Atomized picoscale composition aluminum alloy and method thereof
The invention is a process for manufacturing a nano aluminum/alumina metal matrix composite and composition produced therefrom. The process is characterized by providing an aluminum powder having a natural oxide formation layer and an aluminum oxide content between about 0.1 and about 4.5 wt. % and a specific surface area of from about 0.3 and about 5 m 2 /g, hot working the aluminum powder, and forming a superfine grained matrix aluminum alloy. Simultaneously there is formed in situ a substantially uniform distribution of nano particles of alumina. The alloy has a substantially linear property/temperature profile, such that physical properties such as strength are substantially maintained even at temperatures of 250° C. and above.
1. A process for manufacturing a nano aluminum composite, comprising the steps of:
a) providing, an aluminum powder having a natural oxide formation layer and an aluminum oxide content between about 0.1 and about 4.5 wt. % and a specific surface area of from about 0.3 and about 5.0 m 2 /g;
b) hot working the aluminum powder at a temperature below the recrystallization temperature of the powder, and forming thereby a superfine grained matrix aluminum alloy; and
c) simultaneously with the hot working of step b), redistributing the aluminum powder into uniformly dispersed nano particles of alumina throughout said alloy;
wherein said alloy has a substantially linear ultimate tensile strength vs temperature.
2. The process as claimed in claim 1 , wherein said aluminum powder has an average particle size of less than about 30 μm.
3. The process as claimed in claim 1 , wherein said superfine grained matrix aluminum alloy has an average particle size of about 200 nm.
4. The process as claimed in claim 1 , wherein the step of hot working is carried out at a temperature less than the melting point of said alloy.
5. The process as claimed in claim 1 , wherein the aluminum powder is formed by a powder atomization manufacturing process and has a particle size of less than about 30 nm in diameter and the natural layer of aluminum oxide has a thickness of between 3-7nm regardless of the type of atomization gas and alloy type used during the powder atomization manufacturing process.
6. The process as claimed in claim 1 , wherein the aluminum powder comprises a particle size distribution (PSD) such that 100% of the aluminum powder is less than about 30 μm and the aluminum powder comprises a d50 between about 1 and about 20 μm regardless of an atomization gas or alloy composition used in forming said powder.
7. The process as claimed in claim 1 , wherein said process is free of mechanical alloying.
8. A nano aluminum powder, comprising an aluminum matrix; and from about 0.1 to about 4.5 wt. % aluminum oxide having a particle size of less than 30 microns and a surface area of from about 0.3 to about 5.0 m 2 /g, wherein the aluminum oxide particles are uniformly distributed in the aluminum matrix.
9. The nano aluminum powder as claimed in claim 8 further comprising from about 5 to about 40 wt. % of ceramic particulates selected from the group consisting of silica, silicon carbide, boron carbide; boron nitride, titanium oxide, titanium diboride, and mixtures thereof, wherein the aluminum oxide particles have an oxide skin of 3-7 nm and a grain size of about 200 nm and are present in the amount of up to about 4 wt. %.
10. The nano aluminum powder as claimed in claim 9 , comprising from about 5 to about 40 wt. boron carbide particles having a particle size distribution of 100% less than about 250 μm, and wherein the boron carbide panicles are nuclear grade.
11. The nano aluminum powder as claimed in claim 10 , wherein the boron carbide particles are uniformly dispersed throughout the aluminum matrix.
12. A nano aluminum composite consisting essentially of a pure aluminum powder comprising, an aluminum matrix and from about 0.1 and about 4.5 wt. % aluminum oxide particles having a surface area of from about 0.3 and about 5.0 m 2 /g.