JP4726011B2 - Method for producing metal matrix composite material, method for producing metal matrix composite material member, and stirring device - Google Patents

Description

  The present invention relates to a method for producing a granular or piece-like metal matrix composite in which a reinforcing material is dispersed in a pure metal or an alloy (hereinafter simply referred to as metal), a method for producing a member using the metal matrix composite, and the metal The present invention relates to a stirrer suitably used in a method for producing a matrix composite material.

2. Description of the Related Art Conventionally, as a method for producing a composite-material part using a metal as a matrix, a method is known in which a preformed reinforcement preform is prepared and impregnated with molten metal. For example, Patent Document 1 discloses a method of manufacturing a TiO ₂ / Al composite material by pressure-infiltrating molten Al into a preform obtained by press-forming TiO ₂ particles.

As another method for producing a composite part made of metal as a matrix, a powder metallurgical method is known. In this method, a metal powder and a reinforcing material powder are mixed, compressed and sintered with a hot press, etc., and further extruded into this sintered body, and subjected to plastic working such as forging and rolling to make a composite material. It is. Non-Patent Document 1 introduces an example in which SiC particles are manufactured on an Al matrix by powder metallurgy.
JP 2005-334953 A “Composite Materials Use Dictionary”, edited by Japan Society for Composite Materials (published by Industry Research Council), April 20, 2001 (first edition, first print), pages 752-764

However, the conventional method using the preform as described above requires a step of forming a preform, which causes an increase in cost. Also, with this method, it is not easy to obtain the required complex shape, dimensional accuracy, and surface accuracy, and there are limits to the products that can be applied. Moreover, impregnation of molten metal into a preform is a time-consuming construction method, and there is a problem that productivity is inferior as an industrial production means.
Further, when the powder metallurgical method is applied to, for example, a magnesium alloy, there is a problem that it is difficult to apply the method to the production of a magnesium-based composite material because the powder has a high risk of causing a dust explosion.

The present invention has been made to solve the above-described problems of the prior art.
In the present invention, firstly, an object is to provide a method for efficiently producing a granular or flake shaped raw material in which a composite reinforcing material (powder / particle / fiber) is uniformly dispersed in a matrix metal. .
Secondly, an object of the present invention is to provide a method that makes it possible to produce metal matrix composite parts with high productivity by using the granular raw material thus produced.
Thirdly, an object of the present invention is to provide a stirring device suitable for uniformly dispersing a reinforcing material in the molten metal.

That is, the invention of the method for producing a metal matrix composite material according to claim 1 includes a rotating shaft capable of moving a molten metal (including an alloy; the same applies hereinafter) and a reinforcing material up and down in a crucible, and the rotating shaft. Rotation and vertical movement using a stirring device having a plurality of stirring blades fixed to each other and having different twist angles, and a vertical stirring plate fixed to the rotating shaft and having a plate surface extending in the lateral direction. Mixing by stirring, the molten metal in which the reinforcing material is dispersed is rapidly cooled and solidified into a foil strip shape, and the foil strip is pulverized into a granular or flake shape.

  An invention of a method for producing a metal matrix composite material according to claim 2 is characterized in that, in the invention according to claim 1, the foil strip has a thickness of 0.01 to 2.5 mm.

According to a third aspect of the present invention, there is provided a method for producing a metal matrix composite material comprising: a rotating shaft capable of vertically moving molten metal and a reinforcing material in a crucible ; and a plurality of rotating shafts fixed to the rotating shaft and having different twist angles. The stirrer blades and a vertical stirring plate fixed to the rotary shaft and having a plate surface along the lateral direction are mixed by stirring including rotation and vertical movement, and the reinforcing material is dispersed. The molten metal is dispersed and rapidly cooled to solidify in a granular or piece form.

  The invention of the method for producing a metal matrix composite material according to claim 4 is the invention according to any one of claims 1 to 3, wherein the amount of the reinforcing material is 0.00% by volume with respect to the metal matrix composite material. It is characterized by being 5% to 40%.

The invention of the method for producing a metal matrix composite material according to claim 5 is the invention according to any one of claims 1 to 4, wherein the temperature at which stirring and mixing in the crucible is performed is the melting point of the metal (liquid phase). Line temperature) It is characterized by being in the range of T _L to T _L + 250 ° C.

