JPH04154927A - Manufacture of partially reinforced frm material - Google Patents

Abstract

PURPOSE:To form a joined face with a rigid integral structure between a composite base metal obtd. by dispersing a short fiber reinforced material into an Al-based matrix metal and a cast-in metal, at the time of setting the composite base metal in a mold and pouring the molten metal of the metal therein, by previously subjecting the joining face of the composite base metal to mechanical grinding. CONSTITUTION:A composite base metal obtd. by dispersing a short fiber reinforced material (such as SiC) into an Al-based matrix metal (Al base alloy) is set in a mold, in which the molten metal of an Al-based cast-in metal is poured, and solidification is executed. At this time, previously, the joining face of the composite base metal is subjected to mechanical grinding to remove oxidized components and to regulate its surface roughness to about 10 to 500mum Rz. This composite base metal is preheated to a prescribed temp. and is set to a prescribed place in the mold, in which the molten metal of the Al-based metal same as or different from the matrix metal is poured, which is pressurized under the pressure of about 10 to 3000kg/cm<2> to solidify the cast-in metal. In this way, the partially reinforced FRM material in which the composite base metal and the cast-in metal are rigidly joined is manufactured.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides a partially reinforced FRM in which predetermined parts of Al or Al-based metal materials such as Al-based alloys are composited with short fiber reinforcement.
It relates to a method of manufacturing materials.

[Conventional technology]

Whiskers and short fibers made of ceramic materials such as S i C, S iy Na, A11z Oa, etc. are thermally and chemically stable and have excellent strength characteristics.
It is useful as a composite reinforcing material for metal materials, especially light metal materials such as A2 and Mg.

Among these, an example of partially reinforced FRM is a composite structure in which the pistons, rocker arms, connecting rods, etc. of an internal combustion engine are made of light 1 Affi alloy, and parts that are subject to severe thermal shock or sliding are locally strengthened with SiC whiskers. As a composite means, a method has been developed in which a preform of SiC whiskers is set in a predetermined position of a mold and molten Affi alloy is pressure cast (for example, in Japanese Patent Application Laid-Open No. 55
-24763, 55-24945). However, since the SiC whisker preform is an extremely fragile aggregate, it often suffers from deformation, destruction, etc. during the pressure casting stage. For this reason, research on methods for strengthening preforms has been actively conducted, but none has been found to be fully satisfactory.

Regarding the above point, a composite base material of a predetermined shape made of short fiber reinforcement material and matrix metal is formed in advance by suitable means such as forging, and after setting it in a predetermined position of a mold, molten metal is poured. It is believed that the process of casting the composite base material in a molded form will be an effective means for partially reinforced FRM. However, in this case, the surface is oxidized during the process of forming the composite base material or the preheating process during poetry, and the formed oxide film significantly inhibits the wettability of the poetry metal with the molten metal, thereby increasing the bonding strength at the interface. resulting in a decline in

As a partial reinforcement composite means to solve this problem,
Precious metal materials and AI! , 11 film is adhered and formed, and this is set on the reinforced part to cast the A2 molten metal (Japanese Patent Application No. 1-293367, 2006-1
No. 14871), a process in which the surface of the composite base material is plasma treated to remove the oxide film, and then Affi molten metal is melted to partially strengthen the composite (Japanese Patent Application No. 2-29899)
) etc. have already been proposed by the applicant.

[Problem to be solved by the invention]

Among the above processes, the method of depositing and forming a noble metal-based substance or an Al thin film has problems in that the depositing material is expensive and a coating process is complicated.

On the other hand, the method of Japanese Patent Application No. 2-29899 is contrary to the above-mentioned process of preventing the formation of an oxide film by coating the surface of the composite base material with noble metal, AP, etc. The aim is to obtain a normal partial composite structure by actively removing the oxidized film before casting. Therefore, if the treatment can be carried out efficiently, it is likely to be cost-friendly. However, in this method, the plasma treatment of the composite base material can be carried out under reduced pressure of 200 Torr or less in a reducing or rare gas or mixed gas system. It is necessary to carry out the process in the same condition, and as an industrial process, it is difficult in terms of efficiency.

An object of the present invention is to provide a method for manufacturing a partially reinforced FRM material that can modify the surface of a composite base material through an easy-to-operate preliminary process, thereby effectively improving the bondability with poetry metal. It is in.

