JPH03234355A - Production of fiber reinforced composite member - Google Patents

Abstract

PURPOSE:To obtain the fiber reinforced composite member having the volumetric fraction uniform over the entire part by uniformly impregnating a molten metal into a fiber molding and generating uniform collapses therein. CONSTITUTION:A porous layer 6 which has the permeability of the molten metal and varies the impregnation resistance to the molten metal from the fiber molding 3 in formed in the end face 5, at the molten metal impregnating side of the molding 3 at the time of producing the fiber reinforced composite part by installing the fiber molding 3 in a metallic mold and impregnating the molten metal into the fiber molding 3. The molten metal is uniformly impregnated into the fiber molding 3 and the uniform collapses are generated in the initial period of the impregnation stage of the molten metal, by which the fiber reinforced composite member having the high volumetric fraction of the reinforcing fibers and the volumetric fraction approximately uniform over the entire part is obtd.

Description

Detailed Description of the Invention A0 Object of the Invention (1) Industrial Application Field The present invention relates to a method for manufacturing a fiber-reinforced composite member, in particular, a method for manufacturing a fiber-reinforced composite member, in which a fiber molded body is placed in a mold, and then a molten metal is added to the fiber molded body. The present invention relates to an improvement in a method of manufacturing a fiber reinforced composite member by impregnating the same.

(2) Conventional technology Conventionally, this type of manufacturing method has adopted a molten metal forging technology in which molten metal is pressurized by a pressure punch and impregnated into a fiber molded body (for example, see Japanese Patent Publication No. 55-42906).
.

(3) Problems to be Solved by the Invention However, in the above-mentioned conventional method, due to variations in the impregnation resistance of the fiber molded body to the molten metal, there is a problem in the early stage of the molten metal impregnation process (for example, the stroke of the pressure punch is 10 to 20+ ms). Since the impregnation of the molten metal into the fiber Ii molded body becomes non-uniform (when the fiber Ii is in between), the fiber molded product collapses unevenly, and as a result, the volume fraction Vf of the reinforcing fibers in the composite member partially changes. It is difficult to obtain a high-quality composite member due to differences in the quality of fibers or cracks in the fiber molded product.
There are problems like this.

In view of the above, the present invention provides the above-mentioned manufacturing method, which makes it possible to uniformly impregnate the fiber molded body with the molten metal and generate uniform collapse in the early stage of the molten metal impregnation process, thereby obtaining a high-quality composite member. The purpose is to provide.

B0 Structure of the Invention (1) Means for Solving the Problems The present invention provides the steps for manufacturing a fiber-reinforced composite member by installing a fiber molded body in a mold, and then impregnating the fiber molded body with molten metal. A porous layer having molten metal permeability and having a different impregnation resistance to the molten metal than that of the fibrous molded body is formed on the end face of the molten metal impregnation side of the fibrous molded body, and the fibrous molded body is formed at an early stage of the molten metal impregnation process. It is characterized by uniformly impregnating the molten metal and causing uniform collapse.

(2) Effect When the above method is adopted, at the beginning of the molten metal impregnation process,
The porous layer increases the impregnation resistance of the fiber molded body to the molten metal, and the pressure of the molten metal acts on the porous layer approximately evenly.

As a result, uniform collapse occurs in the fiber molded body, and as a result, the impregnation resistance of the fiber molded body to the molten metal is made uniform throughout the fiber molded body, so that the molten metal is uniformly impregnated into the fiber molded body. .

During this impregnation, the volume fraction Vf of the reinforcing fibers in the fiber molded body increases due to the collapse, so the impregnation resistance increases, but the molten metal is subjected to a rectifying effect when flowing through the porous layer, and Since the force of the flow can be moderated, the fiber molded article can be impregnated smoothly.

In this way, it is possible to obtain a composite member in which the volume fraction Vf of the reinforcing fibers is high and the volume fraction Vf is substantially square throughout.

(3) Example Figure 1 shows a connecting rod material 1 for an internal combustion engine as a fiber-reinforced composite member manufactured by applying a molten metal forging method. Ibe 2
．． and a second structural part 2 □ connected thereto and corresponding to the ring part and the small end part, and comprising a fiber molded body made of reinforcing fibers and a light alloy matrix such as an aluminum alloy impregnated therein. configured.

