Patent Number: 
Section: claims

1. A process for making an aluminum alloy comprising:a) providing an aluminum composite powder having an aluminum microstructure with an ultra-fine grain size and aluminum oxide particles distributed throughout the aluminum microstructure; andb) mixing a ceramic particulate with the aluminum powder to form a powder mixture, the ceramic particulate is selected from the group consisting of silica, silicon carbide, boron carbide, boron nitride, titanium oxide, titanium diboride, and mixtures thereof. 2. The process of claim 1, wherein the powder mixture comprises about 5 wt. % to about 40 wt. % of the ceramic particulate. 3. The process of claim 1, wherein the ceramic particulate is boron carbide having a particle size distribution of 100% less than about 250 microns and the boron carbide is nuclear grade. 4. The process of claim 1, wherein the aluminum composite powder has a particle size that is less than about 30 microns. 5. The process of claim 1, wherein subsequent to step b), the powder mixture is sintered to form a billet. 6. The process of claim 5, wherein the billet is subsequently extruded. 7. The process of claim 1, wherein the ultra-fine grain size is about 200 nm. 8. An aluminum alloy comprising a sintered blend of:an aluminum composite powder having an aluminum microstructure with an ultra-fine grain size; anda ceramic particulate selected from the group consisting of silica, silicon carbide, boron carbide, boron nitride, titanium oxide, titanium diboride, and mixtures thereof. 9. The aluminum alloy of claim 8, wherein the sintered blend comprises about 7 wt. % to about 40 wt. % of the ceramic particulate. 10. The aluminum alloy of claim 8, wherein the ceramic particulate is boron carbide having a particle size distribution of 100% less than about 250 microns and the boron carbide is nuclear grade. 11. The aluminum alloy of claim 8, wherein the aluminum composite powder comprises aluminum oxide particles distributed throughout the aluminum microstructure. 12. The aluminum alloy of claim 11, wherein the oxide content of the aluminum composite powder ranges from about 0.1 wt. % to about 4.5 wt. %. 13. The aluminum alloy of claim 11, wherein the ultra-fine grain size is about 200 nm. 14. The aluminum alloy of claim 8, wherein the aluminum composite powder has a particle size that is less than about 30 microns. 15. A radiation shield comprising the aluminum alloy of claim 8. 16. A process for making an aluminum nano-composite comprising:a) providing an aluminum powder having an oxide content between about 0.1 wt. % and 4.5 wt. %; andb) hot-working the aluminum powder such that a microstructure grain size of the aluminum powder is reduced by a factor of at least 10 to form an aluminum nano-composite. 17. The process of claim 16, wherein the hot-working is performed at a temperature below the recrystallization temperature of the aluminum powder. 18. The process of claim 16, wherein the oxide content is derived from a natural aluminum oxide formation layer on the aluminum powder. 19. The process of claim 16, wherein during step b) the natural aluminum oxide is distributed throughout a microstructure of the aluminum powder. 20. The process of claim 16, wherein the aluminum nano-composite is subsequently formed into a radiation shield.