US-12623976-B2 - Method for producing metal matrix composite and method for preparing preform

Abstract

The present invention relates to a technique of dramatically improving a method for causing a molten metal of an Al alloy or the like to infiltrate without pressurization into a preform obtained by molding and hardening a ceramic powder, and obtaining “a metal matrix composite formed from a ceramic powder and an Al alloy or the like” in a uniform state as a whole more simply and stably, and the present invention provides “a production method for producing a metal matrix composite containing aluminum and ceramic, the method including: obtaining a mixed body by performing molding using a mixture containing a magnesium-containing powder, a ceramic powder, and an inorganic or organic/inorganic binder that is hardened when heated to 500° C. or lower; preparing a preform by calcining the mixed body at a temperature of 500° C. or lower; and causing an Al alloy or the like to infiltrate without pressurization into the obtained preform to produce the metal matrix composite containing aluminum and ceramic, and a method for preparing the preform.”

Inventors

• Mutsuo Hayashi
• Zhipu PEI
• Pailin SILIPATTANAKITKUL

Assignees

• ADVANCED COMPOSITE CORPORATION

Dates

Publication Date

20260512

Application Date

20220208

Priority Date

20210419

Claims (7)

1. 1 . A method for producing a composite, comprising: performing molding by using a mixture so as to form a mixed body, the mixture comprising: a magnesium-containing powder, a ceramic powder, and an inorganic binder or an organic/inorganic binder, and the binder being hardened when heated to 500° C. or lower, wherein to the mixture, an organic solvent or a mixed solvent that comprises 100 parts by mass or less of water based on 100 parts by mass of an organic solvent is added; calcining the mixed body at a temperature of 500° C. or lower so as to form a preform; and causing metal aluminum or an aluminum alloy to infiltrate without pressurization into the obtained preform in a nitrogen atmosphere to produce a metal matrix composite comprising aluminum and ceramic.
2. 2 . The method for producing a composite according to claim 1 , wherein the magnesium-containing powder is a powder being at least one material in powder form selected from the group consisting of metal magnesium, a magnesium alloy, and magnesium silicide and has an average particle size in a range from 0.5 μm to 150 μm.
3. 3 . The method for producing a composite according to claim 1 , wherein the magnesium-containing powder is contained in the mixture within a range from 0.3% to 10% based on 100 parts by mass of the ceramic powder in terms of magnesium on a mass basis.
4. 4 . The method for producing a composite according to claim 1 , wherein the inorganic binder is water glass, and the organic/inorganic binder is at least one material selected from the group consisting of a silicone resin, a Si alkoxide, and an Al alkoxide.
5. 5 . The method for producing a composite according to claim 1 , wherein the organic solvent and the organic solvent in the mixed solvent are each independently at least one solvent selected from the group consisting of lower alcohols and normal alkanes.
6. 6 . The method for producing a composite according to claim 1 , wherein the mixed body is calcined at a temperature in a range from 430° C. to 500° C.
7. 7 . A method for preparing a ceramic preform applicable to production of an aluminum-based metal matrix composite by utilizing a pressureless infiltration process, and the method comprising: performing molding by using a mixture so as to form a mixed body, the mixture comprising: a magnesium-containing powder, a ceramic powder, and an inorganic or organic/inorganic binder, and the binder being hardened when heated to 500° C. or lower, wherein to the mixture, an organic solvent or a mixed solvent that comprises 100 parts by mass or less of water based on 100 parts by mass of an organic solvent is added; and calcining the obtained mixed body at a temperature of 500° C. or lower so as to form the preform.

Description

TECHNICAL FIELD The present invention relates to a method for producing a composite for obtaining a metal matrix composite formed from a ceramic powder and metal aluminum (Al) or an Al alloy, and a method for preparing a preform that can be used in the production method. In more detail, the present invention relates to a technique capable of dramatically improving productivity and product quality of a metal-ceramic composite obtained by forming a composite between an aluminum-based metal matrix and a ceramic powder as a reinforcing material. BACKGROUND ART Recently, an aluminum-based metal matrix composite obtained by forming a composite between an Al alloy or the like and ceramic has been widely used as machine components and as semiconductor/liquid crystal producing apparatuses, robot arms, and the like because of light weight, high strength, and high rigidity. In addition, the aluminum-based metal matrix composite has also been widely used for a heat sink, heat radiation spreader, and the like as a high thermal conductivity and low thermal expansion material. A composite formed from a ceramic powder and an Al alloy or the like, is a kind of so-called MMCs (metal matrix composites), and is usually produced by a method such as a high-pressure impregnation method, a casting method, and a pressureless infiltration process. The high-pressure impregnation method is a method in which a molten metal of an Al alloy or the like is forcibly caused to infiltrate into a ceramic powder or a molded body (preform) of a ceramic powder with a high-pressure press to form a composite between the ceramic powder and the Al alloy or the like. In the high-pressure impregnation method, since impregnation with the molten Al alloy or the like is performed at a high pressure, an expensive apparatus such as a press machine is necessary. Further, in a usual method, since impregnation cannot be performed in a product shape, it is necessary to detach a product from a press impregnation object surrounded by an Al alloy or the like by processing, and thus there is a problem that the processing cost for obtaining the product shape is required. In the casting method, a ceramic powder such as silicon carbide or alumina is stirred at a high speed in a molten metal of an Al alloy or the like to prepare a ceramic powder-containing Al alloy molten metal, and the ceramic powder-containing Al alloy molten metal is cast into a conventional mold such as a sand mold, a metal mold, or a lost wax mold to produce a composite body of the ceramic and the Al alloy or the like. In this method, when the content of the ceramic powder in the metal matrix is high, flowability of the molten metal lowers, and therefore, an upper limit of the content of the ceramic powder in the composite body is generally set to 30 v %, and thus there is a problem that the content ratio of the ceramic in the composite body is low. The pressureless infiltration process is a process in which a molten metal of an Al alloy or the like is caused to infiltrate without pressurization into a ceramic powder filled body or molded body (preform) in an atmosphere of Mg and nitrogen to impregnate the preform or the like with the molten metal, thereby obtaining a composite body. For example, a preform is obtained by adding an inorganic binder such as silica to a powder filled body of a ceramic powder such as SiC or alumina or a ceramic powder and then performing molding and calcining a resultant mixture. Then, a molten metal of an Al alloy or the like is caused to infiltrate without pressurization into gaps of the ceramic powder at a temperature of approximately 700° C. or higher at which the Al alloy or the like is melted under a nitrogen and Mg evaporation atmosphere to produce a composite body of the ceramic powder and the Al alloy or the like. This principle of the pressureless infiltration process is as follows: that is, when the atmosphere is set to the Mg and nitrogen atmosphere, thereby wettability between the ceramic and the Al alloy or the like is improved, and a so-called capillary phenomenon is promoted, so that the molten metal of the Al alloy or the like is caused to infiltrate without pressurization into the gaps (voids) of the powder filled body or the preform. In the pressureless infiltration process, when a ceramic filling rate is increased to decrease voids, thereby the ceramic filling rate in the composite body can be increased, and therefore it is possible to produce a composite body (MMC) of ceramic and an Al alloy in which physical property values such as a Young's modulus, a thermal conductivity, and a thermal expansion coefficient are high. In addition, when the composite body is produced by using a preform, the Al alloy can be caused to infiltrate while maintaining a shape of the preform. Accordingly, the pressureless infiltration process has attracted attention as a method for producing a MMC composite body in a near-net shape close to a product shape that does not