JPH02142683A - Manufacture of thermal expansion adjustment material - Google Patents

Abstract

PURPOSE:To obtain thermal expansion adjustment material changing the thermal expansion coefficient by stages by superposing alternately sheetlike mixed material of a bullet changing a mixing ratio of adjustment materials with the different thermal expansion coefficient and sheetlike insert material of base metal and joining integrally these at the high temperature under high pressure. CONSTITUTION:Cu powder 10 as matrix metal and W powder 11 as adjustment material are subjected to powder adjusting 12 to a prescribed volume percentage of W and mixing 13 processing by the mechanical alloying method and then, formed 14 at the low temperature. In order to improve jointability and reduce a porosity percentage, it is pressed in an active gas atmosphere with the prescribed high temperature and subjected to infiltration processing 15 and then, the mixed material billet of W(P)/Cu is obtained and the sheetlike mixed material 17c is obtained by wire cutting, etc. The material surface is degreased satisfactorily and the mixed material, the insert material 18a, etc., such as Cu and Cu block 19 are arranged on metallic molds 20 of a hot press and combined integrally at the high temperature under high pressure in a vacuum or active gas atmosphere. By this method, the thermal expansion adjust ment material where the insert material 18a and the matrix metal 3 are perfectly integrated is obtained.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Field of Application) The present invention provides a method for manufacturing a thermal expansion adjusting material in which thermal stress in the vicinity of the joint and at the interface thereof is alleviated in joining dissimilar materials. It is related to.

(Conventional technology) In a fusion reactor, impurity control or H
A diverter plate is provided for evacuation of the gas. This divertor plate receives high heat load and high particle load from plasma, so it has a two-layer structure consisting of a protective material to prevent sputtering and melting during disruption, and a heat absorbing material to cool it. It has been adopted.

The protective material is usually made of tungsten (V), molybdenum (Mo), and alloys thereof, which are heat-resistant materials with a high melting point and a high thermal centricity, or ceramics. On the other hand, as the heat absorbing material, copper or its alloys, which have excellent cooling performance, are used. The protective material and the coolant are bonded to form a two-layer structure by brazing or diffusion bonding, which has excellent thermal conductivity.

The coefficient of thermal expansion of V or MO at 1000°C or lower is as small as 4.5 to 5.5 x 10-@/'C. On the other hand, copper and its alloys have a large value of 16 to 17X10-'/''C, so due to the heat load on ν and No.

Thermal stress due to the difference in these thermal expansion coefficients occurs with each repetition of thermal load, and thermal fatigue failure of this joint becomes a serious problem.

Another structural component that requires a similar function to the divertor plate is a heat receiving plate installed in a neutral particle injection heating device that heats plasma in a fusion reactor.

As a measure to prevent thermal fatigue failure of these two-layer structures, 1. For example, a method of inserting and bonding a material with a coefficient of thermal expansion between the protective material and the coolant, a so-called thermal expansion adjustment material. Alternatively, there is a method of using a brazing filler metal with improved thermal and strength properties.

As this thermal expansion adjusting material, copper-carbon fiber composite material (C(
j' )/Cu) (Public publication, 1982-151437
), copper-carbon fiber composite material (W(J')/CIJ), etc. are used.

The former C(f 2 )/Cu has a drawback that the cooling performance as a two-layer structure is poor because the C fiber has a low thermal conductivity, and the temperature of the protective material increases.

On the other hand, in the W(j')/Cu composite material, since W(f) has good thermal conductivity, the thermal conductivity at the joint does not deteriorate.

An example of v(f)/Cu composite material is shown in Fig. 6 (A), (B
), shown in (C). A wire mesh is made using w fibers 1 with a diameter of 0.5 m or less (Fig. 6 (A)). Next, the wire mesh and thin copper plates 2 are cut into a predetermined shape, and they are stacked alternately (Fig. 6 (A)).
Figure (B)), using a hot press or the like, the thin copper plates 2 are diffusion bonded to each other under high temperature and pressure conditions, and the IJ(f) and Cu
are completely combined (Fig. 6(C)).

