JPH076013B2 - Method for producing aluminum- and magnesium-based metal composite material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an aluminum- and magnesium-based metal composite which is effective for composite of short fibers or fine particles such as ceramic whiskers into an aluminum- and magnesium-based matrix metal. The present invention relates to a manufacturing method of wood.

[Conventional technology]

Powder sintering, molten metal forging (pressure casting), etc. are considered to be practical methods for the composite strengthening of aluminum and magnesium or their alloys by ceramic materials, but they are formed by these methods. It is known that the properties of composite materials depend greatly on the wettability and dispersibility of the composite material at the composite interface of the ceramic material to the matrix metal.

However, ceramic materials generally do not have good wettability with molten aluminum and magnesium-based metals. For example, even if silicon carbide whiskers are placed in a molten metal of aluminum or magnesium and stirred, the interfaces are not wet at all and smooth mutual dispersion cannot be obtained. Further, in the case of powder sintering, a uniform dispersion structure cannot be obtained unless the particle size adjustment of the composite components is strictly controlled.

Although many means for improving the composite performance by improving such wettability and dispersibility have been proposed, Japanese Patent Publication No. 61-51618, which was developed by the present applicant as a highly practical method among the prior art. There is an invention of the issue. This invention is directed to a method for producing FRM by using SiC whiskers, and the structural feature is that Al, Mg, or a matrix metal composed of an alloy thereof is compositely strengthened with SiC whiskers, and the SiC whiskers are compressed. The point is that the molded body is impregnated with a matrix metal heated and melted at 800 ° C. or more and brought into contact with each other to form a precursor, and the precursor is stirred and dispersed in a molten metal of the matrix metal to form an ingot.

[Problems to be Solved by the Invention]

The invention of Japanese Patent Publication No. 61-51618 described above improves the wettability between interfaces by forming a precursor of FRM in advance under specific conditions.
Since it is necessary to make a SiC whisker molded body (preform) and to impregnate the matrix metal that has been heated and melted to 800 ° C or higher, this method often results in a complex interface at 1100 to 1200 ° C. There is a problem that a part of the matrix metal is converted into a brittle carbide due to an interfacial reaction, resulting in material deterioration.

The present invention, as a result of intensive studies aimed at solving the above-mentioned problems, does not cause a chemical reaction at the composite interface when a pressure of a certain value or more is applied during the formation of the precursor composite matrix. The wettability is sufficiently improved even by the composite treatment at 800 ° C or less, and the short matrix or fine particles such as ceramic whiskers are used as the reinforcing material, and the composite base material is formed without forming a preform in advance. Has been developed by elucidating the fact that excellent composite performance is added.

Therefore, an object of the present invention is to provide a method for producing a high-performance aluminum- and magnesium-based metal composite material which is always homogeneous and does not cause material deterioration by using short fibers or fine particles such as ceramic whiskers as a reinforcing material.

[Means for Solving the Problems]

The method for producing an aluminum- and magnesium-based metal composite material according to the present invention for achieving the above object is to mix short fibers or fine particles such as ceramic whiskers with aluminum powder or magnesium powder or an alloy powder thereof, and then the temperature of 400 ~ 800 ℃, to create a composite base material of Vf5 ~ 90% by hot pressure sintering under the conditions of pressure 10 Kg / cm ² or more, the composite base material is the same as the aluminum powder or magnesium powder or its alloy powder The compositional requirement is that the matrix metal is heated and melted and stirred in the melting temperature range of the matrix metal to composite the whole, and it is characterized in that the composite base material is formed by powder sintering means.

The ceramic material that serves as the reinforcing material of the present invention includes a wide range of general ceramic materials regardless of whether they are oxide-based or non-oxide-based, but especially when silicon carbide and silicon nitride whiskers or fine particles are used. Highly effective.

To mix short fibers or fine particles such as these ceramic whiskers with a matrix metal powder consisting of aluminum powder and magnesium powder or its alloy powder,
A method is used in which both powders are sufficiently stirred and dispersed in an organic solvent such as alcohol or acetone, and then filtered and dried. The mixing ratio of the reinforcing material and the matrix metal powder is set so that the Vf of the reinforcing material in the composite base material is a desired value in the range of 5 to 90%.

The mixed powder is then filled in a mold and once pre-compressed at room temperature, and then hot-press sintering under conditions of a temperature of 400 to 800 ° C and a pressure of 10 Kg / cm ² or more to produce a composite base material of Vf 5 to 90%. To do.
In this case, when the temperature is lower than 400 ° C and the pressure is lower than 10 kg / cm ² , the wettability of the interface is not effectively improved, and the temperature is lower than 80 Kg / cm ^2.
Above 0 ° C, there is a risk of interfacial reaction.

