showing the Vickers hardness of the sintered bodies obtained by sintering the alloy powders of Examples 1 to 3 and Comparative Example. FIG. 13 shows the Vickers hardness (hardness symbol: HV0.1) of the sintered bodies measured using a micro-Vickers hardness tester. FIG. 13 also shows the Vickers hardness of Example 1 (CuYZr-1.3WO), Example 2 (CuYZr-2.5WO), Example 3 (CuYZr-5WO), and Comparative Example (Cu-YO-Zr), as well as a sintered body of Cu powder (MAedCu) and three sintered bodies of Cu alloys containing Y oxide particles (Cu-0.5YO, Cu-1YO, and Cu-2YO). Note that in FIG. 13, the Comparative Example (Cu-YO-Zr) is referred to as Cu-1YO-Zr.

[0043] The three sintered bodies (Cu-0.5Y2O3, Cu-1Y2O3, and Cu-2Y2O3) were produced by mechanically alloying a mixture of Cu powder and Y2O3 powder to produce an alloy powder, which was then sintered to produce the sintered bodies. The proportion of Y2O3 powder in the mixture for the three sintered bodies was 0.5 wt% for the sintered body (Cu-0.5Y2O3), 1 wt% for the sintered body (Cu-1Y2O3), and 2 wt% for the sintered body (Cu-2Y2O3).

[0044] As shown in the figure, the Vickers hardness of the first example is slightly lower than that of the comparative example, but is comparable to that of the comparative example. The Vickers hardness of the second example and the third example is higher than that of the comparative example and the first example. Furthermore, the Vickers hardness of the second example is 274 HV0.1, which is higher than that of the third example, making it the highest of the Vickers hardnesses compared. Thus, the Vickers hardness of the sintered body varies depending on the proportion of WO powder in the mixed powder, and the highest Vickers hardness is achieved when the proportion of WO powder in the mixed powder is 2.5 wt%.

[0045] Fig. 14 is a graph showing the thermal diffusivity of sintered bodies obtained by sintering the alloy powders of Examples 1 to 3 and Comparative Example. In Fig. 14, the thermal diffusivity (unit: mm 2 / s). Figure 14 also shows the thermal diffusivity of the first example (CuYZr-1.3WO3), second example (CuYZr-2.5WO3), third example (CuYZr-5WO3), and comparative example (Cu-Y2O3-Zr), as well as the thermal diffusivity of a Cu standard. Thermal conductivity is evaluated by thermal diffusivity.

[0046] As shown in the figure, the thermal diffusivities of Examples 1 to 3 are higher than that of the Comparative Example, and are comparable. Therefore, Examples 1 to 3, in which WO3 powder was added to the mixed powder, have improved thermal conductivity compared to the Comparative Example, in which no WO3 powder was added to the mixed powder. As described above, in Examples 1 to 3, the addition of WO3 powder to the mixed powder ensures both strength (Vickers hardness) and thermal conductivity compared to the Comparative Example.

Claims

1. A Cu alloy in which Y-Zr composite oxide particles and W particles are dispersed and precipitated in a Cu matrix.

2. CuZr powder and Y ２ O ３ Powder and WO ３ Mixture of powders, or Cu powder, Zr powder and Y powder ２ O ３ Powder and WO ３ a step of subjecting the powder mixture to a mechanical alloying treatment to produce an alloy powder; sintering the alloy powder; A method for producing a Cu alloy having the above formula.

3. The method for producing a Cu alloy according to claim 2, The WO in the mixed powder ３ A method for producing a Cu alloy in which the powder ratio is 1.3 to 5 wt %.

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