[Means to solve the problem]

The first method of manufacturing a partially reinforced FRM material according to the present invention to achieve the above object is to set a composite base material in which short fiber reinforcement is dispersed in an Al-based matrix metal in a mold, and then In the process of injecting and solidifying molten casting metal, the joint surfaces of the composite base material are mechanically polished in advance to remove oxidized components and roughen the exposed surfaces, and the composite base material after the polishing process is used as a mold. AI that is the same or different from the matrix metal by setting it in a predetermined location! The structural feature is that molten metal is injected and then solidified under pressure.

The second method of manufacturing a partially reinforced FRM material according to the present invention is to set a composite base material in which short fiber reinforcement is dispersed in an Al-based matrix metal in a mold, and then inject and solidify molten Al-based cast metal. In the process of manufacturing a composite base material, a thin layer of matrix metal alone is formed in advance on the joint surface of the composite base material, and the composite base material with the thin layer formed is set in a predetermined place in a mold to form a matrix metal of the same or different type. A of
The structural feature is that molten l-type casting metal is injected and then solidified under pressure or no pressure.

Suitable short fiber reinforcing materials used in the present invention include, for example, S r C, S is Na, Al2z 03,
K, ClnTi0. , TiB, and other ceramic whiskers or chopped short fibers, but any short fiber reinforcing material that is normally used for FRM can be used without any particular restrictions.

For the matrix metal, a /l-based light metal such as Affi or Al-based alloy is used.

The composite base material used to construct the reinforced part is created using a pressure casting method in which a preform of short fiber reinforcement is set in a mold, impregnated with molten matrix metal, and solidified under pressure. (molten metal forging method), or by a powder metallurgy method in which reinforcing material and matrix metal powder are wet mixed and this mixture is sintered into a predetermined shape using hot pressing, HIP, etc. in a vacuum or inert atmosphere. Ru.

At this time, the mixing ratio of the short fiber reinforcement material and the matrix metal is such that the Vf of the short fiber reinforcement material in the composite matrix is 1 to 50.
It is preferable to set it to a desired value within the % range.

If the Vf of the whisker is less than 1%, the composite effect will be insufficient, and if it exceeds 50%, it will not be possible to obtain a composite matrix with a good structure, and the cost will increase.

Note that the produced composite base material may be subjected to secondary processing such as forging in order to form a more complex shape.

In the first method, the bonding surface of the composite base material produced is mechanically polished in advance before the poem is made. Mechanical polishing methods include shot blasting, barrel polishing, file polishing,
Appropriate means such as wire brush polishing can be applied. However, the most practical polishing method is shot blasting, which uses carporundum, steel, sand, etc. as shot particles. The polishing process is continued until the oxide components generated and adhered to the joint surface are removed and the exposed surface is appropriately roughened. A suitable degree of surface roughening is in the range of 10 to 500 μmRz in terms of surface roughness, and in this surface condition a strong interfacial bond with the molten metal can be obtained.

The mechanically polished composite base material is preheated and then set at a predetermined location corresponding to the reinforced region of the mold, and molten Al-based casting metal of the same or different type as the matrix metal is injected. The temperature during preheating is 30°C if the atmosphere is in the air.
The temperature is preferably 0°C or lower, or 450°C or lower in the case of an inert atmosphere.

The pressure casting method is effectively used for poetry, and the conditions for this are that the temperature of the molten metal is 50°C or higher than its liquidus temperature, and the pressure during casting is set in the range of 10 to 3000 kg/cm. If the molten metal temperature falls below the liquidus line +50°C, the molten metal cools down rapidly and inhibits interfacial bonding, and if the casting pressure is less than 10 kg/cm, the interfacial bonding force between the composite base material and the poem metal decreases. becomes insufficient, and if it exceeds 3000 kg/cm2, material deformation will occur.

When the second method according to the present invention is adopted, a thin layer of matrix metal alone is formed in advance on the joint surface of the composite base material by the above-described pressure casting method (molten metal forging method) or powder metallurgy method. It is a requirement to keep the For example, when a composite base material is produced by a pressure casting method (molten metal forging method), the thin layer of the matrix metal alone is formed so that a solidified layer of the matrix metal alone remains at the joint surface with the poetry metal. A short fibrous reinforcing material preform was set in a mold and impregnated with molten metal, and in the case of powder metallurgy, a layer of only matrix powder was spread on the part of the mold located at the joint surface with the poem metal. It can be formed by performing normal composite sintering in the state. The thickness of the thin layer is sufficient as long as it can be mutually dissolved with the haiku metal during haiku, and usually 1 to 2 ml is sufficient.

The composite base material in which a thin layer of matrix metal alone has been formed is preheated according to the first method, and then set in a predetermined position corresponding to the reinforced part of the mold to form a molten metal of Al-based poetry metal of the same or different type as the matrix metal. inject.