The composite base material created by such powder sintering means,
As it is or after being processed into an appropriate agglomerate, it is heated, melted and stirred in the melting temperature range of the matrix metal together with the same matrix metal powder as in the formation of the composite base material. In this step, it is possible to add the composite base material to the molten metal of the matrix metal that has been melted in advance and to stir it. However, considering the safety of the operation, the composite base material and the matrix metal are in a solid state in a crucible. It is desirable to adopt a treatment method of heating, melting and stirring in a container. At this time, the Vf value can be adjusted to a desired ratio from the relationship between the Vf of the composite base material and the amount of the matrix metal co-melted.

The composite molten metal that has been heated, melted and stirred is poured into a mold to form an ingot.

The composite ingot thus obtained has a composite structure in which short fibers or fine particles such as ceramic whiskers are uniformly dispersed, but after forging, rolling, extruding, etc., depending on the purpose of use, it is pressed. Is applied.

[Work]

According to the present invention, the wettability of the interface is effectively improved in the step of forming the composite base material in which the matrix metal is forcibly fused by the pressure of a certain value or more against the reinforcing material, and the two components are no longer separated. To form an interface-free state with no interface. Therefore, in the subsequent step of heating, melting and stirring, the matrix metal that is co-melted through the matrix metal layer encapsulating the reinforcing material is smoothly and rapidly interdispersed and converted into a homogeneous composite structure.

Based on such an action, it becomes possible to impart a high-performance composite structure even in a temperature range of 800 ° C. or lower at which an interfacial reaction does not occur.

〔Example〕

 Hereinafter, the present invention will be described with reference to examples.

Examples 1 and 2 and Comparative Example 1 Silicon carbide whiskers having a diameter of 0.2 to 0.5 μm and a length of 100 to 200 μm (“Tokai Carbon” manufactured by Tokai Carbon Co., Ltd.)
And aluminum alloy powder (AC8A) were weighed in a volume ratio of 30:70, put into ethanol, sufficiently stirred and mixed, and then filtered and dried to obtain 1.5 kg of mixed powder. Fill the mold with the mixed powder and pre-compress it, then continue at 450 ℃
The pressure was changed at the temperature of 5 to heat-sinter for 5 minutes to form a Vf 30% composite base material.

750g of the composite base material and 500g of the same matrix metal as the aluminum alloy (AC8A) were placed in a graphite crucible and 750
The ingredients were melted by heating to ° C and stirred. The molten metal after stirring was poured into a mold and solidified to obtain a Vf15% composite ingot.

From the results in Table 1, it was confirmed that in the examples of the present invention, the interfacial wettability and the dispersibility were effectively improved.

Example 3, Comparative Example 2 Instead of the silicon carbide whiskers of Example 1, an average particle size of 3μ
An aluminum-based metal composite material was manufactured under the same conditions as in Example 1 except that silicon nitride fine powder of m was used as a reinforcing material.

The strength characteristics of the composite material thus obtained are shown in Table 2. As a comparative example, Table 2 also shows the strength characteristics of the aluminum alloy alone.

Example 4 and Comparative Example 3 Magnesium powder (Mg purity 99.9% or more, particle size 0.2 to 1.0 mm) 680 g and the same silicon carbide whiskers as Example 1 540 g
Was dispersed and mixed in ethanol and dried in vacuum to obtain a mixed powder corresponding to Vf30%. This powder was filled in a die having a diameter of 100 mm, pre-compressed, heat-treated at 630 ° C. in a vacuum furnace, and further hot-pressed at 630 ° C. to obtain a composite base material. The pressure in this case was 800 Kg / cm ² .

500 g of this base material was heated at the same time as 280 g of magnesium lump in an inert atmosphere, dissolved and stirred to obtain a magnesium-based metal composite material with Vf of 17%.

The properties of the composite obtained are shown in Table 3 in comparison with the plain magnesium used as matrix.

[Effects of the Invention] As described above, the use of the manufacturing method of the present invention, due to the unique function of improving the wettability and dispersibility, makes aluminum having excellent composite performance at a composite temperature of 800 ° C. or lower that does not cause characteristic deterioration, and A magnesium-based metal composite material can be obtained. Moreover, since it is not necessary to precisely form a preform and adjust the particle size, it is possible to supply a desired Vf composite structure with good mass productivity.

Claims (1)

[Claims] 1. Short fibers or fine particles such as ceramic whiskers are mixed with aluminum powder or magnesium powder or its alloy powder, and then the temperature is 400 to 800 ° C. and the pressure is 10
Vf5 ~ 90% by hot pressure sintering under the condition of Kg / cm ² or more
A composite base material is prepared, and the composite base material is heated and melted and stirred in the melting temperature range of the matrix metal together with the same matrix metal as the aluminum powder or magnesium powder or its alloy powder to form a composite as a whole. Method for producing aluminum-based and magnesium-based metal composite material.