Anodized metal matrix composite

Abstract

Metal matrix composite articles are made with a substrate and an anodized layer. The anodized layer includes matrix phase and a dispersed phase of reinforcement particles in the matrix, the matrix being an oxide of aluminum or an aluminum alloy. The ratio of the thickness of the anodized layer to the average particle size (D50) of the reinforcement particles is at least 1.3.

1 . A metal matrix composite article comprising:
 a substrate; and   an anodized layer;   wherein the substrate comprises:
 an aluminum or aluminum alloy matrix; and 
 reinforcement particles dispersed in the matrix; 
   wherein the anodized layer comprises:
 an aluminum oxide matrix; and 
 reinforcement particles dispersed in the aluminum oxide matrix; and 
   wherein a ratio of a thickness of the anodized layer to an average particle size (D50) of the reinforcement particles is at least 1.3.   
     
     
         2 . The article of  claim 1 , wherein the ratio is at least 1.6. 
     
     
         3 . The article of  claim 1 , wherein the ratio is at least 3. 
     
     
         4 . The article of  claim 1 , wherein the thickness of the anodized layer is at least 5 μm; and wherein the average particle size is from about 0.3 μm to about 3 μm. 
     
     
         5 . The article of  claim 1 , wherein the thickness of the anodized layer is from about 1 μm to about 3 μm; and wherein the average particle size is from about 0.3 μm to about 0.7 μm. 
     
     
         6 . The article of  claim 1 , wherein the reinforcement particles comprise at least one ceramic material selected from the group consisting of carbides, oxides, silicides, borides, and nitrides. 
     
     
         7 . The article of  claim 1 , wherein the reinforcement particles comprise at least one ceramic material selected from the group consisting of silicon carbide, titanium carbide, boron carbide, silicon nitride, titanium nitride, and zirconium oxide. 
     
     
         8 . The article of  claim 1 , wherein the aluminum alloy comprises at least one element selected from the group consisting of chromium, copper, lithium, magnesium, manganese, nickel, and silicon. 
     
     
         9 . The article of  claim 1 , wherein the aluminum alloy comprises from about 91.2 wt % to about 94.7 wt % aluminum, from about 3.8 wt % to about 4.9 wt % copper, from about 1.2 wt % to about 1.8 wt % magnesium, and from about 0.3 wt % to about 0.9 wt % manganese. 
     
     
         10 . The article of  claim 1 , wherein the aluminum alloy comprises from about 95.8 wt % to about 98.6 wt % aluminum, from about 0.8 wt % to about 1.2 wt % magnesium, and from about 0.4 wt % to about 0.8 wt % silicon. 
     
     
         11 . The article of  claim 1 , wherein the composite article comprises from about 15 vol % to about 50 vol % of the reinforcement particles. 
     
     
         12 . A method for producing a metal matrix composite article, comprising:
 anodizing a surface of a substrate comprising a metal matrix composite to form an anodized layer on the surface;   wherein the metal matrix composite comprises reinforcement particles dispersed in an aluminum or aluminum alloy matrix;   wherein a ratio of a thickness of the anodized layer to an average particle size (D50) of the reinforcement particles is at least 1.3.   
     
     
         13 . The method of  claim 12 , wherein the anodizing is performed at a voltage of about 10 volts to about 60 volts. 
     
     
         14 . The method of  claim 12 , wherein the anodizing is performed for a time period of about 15 minutes to about 90 minutes. 
     
     
         15 . The method of  claim 12 , wherein the anodizing is performed at a bath temperature of about 15° C. to about 30° C. 
     
     
         16 . The method of  claim 12 , wherein the ratio is at least 3. 
     
     
         17 . The method of  claim 12 , wherein the thickness of the anodized layer is from about 1 μm to about 3 μm; and wherein the average particle size is from about 0.3 μm to about 0.7 μm. 
     
     
         18 . The method of  claim 12 , wherein the thickness of the anodized layer is at least 8 μm. 
     
     
         19 . An article comprising an anodized layer, wherein the anodized layer comprises:
 an aluminum oxide matrix; and   reinforcement particles dispersed in the aluminum oxide matrix; and   wherein a ratio of a thickness of the anodized layer to an average particle size (D50) of the reinforcement particles is at least 1.3.   
     
     
         20 . A method of using an article, comprising:
 exposing the article to harsh environmental conditions,   wherein the article comprises an anodized layer, wherein the anodized layer comprises:
 an aluminum oxide matrix; and 
 reinforcement particles dispersed in the aluminum oxide matrix; and 
 wherein a ratio of a thickness of the anodized layer to an average particle size (D50) of the reinforcement particles is at least 1.3.