Second. As shown in FIG. 3, the fiber molded body 3 has a shape between the connecting rod material 1 and the first reinforcing portion 4 corresponding to the first structural portion 2I. And, attached to it, the second structure section 2□
and a second reinforcing section 48 corresponding to the second reinforcing section 48.

The reinforcing fibers constituting the fiber molded body 3 include SiC whiskers, Altos whiskers, 5izN4 whiskers, K
, 0-nTiox (potassium titanate) whiskers,
Graphite whiskers etc. are used.

In order to lower the impregnation resistance of the fiber molded body 3 to the molten metal and to improve the tensile strength and fatigue strength of the connecting rod material, the diameter d of the ceramic whisker is 0.6μ.
m or more, length i is 40 μm or more, aspect ratio f/d
It is desirable to use one having a value of 40 or more. In this case, the upper limit of the diameter d is determined to be 2 to 3 μm based on the relationship between the impregnation resistance and the pressurization rate of the molten metal.

The fiber molded body 3 is aligned with the crank pin axis Y during molten metal forging.
-It is installed in a mold with one of the end surfaces 5+ and 5g orthogonal to the Y direction, for example, the end surface 5I, facing upward, and therefore, the end surface 5. is the molten metal impregnated side.

End face 5. A porous layer 6 is formed in the porous layer 6.
has molten metal permeability and has a different impregnation resistance to the molten metal than the fiber molded body 3. In this case, the impregnation resistance of the porous layer 6 is set higher or lower than that of the fiber molded body 3.

When such a porous layer 6 is used, the impregnation resistance of the fiber molded body 3 to the molten metal is increased by the porous layer 6 at the initial stage of the molten metal impregnation process, and the porous layer 6 is exposed to the pressure of the molten metal approximately at an angle. acts.

As a result, uniform collapse occurs in the fiber molded body 3, and as a result, the impregnation resistance of the fiber molded body 3 to the molten metal is made uniform throughout the fiber molded body 3, so that the molten metal is uniformly applied to the fiber molded body 3. Impregnate.

During this impregnation, the volume fraction Vf of the reinforcing fibers in the fiber molded body 3 increases due to the collapse, so the impregnation resistance increases, but the molten metal is subjected to a rectifying effect when flowing through the porous layer 6. Moreover, since the force of the flow can be moderated, the fiber molded body 3 can be impregnated smoothly.

In this way, it is possible to obtain a connecting rod material 1 in which the volume fraction Vf of the reinforcing fibers is high and the volume fraction Vf is substantially square throughout.

The constituent material of the porous layer 6 is selected on the condition that it is thermally stable at the melting temperature of the matrix and the preheating temperature of the fiber molded body 3, and does not react with the matrix and the fiber molded body 3. In addition to various serra fruits and ivy, there are BN, mullite, Alz Ox, and S is
Various ceramic fine particles such as Na, SiOx-graphite, and metal fine powder such as MO fine powder are used.

When using Cera Q ivy whiskers, those with a smaller diameter than those forming the bottom of the fiber molded body 3 are used. The reason for this is that, at the same volume fraction Vf, ceramic whiskers with a small diameter have lower molten metal permeability than ceramic whiskers with a larger diameter, and therefore have higher impregnation resistance to the molten metal.

FIG. 4 shows the volume fraction Vf of SiC whiskers in the fiber molded body 3 when using a molten aluminum alloy.
When a SiC whisker with a diameter of 1.1 μm is used, and a wire a with a diameter of 0.4 μm is used.
This applies to the case where μm SiC whiskers are used. In this case, high molten metal permeability means good molten metal permeability.

Here, the molten metal permeability KAL is defined as follows.

Ta! ′, Vf is the volume fraction of SiC whiskers, d is Si
The diameter of each C whisker is shown.

As is clear from the lines a and b in Figure 4 and the above equation, for example, when Vf = 20%, the KAA when using a SiC whisker with a diameter of 1.1 t1 m is 0.48, but when using a SiC whisker with a diameter of 0.4 μm, KAL when using whiskers is 0
．． 06, therefore, the molten metal permeability is lower when SiC whiskers with a diameter of 0.4 μm are used.

From the viewpoint of impregnation resistance, ceramic fine particles having a diameter of 1 to 5 μm are used. In this case, as the amount of ceramic fine particles used increases, the porous layer 60 increases accordingly.
Since the impregnation resistance increases, the fiber molded body 3 is more likely to collapse, and as a result, the volume fraction of reinforcing fibers in the connecting rod material 1 increases.

