Method for producing high metal powder content aluminum composite body, method for preparing preform, and high metal powder content aluminum composite body

Abstract

The present invention provides a technique of obtaining a high metal powder content aluminum composite body, in which the numbers of cracks and defects are small and a metal content ratio is high, by impregnating a preform with an Al alloy or the like at a high pressure or by causing an Al alloy or the like to infiltrate without pressurization into a preform. This technique can be provided by establishing a preparation technique of obtaining a uniform preform of a metal powder in which the filling rate of the metal powder can be increased and there are no defects in the inside thereof. The present invention provides a method for producing a high metal powder content aluminum composite body, wherein: in a preform preparation step, two or more materials each having a different particle size are selected from metal powder materials having a particle size of 1 to 200 μm; a molded product obtained from a material obtained by adding and mixing an organic/inorganic binder to these metal raw materials is calcined at a temperature of 300° C. or higher to obtain a preform having a metal raw material content ratio of 55 v % or more; and the obtained preform is impregnated with a molten metal of an aluminum alloy or the like at a high pressure, or a molten metal of an aluminum alloy or the like is caused to infiltrate without pressurization into the obtained preform. The present invention also provides a composite body obtained by these production methods, and a method for preparing the preform.

1 . A method for producing a high metal powder content aluminum composite body, the method comprising:
 a preform preparation step for obtaining a metal powder molded body (preform) having a high metal content ratio; and   an aluminum or aluminum alloy impregnation step of impregnating the obtained preform with molten aluminum or a molten aluminum alloy, or causing molten aluminum or a molten aluminum alloy to infiltrate into the obtained preform, wherein   in the preform preparation step, two or more metal powder materials each having a different average particle size are selected from metal powder materials each having an average particle size of 1 μm or larger and 200 μm or smaller to use the two or more metal powder materials as metal raw materials for the preform, molding is performed using a mixture obtained by adding and mixing an organic/inorganic binder being at least any one selected from the group consisting of a silicone resin, a Si alkoxide, and an Al alkoxide, which are in a liquid form or in a state of having been made into a liquid form, into the metal raw materials, and a resultant molded product is calcined at a temperature of 300° C. or higher and 800° C. or lower, and thereby an organic substance in the molded product is removed and an inorganic substance functions as an inorganic binder to obtain a metal powder molded body having a content ratio (volume content ratio) of the metal raw materials of 55 v % or more, and   in the aluminum or aluminum alloy impregnation step, the metal powder molded body obtained in the preform preparation step is impregnated with a molten metal of the aluminum or the aluminum alloy at a high pressure of 10 MPa to 200 MPa.   
     
     
         2 . A method for producing a high metal powder content aluminum composite body, the method comprising:
 a preform preparation step for obtaining a metal powder molded body (preform) having a high metal content ratio; and   an aluminum or aluminum alloy impregnation step of impregnating the obtained preform with molten aluminum or a molten aluminum alloy, or causing molten aluminum or a molten aluminum alloy to infiltrate into the obtained preform, wherein   in the preform preparation step, two or more metal powder materials each having a different average particle size are selected from metal powder materials having an average particle size of 1 μm or larger and 200 μm or smaller (excluding powder materials of a Mg powder, an AlMg powder, a ZnMg powder, a ZnAl powder, and a Mg 2 Si powder) to use the two or more metal powder materials as metal raw materials for the preform, molding is performed using a mixture obtained by adding one or more powders selected from the group consisting of a Mg powder, an AlMg powder, a ZnMg powder, a ZnAl powder, and a Mg 2 Si powder in an amount within a range of 0.2 to 5 parts by mass based on 100 parts by mass of the metal raw materials, and further adding and mixing an organic/inorganic binder being at least any one selected from the group consisting of a silicone resin, a Si alkoxide, and an Al alkoxide, which are in a liquid form or in a state of having been made into a liquid form, and a resultant molded product is calcined at a temperature of 300° C. or higher and 500° C. or lower, and thereby an organic substance in the molded product is removed and an inorganic substance functions as an inorganic binder to obtain a metal powder molded body having a content ratio (volume content ratio) of the metal raw materials of 55 v % or more, and   in the aluminum or aluminum alloy impregnation step, aluminum or an aluminum alloy is caused to infiltrate without pressurization in a nitrogen atmosphere into the metal powder molded body obtained in the preform preparation step.   
     
     
         3 . The method for producing a high metal powder content aluminum composite body according to  claim 1 , wherein the metal powder is one, or two or more selected from a silicon powder or a silicon-based alloy powder containing silicon, a titanium powder, an iron powder or an iron-based alloy powder containing iron, and a nickel powder or a nickel-based alloy powder containing nickel. 
     
     
         4 . The method for producing a high metal powder content aluminum composite body according to  claim 1 , wherein the content ratio (volume content ratio) is 55 v % or more and 85 v % or less. 
     
