JPH0542356A - Production of fiber reinforced composite member - Google Patents

Abstract

PURPOSE:To provide the process for production of the fiber reinforced composite member which exhibits a good compounded state. CONSTITUTION:This process for production of the fiber reinforced composite member consists in rapidly pressurizing a molten metal until the molten metal poured into metallic molds for casting attains the threshold value at which the molten metal starts infiltrating a preform, increasing the pressure at a specified gradient after the start of the infiltration into the molten metal and rapidly pressurizing the molten metal up to the max. value as soon as the packing into the preform ends in the case of production of the fiber reinforced composite member by setting the preform into the above-mentioned molds, pouring the melt of a matrix metal therein and pressurizing the molten metal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a metal composite member reinforced with an inorganic fiber, more specifically, high pressure solidification casting method (pressure casting, molten metal forging, squeeze casting, etc.).
The present invention relates to a method in which an inorganic fiber molded body (preform) is impregnated with a molten metal by using to form a composite.

[0002]

2. Description of the Related Art Conventionally, when a preform formed of inorganic fibers such as ceramics and whiskers is filled with a molten metal matrix by a high pressure solidification casting method,
A method is known in which the pressure of the molten metal is gradually and continuously increased at the initial stage of pressurization, then rapidly raised to a maximum value, and the pressurized state is maintained for a certain period of time (Japanese Patent Publication No. 53-12446 gazette).

Similarly, after a molten metal matrix is poured into a preform housed in a mold, the molten metal is first pressurized at a constant low pressure in a pressure cylinder equipped with a molten metal press punch. Soak into the preform,
A method is known in which, immediately after the completion of filling, the pressure is increased to the maximum pressure (see Japanese Patent Publication No. 3-3539).

[0004]

In the former method of the conventional example, the bulk density of the preform is about 0.6 g / cm ^3.
If it exceeds, the resistance to infiltration of the molten metal into the preform increases, the deformation of the preform increases, and there is a problem that it cannot be applied.

On the other hand, the latter conventional example has a drawback that the molten metal infiltrating speed caused by a constant resistance is slow, so that the molten metal is cooled during that period, and as a result, sufficient complexing cannot be achieved.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a method for manufacturing a fiber-reinforced composite member that solves the above problems.

[0007]

Means for Solving the Problems In accordance with the above object, the present inventor has earnestly studied and, as a result, has learned the following fact. That is, 1) The preform has a threshold value at which the molten metal starts to infiltrate depending on its type, density, configuration, and the like. 2) The molten metal pressure after starting to penetrate the preform must be proportional to the molten metal infiltration rate and the infiltration distance. 3) The deformation of the preform at the time of compounding is caused by the force at the time of infiltration of the molten metal, and occurs when the strength of the preform itself is insufficient with respect to this force. 4) When the mold temperature is lower than the liquidus temperature of the molten metal, the molten metal injected into the mold quickly starts solidification. This is also the case when the complexing process takes a long time, and good complexing cannot be achieved when the solid fraction of the molten metal increases.

Therefore, based on these findings, according to the present invention, when a preform is set in a casting mold and a molten metal of a matrix metal is injected and pressurized to produce a fiber-reinforced composite material, the injected molten metal is Rapidly pressurize the molten metal until reaching the threshold value to start the infiltration into the preform, and increase the pressure at a constant gradient after the infiltration into the preform. The above-mentioned problem was solved by pressurizing to the maximum value.

That is, as shown in FIG. 2, the molten metal is rapidly pressurized until it reaches a threshold value (the molten metal pressure A at the position of the pressurizing time a in the figure) at which the molten metal starts to infiltrate the preform, and the molten metal is melted. Starts to infiltrate into the preform, and the molten metal pressure increases at a constant gradient until time b (molten metal pressure B) when the filling into the preform is completed. Then, as soon as the filling of the preform is completed, the pressure is rapidly increased to the maximum value (molten metal pressure C at the position of time C in the figure).

Embodiments of the present invention will be described below in detail with reference to the drawings.

[0011]

【Example】

(1) FIG. 1 conceptually shows an apparatus used for carrying out the present invention, 1 is a mold, 2 is a pressure punch, 3 is a hydraulic cylinder which pressurizes the pressure punch, and 4 is set in the mold 1. The formed preform 5 shows the injected molten metal.

