JP3266792B2 - Lightweight Al-based composite member with wear resistance, heat resistance and corrosion resistance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lightweight Al-based composite member having wear resistance, heat resistance and corrosion resistance, and more particularly to an Al-based composite member in which at least a part of the member is composed of a composite portion.

[0002] Such members include, for example, a composite brake disc composed entirely of a composite part, a composite cylinder block composed of a composite part around a cylinder bore, and the like in an automobile part.

[0003]

2. Description of the Related Art For example, brake disks for automobiles are required to have a stable friction coefficient, abrasion resistance, high thermal conductivity and heat resistance. In this case, the heat resistance includes high-temperature strength, heat deformation resistance, and the like.

[0004] In order to satisfy the required characteristics, the conventional brake disc is entirely made of cast iron.

[0005]

However, cast iron has a high specific gravity. Therefore, there is a problem that the conventional cast iron brake disc does not meet the current demand for reducing the weight of vehicles, and is susceptible to rust and has low corrosion resistance.

[0006]

SUMMARY OF THE INVENTION The present invention uses a porous alumina preform as a reinforcing material in a composite part, and uses an Al-based matrix as a matrix to achieve a reduction in weight and an improvement in corrosion resistance and to achieve the same. An object of the present invention is to provide an Al-based composite member in which an increase in production cost due to the use of a porous alumina preform is suppressed and other characteristics are equal to or higher than those of a cast iron member.

[0007] To achieve the above object, according to the present invention,
At least a part of the member is composed of a composite part composed of a porous alumina preform and an Al-based matrix impregnated in the porous alumina preform, and has an average particle diameter d as a raw material powder of the porous alumina preform.
_The present invention provides an Al-based composite member using a mixed powder of calcined alumina powder having a particle diameter of 20 μm ≦ d ₁ ≦ 200 μm and pulverized alumina powder having an average particle diameter d ₂ of 0.5 μm ≦ d ₂ ≦ 10 μm.

[0008] The calcined alumina powder is obtained from aluminum hydroxide by the Bayer method and has not been subjected to pulverization, and is an aggregate of alumina single crystals of 10 µm or less.

Therefore, the calcined alumina powder is
Inexpensive compared to crushed alumina powder obtained by crushing
However, the average particle diameter d₁Is 20 μm
≦ d ₁Calcined alumina powder because it is as large as ≤200μm
When used alone, the porous aluminum
The volume fraction Vf of the napreform decreases. For example, flat
Uniform particle size d₁Is d₁= Using 20μm calcined alumina powder
The volume fraction Vf of the porous alumina preform is
Vf ≒ 32% and average particle diameter d₁Is d₁= 200 μm
When calcined alumina powder is used, the porous alumina
The volume fraction Vf of the foam is Vf ≒ 25%.

In the case of a composite brake disk which is an example of an Al-based composite member, for example, a composite brake disk which is composed entirely of a composite portion and has a homogeneous porous alumina preform, the sliding characteristics of the composite disk portion, etc. Considering that the porous alumina preform has about 60%
Is required.

Therefore, the calcined alumina powder has an average particle diameter d.
₂ is used in combination with pulverized alumina powder of 0.5 μm ≦ d ₂ ≦ 10 μm, whereby, in the porous alumina preform, the voids between the particles of the calcined alumina powder are filled with the particles of the pulverized alumina powder, It is possible to increase the volume fraction Vf of the porous alumina preform.

In this case, the amount of the inexpensive calcined alumina powder in the mixed powder can be increased to 50% by weight or more, so that the production cost of the Al-based composite member due to the use of the porous alumina preform is increased. It is possible to suppress.

The Al-based composite member is lighter in weight than a cast iron member and an Al-based member partly made of cast iron, and has a higher wear resistance than the cast iron member and the cast iron-made member of the Al-based member. It has stability of resistance, corrosion resistance, thermal conductivity and coefficient of friction. In addition, in terms of heat resistance and machinability, the Al-based composite member is equivalent to a cast iron member and a cast iron component.

However, when the average particle diameters d ₁ and d _{2 of} the calcined alumina powder and the pulverized alumina powder are out of the above ranges, respectively, the volume fraction of the porous alumina preform Vf
Adjustment becomes difficult.

According to the present invention, in order to achieve the above object, at least a part of the member is made of a porous alumina preform and an A impregnated with the porous alumina preform.
The composite part has a sliding area in a part thereof, and the porous alumina preform includes a first reinforcing part for reinforcing the sliding area, A first reinforcement part and an integral second reinforcement part,
As the raw material powder of the first reinforcing portion, the average particle size d ₁ is 20
A mixed powder of calcined alumina powder having a particle diameter of μm ≦ d ₁ ≦ 200 μm and ground alumina powder having an average particle diameter d ₂ of 0.5 μm ≦ d ₂ ≦ 10 μm is used. There is provided an Al-based composite member using calcined alumina powder in which d ₁ is 20 μm ≦ d ₁ ≦ 200 μm.

Since both powders are used in combination in the first reinforcing portion for reinforcing the sliding region, the volume fraction Vf of the first reinforcing portion is increased to provide the sliding region with abrasion resistance and friction coefficient. Stability can be provided.

Further, since only the inexpensive calcined alumina powder is used for the second reinforcing portion which is the main component of the porous alumina preform, the production cost of the porous alumina preform can be reduced as compared with the above case. It is possible.

Further, the Al-based composite member is lightweight as described above, and has excellent corrosion resistance and thermal conductivity.

Although the volume fraction Vf of the second reinforced portion is lower than that of the first reinforced portion, since sufficient strength can be obtained by compounding with the Al-based matrix, there is no practical problem.

The reasons for limiting the average particle diameters d ₁ and d ₂ of the calcined alumina powder and the pulverized alumina powder are the same as described above.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION

[Embodiment 1] FIGS. 1 and 2 show an example of an automobile composite brake disc 1 as an Al-based composite member entirely composed of a composite portion. The complex brake disc 1, the porous alumina preform 5 ₁ having a flange-shaped disk portion 4 which is provided continuously to the opening outer circumferential edge of the cylindrical portion 3 and the cylindrical portion 3 having an end plate 2, the porous alumina more composed and Al matrix 6 impregnated in the preform 5 _1.

In the composite brake disc 1, the composite end plate 1a has a plurality of bolt insertion holes 1b formed therein.
And a wheel rim via a bolt and a nut, and the composite disc portion 1c is disposed between a pair of friction pads.

[0023] As the raw material powder of the porous alumina preform 5 _1, the average particle diameter d ₁ is 20 [mu] m ≦ d ₁ ≦ 200 [mu]
m calcined alumina powder 7 and average particle size d ₂ is 0.5 μm ≦
A mixed powder with pulverized alumina powder 8 having d ₂ ≦ 10 μm is used. Al-based matrix is Al or Al
Made of alloy.

When both powders 7 and 8 are used together as described above,
In the porous alumina preform 5 _1, the voids between the particles each other coarse calcined alumina powder 7 filled with particles of pulverized alumina powder 8, can enhance the porous alumina preform 5 ₁ volume fraction Vf Becomes

[0025] In this case, in the mixed powder, because the amount of expensive calcined alumina powder 7 can be increased to more than 50 wt%, the production cost of the composite brake disk 1 by using a porous alumina preform 5 ₁ Can be suppressed.

The composite brake disc 1 is much lighter than a cast iron brake disc, and has more excellent wear resistance, corrosion resistance, heat conductivity and friction coefficient stability than a cast iron brake disc. . In addition, with regard to heat resistance and machinability, the composite brake disc 1 is equivalent to a cast iron brake disc.

[0027] The hitting the production of a composite brake disc 1, the molding of the porous alumina preform 5 _1, impregnation and predetermined machining molten Al or Al alloy melt to the porous alumina preform 5 _1, such operations Are sequentially performed.

The molding of the porous alumina preform 5 ₁ is performed in the following procedure.

(1) The average particle diameter d ₁ is 20 μm ≦ d ₁ ≦
A calcined alumina powder 7 of 200 μm and an average particle diameter d ₂ of 0.
A mixed powder is prepared by mixing with 5 μm ≦ d ₂ ≦ 10 μm pulverized alumina powder 8.

[0030] In the mixed powder, the amount A ₁ of calcined alumina powder 7 to 50% by weight ≦ A ₁ ≦ 80% by weight, also the amount A ₂ is 20% by weight ≦ A ₂ of pulverized alumina powder 8
≦ 50% by weight. In this case, if the blending amount A ₁ of the calcined alumina powder 7 is A ₁ <50% by weight, the economic efficiency of the composite brake disc 1 is impaired, while A ₁ > 8.
At 0% by weight, the amount of the pulverized alumina powder 8 is too small, so that the particles of the pulverized alumina powder 8 cannot sufficiently fill the gaps between the particles of the calcined alumina powder 7, and as a result it is impossible to increase the volume fraction Vf of quality alumina preform 5 ₁ to the target street.

[0031] The mixed powder, the binder is mixed aiming improving the strength of the porous alumina preform 5 _1.
As this kind of binder, an organic binder is mainly used, and the organic binder corresponds to a polymer binder or the like.

The blending amount B of the binder is set to 1% by weight ≦ B ≦ 2% by weight in the raw material composed of the mixed powder and the binder. Setting this case, the amount B is B binder <The 1 wt%, it is impossible to improve the strength of the porous alumina preform 5 ₁ for the amount thereof is too small, whereas, B> to 2 wt% also, the strength of the porous alumina preform 5 ₁ hardly changes. Therefore, only it leads to the production cost increase of the porous alumina preform 5 ₁ by using the excessive binder.

(2) As shown in FIG.
The raw material 12 is charged into the porous alumina preform molding cavity 11 of the lower mold 10 in
Is heated to 100 to 200 ° C. to melt the organic binder,
Thereafter, as shown in FIG. 4, the upper mold 13 is lowered, and the molding pressure P is set to 3 kgf / cm ² ≦ P ≦ 10 kgf / cm ² to perform compression molding, thereby forming the porous alumina preform 5.
_{Get one} . In this case, if the molding pressure P is P <3 kgf / cm ² , sufficient molding cannot be performed, while P> 10 kgf / cm ²
It is not necessary to set it to cm ² , it only causes a rise in the pressure equipment.

[0034] Al into the porous alumina preform 5 ₁
The impregnation of the molten metal or the molten Al alloy is performed in the following procedure.

As shown in FIG. 5, a porous alumina preform 5 ₁ was placed in the recess 15 of the mold 14, and then the porous alumina preform 5 ₁ 300 to 500 ° C. (organic binder does not ceramization temperature ) the preheated, then placing the porous alumina preform 5 ₁ into a furnace held in a nitrogen gas atmosphere with the mold 14. And
A molten aluminum or molten aluminum alloy 16 at 700 to 900 ° C. is poured into the recess 15, and the porous alumina preform 51 is buried in the molten metal 16, and this state is maintained for ₁ to 60 minutes. During this time, molten Al or the like 16 is a composite brake disk material is impregnated by capillary action is obtained porous alumina preform 5 ₁ hole portion, then molten Al or the like 16 solidifies.

The mold 14 is taken out of the furnace together with the composite brake disc material, air-cooled, and then the composite brake disc material is released.

As the Al alloy, for example, JIS AC
7A or the like is used.

The machining of the composite brake disc material includes cutting for removing excess Al or Al alloy, drilling for forming the bolt insertion hole 1b, and the like.

Hereinafter, the production of the composite brake disc 1 will be specifically described.

(1) A mixed powder was prepared by mixing 70% by weight of calcined alumina powder having an average particle diameter d ₁ = 55 μm and 30% by weight of ground alumina powder having an average particle diameter d ₂ = 2.5 μm. Next, a raw material was prepared by mixing a polymer binder having a compounding amount B of 1.5% by weight into the mixed powder.

(2) As shown in FIG.
2 kg of the raw material 12 is charged into the lower mold cavity 11, and then the raw material 12 is heated to 150 ° C. to melt the polymer binder, and then the upper die 13 is lowered as shown in FIG. = performs compression molded at 7 kgf / cm ^2, which gave a porous alumina preform 5 ₁ volume fraction Vf = 60%.

[0042] (3) As shown in FIG. 5, a porous alumina preform 5 ₁ was placed in the recess 15 of the mold 14, and then the porous alumina preform 5 ₁ 400 ° C.
Preheated to, after which the porous alumina preform 5 ₁ was placed in a furnace which is held in a nitrogen gas atmosphere with the mold 14. Then, a 800 ° C. of molten Al 16 is injected into the recess 15, the in molten Al 16 to obscure the porous alumina preform 5 _1, to obtain a composite brake disc material by holding the state for 30 minutes.

The mold 14 was taken out of the furnace together with the composite brake disk material, air-cooled, and then the composite brake disk material was released.

(4) The composite brake disc material was machined to obtain the composite brake disc 1 shown in FIGS.

Next, regarding the composite brake disc 1 and the brake disc made of cast iron (JIS FC250),
Comparing those characteristics, the following results were obtained.

(1) Lightweight The specific gravity s of the composite brake disc 1 was s = 3, while the specific gravity s of the cast iron brake disc was s = 7. From this, it was found that the weight of the composite brake disc 1 was about one half of the weight of the cast iron brake disc.

(2) Abrasion resistance and squeal The composite brake disc 1 and the cast iron brake disc were each incorporated into a disc brake device of an automobile.
In this case, as the two friction pads, those made of graphite, aramid fiber and phenol resin were selected.

Then, after a running distance of 50,000 km, the wear amount of the disc and the pad was measured for the combination example 1 of the composite brake disc 1 and the friction pad and the combination example 2 of the cast iron brake disc and the friction pad. Table 1 shows the measurement results.

[0049]

[Table 1]

As is apparent from Table 1, the wear amount of the composite brake disc 1 and the friction pad in the combination example 1 is one half of the wear amount of the cast iron brake disk and the friction pad in the combination example 2. . Therefore, it has been found that the composite brake disc 1 not only has excellent wear resistance than the cast iron brake disc, but also has the property of suppressing the wear of the friction pad which is the mating member.

When the squeal at the time of braking was examined, the squeal was at a level of no concern in the case of the composite brake disc 1, but at a level of concern in the case of the cast iron brake disc. It turned out that the disc 1 has a brake noise suppressing effect.

(3) Corrosion Resistance The salt water spray test was performed on the composite brake disc 1 and the cast iron brake disc. This test is based on JIS
The spraying was performed according to Z2371 and the spraying time was set to 1000 hours.

After a visual inspection was conducted after the test, rust was found to be slightly generated on the composite brake disc 1.
Significant red rust was found on the cast iron brake disc.

Further, the weight loss due to corrosion was determined by the composite brake disc 1
Was 1.8 g in the case of, but in the case of a cast iron brake disc, it was 21 g, and the weight loss of corrosion of the composite brake disc 1 was about 1/10 of that of the cast iron brake disc.
Met.

From these facts, it was found that the composite brake disc 1 had better corrosion resistance than the cast iron brake disc.

(4) Stability of friction coefficient μ A disk brake device provided with a composite brake disk 1 and a disk brake device provided with a cast iron brake disk are mounted on a brake dynamo, respectively, for the composite brake disk 1 and the cast iron brake disk. , 50-250 ° C., and a change in friction coefficient μ in a deceleration range of 0.3-1.2 G (G is power acceleration). Table 2 shows the measurement results.

[0057]

[Table 2]

As is clear from Table 2, with respect to the amount of change in the friction coefficient μ in the temperature range, the composite brake disc 1 is about one fifth of the cast iron brake disc, and the friction coefficient in the deceleration range. As for the change in μ, the composite brake disk 1 was about one third of the cast iron brake disk.

From these results, it was found that the composite brake disk 1 has a stable friction coefficient μ as compared with the cast iron brake disk even when the temperature and the deceleration change respectively.

[Embodiment 2] FIG. 6 shows another example of a composite brake disc 1 for an automobile as an Al-based composite member entirely composed of a composite portion. The composite brake disc 1
Is the same manner as in Example 1, the porous alumina preform 5 ₂ having a flange-shaped disk portion 4 which is provided continuously to the opening outer circumferential edge of the cylindrical portion 3 and the cylindrical portion 3 having an end plate 2, the porous more composed and Al matrix 6 impregnated alumina preform 5 _2.

In the composite brake disc 1, the composite end plate 1a has a plurality of bolt insertion holes 1b formed therein.
And a wheel rim via a bolt and a nut, and the composite disc portion 1c is disposed between a pair of friction pads. Therefore, the composite disk unit 1c is partially
In the illustrated example, an annular sliding region R is provided on each of the outer surfaces. In the composite disc portion 1c, an annular portion a excluding both sliding regions R and a composite end plate 1 integrated with the annular portion a.
The composite cylindrical portion 1d provided with a constitutes the main body M of the composite brake disc 1.

[0062] Porous alumina preform 5 ₂ has a pair of annular first reinforcement portion 5a for enhancing both sliding region R, respectively, integral with the first reinforcing portion 5a, and to strengthen the body M And the second reinforcing portion 5b.

The raw material powder of each annular first reinforcing portion 5a has an average particle diameter d ₁ of 20 μm ≦ d ₁ ≦ 2 as in the first embodiment.
A calcined alumina powder 7 of 00 μm and an average particle size d ₂ of 0.5
A mixed powder with a crushed alumina powder 8 having a diameter of μm ≦ d ₂ ≦ 10 μm is used, and the calcined alumina powder 7 having an average particle diameter d ₁ of 20 μm ≦ d ₁ ≦ 200 μm is used as a raw material powder of the second reinforcing portion 5b. Is used. The Al-based matrix is made of Al or an Al alloy as in the first embodiment.

As described above, when both the powders 7 and 8 are used together in each of the annular first reinforcing portions 5a, the voids between the particles of the coarse calcined alumina powder 7 are filled with the particles of the pulverized alumina powder 8, and The volume fraction Vf of the first reinforcing portion 5a can be increased, whereby each of the annular sliding regions R can have the same sliding characteristics as in the first embodiment.

[0065] Since only the porous alumina preform 5 ₂ inexpensive calcined alumina powder 7 in the second reinforcement portion 5b forming a main body is used, than in the case of Example 1 of porous alumina preform 5 ₂ It is possible to reduce production costs.

Further, the composite brake disc 1 is lightweight as in the first embodiment, and has excellent corrosion resistance and heat conductivity.

In the production of the composite brake disc 1, a porous alumina preform 5 ₂
Al of the molding, to the porous alumina preform 5 ₂
Impregnation of molten metal or Al alloy molten metal and prescribed machining,
Are sequentially performed.

[0068] forming a porous alumina preform 5 ₂ is performed in the following procedure.

(1) The average particle diameter d ₁ is 20 μm ≦ d ₁ ≦
A calcined alumina powder 7 of 200 μm and an average particle diameter d ₂ of 0.
A mixed powder is prepared by mixing with 5 μm ≦ d ₂ ≦ 10 μm pulverized alumina powder 8. In this mixed powder, for the same reason as in Example 1, the compounding amount A of the calcined alumina powder 7 was
₁ is 50% by weight ≦ A ₁ ≦ 80% by weight, and the compounding amount A ₂ of the ground alumina powder 8 is 20% by weight ≦ A ₂ ≦ 50% by weight.
Are set respectively.

[0070] to the mixed powder, aiming to improve strength of the porous alumina preform 5 ₂ mixed with Example 1 similar binder, thereby the first material for forming the annular first reinforcement portion 5a is prepared You. As in Example 1, the blending amount B of the binder is set to 1% by weight ≦ B ≦ 2% by weight in the first raw material.

The average particle diameter d ₁ is 20 μm ≦ d ₁ ≦ 20
The same binder as in Example 1 is mixed into the 0 μm calcined alumina powder 7 to prepare a second raw material for forming the second reinforcing portion 5b. The blending amount B of the binder is the same as in the case of the first raw material.

(2) As shown in FIG.
In in lower cavity 11, by heating the first material 12 ₁ and spread to uniform thickness on the annular stepped portion 17 for molding a disk unit 4 and then the first raw material 12 ₁ to 100 to 200 ° C. the organic binder to melt, then the upper die 13 is lowered as shown in FIG. 8, the same manner as in example 1, subjected to compression molding by setting the molding pressure P in ^{3kgf / cm 2 ≦ P ≦ 10kgf} / cm 2 Thereby, one annular first reinforcing portion 5a is formed.

(3) As shown in FIG.
In the cavity 11, one annular first reinforcing portion 5a is covered.
The second raw material 12_TwoAnd then the second raw material 12_Two1
Heat to 00 to 200 ° C to melt the organic binder,
Thereafter, the upper mold 13 is lowered as shown by the solid line in FIG.
Molding pressure P, ie, 3 kgf / cm^Two≦ P ≦ 10kgf / cm ^Two
Compression molding, thereby forming the second reinforcing portion 5b
I do.

(4) As shown by the chain line in FIG. 10, in the lower mold cavity 11, the annular portion a of the second reinforcing portion 5b
The first raw material 12 ₁ and spread to uniform thickness on top, then the organic binder was melted by heating the first material 12 ₁ to 100 to 200 ° C., then 10, the upper mold 13 as indicated by a solid line Lower the molding pressure P as described above, that is, 3 kgf / cm ² ≦ P
Performs compression molded at ≦ 10 kgf / cm ^2, thereby to obtain a porous alumina preform 5 ₂ by molding the other of the annular first reinforcement portion 5a.

