WO2005084853A1

WO2005084853A1 - Method of molding composite metal material

Info

Publication number: WO2005084853A1
Application number: PCT/JP2005/001685
Authority: WO
Inventors: Makoto Fujita
Original assignee: Central Motor Wheel Co., Ltd.
Priority date: 2004-02-09
Filing date: 2005-02-04
Publication date: 2005-09-15
Also published as: JP4291705B2; JP2005219109A

Abstract

A method of molding a composite metal material capable of increasing the smoothness of the specified surface (composite surface) thereof joined to a porous preliminary molding. In the method of molding the composite metal material (3), a releasing material formed of a scale-shaped composition is applied to the molded surface (5) of the porous preliminary molding (1) and the porous preliminary molding (1) is heated to form a scale-shaped coating layer (6), the molded surface (5) is brought into contact with a molding die (22) forming the specified surface (or composite surface (4)) joined to the porous preliminary molding (1), and the molten metal (2a) of a light metal is supplied while pressurizing. Thus, the specified surface (or composite surface (4)) having approximately smooth casting surface can be formed, void is prevented from being formed in the material, and the light metal and the porous preliminary molding can sufficiently develop their excellent characteristics in the composite metal material (3).

Description

Specification

Method of forming metal composite

Technical field

The present invention relates to a method of forming a metal composite formed by combining a light metal with a porous preform formed from a predetermined reinforcing material.

Background art

[0002] For example, in automobiles, there is a tendency to increase parts manufactured by light metals such as aluminum alloys, which are excellent in weight reduction, high durability, low thermal expansivity, etc., in order to improve fuel efficiency and steering stability. It is in. Some of the parts that make up this automobile have harsh environments such as engine parts, etc. For such parts, metal composites formed by combining light metals with reinforcing materials such as ceramics are used. It has further improved weight reduction and high durability. Furthermore, it is possible to form a metal composite that combines the excellent characteristics of light metals and the excellent characteristics of reinforcements by combining them with reinforcements excellent in specific performance, which is the weakness of light metals. It is. For example, by combining an aluminum alloy having low wear resistance and low slidability with a reinforcing material excellent in wear resistance and high slideability, weight reduction, low thermal expansion, etc., wear resistance and wear, etc. It is possible to form a metal composite excellent in both of the properties and the properties.

[0003] As described above, in the case of a metal composite formed by combining a light metal such as aluminum alloy with a reinforcing material having excellent wear resistance and sliding property, high! And wear resistance and sliding property are obtained. The required surface required is formed as a composite surface in which the reinforcing material is composited. Generally, this metal composite is partially composited with a reinforcing material. As a method of molding such a metal composite material, a required surface (composite surface) of a cavity formed on a mold for molding the metal composite material, a porous preform having a predetermined reinforcing material force formed in advance. A well-known truss forming method is known, in which a molten metal of light metal is pressurized and supplied to the cavity after being placed in contact with a molding die for forming the metal mold. In this forming method, the pressure-supplied molten metal is impregnated into the interior of the porous preform, and the properties of the porous preform are exhibited by bonding the preform and the light metal. The resulting composite surface can be formed. [0004] For example, in a method of forming a cylinder block of an engine as the metal composite as described above, the fiber formed body is used as the porous preform described above, and the fiber formed body is preheated. A method has been proposed which is disposed around a cylinder bore forming core so as to be filled with a molten metal and forged (for example, Patent Document 1). In such a method, the melt is sufficiently filled in the fiber formed body by preheating the fiber formed body in advance.

Patent Document 1: Japanese Patent Application Laid-Open No. 62-6766

Disclosure of the invention

Problem that invention tries to solve

[0005] By the way, in general wrought forming, a mold release material is applied in advance to the surface of the mold forming the cavity to which the molten metal is supplied, thereby preventing seizing between the mold and the molten metal, and after molding And molded articles can be easily separated, and can be molded into a smooth, smooth skin. Even in the molding of the metal composite material to form the required surface (composite surface) formed by bonding the porous preforms described above, the mold release material is similarly applied and molded. However, even if a mold release material is applied to a molding die in contact with the porous preform, there is a problem that the composite surface of the metal composite material is molded to a rough, rough skin with irregularities. . For this reason, in order to make the composite surface have the desired smoothness, it is necessary to cut the composite surface in a relatively large amount in a later step, the time required for this cutting becomes longer, and the time to replace the cutter also becomes It gets faster. In particular, in the case where the porous preform is made of ceramic short fibers or ceramic particles, the load on the cutter is large, and therefore, the time-consuming cutting process and the early replacement of the cutter are remarkable. It also contributes to an increase in manufacturing time and cost. In addition, when the composite surface is thus formed into a rough surface, voids (defects) are present at the composite site of the porous preform and the light metal on the inner side of the composite surface. The metal composite material which can be easily formed can sufficiently exhibit the above-described composite effect, and also has problems of wrinkles and wrinkles.

[0006] Here, as the above-mentioned mold release material, it is easily known that a generally well-known particle-force release agent such as titanium-zircoa can be applied with a substantially uniform thickness. !, I have the advantage. However, even if this mold release material is applied to a molding die for forming a composite surface, as described above, the composite surface is molded to have a rough skin. The present invention proposes a method of forming a metal composite material which solves the above-mentioned serious problems and can improve the smoothness of a required surface (composite surface).