  An invention of a method for producing a metal matrix composite material member according to claim 6 is a granular or piece-like metal matrix composite material produced by any one of claims 1 to 5 and containing a reinforcing material dispersed therein. The metal is injection molded in a liquid phase state or in a state containing a solid phase of the metal.

  The invention of the method for producing a metal matrix composite material member according to claim 7 is a granular or flake metal matrix composite material produced by any one of claims 1 to 5 and containing a reinforcing material dispersed therein. And extrusion molding in a state including the solid phase of the metal.

  The invention of the metal matrix composite material member according to claim 8 is the invention according to claim 7, wherein the solid phase of the metal is 30 to 100% by volume with respect to the total metal. .

  According to a ninth aspect of the present invention, there is provided an agitating device comprising: a rotary shaft capable of moving up and down; a plurality of stirring blades fixed to the rotary shaft and having different twist angles; a plate fixed to the rotary shaft and extending in a lateral direction; And an upper and lower stirring plate having a surface.

  According to a tenth aspect of the present invention, in the ninth aspect of the invention, the upper and lower stirring plates have an enclosure portion having an enclosure surface along the upper side and / or the lower side.

  The invention of claim 11 is characterized in that, in the invention of claim 9 or 10, the stirring blades having different twist angles are fixed to the rotating shaft at different axial positions.

  The invention of a stirring device according to a twelfth aspect is characterized in that, in the invention according to any one of the ninth to eleventh aspects, a bubble vent is formed in the upper and lower stirring plates.

According to the method for producing a metal matrix composite material of the present invention, the molten metal and the reinforcing material having different specific gravities are effectively agitated by the agitation including rotation and vertical movement in the crucible. An evenly dispersed molten metal is obtained, and then a granular or piece-like metal matrix composite is obtained by forming a foil strip by rapid solidification, pulverization, scattering, and solidification.
In addition, as for mixing of a reinforcing material, it is desirable to set it as 0.5 to 40% by volume percentage with respect to the metal and the whole reinforcing material. If the mixing ratio is less than 0.5%, it becomes difficult to keep the distribution of the reinforcing material uniform in the entire composite material. On the other hand, if the mixing ratio exceeds 40%, the fluidity of the molten metal decreases, This is because there is an adverse effect that the nozzle cannot be smoothly injected.
In the above stirring and mixing, the molten metal is preferably set to a temperature in the range of the melting point (liquidus temperature) T _L to T _L + 250 ° C. of the metal. If the temperature is less than T _L , a solid phase is partially generated and there is a problem that the dispersion of the reinforcing particles is hindered. If the temperature is T _L + 250 ° C. or more, there is a problem that the vaporization of the metal becomes intense.

  By rapidly cooling the molten metal, the molten metal can be solidified while the reinforcing material is uniformly dispersed. The method of rapidly cooling the molten metal can be performed by solidification by pouring the molten metal between the cooled rolls or by scattering / solidification. In some parts of the invention, the foil strip is produced by rapid solidification as in the former. As a method of using a molten metal as a foil strip, there are known methods such as “melt spin” and “strip cast”. These methods can also be used in the present invention. The foil strip is granulated and crushed by grinding. The pulverization can be performed by a mill or the like, and the present invention is not limited to a specific one. The foil strip preferably has a thickness of 0.01 to 2.5 mm. If the thickness is less than 0.01 mm, it becomes a fine powder when pulverized, and the handling in the subsequent molding process becomes troublesome, and the risk of dust explosion increases depending on the type of metal. On the other hand, if the thickness exceeds 2.5 mm, it becomes difficult to pulverize it into a granular material.

As the metal and the reinforcing material, appropriate materials are selected according to the application field of the metal matrix composite material, and the present invention is not limited to a specific material. However, it is particularly suitable for the field where magnesium or a magnesium alloy, which is difficult to handle the powder, is used as the metal.
As the reinforcing material, powder, granules, fibers, pieces, and the like can be used. The size of the reinforcing material is not particularly limited in the present invention, but, as will be described later, when a metal matrix composite material is used for injection molding or extrusion molding, it enables good molding. Since there is a suitable size of the metal matrix composite material, it is desirable that the major axis is 1 to 1000 μm so that the metal matrix composite material can be evenly dispersed therein.

