Reynolds Metals Company

Aluminum Company of America

Martin Marietta Corporation

Alex Cho

Roberto J Rioja

Joseph R Pickens

Edward L Colvin

Timothy J Langan

Philip E Bretz

Lawrence S Kramer

Asuri K Vasudevan

Frank H Heubaum

Strength anisotropy of aluminum-lithium alloy wrought products is reduced by subjecting these types of alloys to improved T8 temper practice. The wrought product, after solution heat treating and quenching, is subjected to a combination of cold rolling and stretching steps prior to aging. The cold rolling can range between 1 and 20% reduction with the stretching step ranging between 0.5-10%. The cold rolling step may be performed in one or a multiple of passes. When multiple passes are used, the cold rolling may be done in different directions to further enhance reductions in strength anisotropy for these types of alloys. An aluminum-lithium alloy wrought product subjected to the improved T8 temper practice has an increased minimum tensile yield stress throughout its thickness and in various directions to facilitate commercial application of the product in high strength applications.

Method of minimizing strength anisotropy in aluminum-lithium alloy

An aluminum-based alloy useful in aircraft and aerospace structures which has low density, high strength and high fracture toughness consists essentially of the following formula:

Low density, high strength Al-Li alloy having high toughness at elevated

Strength and ductility for a aluminum-lithium alloy wrought product in the transverse direction is improved by subjecting these types of alloys to improved T8 temper practice. The wrought product, after solution heat treating and quenching is subjected to a multiple step stretching sequence prior to aging, the total percent reduction for the multiple step stretching sequence ranging between 1 and 20 percent reduction. In the multiple step stretching sequence, each of the stretching steps may have the same or different amounts of percent reduction to achieve the desired total percent reduction. An aluminum-lithium alloy wrought product subjected to the improved T8 temper practice has increased tensile yield stress and percent elongation in its transverse direction to facilitate commercial application of the product in high strength applications.

Method of improving transverse direction mechanical properties of

Aluminum-base alloys containing Cu, Li, Zn, Mg and Ag are disclosed which possess highly desirable properties, such as relatively low density, high modulus, high strength/ductility combinations, strong natural aging response with and without prior cold work, and high artificially aged strength with and without prior cold work. In addition, the alloys possess good weldability, corrosion resistance, cryogenic properties, and elevated temperature properties. The alloys may comprise from about 1 to about 7 weight percent Cu, from about 0.1 to about 4 weight percent Li, from about 0.01 to about 4 weight percent Zn, from about 0.05 to about 3 weight percent Mg, from about 0.01 to about 2 weight percent Ag, from about 0.01 to about 2 weight percent grain refiner selected from Zr, Cr, Mn, Ti, Hf, V, Nb, B and TiB.sub.2, and the balance Al along with incidental impurities. Preferred alloys comprise from about 3.0-6.5 weight percent Cu, from about 0.5-2.6 weight percent Li, from about 0.05-2 weight percent Zn, from about 0.1-1.5 weight percent Mg, from about 0.05-1 weight percent Ag, from about 0.05-0.5 weight percent grain refiner, and the balance Al and incidental impurities. Additional elements selected from Ge, Sn, Cd, In, Be, Sr, Sc, Y, and Ca may be used in addition to, or in place of, Zn in the present alloys.

Ultra high strength aluminum-base alloys

An aluminum based alloy useful in aircraft and aerospace structures which has low density, high strength and high fracture toughness consists essentially of the following formula:

Low density high strength Al-Li alloy

Disclosed is an aluminum base alloy suitable for forming into a wrought product having improved combinations of strength, corrosion resistance and fracture toughness. The alloy is comprised of 0.2 to 5.0 wt. % Li, 0.05 to 6.0 wt. % Mg, at least 2.45 wt. % Cu, 0.01 to 0.16 wt. % Zr, 0.05 to 12 wt. % