JPH0633104A - Distortionless alloy body having graded composition and production thereof - Google Patents

Abstract

(57) [Abstract] [Purpose] A gradient composition of materials with different coefficients of thermal expansion, such as diverter plates for nuclear fusion devices and other energy devices, is used, and there is no peeling and warpage of the sintered body occurs. Provide a non-alloyed body and a method for manufacturing it at low cost. [Structure] A mixed powder of a base material powder having a high melting point such as W and Mo having different particle diameters and an infiltration material powder having a low melting point material such as Cu, Ag and Al having a different mixing ratio is laminated and filled, and added. After pressure molding, it is heated to a temperature above the melting point of the infiltration material powder and sintered and infiltrated.By adjusting the amount of the compounded powder, the composition gradient of each layer is adjusted and the thermal expansion coefficient is adjusted. It is possible to easily manufacture the thermal expansion adjusting member in which the temperature is changed stepwise.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alloy body having a graded composition of materials having different thermal expansion coefficients, such as a diverter plate of a nuclear fusion device or other energy equipment, and a method for producing the alloy body by powder metallurgy. .

[0002]

2. Description of the Related Art A diverter plate of a fusion device receives a high heat load and a high particle load from plasma in a fusion reactor, and therefore a protective material and a protective material for preventing spattering and melting during disruption. It consists of a two-layer laminate with an endothermic material for cooling. As a laminated plate having such a structure, there are those conventionally disclosed in Japanese Patent Laid-Open Nos. 1-312015, 2-142683, 4-83779, and the like.

Among them, as a manufacturing method by powder metallurgy, a powder metallurgy method is used in which a mixing ratio of powder materials having different thermal expansion coefficients is changed at a joint portion between a protective material and an endothermic material as disclosed in Japanese Patent Laid-Open No. 1-312015. Disclosed is a thin plate-shaped composite material obtained from a composite of a plurality of types of billets, which are stacked in order of magnitude of thermal expansion coefficient and integrated under high temperature and pressure to form a composition portion having a gradient gradient. .

However, since the constituent material of the joint is made of a brazing material, a crack is likely to occur at the joint, and
Since the joining is performed at a temperature lower than the melting point of copper, a sufficient joined state cannot be obtained.

In addition, the 123rd Committee Research Report on Refractory Metal Materials vol. In No. 32 No. 1, as a method for producing a W-Cu gradient material, a laminated body of W powders having different grain sizes is molded and sintered, and then a capsule-free hot isostatic pressing (HIP) treatment is performed. , Cu infiltration is disclosed.

[0006] By this sintering infiltration method, cracks at the joint are less likely to occur, but warpage occurs because the shrinkage ratio of each layer during sintering is different. If this difference in shrinkage ratio becomes large, delamination and cracking will occur. It tends to occur, and its control is difficult. Further, there is a problem that the manufacturing cost becomes high due to the use of HIP.

[0007]

SUMMARY OF THE INVENTION The object of the present invention is to provide HI
It is an object of the present invention to provide a method for producing an alloy body having a gradient gradient composition by a sinter infiltration method with a relatively simple method without using P.

[0008]

According to the present invention, a mixed powder of a base material powder and an infiltrating material powder is laminated in a mold into layers each having an increasing amount of the infiltrating material powder, and the mixture is pressure-molded. It is characterized in that the same infiltration material as the infiltration material powder in the mixed powder is placed on this molded body and heated and sintered to a temperature equal to or higher than the melting point of the infiltration material.

Further, when the mixed powder of the base material powder and the infiltration material powder is laminated in the mold while sequentially changing the compounding ratio thereof, a sintered plate composed of only the base material is arranged at the bottom of the mold, It is possible to obtain an alloy body in which the lowermost layer is the base material and the uppermost layer is only the infiltrant, and the alloy distribution in the middle thereof is sequentially changed. It is possible to obtain a graded alloy body excellent in a bonded state by embedding the base material to be placed on the mold bottom in the laminated mixed powder, and by embedding the base material having wedge-shaped ends.