In addition, as shown in FIG. 7, by a powder method, thin plate-shaped W(P)/Cu composite materials 5a, 5b, and 5c with different content ratios shown in FIG. It is also possible to obtain the I'(p)/cu composite material 6 (FIG. 7(B)) by molding the composite material.

(Problem to be solved by the invention) 'JCf )/Cu and W(P
)/Cu composite materials are as shown below.

In the conventional 'jcf)/Cu material, V in Fig. 6(A)
In manufacturing wire mesh using wire, since the bending rigidity of W(,?') is large, the volume fraction of wire mesh (νCf)/Cu
It was impossible to increase the proportion of 1Il(f) to 15% or more. Therefore, the coefficient of thermal expansion is 13
It was not possible to obtain a thermal expansion adjusting material having a coefficient of less than 10-'/''C.

Furthermore, for the W(P)/Cu stone shown in Fig. 7, it is possible to vary the magnitude of the thermal expansion coefficient;
) When W(P)/Cu sheets 5a and 5b with different V(P) contents shown in ) are stacked and integrated as shown in the same figure (B), 1it(P)7 is formed where the two sheets come into contact with each other as the base material. copper 3
An unbonded portion 8 is formed without impregnation. Since this unbonded portion 8 is a void in the bonded portion and is also a defect, this portion becomes the starting point of destruction when subjected to thermal cycle deformation, and the life of the material as a thermal expansion adjusting material is significantly shortened.

The purpose of the present invention is to freely control the volume fraction of W/Cu composite material and to change the coefficient of thermal expansion in stages.
It is an object of the present invention to provide a method for manufacturing a Cu composite material and obtain a thermal expansion adjusting material that is resistant to thermal deformation.

[Structure of the invention]

(Means for solving problems) The invention relates to a matrix metal (e.g. copper).

Adjusting materials with different coefficients of thermal expansion (e.g. V powder, M.

powder, short carbon fibers, etc.) are composited using powder metallurgy to produce billets with different volume ratios of conditioning materials. Next, the billet is processed or cut into thin plates to obtain thin plates of composite materials having different volume ratios of conditioning materials. Next, a manufacturing method is provided in which a thin plate-like insert material made of a matrix metal or an alloy thereof is placed between these thin plates, and the two are overlapped and joined together using a hot press or the like.

(Function) In this way, the adjustment material in the composite material does not come into direct contact with each other, and
Since they are joined via insert material, there are no gaps,
Fatigue strength etc. are improved.

(Example) An embodiment of the present invention will be described below with reference to FIG.

In this embodiment, copper is used as the matrix metal and V is used as the adjustment material. FIG. 1 shows a thin plate-like (sheet-like) W(P)/Cu composite material 17a with different volume fractions of V,
17b and 17c are shown. Using copper powder 10 with a diameter of 50 μs or less and glue powder 11 with a diameter of 3 to 6 voices, the powder is prepared 12 in an amount that provides the target volume ratio of V, and the copper powder and powder are combined by a mechanical alloying method. After the mixing 13 process, cold forming 14 is performed. Furthermore, It(
In order to improve the bonding properties of P)/Cu and to reduce the porosity, infiltration treatment 15 is carried out to impregnate Cu under pressure in an active gas atmosphere at 1000 to 1200°C, followed by III(P)
/Cυ composite material billet is obtained (for example, Elconite Co., Ltd. manufactured by Toshiba), the W/Cu produced in this way
The composite materials have different volume fractions of V (V, f
= 30.50.70%) by wire cutting etc. to form a sheet-like W(P)/Cu composite material 17 with a thickness of 0.2 to 1 m.
get.

W(P)/Cu composite material (17a, 17b, 17c
) and copper into the shapes required as the coolant (Cu) for the diameter plate, respectively, and then the surfaces of these materials are sufficiently degreased to remove oxides and the like on the surfaces.

Next, the same shape as the sheet-like W(P)/Cu composite material.

Insert material 1 made of a sheet-like matrix metal or its alloy that is thinner than the W(P)/Cu composite material
8a and 18b are placed between the W(P)/Cu composite (
Figure 2 (A)).