Further, when the metal matrix composite material is used for injection molding or extrusion molding, it is desirable that the major axis side has a size of 0.5 to 10 mm in order to ensure good moldability.
The metal matrix composite material of the present invention can be suitably used for injection molding and extrusion molding, which will be described later, but is not limited thereto, and a desired molded body can be obtained by press solidification and plastic deformation. it can. This method has an effect that a forged product of a composite reinforcing material can be easily formed. The reason is that since the granular raw material is manufactured by rapid cooling, the crystal grains are fine and plastic working is possible in the solid phase temperature range.

  Moreover, according to the manufacturing method of the metal matrix composite material member of the present invention, molding can be performed while the reinforcing material is uniformly dispersed by molding using the metal matrix composite material. Further, the deterioration (recrystallization) of the rapidly cooled structure (microcrystal grains) is reduced, and good workability (elongation, drawing) is maintained.

  In addition, when injection molding or extrusion molding is performed in a state including the solid phase of the metal, the ratio of the solid phase is 50% or less by volume in injection molding, and 30 to 100% in the case of extrusion molding. desirable. In the case of injection molding, if it exceeds 50%, the fluidity of the alloy decreases, making it difficult to obtain a sound molded body. In the case of extrusion molding, if it is less than 30%, the liquid phase ratio increases, and the structure This is because there are many alterations. In extrusion molding, as shown in the solid phase ratio, it is possible to perform molding only with a solid phase without including a liquid phase.

Further, according to the stirring device of the present invention, forward and reverse rotation accompanied by twisting is performed by the stirring blades having different twist angles, and further the vertical stirring is performed by the upper and lower stirring plates, whereby the liquid can be effectively stirred, When the liquid contains a solid, the solid can be evenly dispersed in the liquid.
Stirring blades having different twist angles are fixed with their positions shifted in the axial direction with respect to the rotating shaft, so that the gyrations of the respective stirring blades act to enhance the stirring action. Vertical stirring which allows the yo RiHitoshi such agitation that is synergistic. By providing the upper and lower stirring plates with an enclosure having an enclosure surface above or below, the vertical stirring is more effective. Note that the surrounding surfaces can be provided at a predetermined interval via a gap in the circumferential direction. As a result, the vertical movement of the molten metal and the radial flow leaking from the gap overlap to enhance the stirring action. In addition, it is preferable that the upper and lower stirring plates are provided with a bubble releasing hole so that bubbles can be released as the upper and lower stirring plates are lowered.

The stirring device of the present invention is suitably used for the production of the metal matrix composite material. However, the application of the present invention is not limited to this, and can be used to effectively stir liquids in a wide range of fields, and particularly preferably used when solids having different specific gravity are dispersed in the liquid. It is done.
For example, in order to obtain a Mg alloy foil body in which Mg alloy and SiC fine particles are uniformly mixed, the Mg alloy and SiC being melted must be mixed well. In the present invention, a stirring method preferably having a function of a vertical motion in addition to rotational stirring capable of alternately rotating forward and reverse, and a single and comprehensively effective in the downward and lateral directions, and further in the vertical direction. A strong turbulent flow is generated in the crucible (or container) by a combination of stirring having stirring ability, and the molten metal of SiC and Mg alloy can be uniformly mixed. In particular, by vigorous stirring, it is effective for mixing those having a large specific gravity difference and those having strong cohesiveness and easily segregating. Further, since Mg reacts with air and ignites in the atmosphere, it is desirable that stirring in a vacuum or an inert gas is possible.