Means to solve the problem

[0008] First, the present invention relates to a method of forming a metal composite in which a porous preform having a predetermined reinforcing material force is formed on a required surface, the required surface of the porous preform. A mold-releasing material comprising a scaly-shaped composition is applied to a molding surface to be in contact with a molding die for forming a coating, and the porous preform is heated to cover the molding surface. After forming the covering layer, the molding die is brought into contact with the molding surface of the porous preform, and the molten metal of light metal is pressurized and supplied to the back of the porous preform. It is a molding method of the metal composite material to be made into merit.

According to a second aspect of the invention, there is provided a first molding die for forming a composite surface to which a porous preform having a predetermined reinforcing material force is formed, and the other surface. Forming a cavity between the second forming molds for forming, and filling the cavity with a molten metal of light metal to form a metal composite having a composite surface formed by combining porous preforms. In the method, a mold release material comprising a scaly-shaped composition is applied to a molding surface of the porous preform in contact with the first molding die for forming the composite surface, and the porous preliminary molding is applied. After forming a bowl-shaped covering layer covering the molding surface by heating the molding, the first molding die is brought into contact with the molding surface of the porous preform to make the molten metal of the light metal into a cavity. The metal composite characterized in that the pressure is supplied It is in the form method.

[0010] Here, in the conventional molding method for applying a mold release material to a molding die for forming a required surface (or composite surface) described above, the required surface (or composite surface) is molded on rough skin. Be done. As a result of the inventors' keen research on this conventional forging method, it has come to be elucidated the cause of formation of rough rough skin with irregularities. The main cause of this is the effect of the shape of the porous preform and the preheating temperature of the molding die. In this porous preform, the size is different for each hole, and the forming position is also random, and the surface shape is uneven according to the various hole forms. For this reason, since the molten metal supplied under pressure is preferentially filled so as to easily pass through the relatively large holes, it is present on the molding surface. The molten metal coming through the large holes comes into contact with the molding die in a relatively short time. That is, in each place of the forming surface, a difference occurs in time until the pressure-supplied molten metal contacts the forming die. On the other hand, the porous preform is preheated at a temperature close to the temperature of the molten metal so that the molten metal is easily impregnated, but the molding die is lower in strength than the temperature of the molten metal to prevent seizure with the light metal. Preheated by temperature. For this reason, the molten metal that has passed through the porous preform is brought into contact with the molding die and solidification is started. Therefore, at a place where relatively large holes are present on the molding surface of the porous preform, the molten metal reaches quickly and solidification occurs rapidly, and the solidification sites of the molten metal are dispersed. Then, the solidification that has occurred in this way proceeds to the periphery and also interferes with the filling of the sequentially supplied molten metal. For this reason, there are also places where the molten metal can not reach the molding die on the surface to be molded, and an uneven scaly surface is formed. In addition, since the filling may be prevented by the solidified molten metal also in the inside of the porous preformed body, a part where the molten metal does not sufficiently spread may be generated to form a void. . As described above, even when the mold release material is applied to the molding die in contact with the molding surface, since the temperature of the mold release material is low, a rough surface of the unevenness is similarly formed. Furthermore, when the mold release material is applied to the mold, a slight amount of moisture may remain in the mold release because the preheating temperature of the mold is relatively low. This moisture is heated by the high-temperature molten metal to become water vapor, which also results in the formation of voids and surface irregularities.

In the present invention, a release material comprising a scaly-shaped composition is applied to the surface to be molded of the porous preform so as not to generate such roughened internal skin and internal voids. After forming the weir-like coating layer by heating, the molten metal is pressurized and supplied. Here, in the scaly coating layer formed by heating the mold release material composed of scaly-shaped composition, the scaly-shaped composition adheres so as to close the holes present in the molding surface, and the composition Is present in a disordered state in the scaly coating layer where the water is evaporated. Furthermore, the scaly covering layer is different in the state in which the scaly-shaped composition is irregularly distributed depending on the size of the hole present on the molding surface. That is, where relatively large holes are present, the composition is further disturbed to close the holes, and the voids formed by evaporation of water are also relatively large. Since it is present, it has a thick layer form. On the other hand, in the places where small holes are present, the composition is present in a relatively uniform manner and in the form of a thin-walled layer form with less voids as compared with the large holes. And, such a scaly coating layer is formed in a state in which a scaly-shaped composition is supported on the surface to be molded.

Then, this bowl-shaped covering layer is preheated to a temperature substantially close to the temperature of the molten metal together with the porous preform, and comes into contact with the molding die. For this reason, even if the pressure-supplied molten metal is brought into contact with the sheath-like coating layer through the porous preform, the molten metal does not immediately solidify because the sheath-like coating layer is at a high temperature. Here, as described above, since the pressure-supplied molten metal is first filled through the relatively large holes, the molten metal quickly comes into contact with the bowl-shaped covering layer at the locations of the large holes. The molten metal does not solidify, and is spread and expanded into the preform by the molten metal that is subsequently pressurized and supplied one after another, and the wedge-shaped coating layer is pressed against the molding die. As described above, when the wedge-shaped coating layer is also subjected to the pressing action of the molten metal force, the irregular flake-shaped composition is gradually aligned, and the voids in the layer decrease, and the layer itself is compressed and deformed. It can be Then, when the molten metal comes in contact with the bowl-like coating layer through the gradually smaller holes, it will be compressed and deformed by the same pressing action. Since this pressing action occurs in accordance with the size of the hole on the molding surface, the ridge-like covering layer is deformed into a form in which the scaly-shaped composition is overlapped and laminated as a whole, and a substantially uniform layer is formed. It becomes thickness. Therefore, a substantially smooth surface shape can be formed by solidification of the molten metal in pressure contact with the deformed wedge-shaped covering layer.