Regarding the conditions of the haiku, normal connective tissue can be obtained not only by haiku coagulation under high and low pressure as in the first method, but also by haiku coagulation using only gravity in a non-pressurized state.

Through the above steps, an Al metal-based partially reinforced FRM material having short fiber reinforcement portions at specified locations is manufactured.

[For production]

According to the first method of the present invention, the short fibrous reinforcing material is
In the process of simple mechanical polishing on the bonding surface of the composite base material dispersed and strengthened in the l-based matrix metal structure, the oxide components generated and adhered are completely removed, and at the same time, the polished exposed surface is appropriately roughened. Ru. In this state, immediately use AI with the same or different composition as the matrix metal! Since the process moves to the stage where the molten metal is injected, the molten metal injected always comes into contact with the bonded surface of the composite base material, which has good wettability, and is strongly interlocked by the uneven interface of the rough surface.

In the case of the second method, a thin layer of the matrix metal alone formed on the bonding surface of the composite base material comes into contact with the molten haiku metal injected in the haiku stage, and mutually melts at the interface. Therefore, the contact interface during solidification transforms into a continuous, integrated structure.

Due to this action, the composite base material and the poem metal are reliably bonded, and a partially reinforced FRM form with a monolithic structure is always formed.

〔Example] Examples of the present invention will be described below in comparison with comparative examples.

Example 1 A preform was formed by pressure filtration of dispersion water in which SiC whiskers having an average diameter of 0.5 μm and an average length of 20 μm were uniformly dispersed. The preform was set in a mold, and molten Al1 alloy (AC8A) was poured into it using a plunger at 1000 kg/am! The Vf of SiC whiskers is 1B% and the thickness is 20%.
A disk-shaped composite base material with a diameter of 80 mm and a diameter of 80 mm was prepared.

The obtained composite base material was cut into two semicircular parts from the center.
The cut surface was shot blasted for 10 seconds using carporundum powder with a particle size of 80 mesh, and the surface was mechanically polished.

The composite base material that was mechanically polished was
90 molecules were heated to a temperature of °C and immediately set in a mold with a diameter of 80 + Il + a heated to 300 °C.

Next, A1, which was melted at a temperature of 800 degrees Celsius, was used as poetry metal.
Pour the molten metal of alloy (AC8A) into the mold and make 90Okg/
Pressure casting was performed while applying a pressure of 1.5 cm.

The obtained partially reinforced FRM material has a shape in which the semicircular Affi alloy is joined through the mechanically polished surface of the composite base material, and the joining interface is continuous as shown in the enlarged micrograph in Figure 1. It exhibited a layered structure.

A specimen was cut out from the obtained partially reinforced FRM material in the direction perpendicular to the joint surface, and the tensile strength after T6 treatment was measured, showing a high value of 341 g/m+n, and the fracture point was the poem A2 alloy part. Ta.

Comparative Example 1 The same composite base material as in Example 1 was used, and after preheating to 350°C in Ar gas without shot blasting, a molten metal of A1 alloy was pressure cast under the same conditions as in Example. As shown in the enlarged micrograph of FIG. 2, the bonded interface of the obtained partially reinforced FRM material exhibited a clear graded layer, which was clearly different from the structure of the example.

The tensile strength (T
After 6 treatments), it was measured to be 5 kg/ml! This was a low value. In addition, in this case, the rupture occurs at the joint surface,
A golden yellow area where the A2 alloy was oxidized was observed at the fracture interface.

Example 2 A composite base material produced under the same conditions as Example 1 was cut into two semicircular parts from the center, and the particle size was 30 mm for the cut surface.
Shot blasting was performed for 10 seconds using mesh carporundum powder, and the surface was mechanically polished.

The composite base material after polishing was subjected to AI under the same solidification conditions as in Example 1, except that the pressing force was set at 10 kg/cm.
! , pressure casting of molten alloy (AC8A) was performed.

The tensile strength of the obtained partially reinforced FRM material was measured using the same method as in Example 1 (after Ta treatment).3
0 kg/cwb", and the material structure was also good.

Moreover, the fracture during the tensile test occurred on the poetry Aβ alloy side.

Example 3 Composite matrix matrix metal A2 alloy (
Partially reinforced F
RM material was manufactured. The tensile strength (after T6 treatment) of the obtained material was measured by the same method as in Example 1.3
5 kg/mm2, and it was confirmed that the bonding strength was high.