[0075] Al into the porous alumina preform 5 ₂
The impregnation of the molten metal or the molten Al alloy is performed in the same manner as in the first embodiment as shown in FIG. 5, thereby obtaining a brake disk material.

The mold 4 is taken out of the furnace together with the composite brake disc material, air-cooled, and then the composite brake disc material is released.

As in the first embodiment, for example, JIS AC7A is used as the Al alloy.

As in the first embodiment, the machining of the composite brake disc material includes cutting for removing an excessive Al portion or an Al alloy portion, drilling for forming the bolt insertion hole 1b, and the like.

Hereinafter, the production of the composite brake disc 1 will be specifically described.

(1) As described above, the average particle diameter d ₁ = 55
μm calcined alumina powder 70% by weight and average particle size d ₂ =
A mixed powder was prepared by mixing 2.5 μm of pulverized alumina powder with 30% by weight. Then, 1.5% by weight of the mixed powder
Was mixed to prepare a first raw material for forming the annular first reinforcing portion 5a.

Further, 1.5% by weight of a polymer binder was mixed with calcined alumina powder having an average particle diameter d ₁ = 55 μm,
A second raw material for forming the second reinforcing portion 5b was prepared.

(2) As shown in FIG. 7, in the lower mold cavity 11 of the compression mold 9, 0.14 kg of the first raw material 1 is placed on the annular step 17 for molding the disk portion 4.
2 ₁ is spread to a uniform thickness, and then the first raw material 12 ₁ is
The polymer binder was melted by heating to 0 ° C., and then the upper mold 13 was lowered as shown in FIG.
Compression molding was performed at f / cm ² , whereby one annular first reinforcing portion 5a was molded.

[0083] (3) FIG. 9, as chain line, into the lower cavity 11, and the second raw material 12 _{and second} 1.86kg to cover one of the annular first reinforcement portion 5a is turned on, then the second feedstock 12 ₂ was heated to 0.99 ° C. to melt the polymer binder, then, 9, the upper die 13 is lowered as indicated by a solid line, performs compression molded at molding pressure P = 7 kgf / cm ^2, thereby Then, the second reinforcing portion 5b was formed.

(4) As shown by the chain line in FIG. 10, in the lower mold cavity 11, the annular portion a of the second reinforcing portion 5b
Spray 0.14 kg of the first raw material 12 ₁ on the top to a uniform thickness,
Next, the first raw material 12 ₁ is heated to 150 ° C. to melt the polymer binder. Thereafter, the upper mold 13 is lowered as shown by the solid line in FIG. 10, and compression molding is performed at a molding pressure P = 7 kgf / cm ² . , thereby to obtain a porous alumina preform 5 ₂ by molding the other of the annular first reinforcement portion 5a. In this porous alumina preform 5 _2, the volume fraction Vf of each of the annular first reinforcement portion 5a is Vf = 60%, and the second
The volume fraction Vf of the reinforced portion 5b was Vf = 30%.

[0085] (5) as in the case shown in FIG. 5, a porous alumina preform 5 ₂ is placed in the recess 15 of the mold 14, and then Example 1, similar to the method described in paragraph (3) molten Al 1 in the porous alumina preform 5 ₂ in the process of
6 to obtain a composite brake disc material.

The mold 14 was taken out together with the composite brake disc material from the furnace, air-cooled, and then the composite brake disc material was released.

(6) The composite brake disc material was machined to obtain the composite brake disc 1 shown in FIG.

In this composite brake disc 1, the volume fraction Vf of the second reinforcing portion 5b for reinforcing the main body M is V
Although f = 30%, since sufficient strength can be obtained by compounding with Al, there is no problem in practical use.

The specific gravity s of the composite brake disc 1 is s
= 3 and thus proved to be lightweight.

Further, regarding the composite brake disc 1,
The abrasion resistance, squealing, corrosion resistance and stability of friction coefficient μ were examined in the same manner as in Example 1.
It has been found that the composite brake disk 1 has the same characteristics as those of the composite brake disk 1.

[Embodiment 3] Like the first embodiment, the various Al-based composite members listed in Table 3 are entirely composed of composite parts. In the table, d ₁ and d ₂ mean the average particle size as described above, and A ₁ , A ₂ and B mean the compounding amounts as described above.

[0092]

[Table 3]

In the disc brake of Table 3, the composite caliper, composite back metal and composite piston each weighed about one-half the weight of the cast iron caliper, the steel back metal and the cold forged steel piston. As a result, significant weight savings have been achieved.