  As described above, according to the method for producing a metal matrix composite material of the present invention, molten metal (including an alloy; the same applies hereinafter) and a reinforcing material are mixed in a crucible by stirring including rotation and vertical movement. Then, the molten metal in which the reinforcing material is dispersed is rapidly cooled and solidified into a foil strip shape, and the foil strip is crushed into a granular or flake shape, or the molten metal in which the reinforcing material is dispersed is scattered and quenched. Therefore, it is possible to obtain a granular raw material in which the reinforcing material is uniformly dispersed. The reason is that the uniform dispersion state can be solidified as it is because it is rapidly solidified from the state in which the reinforcing material is uniformly dispersed in the molten metal (the uneven distribution of the reinforcing material accompanying normal solidification can be avoided). .) Moreover, by using a foil strip, it can be easily pulverized and easily made into a granular material, and a granular material can be obtained immediately by scattering and solidification. Moreover, the metal matrix composite material in which the reinforcing material is uniformly dispersed can be efficiently and safely manufactured, and the size of the composite material can be easily managed. On the other hand, it is conceivable to disperse the reinforcing material in the molten metal by the conventional method to make an ingot, and chipping this to produce a granular metal matrix composite material. It is difficult to manage the particle size.

In addition, according to the method for producing a metal matrix composite material member of the present invention, a granular or piece-like metal matrix composite material produced by the above-described metal matrix composite material method and containing a reinforcing material dispersed therein is used. Thus, since the metal is injection-molded in a liquid phase state or a state containing a solid phase, or extrusion-molded in a state containing a solid phase, efficient molding can be performed. In particular, by performing injection molding or extrusion molding in a state including a solid phase, molding while maintaining a rapidly cooled structure becomes possible.
Injection molding has the effect that complex-shaped composite reinforcing material parts can be easily molded with a net shape. The reason is that by using a granular raw material, the conveying and plasticizing action by the screw cylinder of the injection molding machine works, and the molding action of being injected into the mold by the high-speed forward movement of the screw is utilized, and This is because the added reinforcing material is uniformly dispersed in the raw material, and thus does not adversely affect the plasticizing and forming actions.

  Extrusion molding has an effect that an extruded product of the composite reinforcing material can be easily molded. The reason is that by using a granular material, it becomes possible to convey and extrude with a screw. Further, since the granular raw material is manufactured by rapid cooling, the crystal grains are fine, and the extrusion process is possible even in the solid phase temperature range.

  According to the stirring device of the present invention, a rotating shaft that can move up and down, a plurality of stirring blades that are fixed to the rotating shaft and have different twist angles, and a plate that is fixed to the rotating shaft and extends in the lateral direction. Since the upper and lower stirring plates having the surfaces are provided, effective stirring and mixing can be performed even when solids having different specific gravities are dispersed in the liquid, so that the solids can be evenly dispersed in the liquid.

Hereinafter, an embodiment of the present invention will be described.
First, a dissolution / mixing apparatus used in the method for producing a metal matrix composite material will be described.
As shown in FIG. 1, the melting / mixing apparatus includes a vacuum vessel 2 arranged around a crucible 1 for melting metal to form a vacuum melting furnace, and a stirring device 3 for stirring the crucible 1 includes It arrange | positions through this container so that the vacuum state in the vacuum container 2 can be maintained.

  As shown in FIG. 1, the stirring device 3 has a rotary shaft 30 with a stirring bar provided at the tip thereof arranged in the vertical direction, and the rotary shaft 30 passes through a lid 2 a that seals the vacuum vessel 2. In addition, a linear ball bushing 40 is provided in the penetrating portion and gas-sealed. Guide bars 41 and 41 are fixed along the vertical direction on both upper and outer sides of the vacuum vessel 2, and a moving table 44 is attached to the guide bars 41 and 41 so as to be movable up and down. The rotating shaft 30 is suspended so as to be rotatable. The moving table 44 is provided with a stirring motor 45 that rotationally drives the rotary shaft 30. The moving table 44 is provided with an elevating motor 46. The moving table 44 is moved up and down by applying vertical motion to two pairs of ball screws fixed to the moving table 44 by the elevating motor 46. Note that the weight of the balance weight 47 is applied to the moving table 44 as a lifting force by the sprocket 48, and the gravity of the moving table 45, the rotating shaft 30, and the stirring bar is offset.