When the above-mentioned molded body is subjected to the infiltration treatment, the molded body can be previously sintered.

It should be noted that the base material powder and the infiltration material powder have almost no solid solution with each other, and the melting point of the base material powder is much higher than that of the infiltration material powder, and these conditions are satisfied. As the powder, as the base material powder, W, Mo, etc.,
Cu, Ag, Al, etc. are mentioned as an infiltration material powder.

[0012]

[Function] A state in which the base material powder and the infiltration material powder are mechanically preliminarily joined at the time of pressure molding, and further, the infiltration material is spread over the entire formed body by infiltration, and each laminated surface is joined. become,
The bonding state between the layers is sufficient.

Since a layer of only the infiltrant can be easily obtained on one end face of the obtained alloy body in a state of being in close contact with the alloy layer, when the present invention is applied to the production of the diverter material, the heat absorbing material is used. The infiltrant can be formed without undergoing a special processing step.

Since the blending ratio of the base material powder having different particle diameters can be changed, the shrinkage ratio of the laminated pressure-molded body during sintering or infiltration is the same, and the composition of the laminated body is also pressed. It can be controlled during molding. Therefore, abnormal deformation such as warpage does not occur, and delamination and cracks hardly occur.

[0015]

EXAMPLE A thermal expansion adjusting material having a 25 mm × 25 mm plane and a height of 30 mm having a gradient composition in which W is a base material as a protective member of the present invention and Cu is an infiltrant as a heat absorbing material. (Diverter material) was created. The Cu powder used was all 325 mesh or less.

First, a preliminary test was conducted to confirm the shrinkage ratio of the compact in relation to the particle size of the W powder and the blending amount of the Cu powder.

Table 1 shows the shrinkage percentage (%) when a pressure-molded body of a mixed powder of W powder and Cu powder at 200 MPa was sintered at 1350 ° C.

[0018]

[Table 1] Further, FIG. 1 shows the relationship between the blending amount of Cu powder in these mixed powders and the density of the green compact at a pressing pressure of 200 MPa. From the figure, the density of the green compact tends to increase as the particle size of the W powder increases, and decreases even with the same particle as the Cu content increases. However, it turns out that these tendencies are not unique.

From Table 1 and FIG. 1, in the composition of each forming layer of the mixed powder of the W powder and the Cu powder, the composition after infiltration is the target gradient composition, and the shrinkage ratio is the lowest, and
Those having an average particle size were selected and used.

FIG. 2 shows a process diagram for carrying out the present invention.

FIG. 2 (a) shows a W base metal sintered plate 2 (this shape is called a wedge shape) formed in a mold 1 with a thickness of 1.5 mm and both ends being shaped like a bow of a boat. 1 shows a state in which a mixed powder layer 3 consisting of four layers having a mixing ratio shown in Table 2 is laminated in a thickness of 2.5 mm, respectively.

[0022]

[Table 2] Then, from the state of FIG. 2 (a), the mixed powder layer 3 laminated in the mold 1 was subjected to ordinary mechanical pressing to obtain a compact 4 having a density of a predetermined amount of copper after infiltration (FIG. 2). (B)).

Then, the molded body 4 is taken out from the mold 1,
Sintering was performed at 1000 to 1400 ° C. for 1 hour in a reducing atmosphere to obtain a pre-sintered body 5 (FIG. 2 (c)).

Further, the sintered body 5 is placed in an infiltration jig 6, and an infiltration material 7 of Cu mass sufficient for forming the heat absorbing material in an amount necessary for infiltration is placed on the upper surface thereof. Then ((d) of FIG. 2),
By heating in a reducing atmosphere at 1100 ° C to 1400 ° C for 1 hour, Cu was infiltrated into the sintered body 5 to obtain an infiltrated body 8 (Fig. 2 (e)).

Further, the infiltrated body 8 was heated to 1100 to 1400 ° C. in an inert gas atmosphere (even in a nitrogen atmosphere) for degassing (FIG. 2 (f)).