Comparative Example 2 Partially reinforced FRM manufactured using the same composite base material as in Example 3 and under the same conditions without shot blasting.
With this material, a break occurred at the joint interface during test piece processing, making it impossible to measure the strength.

Example 4 Al 20 with an average diameter of 3.2 μm and an average length of 50 μm
3. A suspension in which short fibers are uniformly dispersed is filtered under pressure, and Vf
A 16% preform was created. This preform was placed in a mold, and the molten metal (80
1000 kg with a plunger after injecting 0°C)
/cm" pressure casting, Vf15%, thickness 2
A disc-shaped composite base material with a diameter of 0 mm and a diameter of 80 mm was produced.

The obtained composite base material was subjected to shot blasting under the same conditions as in Example 1, heated in air for 60 molecules at a temperature of 200°C, and then immediately set in a mold with a diameter of 80 mm heated to 300°C. .

Next, a poem metal made by melting A2 alloy (AC8A) at 800'C was poured into the mold, and pressure casting was carried out at a pressure of 900 kg/cm2.

The partially reinforced FRM material manufactured in this way is Example 1
It had an excellent bonding structure similar to that of the FRM material, and its tensile strength was 33 kg/mm2. Also, rupture is verse A
This occurred on the l-alloy side.

Example 5 A preform formed by pressure-filtering and drying water with a homogeneous dispersion of StC whiskers having an average diameter of 0.5 μm and an average length of 20 μm was set in a mold, and molten A1 alloy (AC8A) was poured as a matrix metal. 10 by plunger
Pressure casting was performed by applying a pressure of 0.00 kg/cm2. In this way, a thin layer (approximately 1 mm thick) of matrix A1 alloy alone was formed on the top surface, Vf18%, diameter 30 mm.
A cylindrical composite base material having a length of 50 mm was prepared.

The composite base material in step 1 was set in a mold with an inner diameter of 50 mm heated to 200°C without preheating, and heated to 800°C as a poetry metal.
Melting AI! The alloy (AC8A) was injected and solidified without applying pressure.

The structure of the obtained partially reinforced FRM material was extremely homogeneous, and the joints could not be distinguished. A specimen was cut out from the material so that the joint part was in the center, and the tensile strength after T6 treatment was measured. It showed an excellent value of 35 kg/cm2, and the fracture point was 0 on the side of the single thin Al layer in the composite base material. .5
It was at mm.

Example 6 Composite matrix matrix metal Al (AC
A partially reinforced FRM material was manufactured under the same conditions as in Example 5, except that a 6061 series A1 alloy different from that in Example 8A) was used.

When the tensile strength of this material was measured in the same manner as in Example 5, it was found to be 37 kg/cm2, and the fracture point was 1 mm from the side of the single thin layer of Al in the composite base material.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to form a joint with a strong integral structure between the composite base material and the haiku metal.

Furthermore, it is possible to manufacture partial composite members with a strong homogeneous structure through pre-processing such as easy-to-operate mechanical polishing or simple process changes during the production of composite base materials. It is extremely useful for forming localized short fibrous reinforcing structures in areas subject to severe thermal shock, friction, etc.

[Brief explanation of drawings]

Figure 1 is a micrograph (100x magnification) showing the metal structure at the joint interface of the partially reinforced FRM material according to Example 1, and Figure 2 shows the metal structure at the joint interface of the partially reinforced FRM material according to Comparative Example 1. This is a micrograph (100x magnification). Applicant Tokai Carbon Co., Ltd. Agent Patent Attorney Masaya Takahata

Claims (2)

[Claims] 1. In the process of injecting and solidifying molten Al-based casting metal after setting a composite base material in which short fiber reinforcement is dispersed in an Al-based matrix metal into a mold, the bonding surfaces of the composite base material are preliminarily exposed to oxidizing components. The removed and exposed surface is mechanically polished to a roughened state, and the composite base material after the polishing process is set in a predetermined place in the mold, and molten Al-based casting metal of the same or different type as the matrix metal is injected. Partially reinforced FRM characterized by solidifying the cast iron under pressure.
Method of manufacturing wood. 2. In the process of injecting and solidifying molten Al-based casting metal after setting a composite base material in which short fiber reinforcing material is dispersed in an Al-based matrix metal in a mold, the bonding surface of the composite base material is A thin layer of the matrix metal alone is formed, the composite base material with the thin layer formed is set in a predetermined place in the mold, and a molten Al-based casting metal of the same or different type as the matrix metal is injected, and then pressurized. Or partially strengthened F characterized by solidifying in the casting without pressure.
Method for manufacturing RM material.