The composite piston for the engine is made of a conventional Al
It has better wear resistance, heat resistance (including high-temperature strength, heat-resistant deformation, etc.) and rigidity than alloy pistons, which can improve the output performance of the engine.

Further, the weight of the bearing retainer (bearing cap) for the engine is about one half that of the bearing retainer made of cast iron, so that the weight is significantly reduced.

In the various Al-based composite members exemplified in Examples 1 to 3, the reinforcing material is a porous alumina preform, and the Al-based matrix is Al or an Al alloy. It also has the advantage that it is used and therefore has good recyclability.

In the present invention, an Al-based composite member in which a part of the member is composed of a composite portion, for example, the slipper surface and the vicinity thereof are reinforced with a porous alumina preform in addition to the composite cylinder block. Combined rocker arm, partially reinforced composite shift fork, partially reinforced composite brake master cylinder body, and the like. In this case, the impregnation of the porous alumina preform with the Al-based matrix is performed in a member casting process.

[0098]

According to the first aspect of the present invention, by configuring as described above, an increase in production cost is suppressed, and a lightweight Al-based composite member having wear resistance, heat resistance and corrosion resistance. Can be provided.

According to the second aspect of the present invention, it is possible to provide an Al-based composite member having a production cost lower than that of the above case and having the same characteristics as above.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a composite brake disc.

FIG. 2 is an enlarged cross-sectional view taken along line 2-2 of FIG. 1 in which main parts are enlarged.

FIG. 3 is a cross-sectional view showing a state in which a raw material is charged into a cavity in a molding method of an example of a porous alumina preform.

FIG. 4 is a cross-sectional view showing a state in which an example of a porous alumina preform is molded.

FIG. 5 is a cross-sectional view showing a state in which a porous alumina preform is impregnated with a molten aluminum or a molten aluminum alloy.

FIG. 6 is an enlarged cross-sectional view showing another example of the composite brake disc in which a main part is enlarged, and corresponds to FIG.

FIG. 7 is a cross-sectional view showing a state in which a raw material is sprayed on a part of a cavity in order to form one of the first reinforcing portions in another forming method of the porous alumina preform.

FIG. 8 is a cross-sectional view showing a state where one of the first reinforcing portions is molded.

FIG. 9 is a cross-sectional view showing a state where a second reinforcing portion is formed.

FIG. 10 is a sectional view showing a state in which another example of the porous alumina preform is molded.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Composite brake disk (Al-based composite member) 5 ₁ , 5 ₂ Porous alumina preform 5a, 5b First and second reinforcing parts 6 Al-based matrix 7 Calcined alumina powder 8 Ground alumina powder R Sliding area

Continuation of front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C22C 21/00-21/18 C22C 1/10 B22F 3/26

Claims (2)

(57) [Claims] At least a part of the member is made of porous aluminum.
Na preform (5 ₁) And its porous alumina preform
(5₁)) Impregnated with an Al-based matrix (6)
Consisting of a composite part consisting of
Form (5 ₁), The average particle size d₁Is 2
0 μm ≦ d₁≦ 200 μm calcined alumina powder (7)
Average particle size d_TwoIs 0.5 μm ≦ d_Two≦ 10μm crushed aluminum
It is noted that mixed powder with mina powder (8) is used.
Lightweight with excellent wear, heat and corrosion resistance
Al-based composite member. 2. At least a part of the member is made of porous aluminum.
Na preform (5 _Two) And its porous alumina preform
(5_Two)) Impregnated with an Al-based matrix (6)
Consisting of a composite part consisting of
A porous alumina preform having a sliding region (R);
(5_Two) Is a first for strengthening the sliding area (R).
A reinforcing portion (5a) and a first reinforcing portion (5a) integrated with the first reinforcing portion (5a).
2 reinforced part (5b), and the first reinforced part (5a).
As raw material powder, average particle size d₁Is 20 μm ≦ d₁≦ 20
0 μm calcined alumina powder (7) and average particle size d_TwoIs 0.
5 μm ≦ d_Two≦ 10 μm with pulverized alumina powder (8)
The mixed powder is used, and the raw material powder of the second reinforcing portion (5b) is used.
Finally, the average particle size d₁Is 20 μm ≦ d₁≦ 200 μm
Characterized by using calcined alumina powder (7)
Lightweight with abrasion resistance, heat resistance and corrosion resistance
Al-based composite member.