Therefore, BN is added to the fiber molded body 3 made of SiC whiskers.
When a porous layer 6 made of fine particles was formed and the relationship between the amount of BN fine particles and the average volume fraction Vf of SiC whiskers in the connecting rod material 1 was determined, the results shown in FIG. 5 were obtained. The amount of BN fine particles is determined on the end face 5. of the fiber molded body 3. Since the area A (Fig. 3) of is approximately 72C4, its end face 5.
It is expressed by the weight of the hit.

It can be seen from FIG. 5 that there is a substantially proportional relationship between the amount of BN fine particles and the average volume fraction Vf of SiC whiskers.

To form the porous layer 6, coating methods such as brushing, spraying, dipping, etc. are applied.

FIG. 6 shows a molten metal forging apparatus for manufacturing connecting rod material L. Mold M consists of an upper mold 7, an intermediate mold 8, and a lower mold 9, which define a cavity 10 for the bottom shape of the connecting rod material. will be accomplished. The upper mold 7 is provided with a hot water supply sleeve 12 that opens into the first structure region 11 of the cavity 10, and a hot water supply hopper 13 is attached to the upper peripheral wall of the sleeve 12.

A pressurizing punch 14 can slide on the hot water supply sleeve 12. Further, a knockout pin 15 is provided on the lower die 9 so as to face the pressure punch 14.

Next, an example of manufacturing the connecting rod material 1 will be described.

Second. In FIG. 3, the fiber molded body 3 has a length L of 170 mm.
The thickness T is 30 cm, and the area A of the end face 51 is approximately 72 cm.
The bottom shape is formed by SiC whiskers with a diameter of 1.1 μm and an average length of 50 μm, and the volume fraction of the SiC whiskers is V
f was set at approximately 15%.

A porous layer 6 made of BN fine particles with a diameter of 1 to 5 μm is coated on the end face 51, and the coating amount is 2.8 g/7.
2cj, and the thickness was set to 1 m or less.

As shown in FIG. 6, the fiber molded body 3 that has been preheated at 700°C for 1 hour is placed in the cavity lO of the mold M that has been preheated to 300°C with its porous layer 6 facing upward. did. In this case, a space S for filling the molten metal is formed between the porous layer 6 and the ceiling surface 16 of the cavity 10.

Prepare an aluminum alloy as a matrix having the composition shown in the table below, and use that alloy to heat the aluminum alloy to 760°C.
A molten metal was prepared.

The molten metal is supplied to the cavity 10 and the hot water cylinder 12 via the hot water hopper 13, and then the pressing bunch 14 is slid onto the hot water sleeve 12 at a pressurizing speed of 20 m/s.
The molten metal was pressurized under EC conditions.

Final pressurization force is 700 kg/ell, pressurization holding time is 1
It was set to 00 seconds.

FIG. 7 shows the relationship between the stroke of the pressurizing bunch 14 and the pressure of the molten metal at a pressurizing speed of 20 km/sec, and #IA
In the case of the present invention in which C is the porous layer 6, also the line f
is the SiC whisker (diameter 1.1 μm, average length 50
This applies to the case of a comparative example using a fiber 111-shaped body having a volume fraction of about 15% consisting only of micrometers.

At this N, the initial stage of the molten metal impregnation process, therefore, the pressurized bunch 1
4, the pressure increase when the stroke is between 10 and 20 cm is ΔP, and the stroke is ΔS, and the impregnation resistance value is 1. When defined as IR=ΔP/ΔS, it can be seen that the impregnation resistance value is higher in the case of the present invention shown by line C than in the case of the comparative example shown by line f.

FIG. 8 shows the distribution of the volume fraction Vf of SiC whiskers in the connecting rod materials 1 manufactured according to the present invention and the comparative example. Each test piece t used for this distribution measurement is shown in FIGS. ) was cut out from the position shown. That is, the upper end surface t of the connecting rod material 1 at the end of molten metal forging.
7. Above, 6.26 in the longitudinal direction from the end of the first structure section 2I,
56, 86, 116.146 The left and right positions of six places are determined, and at each left and right position, the top of two places that are 3.5, 20.5 ws away from the lower end surface 17z of the connecting rod material 1. , the lower position was determined, and a test piece was cut out from the same position I above and below.

