Methods of Making Metal Matrix Composites Including Inorganic Particles and Discontinuous Fibers

Abstract

A method of making a porous metal matrix composite is provided. The method includes mixing a metal powder, a plurality of inorganic particles, and a plurality of discontinuous fibers to form a mixture, wherein the metal powder comprises aluminum, magnesium, an aluminum alloy, or a magnesium alloy. The method further includes sintering the mixture to form the porous metal matrix composite. Typically, the inorganic particles comprise porous particles or ceramic bubbles or glass bubbles, and the inorganic particles and the discontinuous fibers are dispersed in the metal. The metal matrix composite has a lower density than the metal and an acceptable yield strength.

1 . A method of making a porous metal matrix composite comprising:
 a. mixing a metal powder, a plurality of inorganic particles, and a plurality of discontinuous fibers, thereby forming a mixture; and   b. sintering the mixture, thereby forming the porous metal matrix composite.   
     
     
         2 . The method of  claim 1 , wherein the mixture is sintered in a die. 
     
     
         3 . The method of  claim 1 , wherein the sintering is performed at a temperature of between 250 degrees Celsius and 1,000 degrees Celsius, inclusive. 
     
     
         4 . The method of  claim 1 , wherein the sintering comprises applied pressure. 
     
     
         5 . The method of  claim 4 , wherein the sintering is performed at a pressure of between 4 megapascals and 200 megapascals, inclusive. 
     
     
         6 . The method of  claim 1 , wherein the mixing is performed using an acoustic mixer, a mechanical mixer, or a tumbler. 
     
     
         7 . The method of  claim 1 , wherein the mixture comprises the inorganic particles and the discontinuous fibers dispersed in the metal powder. 
     
     
         8 . The method of  claim 1 , wherein the plurality of inorganic particles comprises porous particles comprising porous metal oxide particles, porous metal hydroxide particles, porous metal carbonates, porous carbon particles, porous silica particles, porous dehydrated aluminosilicate particles, porous dehydrated metal hydrate particles, zeolite particles, porous glass particles, expanded perlite particles, expanded vermiculite particles, porous sodium silicate particles, engineered porous ceramic particles, agglomerates of nonporous primary particles, or combinations thereof. 
     
     
         9 . The method of  claim 1 , wherein the plurality of inorganic particles comprises ceramic bubbles or glass bubbles. 
     
     
         10 . The method of  claim 1 , wherein the plurality of discontinuous fibers comprises glass, alumina, aluminosilicate, carbon, basalt, or a combination thereof. 
     
     
         11 . The method of  claim 1 , wherein the metal comprises aluminum, magnesium, an aluminum alloy, or a magnesium alloy. 
     
     
         12 . The method of  claim 1 , wherein the metal matrix composite has an envelope density that is at least 8% less than the density of the metal and can withstand a strain of 1% prior to fracture. 
     
     
         13 . The method of  claim 12 , wherein the metal matrix composite can withstand a strain of 2% prior to fracture. 
     
     
         14 . The method of  claim 1 , wherein the metal matrix composite has a yield strength of 50 megapascals or greater.