Next, the detailed structure of the stirring bar will be described with reference to FIG.
The stirrer has four stirring blades 31 fixed at 90 ° intervals with a twist angle of 45 degrees on the lowermost end side, and above the stirring blades 31 with a twist angle of 90 degrees in the vertical direction. Four stirring blades 32 having a stirring surface are fixed at intervals of 90 degrees. Further, a disc-shaped upper and lower stirring plate 33 is fixed above the stirring blade 32. On the outer peripheral edge of the upper and lower stirring plate 33, an upper surrounding plate 34 that is folded upward and a lower surrounding plate 35 that is folded downward are enclosed in a circumferential direction through a small gap as a surrounding portion having a surrounding surface. It is provided alternately. The upper and lower stirring plate 33 is formed with a plurality of bubble vents 37 along the radial direction at equal intervals in the circumferential direction.

  In the stirring / mixing device, the rotating shaft can be rotated forward and backward by the stirring motor 45. Further, the moving table 44 can be lifted and lowered while being guided by the guide bar 41 together with the rotary shaft 30 by the lifting motor 46.

Next, a method for producing a metal matrix composite material using the stirring / mixing apparatus will be described.
The crucible 1 contains a metal and a powdery, granular, or flake-like reinforcing material (SiC in this embodiment), and the metal is in the range of the melting point (liquidus temperature) T _L to T _L + 250 ° C. The inside of the vacuum vessel 2 is evacuated by an exhaust device (not shown). The amount of the reinforcing material is desirably 0.5% to 40% in volume percentage with respect to the metal and the entire reinforcing material. The size of the reinforcing material is preferably 1 to 1000 μm in terms of the major axis.

  The metal is melted by the heating, and the reinforcing material 6 is present in the molten metal 5. The rotary shaft 30 is lowered by the elevating motor 46 so that the stirring bar is positioned in the molten metal 5. At this position, the molten metal 5 is agitated by rotating the agitation blades 31 and 32 forward and backward with the agitation motor 45. In addition to this, the rotary shaft 30 is moved up and down by the lifting motor 46 to change the stirring position, and the molten metal 5 is stirred up and down by the vertical stirring plate 33. Note that the rotation of the stirring blades 31 and 32 and the vertical movement of the rotating shaft 30 may be performed simultaneously, or may be performed at different times.

  Due to the stirring, a rotating flow having an angular difference in the rotation direction is generated by the stirring blades 31 and 32, and the metal melt 5 is stirred by rotating forward and backward. Further, the molten metal 5 is moved up and down by the vertical stirring plate 33 and is effectively stirred, and the reinforcing material 5 having a specific gravity different from that of the molten metal 5 is prevented from accumulating downward or unevenly distributed upward. In the vertical movement, the upper and lower stirring plates 33 are surrounded by the upper enclosure plate 34 and the lower enclosure plate 35, so that the molten metal 5 is reliably moved up and down. Further, in the vertical movement, the molten metal 5 is partially moved radially by the gap between the upper surrounding plates 34, 34 or the gap between the lower surrounding plates 35, 35, so that the stirring action is enhanced. Further, when the upper and lower stirring plate 33 is lowered, the bubbles in the molten metal 5 located below are effectively raised and removed by the bubble removal holes 37.

  The molten metal 5 in which the reinforcing material 6 is evenly dispersed as described above is taken out of the crucible 1 and poured into, for example, a rapidly cooled roll and rapidly solidified, and preferably has a thickness of 0.01 to 2.5 mm. A metal strip composite is obtained by pulverizing into foil strips to form particles or pieces, or rapidly cooling them by a method of scattering / solidification to form particles or pieces.

Next, a method for achieving the object of making it possible to produce a metal matrix composite part with high productivity using the granular raw material thus produced will be described.
First, a method of using a “thixomolding” machine, which is an existing metal injection molding apparatus, will be described. FIG. 4 is a schematic diagram of a thixo molding machine.
Conventionally, the following two methods have been considered as attempts to form a metal matrix composite by thixomolding, but each has its own problems.