Further, as described above, since solidification of the molten metal does not proceed by coming into contact with the bowl-shaped coating layer, the molten metal to be sequentially pressurized and supplied is sufficiently spread and filled in the porous preformed body. It can be By means of the molten metal charged in this way, the air present in the preform is pushed over the wedge-shaped covering layer. Since this air can escape through the overlapping scaly-shaped composition of the scaly coating layer, the formation of voids (defects) inside is also prevented. In addition, the air inherent in the initial scaly coating layer described above is similarly released by the pressing action of the molten metal.

As described above, according to the molding method of the present invention, it is possible to mold the required surface (or the composite surface) of the metal composite into a substantially smooth surface and to form voids (defects) inside. Also in the prevention Can. Thus, it is possible to form a metal composite that can sufficiently exhibit the respective excellent properties of the light metal and the porous preform. In addition, even when the cutting process is performed after that, the cutting amount can be reduced compared to the above-described conventional method, and the manufacturing process can be made more efficient.

On the other hand, in the present invention, as described above, is it possible that the wedge-like covering layer formed on the surface to be molded can be flexibly absorbed by compressive deformation of the pressing action of the pressure-supplied molten metal? In addition, it is possible to reliably block the contact between the molten metal and the molding die by the bowl-shaped covering layer. For this reason, there is also an excellent advantage that the metal composite can be relatively easily released from the molding die even after the molten metal solidifies. For example, when a hollow cylindrical metal composite is formed by an inner first molding die for forming a hollow cylindrical cavity such as the cylinder block described above and an outer second molding die. Usually, due to solidification shrinkage of the light metal, it is difficult to release the metal composite from the first molding die. Here, in the above-described conventional method of applying a mold-releasing material comprising a composition in the form of particles to the first molding die, the mold-releasing material adhered to the molding die surface can hardly be compressed and deformed. Thus, the metal composite material is strongly pressed against the first molding die by the pressing force and solidification contraction force of the molten metal supplied under pressure, and sufficient releasability can not be exhibited. However, according to the method of the present invention, even when forming the hollow cylindrical metal composite material, as described above, the pressing action and the contraction force of the molten metal are compressed and deformed by the wedge-shaped covering layer. Since it can be relieved, the pressing force on the first molding die can be alleviated, and the metal composite can be released relatively easily.

[0016] In such a method of molding a metal composite material, a method is proposed in which the scaly-shaped composition forming the mold release material is graphite having a scaly shape. Alternatively, a method is proposed in which the scaly-shaped composition is a scaly-shaped boron nitride. Here, since graphite and boron nitride are excellent in slidability, they can move relatively easily when subjected to the pressing action of the molten metal, and they will be further aligned and stacked. In order to obtain such a ridge-like covering layer, it is easy to be compressed and deformed and the smoothness is also enhanced. Thus, in the case of a powerful method, the above-mentioned effects of the present invention can be more appropriately exhibited.

In addition, in the method of forming a metal composite material described above, the porous preformed body forms a framework. A method is proposed in which the short staple fibers and particles having predetermined properties are sintered. In this porous preformed body, it is possible to prevent the short fibers forming the framework from being deformed by the force that is also supplied with pressure and to receive the molten metal force that impregnates the inner part, and the composite is suitably bonded to the light metal. Can form a heel site. And, it is possible to form a metal composite which can sufficiently exhibit the improvement of the strength by the short fibers and the characteristics of the particles. Such a preform is in the form of coarse and dense porosity since the short fibers are intricately entangled. When such porous preforms are made, for example, by sintering particles excellent in wear resistance and slidability, which is a weak point of light metals such as aluminum alloys, the porous porosity can be reduced. The metal composite material to be formed by the preformed body strength is excellent in abrasion resistance and sliding property. Thus, according to the molding method of the present invention described above, from such a preformed body, as described above, a metal composite material that can fully exhibit both the characteristics of the light metal and the characteristics of the preformed body is properly obtained. It can be molded.

Effect of the invention

In the present invention, as described above, a mold release material comprising a scaly-shaped composition is applied to the molding surface of the porous preform to be bonded to the required surface of the metal composite, and the porous preform is After forming a bowl-shaped covering layer by heating, the forming surface is brought into contact with a forming mold forming a required surface, and a molten metal of light metal is pressurized and supplied to the back of the porous preform. Molding method. Alternatively, a mold-releasing material having a scaly shape composition is applied to the surface to be molded of the porous preform, and the porous preform is heated to form a scaly coated layer, and then the porous preform is formed. In this method, the molding surface is brought into contact with a first molding die for forming a composite surface to which a preform is to be bonded, and a molten metal of light metal is pressurized and supplied to the cavity. By such a forming method, the wedge-like coating layer covering the surface to be formed is compressed and deformed by the pressing action of the pressure-supplied molten metal, and the entire film becomes substantially uniform in thickness. The molten metal can solidify to form a substantially smooth desired or composite surface of the scale. In addition, a void can be formed because the melt supplied under pressure can be sufficiently spread in the porous preform and the air existing in the porous preform can be discharged to the outside. Can be prevented. The metal composite composited in this manner is characterized by the excellent properties of the light metal and the porous preform respectively. It will be able to fully demonstrate. In addition, since the amount of cutting can be reduced compared to the above-described conventional method also in the cutting process performed after such forming, it is possible to make the manufacturing process more efficient.

On the other hand, in the method in which the scaly-shaped composition forming the above-mentioned release material is either scaly-shaped graphite or scaly-shaped boron nitride, the scaly-shaped covering layer is Since it is formed of graphite or boron nitride having excellent slidability, it is easy to be compressed and deformed by the pressing action of the molten metal, and the smoothness is also enhanced, and the above-mentioned effects of the present invention are more appropriately exhibited. It can be done.

Further, in the method in which the porous preform described above is formed by sintering short fibers forming a skeleton and particles having a predetermined property, the short fibers forming a skeleton However, since it can prevent deformation due to the force of the molten metal that impregnates the inside, the porous preform and the light metal can be properly bonded, and the characteristics possessed by the short fibers and the particles can be sufficiently exhibited. The resulting metal composite can be formed.

Brief description of the drawings

FIG. 1 is an explanatory view showing a step of forming a porous preform 1 according to an embodiment of the present invention.

[FIG. 2] (B) An enlarged photograph showing the surface morphology of the porous preform 1 and (en) an enlarged photograph showing the surface morphology coated with a release agent obtained by diluting scaly graphite.

FIG. 3 is an explanatory view showing a process of tumbling the metal composite 3 of Example 1.

[FIG. 4] An explanatory view schematically showing a process of impregnating a porous preform 1 with a molten metal 2a to form a composite surface 4 in Example 1.

[FIG. 5] (B) A magnified image showing the composite surface 4 of Example 1 and (Z) A magnified image showing the composite surface 4 'of the comparative example.

FIG. 6 is an explanatory view showing a process of tumbling the metal composite 3 of Example 2.

Explanation of sign

[0022] 1, 41 porous preformed body

2 Aluminum alloy (light metal)

2a Molten metal (aluminum alloy)

3, 43 Metal Composites 4, 44 complex surface

5, 45 Surface to be molded

6 bowl-shaped covering layer

7, 47 complexing site

10 alumina short fiber

11 alumina particles

22 Mold

25, 55 Cavity

56 core (first mold)

BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment of the present invention will be described in detail with reference to the attached drawings.

In this embodiment, a rectangular solid metal composite 3 formed by bonding a flat plate-shaped porous preform 1 to a required surface (composite surface 4) is formed on an aluminum alloy 2 and the first embodiment A cylindrical porous preform 41 is illustrated for Example 2 in which a cylindrical metal composite 43 formed by bonding to the inner circumferential surface (composite surface 44) is formed. Further, in order to clearly show the function and effect of the present invention, a mold release material comprising a composition having the same scaly shape as in Example 1 is not applied to the porous preform 1, and a molding die is produced. A comparative example applied to 22 is also illustrated.

(Example 1)

FIG. 1 shows a process of forming a porous preform (so-called preform) 1 according to the present invention. As shown in FIG. 1 (b), the alumina short fibers 10 and the alumina particles 11 are stirred and mixed in water in a predetermined container 61. Furthermore, alumina sol 12 is added as an inorganic binder to form a mixed aqueous solution 13 in which alumina short fibers 10, alumina particles 11 and alumina sol 12 are mixed almost uniformly. Then, the mixed aqueous solution 13 is transferred from the container 61 to the suction shaper 63. A vacuum pump (not shown) is connected to the suction shaper 63, and as shown in FIG. 1 (port), the water in the mixed aqueous solution 13 is sucked by the vacuum pump through the filter 64. As a result, a preformed body 14 is obtained in which the alumina particles 11 are substantially uniformly dispersed in the alumina short fibers 10 and pseudo-bonded. Then, this preformed body 14 is removed from the suction forming device 63. Take out and dry in a drying oven maintained at about 120 ° C. to remove water sufficiently (not shown). Here, in the preform 14, the volume content of the alumina short fibers 10 is about 12%, the volume content of the alumina particles 11 is about 10%, and the remaining region is a void. Incidentally, the above-mentioned mixed aqueous solution 13 is prepared so as to obtain such a volume content rate.

Next, as shown in FIG. 1 (C), this preformed body 14 was placed on a table 66 in a heating furnace 65, and the inside of the furnace was heated to about 1000 ° C. and held for one hour. Thereafter, furnace cooling (not shown) to room temperature was performed to obtain a porous preform 1 having a flat plate shape. The porous preform 1 molded in this manner, as shown in FIG. 2 (a), is formed by combining the alumina short fibers 10 and alumina particles 11 which form a complex intertwining frame, It has a so-called porous form in which sites (relatively large pores) and dense sites (relatively small pores) are mixed.