     
         5 . The method for producing a high metal powder content aluminum composite body according to  claim 1 , wherein the two or more metal powders each having a different average particle size comprise at least: a metal powder A having an average particle size of 10 μm or smaller; and a metal powder B having an average particle size of 40 μm or larger, and comprise at least 3% of the metal powder A and 50% or more of the metal powder B in a total amount of the metal powders on a mass basis. 
     
     
         6 . The method for producing a high metal powder content aluminum composite body according to  claim 1 , wherein the organic/inorganic binder is at least any one selected from the group consisting of a Si alkoxide and an Al alkoxide. 
     
     
         7 . A preform preparation method for obtaining a metal powder molded body (preform) which is used in obtaining a high metal powder content aluminum composite body metal by impregnating the preform with molten aluminum or a molten aluminum alloy at a high pressure and has a high metal powder content ratio, wherein
 two or more metal powder materials each having a different average particle size, the metal powder materials containing at least a metal powder A having an average particle size of 10 μm or smaller, a metal powder B having an average particle size of 40 μm or larger and containing at least 3% of the metal powder A and 50% or more of the metal powder B in the total amount of the metal powders on a mass basis, are selected from metal powder materials having an average particle size of 1 μm or larger and 200 μm or smaller to use the two or more metal powder materials as metal raw materials for the preform, molding is performed using a mixture obtained by adding and mixing an organic/inorganic binder being at least any one selected from the group consisting of a silicone resin, a Si alkoxide, and an Al alkoxide, which are in a liquid form or in a state of having been made into a liquid form, into the metal raw materials, and a resultant molded product is calcined at a temperature of 300° C. or higher and 800° C. or lower, thereby obtaining a metal powder molded body having a content ratio (volume content ratio) of the metal raw materials of 55 v % or more.   
     
     
         8 . A preform preparation method for obtaining a metal powder molded body (preform) which is used in obtaining a high metal powder content aluminum composite body metal by causing molten aluminum or a molten aluminum alloy to infiltrate without pressurization in a nitrogen atmosphere into the preform and has a high metal powder content ratio, wherein
 two or more metal powder materials each having a different average particle size, the metal powder materials containing at least a metal powder A having an average particle size of 10 μm or smaller, a metal powder B having an average particle size of 40 μm or larger and containing at least 3% of the metal powder A and 50% or more of the metal powder B in a total amount of the metal powders on a mass basis, are selected from metal powder materials having an average particle size of 1 μm or larger and 200 μm or smaller (excluding powder materials of a Mg powder, an AlMg powder, a ZnMg powder, a ZnAl powder, and a Mg 2 Si powder) to use the two or more metal powder materials as metal raw materials for the preform, molding is performed using a mixture obtained by adding one or more powders selected from the group consisting of a Mg powder, an AlMg powder, a ZnMg powder, a ZnAl powder, and a Mg 2 Si powder in an amount within a range of 0.2 to 5 parts by mass based on 100 parts by mass of the metal raw materials, and further adding and mixing an organic/inorganic binder being at least any one selected from the group consisting of a silicone resin, a Si alkoxide, and an Al alkoxide, which are in a liquid form or in a state of having been made into a liquid form, and a resultant molded product is calcined at a temperature of 300° C. or higher and 500° C. or lower, thereby obtaining a metal powder molded body having a content ratio (volume content ratio) of the metal raw materials of 55 v % or more.   
     
     
         9 . A high metal powder content aluminum composite body having an extremely small number of internal defects such as blowholes, wherein the high metal powder content aluminum composite body is obtained by the method for producing a high metal powder content aluminum composite body according to  claim 1 , in which high-pressure impregnation is utilized. 
     
     
         10 . A high metal powder content aluminum composite body having a near-net shape close to a product shape, wherein the high metal powder content aluminum composite body is obtained by the method for producing a high metal powder content aluminum composite body according to  claim 2 , in which pressureless infiltration is utilized in a nitrogen atmosphere. 
     
     
         11 . The method for producing a high metal powder content aluminum composite body according to  claim 2 , wherein the metal powder is one, or two or more selected from a silicon powder or a silicon-based alloy powder containing silicon, a titanium powder, an iron powder or an iron-based alloy powder containing iron, and a nickel powder or a nickel-based alloy powder containing nickel. 
     
     
         12 . The method for producing a high metal powder content aluminum composite body according to  claim 2 , wherein the content ratio (volume content ratio) is 55 v % or more and 85 v % or less. 
     
     
         13 . The method for producing a high metal powder content aluminum composite body according to  claim 2 , wherein the two or more metal powders each having a different average particle size comprise at least: a metal powder A having an average particle size of 10 μm or smaller; and a metal powder B having an average particle size of 40 μm or larger, and comprise at least 3% of the metal powder A and 50% or more of the metal powder B in a total amount of the metal powders on a mass basis. 
     
     
         14 . The method for producing a high metal powder content aluminum composite body according to  claim 2 , wherein the organic/inorganic binder is at least any one selected from the group consisting of a Si alkoxide and an Al alkoxide.