First, as a first method, normal metal chips (chips not containing reinforcing particles) and reinforcing particles are mixed at a predetermined ratio and supplied to the thixo molding machine 10, and then screwed in the cylinder of the thixo molding machine. This is a method in which a metal matrix composite material is formed by stirring and mixing and injecting the mixture. However, in this method, a molten metal state in which the reinforcing material is uniformly dispersed cannot be obtained, and a sound composite material molded body cannot be obtained.
The second method is to first mix and disperse the reinforcing material particles in the molten metal by the molten metal stirring method, etc., solidify this into an ingot containing the reinforcing material, and mechanically scrape it into the reinforcing material. In this method, a metal matrix composite material is formed by thixomolding using this chip as a raw material. However, this method is not suitable as an industrial method because it is difficult to mechanically cut an ingot containing a reinforcing material.

  Therefore, in the present invention, the granular raw material 5a of the composite material produced by the above-described process is supplied to the thixomolding machine 10 instead of the normal raw material metal chip. The composite material particles are fed forward of the cylinder 12 by the rotation of the screw 11 while being heated by the heating means 13 disposed around the cylinder 12. The composite material particles are heated, melted, and stored in a certain amount in the cylinder tip 12a. Thereafter, by the forward movement of the screw 11, the stored molten composite material passes through the nozzle 12b at the tip of the cylinder, is filled into the cavity 14a of the mold 14 provided in front of the nozzle, and solidifies to form a composite having a desired shape. It becomes the material part 50. During this time, the molten composite material is constantly agitated by the rotational movement of the screw 11, so that it remains in a uniformly dispersed state with the added reinforcing material in the matrix metal, and is unevenly distributed due to sedimentation and levitation. Never do. Therefore, even in the obtained molded product, the reinforcing material is uniformly dispersed and exhibits excellent performance as a composite material.

Next, a method for extruding a granular material using a screw and a cylinder will be described. Similarly to the above, this utilizes the fact that the granular raw material of the composite material is formed into fine crystal grains because of rapid solidification. Due to the fine crystal grains, the plastic workability is greatly improved and the extrusion process can be performed.
FIG. 5 is a schematic diagram of the extruder 15. This apparatus has a cylinder 16, a screw 17 that rotates in the cylinder 16, a die 19 that is attached to the tip of the cylinder 16 to define the extruded shape of the extrudate, and a heating means 18 for the cylinder.
The granular raw material 5 a supplied from the raw material supply port at the rear of the cylinder is heated by the heating means 18 while being sent forward by the rotation of the screw 17. The raw material is pushed forward of the cylinder 16 by the screw 17, but is compressed by being resisted and compressed by a die 19 installed in front of the cylinder. By passing through the die 19 in a compressed state, the granular raw material becomes a high-density solidified body 51. By making the temperature of the cylinder below the solidus temperature of the magnesium alloy used as the raw material, the granular raw material can be extruded and densified as a solid.

Next, a method using a press will be described.
Conventionally, metal matrix composites have poor plastic deformability and are difficult to process such as forging and rolling.
In the present invention, it is utilized that the granular raw material of the composite material produced by the process described above is formed into fine crystal grains because it is rapidly solidified. Because of the fine crystal grains, the plastic deformability is greatly improved and forging can be performed.
FIG. 6 is a schematic diagram in the case of solidification using a normal vertical press 20. The mold 21 is filled with a granular material, and this is compressed and solidified at room temperature. In this state, complete densification does not occur, and a solidified body 5b having a relative density of about 80 to 90% is obtained. The pre-solidified body 5b is heated by the heating furnace 22 and further plastically processed (extruded, forged, etc.) at a high temperature, whereby the density reaches almost 100% and a dense composite material part is obtained. In this embodiment, the forging device 23 is used to obtain the molded body 52.

(Example 1)
As an example of the granular raw material manufacturing method, a method based on the melt spinning method will be described. The apparatus includes a crucible having a diameter of 120 mm and a depth of 350 mm, a bucket for adding a composite reinforcing material to the molten metal, the stirrer of the embodiment for stirring the molten metal in the crucible, and a water-cooled rotating roll made of copper having a diameter of 400 mm. It is equipped with. At the bottom of the crucible, there are provided a nozzle for dropping molten metal (mixed melt of magnesium alloy and SiC particles) onto the quenching roll, and a stopper for opening and closing the nozzle. All of these are stored in a chamber whose atmosphere can be adjusted.