On the other hand, the water-soluble scale-like graphite 8 (see FIG. 2 (mouth), see FIG. 4) is diluted about twice with water to form a release material (not shown) according to the present invention. In the present embodiment, Hitzole 242B (manufactured by Hitachi) is used as the scaly graphite. This mold release material is applied to the molding surface 5 of the porous preform 1 to form a required surface (hereinafter referred to as a composite surface) 4 formed by combining the porous preform 1 and the aluminum alloy 2 described above. Apply Then, it is dried in a drying oven maintained at about 120 ° C to remove water sufficiently (not shown). In the porous preform 1 after drying, as shown in FIG. 2 (mouth), a scale-like coating layer 6 in which scale-like graphite 8 is randomly present is formed on the surface to be formed. Furthermore, this scaly coating layer 6 has an internal void formed after the evaporation of water (see FIG. 4 (i)). Here, in the rough portion of the formed surface 5 of the scale-like covering layer 6, the randomness of the scale-like graphite 8 is high and a large number of voids are present, and the layer thickness is thick. On the other hand, at the dense portion, the scaly graphite 8 is in a relatively gathered state, and the thickness of the layer with few gaps is thin (see FIG. 4 (i)). It can be said that such a scaly covering layer 6 is formed in a state in which scaly graphite 8 is supported on the molding surface 5 of the porous preform 1.

Here, in the present embodiment, the porous preform 1 has a flat plate shape of about 40 mm × about 40 mm and about 10 mm in thickness. And as a result of measuring a weight after the said drying, it is an increase of about lg, and this is the adhesion amount of scale-like graphite 8. Thereafter, the porous preform 1 having the bowl-shaped covering layer 6 formed on the molding surface 5 is subjected to a predetermined preheating furnace (not shown). Exposed to a high temperature atmosphere and preheat to about 600 ° C. At this time, the wedge-shaped covering layer 6 is also preheated to about 600.degree. In the present embodiment, after the release material is applied, it is once dried in a drying furnace and weight measurement is performed, but it is also possible to carry out preheating directly in a preheating furnace without performing this. A similar scaly covering layer 6 can be formed.

The porous preform 1 preheated by the preheating furnace is immediately placed at a predetermined position of the mold 20 for forming the metal composite 3 of the desired shape as shown in FIG. Here, the mold 20 is a substantially hollow rectangular parallelepiped outer frame mold 21 whose inner four sides are inclined surfaces which are respectively directed downward from above and inclined inward, and the lower part of the outer frame mold 21. It consists of a mold 22 which is fitted and forms the composite surface 4 and a insert 23 which is fitted inside the outer frame mold 21 and whose inner four sides are vertical surfaces. Here, the insert 23 is divided into right and left, and when it is taken out from the outer frame mold 21, it is divided and the metal composite 3 formed on the inside is easily released. It has become possible. Such a mold 20 preheats the outer frame mold 21 to about 300 ° C. and preheats the mold 22 and the insert 23 to about 200 ° C. before the porous preform 1 is placed. It will A mold release material is applied to the inner vertical surface of the insert 23 in advance. This release material may be any of those obtained by diluting the scaly graphite described above or a release material composed of another general particulate composition.

Then, as described above, the preheated porous preform 1 is placed on the molding die 22 with the molding surface 5 facing downward (FIG. 3 (B)). At this time, the surface to be molded 5 is in contact with the molding die 22 through the ridge-like coating layer 6 (see FIG. 2 (opening)) applied to the surface to be molded 5. Thereafter, as shown in FIG. 3 (opening), a predetermined amount of molten metal 2a of aluminum alloy (JIS AC 4 CH alloy) heated to about 760 ° C. is formed in cavity 25 formed by insert 23 and forming die 22. Drain. Then, as shown in FIG. 3 (c) to FIG. 3 (2), the pressing element 24 which has a substantially flat surface and which can be inserted into the cavity 25 is provided by a hydraulic press machine not shown. The upper force molten metal 2a is pressed directly at a pressure of 50 MPa. When the molten metal 2a is pressurized and supplied in this manner, the inside of the porous preform 1 is gradually impregnated. Then, after cooling in this state, it is taken out from the mold 20, and the composite alloy portion 7 in which the porous preform 1 and the aluminum alloy 2 are composite-bonded, and the aluminum alloy 2 are integrally formed. Metal Composite 3 is obtained. In the metal composite 3 thus formed, the composite surface 4 formed by combining the porous preform 1 and the aluminum alloy 2 is, as shown in FIG. It is molded into a smooth, smooth skin. This is in the process of pressure-supplying the above-described molten metal 2a, and as shown in FIG. 4 (i), the porous preform 1 is impregnated with the molten metal 2a on the back side of the surface 5 to be molded. The molten metal 2a travels quickly through the rough portion of the porous preform 1. And, as shown in FIG. 4 (mouth), even if the molten metal 2a comes in contact with the bowl-shaped coating layer 6, the bowl-shaped coating layer 6 is preheated as in the porous preform 1, so that the molten metal 2a is Does not coagulate immediately. For this reason, the molten metal 2a in contact with the bowl-shaped covering layer 6 is pushed and spread around by the molten metal 2a which is sequentially pressurized and supplied, and is filled into the preform 1 and is later pressurized. The wedge-shaped covering layer 6 is pressed against the forming die 22 by the pressing action of the supplied molten metal 2 a. As shown in FIG. 4 (c), the scaly graphites 8 are gradually aligned so as to gradually overlap each other at the portion of the scaly coating layer 6 which has received the pressing action of the molten metal 2 a, The air contained therein flows out to the outside through the surface of the molding die 22 so that the space is reduced and the layer itself is compressed and deformed. Further, the molten metal 2a is gradually supplied to the dense portion of the porous preform 1 by pressure feeding so that the molten metal 2a is in contact with the bowl-shaped covering layer 6 over the entire area of the molding surface 5. I will. Then, as the bowl-shaped covering layer 6 and the molten metal 2a come into contact with each other, they are compressed and deformed in the same manner as described above, and the entire region of the bowl-shaped covering layer 6 is compressed and deformed. Here, this compressive deformation causes the thick portion of the bowl-like covering layer 6 to be greatly compressed and deformed by the relatively large pressing action at the rough portion, and the thin portion by the relatively small pressing action at the dense field position. It will be made small compression deformation. Thus, as shown in FIG. 4 (2), the scale-like coating layer 6 is compressed and deformed into a generally uniform layer thickness in which the scale-like graphites 8 are laminated in a uniform manner. Therefore, the molten metal 2a in pressure contact with the weir-like coating layer 6 solidifies, whereby a substantially smooth composite surface 4 is formed.

