High performance aluminum nanocomposites

Abstract

The high performance aluminum nanocomposites are formed by a combination of mechanical alloying and Spark Plasma Sintering (SPS) in order to obtain reinforced nanostrutured aluminum alloys, The nanocomposites are formed from aluminum metal reinforced with silicon carbide (SiC) particulates, wherein the SiC particulates have a particle diameter between about 20 and 40 nm. The nanocomposites are prepared by mixing aluminum-based metal, e.g., Al-7Si-0.3Mg, (Al=92.7%, Si-7% and Mg=0.3%), with SiC nanoparticles in a conventional mill to form a uniformly distributed powder, which is then sintered at a temperature of about 500° C. for a period up to about 20 hours to consolidate the silicon carbide particulates in order to obtain the reinforced aluminum metal-based silicon carbide nanocomposite.

We claim: 
     
         1 . A high performance aluminum nanocomposite, comprising an aluminum alloy reinforced with uniformly distributed silicon carbide particles, wherein the silicon carbide particles have a diameter between about 20 and 40 nm. 
     
     
         2 . The high performance aluminum nanocomposite of  claim 1 , wherein the aluminum alloy comprises Al-7Si-0.3Mg, having a composition of about 92.7% by weight of Al, 7% by weight of Si and 0.3% by weight of Mg. 
     
     
         3 . The high performance aluminum nanocomposite of  claim 1 , wherein the aluminum alloy comprises Al-12Si-0.3Mg, having a composition of about 87.7% by weight of Al, 12% by weight of Si and 0.3% by weight of Mg. 
     
     
         4 . The high performance aluminum nanocomposite of  claim 1 , wherein the nanocomposite is nano-crystalline in structure, having a crystalline size of up to 100 nm. 
     
     
         5 . The high performance aluminum nanocomposite of  claim 1 , wherein the nanocomposite has an average hardness as measured by Vickers indenters of not less than 40. 
     
     
         6 . The high performance aluminum nanocomposite of  claim 1 , wherein the silicon carbide nanoparticles comprise between 5 wt % and 20 wt % of the nanocomposite, the balance being the aluminum alloy. 
     
     
         7 . A method of making a high performance aluminum nanocomposite, comprising the steps of:
 (a) mixing an aluminum-based metal alloy with silicon carbide nanoparticles by mechanical alloying in a ball mill to form a uniformly distributed powder having a nano-crystalline structure;   (b) sintering the powder to consolidate the powder to obtain a reinforced aluminum alloy nanocomposite, whereby the mechanically alloyed powder retains the nano-crystalline structure after sintering.   
     
     
         8 . The method of making a high performance aluminum nanocomposite according to  claim 7 , wherein step (a) comprises adding to the aluminum alloy between 5% and 20% silicon carbide nanoparticles by weight and milling the mixture at 200 rpm for between 5 hours and 20 hours. 
     
     
         9 . The method of making a high performance aluminum nanocomposite according to  claim 7 , wherein the sintering step is carried out at a temperature of between 400° C. and 500° C. 
     
     
         10 . The method of making a high performance aluminum nanocomposite according to  claim 7 , wherein step (a) comprises adding the aluminum alloy in powder form with an average particle size of 40 microns. 
     
     
         11 . The method of making a high performance aluminum nanocomposite according to  claim 7 , wherein the ball mill comprises a planetary ball mill. 
     
     
         12 . The method of making a high performance aluminum nanocomposite according to  claim 7 , wherein the aluminum-based metal alloy comprises 40 micron particles of an alloy of aluminum, silicon, and magnesium 
     
     
         13 . The method of making a high performance aluminum nanocomposite according to  claim 7 , wherein the aluminum-based metal alloy comprises Al-7Si-0.3Mg. 
     
     
         14 . The method of making a high performance aluminum nanocomposite according to  claim 7 , wherein the aluminum-based metal alloy comprises Al-12Si-0.3Mg. 
     
     
         15 . A method of making a high performance aluminum nanocomposite, comprising the steps of:
 milling a mixture of particles of an Al—Si—Mg alloy having an average particle diameter of 40 μm and particles of silicon carbide having a diameter of between 20 nm and 40 nm in a planetary ball mill for about 20 hours in order to form a reinforced aluminum nanocomposite; and   sintering the reinforced aluminum nanocomposite at a temperature of about 500° C. in order to consolidate the reinforced aluminum nanocomposite while retaining the reinforced aluminum nanocomposite in a nano-crystalline structure.   
     
     
         16 . The method of making a high performance aluminum nanocomposite according to  claim 15 , wherein the silicon carbide particles comprise between 5 wt % and 20 wt % of the mixture. 
     
     
         17 . The method of making a high performance aluminum nanocomposite according to  claim 15 , wherein the Al—Si—Mg alloy comprises Al-7Si-0.3Mg. 
     
     
         18 . The method of making a high performance aluminum nanocomposite according to  claim 15 , wherein the Al—Si—Mg alloy comprises Al-12Si-0.3Mg.