As a result, the graded alloy body 9 shown in FIG. 2 (g) was obtained in which the infiltrant was partially left.

The degree of Cu distribution in this graded alloy body is shown in FIG.

This graded alloy body 9 had a graded gradient composition shown in the right column of Table 2.

This graded alloy body 9 has good bonding property of each layer,
Moreover, the shape of the molded body was not deformed. Furthermore, no damage was observed in a test of 10 thermal cycles with a maximum temperature of 1000 ° C. and a minimum temperature of 400 ° C., which was an extremely excellent application as a diverter for energy equipment. Table 3 shows the conditions of the heat cycle test.

For comparison, the material infiltrated in a non-reducing atmosphere had insufficient bonding.

When the shrinkage rate of the second layer or more was more than 4%, the second layer cracked.

When the W sintered body of the first layer was formed into a rectangular flat plate, the joining was insufficient. By setting the wedge-shaped W sintered body of the first layer in a state in which the second layer is clamped (FIG. 2A), the first layer and the second layer are sufficiently bonded by the clamping effect after infiltration. It is thought that it was done.

[0033]

[Table 3]

[0034]

According to the present invention, the following effects can be obtained.

(1) Since each layer can be joined by the infiltration of the infiltrant at the same time as the joining of the base material sintered plate, the manufacturing efficiency is good.

(2) By varying the compounding ratio of the base material powder and the infiltration material powder and the particle size of the base material powder, the alloy having the desired composition can be adjusted arbitrarily.

(3) No special control is required in the manufacturing process and no costly HIP is used, so that an alloy body having a composition gradient can be manufactured relatively easily and at low cost.

(4) Alloys having the same total shrinkage and different compositions can be produced by variously changing the compounding ratio of the base material powder and the infiltration material powder and the particle size of the base material powder.

(5) Since the base material sintered plate and the gradient composition are joined by the infiltration material, the heating up to near the melting point of the heat absorbing material can be endured.

(6) The heat absorbing material can be simultaneously formed by the infiltration, and the manufacturing efficiency is good.

[Brief description of drawings]

FIG. 1 is a diagram showing the influence of the particle size of W powder and the blending amount of mixed Cu powder on the density of a green compact when a gradient-gradient alloy body is manufactured by stacking W-Cu mixed powders.

FIG. 2 shows a process chart as an embodiment of the present invention.

FIG. 3 is a diagram showing the distribution of Cu in each layer in the laminated powder body and the degree of distribution of Cu in the gradient composition metal body after the sintering infiltration treatment.

[Explanation of symbols]

 1: Formwork 2: W base material sintered plate 3: Mixed powder layer 4: Formed body 5: Pre-sintered body 6: Infiltration jig 7: Infiltration material 8: Infiltration body 9: Gradient alloy body

Claims (3)

[Claims] 1. An almost strain-free alloy body in which the composition is gradually changed stepwise. 2. A layer in which a mixed powder of a base material powder and an infiltrating material powder is mixed in the mold in a successively increasing amount, and the shrinkage rate of each layer is substantially the same. And then press-mold this laminated body, and then place the same infiltrating material as the infiltrating material powder in the mixed powder on this molded body, and place the same infiltrating material in the reducing atmosphere. A method for producing an alloy body having a graded composition, which is heated and infiltrated to a temperature higher than the melting point. 3. A mold in which a wedge-shaped base material plate material is arranged, a mixed powder of the base material powder and the infiltration material powder is formed as a layer in which the blending amount of the infiltration material powder is sequentially increased, and each layer shrinks. The laminate was selected and laminated so that the ratio was less than 4%, the laminate was pressure-molded, and then the same infiltration material powder as the infiltration material powder in the mixed powder was placed on the compact. A method for producing an alloy body having a graded composition, which is heated and sintered and infiltrated to a temperature equal to or higher than the melting point of the infiltration material in a reducing atmosphere.