Incidentally, in the process of filling the porous preform 1 with the molten metal 2a, the air remaining in the porous preformed body 1 has a ridge-like covering layer formed by the molten metal 2a. The mixture is pressed to 6 and flows to the surface of the molding die 22 through between the flaky graphite (not shown) constituting the scale-like coating layer 6 and flows out to the outside. As a result, it is possible to prevent the formation of voids in the composite part 7 consisting of the porous preform 1 and the aluminum alloy 2. Further, as described above, in the case where the molten metal 2a is pressurized and supplied as described above, the bowl-shaped coating layer 6 can be flexibly absorbed by compressively deforming the pressing action of the molten metal 2a. Since it is possible, the molding die 22 and the molten metal 2a can be shielded reliably. Therefore, the composite surface 4 in which the porous preform 1 and the aluminum alloy 2 are combined so that the aluminum alloy 2 is not seized on the forming die 22 can be relatively easily released from the forming die 22. it can. From this point on as well, the smoothness of the composite surface 4 is maintained.

Comparative Example

Next, as a comparative example to Example 1 described above, a mold release material obtained by diluting the scaly graphite as in Example 1 is applied to the surface of the molding die 22 to which the molding surface 5 contacts, and the molten metal 2a The metal composite is formed by pressure supply (see Figures 1 and 3). That is, the porous preform 1 is formed in the same manner as in Example 1 described above, and the molded surface 5 of the porous preform 1 is not coated with a release material obtained by diluting scaly graphite (see FIG. 2) Preheat to about 600 ° C. On the other hand, the mold release material is applied to the surface of the molding die 22 on which the composite surface of the metal composite is to be formed (not shown). Here, the coating amount of the release agent is made to be substantially the same as that of the above-mentioned Example 1. Thereafter, the mold 22 is preheated at about 200 ° C. to form a substantially smooth ridge-like covering layer covering the mold 22. A cavity 25 is formed by the forming die 22 and the outer frame die 21 and the insert 23 which are each preheated. After placing the preheated porous preform 1 on the forming die 22 of the cavity 25, the molten metal 2a of the aluminum alloy 2 is poured, and the molten metal 2a is also directly pressed by the pressing element 24 in the upward direction. As described above, the molten metal 2a is pressurized and supplied to impregnate the porous preform 1 with the molten metal 2a. Then, after cooling, it is taken out of the mold 20, and a metal composite material 3 formed by integrally forming an aluminum alloy 2 and a composite site where the porous preform 1 and the aluminum alloy 2 are composited is obtained. obtain.

In this comparative example, the release material obtained by diluting scaly graphite is not applied to the surface to be molded 5 of the porous preform 1 but applied to the molding die 22. The molding is performed in the same manner as in Example 1 described above, and the same reference numerals and descriptions are omitted.

In the metal composite material thus formed, a composite surface 4 ′ formed by combining the porous preform 1 and the aluminum alloy 2 is as shown in FIG. With rough skin on the ground became. When this composite surface 4 'is compared with the composite surface 4 (Fig. 5 (i)) of the metal composite 3 of Example 1 described above, it can be seen that the bald surface of the composite surface 4' of the comparative example is rough. . In this comparative example, the molten metal 2a of the aluminum alloy 2 is pressure-supplied and impregnated into the porous preform 1 and / or passes quickly through the rough part of the porous preform 1 in the course of the process. When the molten metal 2a comes in contact with the bowl-shaped covering layer present on the surface of the molding die 22, solidification of the molten metal 2a is started. This is because the temperature of this bowl-like covering layer is lower than that of the molten metal 2a. The solidification of the molten metal 2a proceeds gradually from the coarse portion of the porous preform 1 to the dense portion, and proceeds in accordance with the coarse and dense form of the porous preform 1. Then, at the place where the molten metal 2a is solidified, the filling of the new molten metal 2a supplied sequentially is hindered, so that the molten metal 2a may not reach the dense portion of the surface 5 to be molded. In this manner, the asperity shape is formed, and the complex surface 4 'of roughened persimmon skin is to be formed. Also, in this way, on the surface to be molded, if solidification proceeds more quickly than in the interior, a void may be contained in the porous preform 1. In the case of the composite part formed in this manner, the effects such as strength improvement and wear resistance improvement by the composite of the porous preform 1 and the aluminum alloy 2 are not sufficiently exhibited.