The molten metal 5 is JIS AC of aluminum alloy.
What melt | dissolved 8A at the temperature of 700 degreeC is used. The preform 4 uses SiC whiskers, and the shape dimensions are 80 × 8.
It was set to 0 × 30 mm and molded into a volume ratio (Vf) of 25%. The preheating temperature was 700 ° C. The mold 1 had an inner diameter of 100 × 100 mm and was preheated to a temperature of 250 ° C.

Under the above conditions, 1.5 kg of the molten metal 5 was poured into the mold 1, and the pressure punch 2 was lowered at a speed of 30 mm / sec. Immediately after the press punch 2 reached the upper surface of the molten metal 5, the molten metal was rapidly pressurized until the molten metal pressure reached 30 kg / cm ² (threshold value), and the composite formation was started. After the start, the pressure was increased at a constant gradient pressure, that is, at a rate of 480 kg / cm ² / sec, and when the pressure reached 240 kg / cm ² , the maximum pressure was rapidly increased to 1000 kg / cm ^{2 for} pressurization. The relationship between the molten metal pressure and the pressurization time at this time is shown in FIG. That is, it takes 0.05 sec until the molten metal pressure reaches 30 kg / cm ² , 0.5 sec before the molten metal pressure reaches 240 kg / cm ^2, and the molten metal pressure 1000 kg / cm ^2.
It took 0.7 seconds to reach.

When the composite material obtained by the above treatment was inspected, it was confirmed that the thickness 30 mm of the preform 4 was deformed to 28 mm, but in practical use, this degree of deformation was at a level without any problem. .. At this time, the preform used was formed without using a binder, and the preform itself had low strength. When the compounding treatment was performed under the same conditions using the preform reinforced with the binder, it was confirmed that the preform was not deformed at all. Therefore, it was found that the binder may be appropriately used according to the necessary conditions as the composite material.

Further, the pressure of the constant gradient (pressurization gradient)
Is 120 to 900 kg / cm ² / sec as a result of the experiment.
A good composite state was obtained within the range.

(2) As a comparative example, only the descending speed of the pressure punch 2 is 3 mm / se under the same conditions as in the above-mentioned embodiment (1).
Similar processing was performed for c. The rising gradient of the molten metal pressure at this time was 48 kg / cm ² / sec.

The composite material treated by this method was cut, and the composite state was investigated. As a result, the molten metal was filled in the lower part of the preform, about 1/4 of the height of the entire preform. There was no part, and the deformation of the preform was beyond the range of allowable deformation in the above-mentioned examples.

The time required for the molten metal to permeate into the preform in this treatment was about 5 seconds, and it is considered that the temperature drop of the molten metal became large during this period and the solid phase increased.

From the results of the above Examples and Comparative Examples, it is necessary to set the pressurizing gradient at the time of compounding to an appropriate range. In the above Examples, the range of the pressurizing gradient for obtaining a good composite state is
^{120kg / cm 2 / sec~900kg / cm} 2 / s
It was ec.

Factors that have a great influence on enabling good composite formation are the size of the preform, strength, and the amount of molten metal. When the size of the preform is large, the pressurizing gradient is used when the amount of molten metal is small. Must be steep and the preform must be strong at this time. When the size of the preform is small and the amount of molten metal is large, the pressure gradient can be made gentle, and at this time, good composite formation is possible even if the strength of the preform is small. Needless to say, it is also affected by other factors such as mold temperature, molten metal degree, molten metal type, preform type, and volume ratio.

[0021]

According to the method of the present invention, a fiber-reinforced composite member exhibiting a good composite state can be obtained.

[Brief description of drawings]

1 is a schematic illustration of a device for carrying out the method according to the invention.

FIG. 2 is a diagram showing a relationship between a molten metal pressure and a pressurizing time regarding a method according to the present invention.

FIG. 3 is a diagram showing a relationship between a molten metal pressure and a pressurizing time in an example of the method according to the present invention.

[Explanation of symbols]

 1 mold 2 pressure punch 4 preform 5 molten metal

Claims (2)

[Claims] 1. A preform is set in a casting mold,
When producing a fiber reinforced composite material by injecting and pressing a molten metal of a matrix metal into this, the molten metal is rapidly pressurized until the injected molten metal reaches a threshold value at which the molten metal begins to penetrate into the preform, and the preform A method for producing a fiber-reinforced composite member, characterized in that the pressure is increased at a constant gradient after infiltration into the preform, and the pressure is rapidly increased to the maximum value as soon as the filling into the preform is completed. 2. The constant gradient increasing pressure is 120 to 90.
It is 0 kg / cm < ² > / sec, The manufacturing method of the fiber reinforced composite member of Claim 1 characterized by the above-mentioned.