JPH02217404A - Method for forming al-base composite material - Google Patents

Abstract

PURPOSE:To easily obtain an Al-base composite material having high density by forming a capsule with bellows body at the time of packing mixed powder of the Al base powder and reinforcing material powder into the cylindrical capsule and executing hot isostatic pressing (HIP) to deeply shrink the capsule in the axial direction. CONSTITUTION:The cylindrical capsule 1 formed with the bellows body 3, the side wall part 2 of which shrinks to the axial direction, is prepared. Further, the mixed powder 9 of the Al (alloy) powder and the reinforced material powder, is manufactured. This mixed powder 9 is packed into the above capsule 1 and degassed, and after sealing, this is pressurized and formed with the HIP.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to hot isostatic pressing (hereinafter referred to as HIP).

) relates to a method for integrally molding an N-based composite material.

(Prior art) N-based composites, which are made by integrating N or N alloy, which is a lightweight metal, with reinforcement powder such as ceramic whiskers, short fibers, and ceramic particles, have high pressure strength, high specific modulus, and high It has excellent mechanical properties such as fatigue strength and high wear resistance. For this reason, spacecraft are becoming more lightweight and have higher performance.
As a material for parts and structural members of automobiles, OA equipment, etc.
It is also attracting attention as a material for sporting goods.

As a method for molding the N-based composite material, a mixed powder of N or N alloy (hereinafter simply referred to as N alloy) powder and reinforcing material powder is filled into a HIP molding capsule, degassed, and sealed. There is a method of integrally molding by HIP. In this case, the capsule is usually a cylindrical capsule made by welding a bottom plate and a cover plate made of a mild steel plate to a mild steel pipe. In addition, when filling mixed powder into capsules, unlike ordinary metal powder, it is difficult to fill the mixed powder densely by tapping alone, so in order to increase the filling rate, pressure is applied using a press. Filled. In addition, the composite material after HIP molding, after capsule removal,
It is finely processed into a cylindrical body and finished into various shapes by extrusion processing, etc.

(Problem to be Solved by the Invention) However, when HIPing capsules filled with mixed powder, the capsules do not soften sufficiently during HIP due to the low molding temperature of the N alloy, resulting in non-uniformity as shown in Figure 3.4. When a cylindrical product is obtained due to severe shrinkage, there is a problem in that the cutting allowance for the material becomes large and the yield is extremely low. This is particularly noticeable when the filling rate is low.

Incidentally, if the mixed powder inside the capsule is filled under high pressure, uneven shrinkage of the capsule during HIP can be reduced, but degassing and degassing inside the capsule becomes difficult. For this reason, it is not possible to increase the filling rate extremely high, and it is usually 60% to 70%.
It is said that

The present invention was made in view of such problems, and an object of the present invention is to provide a method of forming an N-base composite material by HIP, which has a high yield.

(Means for Solving the Problems) A method for forming an N-base composite material of the present invention, which has been made to achieve the above object, is to form a mixed powder of aluminum or aluminum alloy powder and reinforcing material powder into a cylindrical capsule. After filling, degassing and sealing, press molding by hot isostatic pressing A.
In the f-base composite material molding method, the invention is characterized in that the capsule has a side wall portion formed of a bellows body that contracts in the axial direction.

(Function) Since the side wall of the cylindrical capsule for HIP molding used in the present invention is formed of a bellows body that contracts in the axial direction, the radial strength of the capsule can be improved, and the HIP
In some cases, it is possible to make a large contraction in the axial direction without causing much contraction in the radial direction. Furthermore, since the shrinkage in the axial direction can be large, a high-density N-based composite material can be easily obtained even when the filling rate of the mixed powder in the capsule is low. Therefore, it is possible to omit the step of pressurizing the mixed powder to increase the filling rate. Furthermore, since the filling rate is low, degassing becomes easy.

(Example) Fig. 1 shows an example of a capsule for HIP molding used in the present invention, in which a side wall part 2 is formed by a cylindrical bellows body 3, a bottom plate 4 is provided at one end of the side wall part 2, and a bottom plate 4 is provided at the other end. A lid 6 having a degassing tube 5 is provided.