Furthermore, in order to obtain the desired smooth surface of the rough complex surface 4 ′ of the rough skin, it is necessary to cut a relatively large amount. However, even if the composite surface 4 'is cut, the internal voids appear on the surface, which limits the generation of the effect of the composite. On the other hand, in the metal composite 3 of Example 1 described above, since the surface of the composite surface 4 is smooth, the amount of cutting is small compared to the case of this comparative example. Can be shortened. Therefore, according to the molding method of Example 1 of the present invention, it is possible to obtain the metal composite 3 which can sufficiently exhibit the composite effect while reducing the time and cost required for the manufacturing process.

In the above-described comparative example, although the one obtained by diluting scaly graphite 8 is used as the mold release material, when the mold release material comprising a composition having a general particle shape is applied to the molding die 22 However, similarly, the composite surface of the metal composite will be formed into a roughened rough skin.

Example 2

Next, in the second embodiment, a hollow cylindrical gold having a composite surface 44 formed on the inner peripheral surface thereof. The metal composite 43 is molded (see FIG. 6). First, a hollow cylindrical porous preform 41 is molded by the same molding method as in Example 1 described above (see FIG. 1). Here, the inner peripheral surface of this porous preformed body 41 is a molding surface 45 forming the composite surface 44 of the metal composite 43. Further, in the metal composite material 43, a composite gauze portion 47 in which a porous preformed body 41 and the aluminum-um alloy 2 are composited is formed on the inner side in the cylindrical diameter direction. It is assumed that aluminum alloy 2 is integrally formed on the outside (Fig. 6 (2)). In addition, this embodiment 2 is the same as the above-described embodiment except that the hollow cylindrical metal composite 43 having the composite surface 44 combined with the porous preform 41 on the inner peripheral surface is formed. This is the same shaping method as in Example 1, and in the same process, symbols and explanations are appropriately omitted.

In Example 2, a mixed solution 13 in which alumina short fibers 10, alumina particles 11 and alumina sol 12 are substantially homogeneously mixed is drawn into a cylindrical storage tank in which a cylindrical core is disposed at the center thereof. Then, a hollow cylindrical preform is obtained by suction with a vacuum pump (see FIG. 1). Then, when the preform is dried in a drying furnace, the volume fraction of alumina short fibers 10 is about 12%, and the volume fraction of alumina particles 11 is about 12 as in Example 1 described above. It is 10%. Thereafter, this preform was sintered by heating at about 1000 ° C. for one hour to obtain a hollow cylindrical porous preform 41 (see FIG. 6). Here, in Example 2, the porous preformed body 41 has a tapered shape in which the outer peripheral surface is substantially straight and the inner peripheral surface is inclined by about 0.5 degrees. Then, it is molded to have a height of about 80 mm, an outer diameter of about 80 mm, and a minimum inner diameter of about 70 mm.

On the surface 45 (inner peripheral surface) of the porous preformed body 41 as described above, a mold release material obtained by diluting scaly graphite as in Example 1 described above is applied, and Remove moisture thoroughly in a drying oven held at ° C and dry. After the drying, a scaly covering layer (not shown) formed by overlapping scaly graphite on top of the molding surface 45 is formed (see FIG. 2 (opening), FIG. 4). Here, the scaly coated layer is formed in a state in which the scaly graphite is scattered differently depending on the rough and dense form of the molding surface 45 as in the first embodiment described above. As a result of measuring the weight after this drying, the adhesion amount of scaly graphite was about 2 g. Thereafter, the porous preformed body 41 is preheated to about 600 ° C. in a preheating furnace as in the above-mentioned Example 1.

On the other hand, as shown in FIG. 6, the cavity 55 forming the hollow cylindrical metal composite 43 has an internal structure as shown in FIG. An outer frame mold 51 having an inner peripheral inclined surface which inclines inward from the upper side to the lower side on the side, and the lower end of the outer frame mold 51 are fitted to one open end face of the metal composite 43 A lower mold 52 to be formed, a nest 53 having a vertical surface internally fitted to the outer frame mold 51 and forming an outer peripheral surface of the metal composite 43 inside, and detachable from the center of the lower mold 52 It is comprised of a core 56 which is arranged and has an outer peripheral surface with a taper angle which is directed upwards and inclined inwards. Here, the core 56 is formed such that the upper outer diameter is about 70 mm and the taper angle of the outer peripheral surface is about 0.5 degree, and the porous preform 41 described above is externally fitted by a slightly provided tolerance. It is possible. The nest 53 is divided into right and left as described above. Here, the core 56 in contact with the molding surface 45 of the porous preform 41 is the first molding die according to the present invention, and the insert 53 and the lower die 52 are the second molding die. is there.