The V(P)/Cu composite material 17, the sheet-like insert material 18, and the copper block 19 are placed in a mold 20 such as a hot press, and heated at a high temperature (900°C) in a vacuum or active gas atmosphere.
~1050℃) and high pressure (0.5~2kg/w+m'').The applied pressure and temperature are V(P)/C
It is determined from the conditions under which the composite material u and the insert material 18 are bonded and not deformed, and further from the conditions under which the copper block 19 and the W(P)/Cu composite material are diffusion bonded.

W(P)/Cu composite material manufactured in this manner 17. Insert material 18. FIG. 2(C) shows a combination of copper blocks 19 and 19.

Figure 3 shows 'J(P)/Cu composite material 17 and insert material 1.
FIG. Same figure (A)
The state shown in FIG. 3B is formed by joining from the state shown in FIG. 2, and the insert material 18 is completely integrated with the matrix metal 3, and furthermore, direct contact between the combined bodies 7 of W particles is prevented. Therefore, the generation of voids 8 as shown in FIG. 8(B) is prevented, and stronger integration between the V(P) and Cu materials is achieved.

FIG. 4 shows the original shape of the divertor plate, in which the V(P)/Cu composite material and the cooling plate 19 of the divertor plate are integrated, and then the protective material 30, which is a glass plate, is brazed in a vacuum. Since the difference in thermal expansion coefficient between the protective material (W) and the V(P)/Cu composite material 17 is small (FIG. 5), it is possible to reduce the thermal stress generated in the vicinity of the brazing part 31. Therefore, it is possible to prevent minute cracks on the outer periphery of the V that occur during soldering, as well as the occurrence and propagation of cracks due to delamination between the beam and the 'I (P)/Cu composite material and thermal fatigue due to heat load. be. In addition, in conventional glue-Cu direct bonding, there was a limit to the size of the shape that could be manufactured in order to prevent the above-mentioned cracks, but V
The use of the (P)/Cu composite material allows for the manufacture of larger divertor plates than previously possible.

In this example, W-Cu is composited, but Mo
It is possible to obtain the same effect as in this embodiment by using powders such as p-carbon or stainless steel, or even short fibers.

〔Effect of the invention〕

As described above, according to the present invention, thin plate-shaped V(P)/Cu composite materials having different volume fractions of ν are manufactured by powder metallurgy, and the insert material 4 made of the base metal is superimposed and hot By performing diffusion bonding using a press, it has become possible to obtain a thermal expansion adjusting material whose coefficient of thermal expansion is changed in stages. This makes it possible to extend the thermal cycle life of the thermal expansion adjusting material, prevent the occurrence of cracks near the joint interface when joining dissimilar materials, and further improve thermal fatigue characteristics against heat loads. As a result, the reliability of nuclear fusion reactor equipment, etc. will be further improved.

[Brief explanation of the drawing]

FIG. 1 shows a sheet-like W (
Figure 2 shows the manufacturing process of P)/Cu composite material.
A), (B), (C) are 1it(P) according to the present invention
/Cu composite material, insert material and copper block are integrated. Figure 3 (A) and (B) are diagrams showing the advantages of inserting the insert material. Figure 4 is a diagram showing the manufacturing method of integrating the insert material and the copper block. Fig. 5 is an example of experimental data showing the relationship between the volume fraction of the buttocks and the coefficient of thermal expansion, and Fig. 6 (A), (B), and (C) are examples of conventional fiber-reinforced composites. Figures 7(A) and 7(B) are diagrams showing conventional particle-reinforced composite materials, and Figures 8(A) and CB) are diagrams explaining defects in conventional composite materials. 10...Copper powder 11...V powder 17
, 17a, 17b, 17c - sheet-like W(P)
/Cu composite material 18, 18a, 18b, 18cm Insert material 19...Copper block 30...Protective material (11) 31...Representative of Roka Department Patent attorney Nori Ken Yudo Daishimaru Kendai figure lcL Figure W/l Ihono Negative (/-JVf・30'/.

Claims (1)

[Claims] By changing the mixing ratio of adjusting materials with different coefficients of thermal expansion, sheet-shaped composite materials manufactured from billets made by powder metallurgy and sheet-shaped insert materials made of base materials are alternately layered, and they are heated and pressurized at high temperatures. By integrally joining inside,
A method for producing a thermal expansion adjustment material, characterized by controlling the thermal expansion coefficient in stages.