JP4781934B2 - Method for producing aluminum alloy matrix composite - Google Patents

Description

The present invention relates to a method for producing an aluminum alloy matrix composite material. More specifically, the present invention relates to an aluminum alloy matrix obtained by a pressure infiltration method (also referred to as a high pressure casting method) and having improved workability than before. The present invention relates to a method for manufacturing a composite material.

Metal matrix composites composed of a metal matrix and a ceramic reinforcing phase have both the rigidity and wear resistance of the reinforcing phase and the ductility and toughness of the metal matrix, and are thus being used in various applications. .
Further, such a composite material can increase the specific Young's modulus, which is a value obtained by dividing the Young's modulus by the density, and thus has a large natural sound speed and has excellent vibration damping characteristics. Therefore, it is possible to apply such a composite material having excellent vibration control properties to, for example, a high-speed moving arm of a robot.

However, the conventional metal matrix composite has insufficient workability. This is because alumina, SiC, or the like having high hardness is often used as a ceramic material as a reinforcing material, and therefore workability is poor. Therefore, in order to process the metal matrix composite material, wet grinding using a diamond grindstone as a processing tool is required.

On the other hand, an aluminum-based composite material using aluminum borate particles having low hardness has been proposed as ceramic as a reinforcing material (see, for example, Patent Document 1).

However, even with the above-described method, defects due to poor penetration of molten metal may occur. Furthermore, when processing the obtained composite material, it cannot be said that the tool used for processing has a long service life, and further improvement in workability has been desired.
JP 2004-353049 A

The present invention has been made in view of the problems of the above-described metal matrix composite material, and the object thereof is that of a metal matrix composite material that does not cause poor penetration and has improved workability as compared with the prior art. It is to provide a manufacturing method.

As a result of intensive studies in view of the above problems, the present inventors have filled an aluminum borate powder raw material in which the proportion of particles having a particle size of 100 μm or more is 0 to 20% by volume in the method for producing an aluminum alloy matrix composite material The present invention has been completed by finding that the workability of the composite material can be improved as compared with the prior art by forming the body and forming the aluminum alloy matrix composite material by the pressure infiltration method. That is, the present inventors provide the following as means for solving the above problems.

(1) A method for producing an aluminum alloy-based composite material in which aluminum borate powder is composited in an aluminum alloy, which is filled with an aluminum borate powder raw material in which the proportion of particles having a particle size of 100 μm or more is 0 to 20% by volume A step of obtaining a filler, a step of preheating the filler, a step of heating an aluminum alloy containing 1 to 5% by mass of Cu at 700 to 900 ° C. to obtain a molten aluminum alloy, and the preheating And a step of pressurizing and infiltrating the molten aluminum alloy with a pressure of 50 to 200 MPa into the filled body.

According to the present invention, the permeability of the molten aluminum alloy can be improved. And workability can be improved by using the aluminum borate powder raw material whose ratio for which the particle diameter is 100 micrometers or more accounts for 0-20 volume%.
Therefore, it is possible to reduce penetration defects and to produce an easily processable aluminum alloy matrix composite material with few defects with a high yield.

Hereinafter, the present invention will be described in more detail.
In the present invention, a method for producing an aluminum alloy-based composite material in which aluminum borate powder is composited in an aluminum alloy, wherein the proportion of particles having a particle size of 100 μm or more is 0-20 vol% A step of filling a container to obtain a filler, a step of preheating the filler, a step of heating an aluminum alloy containing 1 to 5% by mass of Cu at 700 to 900 ° C. to obtain a molten aluminum alloy, and And a step of pressure infiltrating the molten aluminum alloy into the preheated filler at a pressure of 50 to 200 MPa, and a method for producing an aluminum alloy matrix composite material is proposed.

Here, as a raw material of the aluminum alloy as the metal matrix according to the present invention, aluminum or a known aluminum alloy ingot or powder can be used.

Next, as the ceramic powder raw material as the reinforcing material according to the present invention, aluminum borate powder having low hardness is used. Here, the shape of the aluminum borate powder is preferably particulate.
Moreover, it is preferable to use an aluminum borate powder raw material in which the proportion of particles having a particle size of 100 μm or more is 0 to 20% by volume in order to improve workability.
The reason for this is that when using a coarse aluminum borate powder in which the proportion of particles having a particle size of 100 μm or more exceeds 20% by volume, the machining tool surface and the work piece are compared with the case of using a fine aluminum borate powder. It is presumed that the processing becomes difficult because the proportion of the aluminum borate powder in the contact area with the surface increases.

Next, it is preferable that the filling rate of the aluminum borate powder in the composite material according to the present invention is 40 to 60% by volume. The reason is that if the filling rate of the aluminum borate powder is smaller than 40% by volume, the rigidity becomes unfavorable.
Moreover, it is because a workability will fall when the filling rate of an aluminum borate powder is larger than 60 volume%, and is unpreferable.

