Nanoporous alloys

Abstract

The disclosure relates to nanoporous alloys, and methods to prepare them.

What is claimed is: 
     
         1 . A nanoporous alloy prepared by a process comprising:
 (i) admixing at least three different elements, wherein each of the at least three different elements are selected from the group consisting of aluminum (Al), chromium (Cr), iron (Fe), cobalt (Co), nickel (Ni), vanadium (V), niobium (Nb), molybdenum (Mo), tantalum (Ta), tungsten (W), titanium (Ti), zirconium (Zr), zinc (Zn), halfnium (Hf), copper (Cu), with a sacrificial element selected from the group consisting of lead (Pb), tin (Sn), magnesium (Mg), and bismuth (Bi);   wherein each of the at least three different elements is present in a molar equivalent from about 0.0 to about 1.0;   wherein each of the at least three different elements independently has an average particle size of from 10 nm to 500 nm as measured by dynamic light scattering;   (ii) heating the resulting admixture to an elevated temperature of from about 800° C. to about 2500° C. at atmospheric pressure for a period of time to provide a precursor alloy; and   (iii) dealloying the precursor alloy to remove the sacrificial element to provide a nanoporous alloy wherein the nanoporous alloy has a specific strength that is from about 2× to about 10× greater than a bulk alloy comprising the same at least three different elements and having the same molar equivalents as after the dealloying, except without the nanoporous structure.   
     
     
         2 . The nanoporous alloy of  claim 1  wherein the dealloying comprises mixing the precursor alloy with an acidic liquid composition to remove substantially all the sacrificial element. 
     
     
         3 . The nanoporous alloy of  claim 1  wherein the dealloying comprises heating the precursor alloy to the sublimation temperature of the sacrificial element at atmospheric pressure or below atmospheric pressure. 
     
     
         4 . The nanoporous alloy of  claim 1 , wherein a specific modulus of the nanoporous alloy is from about 10 −3  to about 10 −2  GPa/(kg/m 3 ). 
     
     
         5 . The nanoporous alloy of  claim 1 , wherein a specific strength of the alloy is from about 10 −1  to about 10 0  MPa/(kg/m 3 ). 
     
     
         6 . The nanoporous alloy of  claim 1 , which comprises a face-centered cubic phase. 
     
     
         7 . The nanoporous alloy of  claim 1 , which comprises a body-centered cubic phase. 
     
     
         8 . The nanoporous alloy of  claim 1 , which comprises multiple phases. 
     
     
         9 . The nanoporous alloy of  claim 1 , which has a relative density of from 20% to 80% of a bulk alloy of the same at least three different elements and having the same molar equivalents as after the dealloying, except without the nanoporous structure. 
     
     
         10 . The nanoporous alloy of  claim 1 , which has a relative density of from 30% to 80% of a bulk alloy of the same at least three different elements and having the same molar equivalents as after the dealloying, except without the nanoporous structure. 
     
     
         11 . The nanoporous alloy of  claim 1 , which has a relative density of from 40% to 80% of a bulk alloy of the same at least three different elements and having the same molar equivalents as after the dealloying, except without the nanoporous structure. 
     
     
         12 . The nanoporous alloy of  claim 1 , which has a relative density of from 50% to 80% of a bulk alloy of the same at least three different elements and having the same molar equivalents as after the dealloying, except without the nanoporous structure. 
     
     
         13 . The nanoporous alloy of  claim 1 , wherein one of the at least three elements are selected from the group consisting of aluminum, vanadium, and halfnium. 
     
     
         14 . The nanoporous alloy of  claim 1 , wherein one of the at least three elements are selected from the group consisting of chromium, manganese, and niobium. 
     
     
         15 . The nanoporous alloy of  claim 1 , wherein one of the at least three elements are selected from the group consisting of iron, molybdenum, tantalum, and copper. 
     
     
         16 . The nanoporous alloy of  claim 1 , wherein one of the at least three elements are selected from the group consisting of cobalt, copper, tantalum, titanium, and nickel. 
     
     
         17 . The nanoporous alloy of  claim 1 , wherein one of the at least three elements are selected from the group consisting of nickel, tungsten, zirconium, and zinc. 
     
     
         18 . The nanoporous alloy of  claim 1 , which has the following formula:
 face-centered cubic (fcc) or body-centered cubic (bcc) Al 0.1 CoCrFeNi,   fcc or bcc NbMoTaW,   CrMnFeCoNi,   bcc VNbMoTaW,   bcc HfNbTaTiZr,   fcc AlCoNiCuZn; or   AlxCrFeCoNiCu, wherein x is less than 1.   
     
     
         19 . A continuous nanoporous alloy comprising at least three different elements, wherein each of the at least three different elements are selected from the group consisting of aluminum (Al), chromium (Cr), iron (Fe), cobalt (Co), nickel (Ni), vanadium (V), niobium (Nb), molybdenum (Mo), tantalum (Ta), tungsten (W), titanium (Ti), zirconium (Zr), zinc (Zn), halfnium (Hf), copper (Cu);
 wherein each of the at least three different elements is present in a molar equivalent from about 0.0 to about 1.0;   wherein the continuous nanoporous alloy comprises an average ligament size of about 3 nm to about 100 nm when measured by SEM, TEM, and/or small angle neutron scattering;   wherein the continuous nanoporous alloy has a specific strength that is from about 2× to about 10× greater than a reference specific strength of a bulk alloy comprising the same at least three different elements in the same molar equivalents except without the continuous nanoporous structure.