Reference numeral 7 denotes a cylindrical mesh body for preventing the mixed powder from entering the corrugated recesses 8 on the inner circumferential surface of the bellows body 3. When the powder enters the recess 8, the capsule is prevented from shrinking in the axial direction, and the mixed powder filled inside the capsule is not solidified sufficiently. A mixed powder 9 is accommodated inside the mesh body 7. The lid plate 6 is constructed by placing the net body 7 inside a container in which the bottom plate 4 is welded to one end of the bellows body 3 in advance, and placing the mixed powder 9 inside the cord body 7.
After loading, it is welded to the open end of the container. When filling the mixed powder, there is no need to apply pressure using a press or the like, and it is sufficient to tighten the powder with a rod. These treatments may be performed in the atmosphere.

The capsule 1 is made of a metal plate that is easily plastically deformed (for example, an aluminum plate, an aluminum alloy plate, a mild steel plate, a stainless steel plate, a copper plate, a copper alloy plate), and the 0M4 body 7 is also made of a similar metal wire. used.

Incidentally, the wall surface bending shape of the bellows body 3 is not limited to the circular arc wave shape as shown in the figure, but may also be a triangular wave shape or the like.

As mentioned above, the mixed powder 9 is a mixture of N alloy powder and reinforcing material powder, but as the N alloy, 606
Various materials such as 1 material and 7075 material can be used.
- SiC, Si3N as force reinforcement powder.

, N! (11, /Vz03 +SiO□ and other ceramic whiskers and particles, and various other short metal fibers and whiskers can be used.

The mixing ratio of the N alloy powder and the reinforcing material powder is preferably such that the volume content of the reinforcing material powder is about 10 to 50%.

If it is less than 10%, the reinforcing ability will be insufficient, while if it exceeds 50%, the ductility and toughness of the composite material will be significantly reduced, and the processing difficulty will increase.

It is preferable that the mixed powder 9 is a uniformly dispersed mixture of N alloy powder and reinforcing material powder that is filled into a capsule.

A suitable method for uniformly mixing N alloy powder and ceramic reinforcing material powder is disclosed in JP-A No. 607251922, in which the reinforcing material is subjected to ultrasonic vibration in an organic solvent to disentangle it. N alloy powder was added to the mixture, stirred, and the resulting mixed slurry was suction-filtered.
There is a way to vacuum dry the cake.

In addition, as a mixed powder, a mixed pellet in which reinforcing material powder is uniformly dispersed in N alloy powder and maintained in a granular shape (preferably a particle size of about 0.1 to 5 [lIIm)] by an organic binder is debinding. Can be used. This mixed pellet was proposed by the present applicant in Japanese Patent Application No. 173695/1982, and is designed to prevent the reinforcing material and metal powder from separating or becoming unevenly distributed due to vibrations and shocks generated during the handling process of the mixed material. The uniformity of the ingredients is ensured,
It also has excellent filling and moldability into capsules.

After filling the capsule with the mixed powder, the air inside the capsule is evacuated through the deaeration pipe 5 of the lid plate 6. At this time, it is best to heat the capsules. After degassing, the degassing tube 5 is crimped and sealed, and then HIP processing is performed.

FIG. 2 is an explanatory view of the capsule after the HIP treatment (deaeration tube is not shown), and the contraction of the capsule is concentrated in the axial direction, with almost no contraction occurring in the radial direction. The mixed powder in the capsule is pressure-sintered by HIP treatment at a temperature in the solid phase region or solid-liquid coexistence region of 400 to 660° C. to form the desired composite material. The product is obtained by removing the capsule using an appropriate cutting machine and finely processing the composite material into a cylindrical shape.

Next, specific examples are listed.

(1) A uniform mixed powder consisting of 2024A7 alloy powder and SiC whiskers was prepared. The mixing ratio of SiC whiskers was 20% by volume. The N alloy powder was an atomized powder, which was classified to have a particle size of 44 μm or less.