In FIG. 8, 1IAh1. ht indicates the case of the present invention, where the line h1 corresponds to the upper side (separated by 20,51 points) and the line ht corresponds to the lower side (separated by 3,5 points), respectively. The case of a comparative example is shown, and line 2 corresponds to the upper side, and line 2 corresponds to the lower side.

Comparing the lines h+, ho and the lines kt, kg, in the case of the present invention, the variation in volume fraction Vf between the upper side and the lower side is smaller than in the comparative example, and moreover, the volume fraction Vf is higher. I know that there is.

FIG. 10 shows the relationship between the volume fraction Vf of SiC whiskers and the tensile strength σ in the connecting rod material 1 which has been subjected to T6 treatment as heat treatment after molten metal forging, and Dl is the volume fraction Vf in the present invention. D8 shows the variation (circles) in the volume fraction Vf in the comparative example.

As is clear from FIG. 10, according to the present invention, the variation DI in the volume fraction Vf can be made equal to or less than A of D2 in the case of the comparative example, and the strength can also be improved.

The line m in FIG. 7 indicates the porous layer 6 with a diameter of 0.4 μm and an average length of 30 μm, using the same fiber molded body as above.
The impregnating resistance value I in this case, which shows the case where the SiC whiskers are formed to a thickness of 5 to 6 m, is lower than that when BN fine particles are used.

The glue in Figure 10 indicates the SiC whisker (diameter 0°4 μm).
, the variation in volume fraction Vf (triangle mark) when using a porous layer 6 with an average length of 30 μm>, and the variation D3 is larger than when using BN fine particles, but the variation in the comparative example is .

It can be seen that it is significantly smaller than the

Note that the composite part whose bottom shape is formed by the porous layer 6 is removed by machining, but since this composite part functions as a separation part between the product part and the matrix single part of the 12 examples of hot water supply sleeves, Single matrix parts can be easily separated.

FIG. 11 shows a modification of the porous layer 6. This porous layer 6
is the first reinforcing portion 4 of the fiber molded body 3. The first area corresponding to 6. and a second reinforcing portion 4. connected to the first region 6I. and a 28th area 6□ corresponding to the area 6□.

The first region g is formed with a high density and therefore has a high impregnation resistance, while the second region 6t is formed with a lower density than the first region g and therefore has a low impregnation resistance.

The pressure punch 14 in the mold M for molten metal forging has a first reinforced portion 4. , and the cross-sectional area of the pressure punch 14 is the first
Strengthening section 4. approximately equal to the surface area of

Therefore, when the molten metal is pressurized by the pressure punch 14, the first
Strengthening section 4. The second reinforcement part 4. The molten metal is more easily impregnated.

Therefore, by placing the porous layer 6 at the bottom of the tank from the first and twenty-eighth regions 6+ and 6g as described above, it is possible to uniformly impregnate the fiber molded body 3 with the molten metal and to cause uniform collapse.

FIG. 12 shows a molten metal forging device for a piston material for an internal combustion engine as a fiber-reinforced composite member.

A core 19 is placed in a cavity 18 of a mold M, and a cylindrical fiber molded body 20 made of SiC whiskers or the like is adhered to the core 19. Above the upper end surface 21 of the fiber molded body 20, a pressure punch 22 is slidably provided in the mold M. In this case, the molten metal is impregnated into the molded rod 20 mainly from the upper end surface 21 side of the fiber molded body 20. The upper end surface 21 and the outer circumferential surface 23 of the fiber molded body 20 are provided with B as described above.
A porous layer 24 made of N fine particles etc. is formed,
In this case, the porous layer 24 on the outer circumferential surface 23 side is provided mainly for the purpose of separation from the single matrix portion.

The core 19 is made of a porous body that is permeable to molten metal and is formed using coated sand made of mullite and resin. A release layer 25 having molten metal permeability is formed on the surface of the core 19 facing the fiber molded body 20. The release layer 25 has the same composition as the porous layer 24, but its material is preferably ceramic fine particles or metal fine powder.

When the porous layer 24 is formed in the fibrous molded body 20 as described above, the fibrous molded body 20 can be uniformly impregnated with the molten metal and can be collapsed uniformly in the same manner as described above.