About 1.5 kg of magnesium alloy (AM60, liquidus temperature 620 ° C.) was dissolved using this apparatus. To this, about 0.3 kg of SiC powder having a particle size of 5 to 10 μm (volume ratio 15%) was added and stirred for 10 minutes using a stir bar. After completion of the stirring, the temperature of the molten metal was adjusted to 750 ° C., the stopper at the bottom of the crucible was raised, the nozzle was opened, and an argon gas pressure of 0.5 MPa was added to the crucible. Due to this gas pressure, the molten metal in the crucible is sprayed out of the crucible through a nozzle and dropped onto a rotating roll immediately below the crucible. The rotating roll was rotated at 250 rpm, and the molten metal dropped on the surface of the roll was quenched and immediately solidified to form a thin strip-shaped solidified product (quenched foil strip). The thickness was about 0.2 to 0.6 mm.
The cross section of the foil strip thus obtained was polished and observed with an optical microscope, and it was found that SiC particles were uniformly dispersed throughout the foil strip as shown in FIG.
When this was pulverized with a normal pulverizer, it became a flake shape with a major axis length of about 5 mm and a minor axis length of about 3 mm (the thickness is about the same as the thickness of the foil strip). It became suitable for a certain molding process.

In this example, it was found that the temperature of the molten metal before quenching is suitable between the melting point T _L and T _L + 250 ° C. When the temperature is _lower than _TL , a solid phase is partially generated, and there is a problem that the dispersion of the reinforcing particles is prevented. Further, when the temperature is T _L + 250 ° C. or higher, there is a problem that the vaporization of the metal becomes intense.
In this example, the mixing ratio of the reinforcing material particles was found to be suitably 0.5% to 40% in volume percentage. If the mixing ratio is less than 0.5%, it becomes difficult to keep the distribution of the reinforcing material uniform throughout the foil strip. On the other hand, if the mixing ratio exceeds 40%, the fluidity of the molten metal decreases, and the nozzle There was a bad effect that it could not be smoothly injected.
Moreover, in this Example, it turned out that the thickness of a foil strip is suitable between 0.01 mm and 2.5 mm. If the thickness is less than 0.01 mm, it becomes a fine powder when pulverized, and the handling in the subsequent molding process becomes troublesome, and the risk of dust explosion increases depending on the type of metal. When the thickness exceeded 2.5 mm, it became difficult to pulverize into a granular material.

(Example 2)
The granular composite material (AM60 + SiC powder) produced in Example 1 was supplied to a thixomolding machine having a clamping force of 75 t and molded at a cylinder set temperature of 630 ° C. A test specimen having a tensile test piece shape as shown in FIG. 8 was easily obtained.
FIG. 9 shows the result of observing the microstructures of several places 1, 2, and 3 of this test molded body. As can be seen from this observation result, it was found that the distribution of reinforcing material particles in each part of the molded body was extremely uniform, and a sound composite material molded body was obtained.

(Example 3)
The granular composite material (AM60 + SiC powder) prepared in Example 1 was supplied to an extruder having a cylinder diameter of 51 mm and extruded at a cylinder set temperature of 550 ° C. (solid phase volume ratio 100%). A die having an inner diameter of 45 mm was installed at the tip of the cylinder. The granular raw material was extruded into a rod shape densified to a density of almost 100%.

(Example 5)
The granular composite material (AM60 + SiC powder) produced in Example 1 was filled in a mold having an inner diameter of 29 mm, and was compressed and solidified at room temperature with a compression force of 200 t. Since a compression-solidified body having a theoretical density of about 85% was obtained, this was back-extruded and forged at 350 ° C. and formed into a rod shape having a diameter of 11 mm.

(Comparative Example 1)
The alloy and SiC powder were mixed in the same combination as in Example 1 (AM60 + SiC powder), stirred to form a mixed melt, and then a tensile test piece having the same shape as in FIG. 8 was cast into a mold. An attempt was made to obtain a molded body, but a sound molded body such as that obtained in Example 3 was not obtained due to the fact that the molten metal was not filled in detail and that shrinkage cavities were formed inside the molded body.