(2) As an example, a mild steel capsule with a bellows-shaped side wall as shown in FIG. 1 was prepared. Outer diameter 104 mm, inner diameter 77
am, length 300mm, bellows pitch 10.5mm, and wall thickness 1 piece. The mesh body was made of SUS wire mesh.

On the other hand, as a conventional example, a mild steel capsule with a tubular side wall was prepared. Inner diameter 95m+a, length 190mai, wall thickness 2m
It is m.

Incidentally, when filling the mixed powder, both capsules were used without fluid being welded to them.

(3) Both capsules were filled with the mixed powder of (1), a lid plate was welded, and the air inside the capsules was evacuated through a degassing tube under heating, and the capsules were sealed. In the case of the example, the mixed powder was not pressurized (the filling rate was 36%, as it was only compressed by a bar material.On the other hand, in the case of the conventional example, the mixed powder was not pressurized by a press after being charged. The filling rate was increased to 65%.

(4) Both capsules were subjected to HIP treatment. The processing conditions are
The temperature was 480°C11C115O0/c-. the result,
The capsules contracted and deformed as shown in FIG. 2 (see reference photo 1) for the example and FIG. 3 (see reference photo 2) for the conventional example. In the case of the example, no constriction or irregular contraction occurred in the circumferential direction of the body, and uniform contraction was possible.

(5) When the capsule was removed and a cylindrical body with the largest possible diameter was cut from the material, the yield of the example was approximately 92.
%, but in the conventional example it was 68%.

(6) The composite materials of the example and the conventional example were subjected to T6 heat treatment. The mechanical properties after treatment are shown in Table 1.

From Table 1, it is known that the composite materials of Examples are no inferior to the conventional examples and have good mw properties.

(7) In the same manner, composite materials were HIF-molded using capsules of various sizes and mixed powders. The results are shown in Table 2. Samples Nal~8 are examples, and Nal 9 is a conventional example. In addition, in the same table, the types of mixed powders are as follows, and the mixing ratio of reinforcing material powders was all 20VO1%.

A...Things in (1) above B...6061/V alloy powder, C...7075Aj alloy powder, D...2024/V alloy powder, E...6061Aj alloy powder, whisker whisker particles As shown in Table 2, although the capsule filling ratios of Sake 1 to 8 molded according to the present invention are all low at less than 50%, the yield of the products is all over 90%, and the yield is significantly improved. We were able to achieve this goal.

(Effect of the invention) As explained above, according to the molding method of the present invention, HIP
By forming the side wall of the processing capsule with a bellows body that contracts in the axial direction, it is possible to concentrate the contraction in the axial direction with almost no contraction in the radial direction of the capsule during HIP, and it has a cylindrical shape compared to composite materials. If the product is machined, the product yield can be significantly improved. Further, it is easy to achieve a large contraction in the axial direction, and therefore a low filling rate may be required for filling the capsule with powder, and the pressurizing step during filling, which is conventionally required, can be omitted.

Furthermore, since the capsule shrinks uniformly and does not require pressurized filling, it is possible to design a capsule that matches the required product size, which greatly contributes to improving productivity.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a HIP processing capsule for carrying out the present invention, Fig. 2 is an explanatory front view of the external appearance of the same capsule after HIP processing, and Fig. 3 is an external view of a conventional cylindrical capsule after HIP processing. The front explanatory view, FIG. 4, is a sectional view taken along the line A--A in FIG. 3. DESCRIPTION OF SYMBOLS 1... Capsule, 2... Side wall part, 3... Bellows body,
9...Mixed powder. No.! Figure patent applicant Kobe Steel, Ltd. Figure

Claims (1)

[Claims] (1) A method for forming an N-based composite material by filling a cylindrical capsule with a mixed powder of aluminum or aluminum alloy powder and reinforcing material powder, deaerating and sealing the capsule, and then press-forming it by hot isostatic pressing. A method for molding an Al-based composite material, wherein the capsule is formed of a bellows whose side wall portion contracts in the axial direction.