Furthermore, when the molten metal impregnates the fiber molded body 20, the fiber molded body 20 is impregnated with the molten metal.
Gas such as air existing in the core 1 passes through the mold release layer 25.
Since the molten metal also flows into the pores of the core 19, the impregnating resistance of the fibrous molded body 20 to the molten metal is alleviated, thereby avoiding unnecessary crushing of the fibrous molded body 20. Then, the volume fraction Vf of S'iC whiskers, etc.
The fiber molded body 20 can be made substantially square throughout, and the fiber molded body 20 can be prevented from cracking. Moreover, it is possible to avoid gas remaining in the fiber molded body 20 and obtain a sound piston material free of pores.

Further, the piston material and the matrix alone can be easily separated by the porous layer 24, and the piston material and the core 19 can be easily separated by the mold release layer 25.

Effects of the C0 Invention According to the present invention, by forming the above-mentioned porous layer in the fiber molded body, the volume fraction of reinforcing fibers is high,
Furthermore, it is possible to obtain a fiber-reinforced composite member whose volume fraction is substantially square throughout.

[Brief explanation of drawings]

Figure 1 is a perspective view of the connecting rod material, Figure 2 is a perspective view of a fiber molded body having a porous layer, and Figure 3 is Figure 2.1-111.
Figure 4 is a graph showing the relationship between the volume fraction of SiC whiskers and molten metal permeability, and Figure 5 is a graph showing the relationship between the volume fraction of SiC whiskers and the melt permeability.
A graph showing the relationship between the average volume fraction of iC whiskers, FIG. 6 is a cross-sectional view showing an example of a molten metal forging device, FIG. 7 is a graph showing the relationship between the stroke of the pressure punch and the pressure of the molten metal, and FIG. The figures are graphs showing the relationship between the distance from the first component and the volume fraction of SiC whiskers, Figures 9(a) and (b)
shows how to cut out the test piece.
Figure 10 is a graph showing the relationship between the volume fraction of SiC whiskers and the tensile strength of the connecting rod material, Figure 11 is a plan view showing a modification of the porous layer, and Figure 12 is a side view. FIG. 2 is a sectional view showing another example of the molten metal forging device.

Claims (8)

[Claims] (1) When manufacturing a fiber-reinforced composite member by installing a fiber molded body in a mold and then impregnating the fiber molded body with molten metal, the end face of the fiber molded body on the molten metal impregnated side has a molten metal permeability. and forms a porous layer having a different impregnation resistance to the molten metal from that of the fibrous molded body, so that the molten metal is uniformly impregnated into the fibrous molded body at the early stage of the molten metal impregnation process, and uniform collapse occurs. A method for producing a fiber-reinforced composite member, the method comprising: (2) The method for manufacturing a fiber-reinforced composite member according to item (1), wherein the porous layer is composed of reinforcing fibers. (3) The method for manufacturing a fiber-reinforced composite member according to item (1), wherein the porous layer is composed of at least one of ceramic fine particles and metal fine powder. (4) the porous layer has a first region having high impregnation resistance;
a second region with low impregnation resistance connected to the first region, the first region with high impregnation resistance is disposed in a portion of the fiber molded article that is easily impregnated with molten metal, and the low impregnation resistance The method for producing a fiber-reinforced composite member according to item (1), item (2), or item (3), wherein the second g region having resistance is disposed in a portion of the fiber molded body that is difficult to be impregnated with molten metal. (5) When manufacturing a fiber-reinforced composite member by installing a core and a fiber molded body adhered to the core in a mold and then impregnating the fiber molded body with molten metal, The core is made of a porous body that is permeable to the molten metal, and a release layer that is permeable to the molten metal is formed on the surface of the core opposite to the fibrous molded body, and the fibrous molded body is formed in the early stage of the molten metal impregnation process. In order to uniformly impregnate the fiber molded body with the molten metal and cause uniform collapse, the fiber molded body has molten metal permeability on the end face on the molten metal impregnated side, and has a different impregnation resistance to the molten metal from that of the fiber molded body. A method for producing a fiber-reinforced composite member, comprising forming a porous layer. (6) The method for manufacturing a fiber-reinforced composite member according to item (5), wherein the porous layer is composed of reinforcing fibers. (7) The method for manufacturing a fiber-reinforced composite member according to item (5), wherein the porous layer is composed of at least one of ceramic fine particles and metal fine powder. (8) The method for manufacturing a fiber-reinforced composite member according to item (5), item (6), or item (7), wherein the release layer is composed of at least one of ceramic fine particles and metal fine powder.