Then, the outer frame mold 51, the lower mold 52, and the insert 53 described above are preheated to about 300 ° C. before the porous preform 1 is placed, and the core 56 is about 200 °. Preheat to C. A mold release material is applied in advance to the surface of the lower mold 52 and the insert 53 on which the cavity 55 is to be formed. Thereafter, the preheated porous preform 41 is immediately fitted on the core 56 and placed in the center of the lower mold 52 as shown in FIG. This results in the porous preform 45 being placed within the cavity 55. Here, the porous preform 41 is not in contact with the inner circumferential surface of the insert 53 and is disposed inside the cavity 55. Then, as shown in FIG. 6 (opening), a predetermined amount of molten metal 2a of aluminum alloy (JIS AC 4 CH alloy) heated to about 760 ° C. is poured into this cavity 55, as shown in FIG. As in the above, the pressure applied to the inner side of the insert 52 by the pressure of about 50 MPa also directly presses the upward force of the molten metal 2a. As described above, the molten metal 2a is gradually impregnated into the porous preformed body 41 by pressure supply of the molten metal 2a. Then, after cooling in this state, it is taken out, and on the inner peripheral side, a composite metal portion 47 where the porous preform 41 and the aluminum alloy 2 are complexed, and the aluminum alloy 2 hardened on the outer side. A hollow cylindrical metal composite 43 obtained by integrally forming

Even in the hollow cylindrical metal composite 43 molded in this manner, the composite surface 44 is formed to have a substantially smooth skin as in Example 1 described above (see FIG. 5 (c)). )reference). This is because, as shown in Example 1, a gauze-like object formed on the molding surface 45 of the porous preform 41. This is because the coating layer is compressed and deformed by the pressing action of the pressure-supplied molten metal 2a, so that an effect that can form a substantially smooth composite surface 44 can be exhibited (see FIG. 4).

On the other hand, in the case of molding such a hollow cylindrical shaped article, the core is generally removed because the molten aluminum alloy supplied into the cavity shrinks and deforms in the cooling process. difficult. Here, in the case of Example 2 described above, the load required to extract the core 56 (hereinafter referred to as the extraction load) was measured. In addition, as a comparative object, a mold release material in which flake graphite is diluted is not applied to the molding surface 45, and an outer surface of the core 56 is coated with a mold release material having a general particle shape. Similarly, a metal composite was formed, and the unloading load of the core 56 was measured. As a result, in the case of the second embodiment of the present invention, the removal load of the core 56 is about 70% as compared with the case where the release agent composed of the particle shape of the particle is applied. It has fallen. Here, in the case of this comparison object, the mold release layer formed by the adhesion of the mold release agent applied to the outer peripheral surface of the core 56 can hardly be compressed and deformed. The metal composite is strongly pressed against the core 56 by the pressing force of the metal and the solidification contraction force of the molten metal. On the other hand, in the case of Example 2 in which the present invention works, as described above, since the wedge-shaped covering layer can be compressed and deformed, the pressing force and the contraction force of the molten metal can be relaxed. The force applied to the core 56 is reduced as compared to the above. Thus, according to the molding method of the present invention, the metal composite can be removed relatively easily. Therefore, in order to facilitate mold removal, it is necessary to increase the taper angle of the outer peripheral surface of the core, and to use the method of cutting after molding, etc. to reduce the time and cost required for the molding process. Is also possible.

The present invention is not limited to the embodiment described above, and can be used without departing from the scope of the present invention described above. For example, in the above-described embodiment, the porous preform is formed by sintering alumina short fibers and alumina particles, but in addition, shorts such as metal fibers, ceramic fibers, carbon fibers, etc. Even in the case of using fibers and particles such as ceramic particles and metal particles, and porous metals, etc., the effects and advantages of the present invention can be appropriately exhibited. The same applies to the case of pressure supply of a molten magnesium alloy in addition to the aluminum alloy. And the method of forming the metal composite material of the present invention, by high pressure structure, die casting, gas pressure structure, etc. It can be suitably used in various methods for filling.

Claims

The scope of the claims

[1] In a method for forming a metal composite, in which a porous preform formed from a predetermined reinforcing material is bonded to a required surface,

A mold release material comprising a scaly-shaped composition is applied to a molding surface of the porous preform in contact with the molding die for forming the required surface, and the porous preform is heated. After forming a cocoon-shaped coating layer covering the molding surface, the molding surface of the porous preform is brought into contact with a molding die, and a molten metal of light metal is placed on the back of the porous preform. A method of forming a metal composite, characterized in that the pressure is supplied.

[2] A first molding die for forming a composite surface to which a porous preform formed from a predetermined reinforcing material is bonded, and a second molding metal for forming the other surface In the method of forming a metal composite having a composite surface formed by combining a porous preform with a cavity by forming a cavity between molds and filling the cavity with a molten metal of a light metal, the porous preform A mold release material comprising a scaly-shaped composition is applied to the molding surface of the body to be in contact with the first molding die for forming the composite surface, and the porous preform is heated to heat the porous preform. After forming a weir-like covering layer covering the molding surface, the first molding die is brought into contact with the molding surface of this porous preform to pressurize the molten metal of light metal to the cavity. A method of forming a metal composite characterized in that

[3] The method for forming a metal composite according to claim 1 or 2, wherein the scaly-shaped composition forming the mold release material is scaly-shaped graphite.

[4] The method for forming a metal composite according to claim 1 or 2, characterized in that the scaly-shaped composition forming the mold release material is scaly-shaped boron nitride.

[5] The porous preform according to any one of claims 1 to 4, wherein the porous preform is obtained by sintering short fibers forming a skeleton and particles having predetermined properties. Method of forming metal composites.