Aluminum-based composite material and method for producing the same

Abstract

An aluminum-based composite material includes a plurality of coarse crystalline grains ( 3 ) of pure aluminum, and a plurality of fine crystalline grains ( 4 ) each having an aluminum matrix ( 1 ), and a dispersion material ( 2 ) dispersed inside the aluminum matrix and formed by reacting a portion or all of an additive with aluminum in the aluminum matrix. The fine crystalline grains exist among the coarse crystalline grains, and the fine crystalline grains have crystalline grain diameters smaller than crystalline grain diameters of the coarse crystalline grains.

What is claimed is: 
     
         1 . An aluminum-based composite material comprising:
 a plurality of coarse crystal grains of pure aluminum; and   a plurality of fine crystal grains each having an aluminum matrix, and a dispersion material dispersed inside the aluminum matrix and formed by reacting a portion or all of an additive with aluminum in the aluminum matrix, wherein   the fine crystal grains exist among the coarse crystal grains, and   the fine crystal grains have crystal grain diameters smaller than crystal grain diameters of the coarse crystal grains.   
     
     
         2 . The aluminum-based composite material according to  claim 1 , wherein the additive is at least one selected from the group consisting of carbon nanotubes, carbon nanohorns, carbon blacks, boron carbides, and boron nitrides. 
     
     
         3 . The aluminum-based composite material according to  claim 1 , wherein
 a ratio of a long axis to a short axis (long axis/short axis) of the dispersion material is 1 to 30,   the long axis ranges from 0.01 nm to 500 nm, and   the short axis ranges from 0.01 nm to 200 nm.   
     
     
         4 . An aluminum-based composite material comprising:
 a plurality of coarse crystalline grains each having an aluminum matrix, and a dispersion material dispersed inside the aluminum matrix and formed by reacting a portion or all of an additive with aluminum in the aluminum matrix; and   a plurality of fine crystalline grains each having an aluminum matrix, and a dispersion material dispersed inside the aluminum matrix and formed by reacting a portion or all of an additive with aluminum in the aluminum matrix, wherein   at least one of a purity of aluminum constituting the aluminum matrix and a content of the additive in the fine crystalline grains is different from that in the coarse crystalline grains,   the fine crystalline grains exist among the coarse crystalline grains, and   the fine crystalline grains have crystalline grain diameters smaller than crystalline grain diameters of the coarse crystalline grains.   
     
     
         5 . The aluminum-based composite material according to  claim 4 , wherein the additive is at least one selected from the group consisting of carbon nanotubes, carbon nanohorns, carbon blacks, boron carbides, and boron nitrides. 
     
     
         6 . The aluminum-based composite material according to  claim 4 , wherein
 a ratio of a long axis to a short axis (long axis/short axis) of the dispersion material is 1 to 30,   the long axis ranges from 0.01 nm to 500 nm, and   the short axis ranges from 0.01 nm to 200 nm.   
     
     
         7 . A method for producing the aluminum-based composite material according to  claim 1 , the method comprising:
 mixing an aluminum powder having a purity of 99% by mass or more with at least one additive selected from the group consisting of carbon nanotubes, carbon nanohorns, carbon blacks, boron carbides, and boron nitrides to obtain a fine crystalline grain precursor;   mixing the fine crystalline grain precursor with a coarse crystalline grain precursor made of pure aluminum, followed by powder compacting to obtain a compact; and   heating the compact at a temperature of 600 to 660° C.