JP2925378B2 - Manufacturing method of composite material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for producing a composite material having substantially equal strength in different directions.

[0002]

2. Description of the Related Art Conventionally, in the production of a composite material, for example, a whisker and a binder are dispersed in a solvent, and a fiber preform is formed by suction or compression.
For example, Japanese Patent Application Laid-Open No. 61-14782 discloses a preform.
A composite material is manufactured by dispersing a metal compound by a method as shown in No. 5.

[0003]

However, in the conventional case, the preform formed by whiskers has an arrangement structure in which the fibers are directed in one direction, and it is difficult to obtain isotropy in strength. Such a composite material has a problem that the applicable area of the article is greatly limited. For this reason,
It has been desired to produce a composite material having less strength anisotropy.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a method of mixing two- to three-volume whiskers with one-dimensional whiskers, uniformly dispersing the mixed whiskers in the solvent liquid, and sucking the solvent liquid. After the removal, pressure was applied to form a preform, and a light alloy was infiltrated into the preform. The one-dimensional whiskers were aluminum borate whiskers, and the three-dimensional whiskers were zinc oxide whiskers.

[0005]

[Function] By mixing 2 to 10 vol% of three-dimensional whiskers with one-dimensional whiskers, the fiber orientation during preform molding becomes a three-dimensional random structure instead of a one-way array structure, and strength isotropic. Property is obtained.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the method for producing a composite material according to the present invention will be described with reference to the accompanying drawings. 1 to 4 show a manufacturing process, FIG. 1 is an explanatory diagram for explaining mixing and dispersion of whiskers, FIG. 2 is an explanatory diagram for forming a preform by suction and pressure, and FIG. 3 is an explanatory diagram for explaining infiltration. FIG. 4 is an explanatory view showing an example of a completed product.

Whiskers in which metal or other solid crystals have grown into thin fibrous shapes are widely used as reinforcing fibers for composite materials. For example, aluminum borate whiskers have a needle-like crystal structure oriented in one direction. It is known as a whisker having a one-dimensional structure.

Then, as shown in FIG. 8, only such aluminum borate whiskers are dispersed in an aqueous solution as a solvent solution, water is sucked through a filtration membrane 11, and then pressure is applied to form a preform 12, whereby: As shown in the enlarged microstructure diagram (A), the directions of the fibers are arranged in one direction to exhibit a unidirectional arrangement structure.

The composite material produced from such a preform 12 shows high values of tensile modulus and tensile strength in the fiber arranging direction, but almost no matrix in the direction perpendicular to the fiber arranging direction. And a low value with no change,
There was a situation where so-called isotropic properties could not be obtained.

Therefore, the present invention is to manufacture a composite material whose strength does not change depending on the direction.

First, aluminum borate whiskers having a one-dimensional structure and zinc oxide (Zn) having a three-dimensional structure
O) Whiskers are placed in a volume ratio of 98: 2 to 90:10.
And uniformly dispersed in water as a solvent liquid shown in FIG. 1 by using a stirrer 1 or an ultrasonic generator 2 or both of them 1 and 2 to obtain a whisker dispersion solvent 3.

Here, the zinc oxide whisker has a shape in which the needle-shaped crystal parts project three-dimensionally in four directions, and has a tetrapod shape in appearance.

Next, when the particles are uniformly dispersed, water (solvent) is sucked through the filtration membrane 4 and pressurized to form the preform 5 as shown in FIG. Preform 5 at this time
Has a three-dimensional random structure as shown in the enlarged microstructure diagram (A), and the directivity in one direction is lost.

Then, such a preform 5 is set in a mold 6 as shown in FIG. 3, and a molten aluminum alloy as a light alloy is infiltrated by a high-pressure casting method. In other words, after the mold is clamped and the molten aluminum is poured, pressure is applied by the plunger 7 so that the aluminum penetrates between the fibers and adheres strongly to the fibers. At this time, the adhesion between the aluminum borate whisker, which is the main component of the fiber, and the metal aluminum is good. At this time, the fiber content Vf of the composite material is set to 24%.

Forming a composite material by such a casting method not only strengthens the bond between the fiber and the metal and makes it possible to obtain a composite material having excellent mechanical properties. It has advantages such as easy secondary molding for softening the composite material at a high temperature and molding it into a desired shape.

Such a composite material has an isotropic strength as described below. In this embodiment, a connecting rod 8 of an automobile engine as shown in FIG. 4 is formed from this composite material. .

FIGS. 5 to 7 show the relationship between the mixing amount of zinc oxide and the strength of the composite material. In other words, in each of the tables, the horizontal axis shows the mixed volume ratio of zinc oxide (ZnO), the vertical axis shows the isotropic property in FIG. 5, the strength in the stacking direction in FIG. 6, and the strength in the parallel direction in FIG. It shows.

According to FIG. 5, the mixing amount of zinc oxide is 2 Vo
It is understood that when the content is 1% or more, the anisotropy is not recognized. That is, as shown in FIG. 6, the strength in the laminating direction starts to increase with an increase in the volume ratio of zinc oxide up to 2% by volume, and gradually decreases when the volume ratio exceeds 10% by volume. And from 2Vol% to 10Vol%,
It turns out that it shows a substantially constant value of about 55 kg / mm ² .

On the other hand, the intensity in the parallel direction is as shown in FIG.
It begins to gradually decrease with an increase in the mixing amount of zinc oxide, and 2V
It can be seen that from 55% by volume to 10% by volume, the strength in the laminating direction is approximately 55 kg / mm ² , which substantially coincides with the strength. Therefore, no anisotropy is recognized in such a range, and although the strength in the parallel direction is slightly reduced, the isotropic strength of the strength can be obtained instead.

[0020]

As described above, the method for producing a composite material of the present invention exhibits isotropic mechanical properties, so that the applicable range as a component material is greatly expanded and the degree of freedom in design is increased. Can be done.

[Brief description of the drawings]

FIG. 1 shows the manufacturing process of the present invention, mixing whiskers,
Explanatory diagram for explaining dispersion

FIG. 2 is an explanatory view of forming a preform by suction and pressure.

FIG. 3 is an explanatory diagram illustrating infiltration.

FIG. 4 is a completed view of a connecting rod as a manufactured product.

FIG. 5 is a graph showing the relationship between the volume fraction of zinc oxide and isotropicity.

FIG. 6 is a graph showing the volume ratio of zinc oxide and the strength in the stacking direction.

FIG. 7 is a graph showing strength in a direction parallel to a volume ratio of zinc oxide.

FIG. 8 is an explanatory view of a preform molded only with one-dimensional whiskers.

[Explanation of symbols]

 3 whisker dispersion solvent 5 preform 8 connecting rod

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C22C 1/09-1/10 B22D 19/14

Claims (2)

(57) [Claims] 1. A three-dimensional whisker of 2 to 10 vol% is mixed with a one-dimensional whisker and uniformly dispersed in a solvent solution. The solvent solution is removed by suction, followed by pressurization to form a preform. A method for producing a composite material, comprising infiltrating a preform with a light alloy. 2. The method according to claim 1, wherein the one-dimensional whiskers are aluminum borate whiskers, and the three-dimensional whiskers are zinc oxide whiskers.