Next, as a method of filling the powder raw material in the step of filling the aluminum borate powder raw material according to the present invention to obtain a filler, a method of giving vibration while filling the powder raw material into a container is preferably mentioned. Here, it is preferable that it is 40-60 volume% as a filling rate of the aluminum borate in a filler for the reason mentioned above.
Moreover, as a process of obtaining a filler, a method of adding an organic binder and an inorganic binder to an aluminum borate powder raw material and forming a filler by pressing, a solvent such as water and a powder raw material, an inorganic binder, a filter press, etc. You may use the method of forming a filler by this method.

Next, as the step of heating the filling body, the heating temperature of the filling body is 500 to 1000 ° C., preferably 700 to 800 ° C.

Next, in the step of heating the aluminum alloy to obtain a molten aluminum alloy, the reason for setting the heating temperature to 700 to 900 ° C. is that if the melting temperature of the aluminum alloy is lower than 700 ° C., the viscosity of the molten aluminum alloy is high and penetrates. This is because it becomes difficult to cause penetration failure and is not preferable. When the temperature is higher than 900 ° C., the aluminum alloy is easily oxidized, and alumina is mixed into the composite material, so that the workability is lowered.

Here, the reason for using an aluminum alloy containing 1 to 5% by mass of Cu is not preferable because the workability deteriorates when the content of Cu in the aluminum alloy is less than 1% by mass, and the content of Cu is not preferable. This is because if it exceeds 5% by mass, the ductility of the composite material becomes small and it becomes brittle, which is not preferable.

Next, the applied pressure in the step of pressure infiltrating the molten aluminum alloy into the filler is preferably 50 MPa to 200 MPa. The reason for this is that if the applied pressure is less than 50 MPa, penetration failure occurs, which is not preferable. In addition, it is not preferable in designing the apparatus to increase the applied pressure beyond 200 MPa.

Next, the excess aluminum alloy part adhering around the composite material thus obtained is removed by processing to obtain an aluminum alloy matrix composite material having a desired shape.

Hereinafter, the present invention will be described in more detail with specific examples and comparative examples of the present invention.
(1) Production of aluminum alloy matrix composite The aluminum borate powder raw material as a reinforcing material was a commercial product and powder raw materials having various particle size distributions were used. (The proportion of particles having a particle size of 100 μm or more in the aluminum borate powder raw material was evaluated by a known particle size analyzer.) Each powder raw material was filled in a 100 × 150 × 50 mm iron container with vibration. And the filling body from which the filling rate of aluminum borate powder will be 50 volume% was obtained. Next, the obtained packing was preheated at 700 ° C.
Next, aluminum alloys containing Cu having various contents were heated at various temperatures to obtain molten aluminum alloys. Next, the preheated filler was placed in a mold in a pressure infiltration apparatus, and the molten aluminum alloy was infiltrated under pressure at a pressure of 60 MPa for 10 minutes, combined, and cooled to produce a composite material. . Then, the excess aluminum alloy adhering to the circumference was cut and removed to obtain an aluminum alloy matrix composite material.

(2) Evaluation method The resulting composite material was checked for the presence or absence of penetration failure by visually observing the appearance of the cut surface. Was determined to be defective.
Next, the evaluation of workability was performed by chamfering a 100 × 150 mm surface of the obtained composite material with a milling machine (MILLAC 415V, manufactured by Toyokazu Okuma). At this time, as a machining tool, use a set of 4 carbide tools (R245-12T3E) made by Sandvik, and set the maximum number that can be obtained without changing the carbide tool. Examined.
Further, for the purpose of evaluating the ductility of the obtained composite material, the elongation was evaluated by evaluating the elongation according to a method according to JIS Z 2241. The obtained evaluation results are summarized in Table 1.

(3) Evaluation results As is clear from Table 1, in Examples 1 to 3, since the particle size of aluminum borate, the composition of the aluminum alloy, and the melting temperature are all within the scope of the present invention, good processing is achieved. Had sex.
On the other hand, since the aluminum borate of 100 μm or more is as large as 30% by volume in Comparative Example 1, and since the aluminum alloy does not contain Cu in Comparative Example 2, all of the workability deteriorated.
Further, in Comparative Example 3, since the Cu content of the aluminum alloy was as large as 6% by mass, the elongation was lowered. Further, in Comparative Example 4, since the melting temperature of the aluminum alloy was lowered to 600 ° C., a penetration failure occurred. Further, in Comparative Example 5, the melting temperature of the aluminum alloy was increased to 950 ° C., so that the workability was lowered. Moreover, in the comparative example 6, since the osmotic pressure was lowered to 30 MPa, a penetration failure occurred.

  From the above, it was found that according to the present invention, it is possible to produce a metal matrix composite material that does not cause poor penetration and has improved workability.

Claims (1)

A method for producing an aluminum alloy-based composite material in which aluminum borate powder is composited in an aluminum alloy, in which an aluminum borate powder raw material in which the proportion of particles having a particle size of 100 μm or more is 0 to 20% by volume is filled A step of preheating the filler, a step of heating an aluminum alloy containing 1 to 5% by mass of Cu at 700 to 900 ° C. to obtain a molten aluminum alloy, and the preheated filler And a step of pressure infiltrating the molten aluminum alloy at a pressure of 50 to 200 MPa.