(Comparative Example 2)
The alloy and SiC powder were mixed in the same combination as in Example 5 (AM60 + SiC powder), stirred to form a mixed melt, and then cast into a die having an inner diameter of 29 mm to form an ingot. This was subjected to backward extrusion forging at 350 ° C., but it was cracked and could not be molded.

It is a figure which shows the stirring and mixing apparatus used for the manufacturing method of the metal matrix composite material of one Embodiment of this invention. Similarly, it is detail drawing which shows the stirring element part of a stirring apparatus. Similarly, it is a figure which shows the stirring state in the crucible using a stirring apparatus. Similarly, it is a figure which shows the state which manufactures a metal-matrix composite material member by injection molding. Similarly, it is a figure which shows the state which manufactures a metal-matrix composite material member by extrusion molding. Similarly, it is a figure which shows the state which manufactures a metal-matrix composite material member by press molding. It is a drawing substitute photograph which shows the structure | tissue of the foil strip in the Example of this invention. Similarly, it is a figure which shows the molded object test material manufactured in the Example. Similarly, it is a drawing-substituting photograph showing cross-sectional structures at a plurality of positions in a molded body specimen.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Crucible 2 Vacuum container 3 Stirrer 30 Rotating shaft 31 Stirring blade 32 Stirring blade 33 Upper and lower stirring plate 34 Upper enclosure plate 35 Lower enclosure plate 37 Bubble hole 5 Molten metal 6 Reinforcement material 10 Thixomolding machine 15 Extruder 20 Vertical type pre The

Claims (12)

In a crucible, molten metal (including an alloy; the same applies hereinafter) and a reinforcing material, a rotating shaft capable of moving up and down, a plurality of stirring blades fixed to the rotating shaft and having different twist angles, and the rotating shaft And a stirring device including a vertical stirring plate having a plate surface along the horizontal direction, and mixed by stirring including rotation and vertical movement, and the molten metal in which the reinforcing material is dispersed is rapidly cooled to obtain a foil. A method for producing a metal matrix composite material, characterized by solidifying into a band shape and crushing the foil band into a granular or piece-like shape.   The method for producing a metal matrix composite material according to claim 1, wherein the foil strip thickness is 0.01 to 2.5 mm. In the crucible, the molten metal and the reinforcing material can be moved up and down, and the rotating shaft is fixed to the rotating shaft and has a plurality of stirring blades having different twist angles. Using a stirrer equipped with a vertical stirring plate having a flat plate surface, mixing is performed by stirring including rotation and vertical movement, and the molten metal in which the reinforcing material is dispersed is dispersed and rapidly cooled to solidify in a granular or flake form. A method for producing a metal matrix composite material.   The amount of the reinforcing material is 0.5% to 40% by volume with respect to the metal matrix composite material, and the metal matrix composite material according to any one of claims 1 to 3 is manufactured. Method. 5. The temperature at which stirring and mixing in the crucible is performed within the range of the melting point (liquidus temperature) T _L to T _L + 250 ° C. of the metal. A method for producing a metal matrix composite material.   Using the granular or piece-like metal matrix composite material produced by the method of any one of claims 1 to 5 and containing a reinforcing material dispersed therein, the metal is in a liquid phase state or a solid state of the metal. A method for producing a metal-based composite material member, wherein injection molding is performed in a state including a phase.   Extrusion molding in a state including a solid phase of the metal, using a granular or piece-like metal matrix composite material produced by the method of any one of claims 1 to 5 and containing a reinforcing material dispersed therein. A method for producing a metal-based composite material member.   The method for producing a metal-based composite material member according to claim 7, wherein the solid phase of the metal is 30 to 100% by volume with respect to all metals.   A rotating shaft capable of moving up and down; a plurality of stirring blades fixed to the rotating shaft and having different twist angles; and an upper and lower stirring plate fixed to the rotating shaft and having a plate surface along a lateral direction. Stirring device characterized.   The stirring device according to claim 9, wherein the upper and lower stirring plates have an enclosure portion having an enclosure surface along the upper side and / or the lower side.   The stirring device according to claim 9 or 10, wherein the stirring blades having different twist angles are fixed to the rotating shaft at different axial positions.   The agitation device according to any one of claims 9 to 11, wherein a bubble removing hole is formed in the upper and lower agitation plates.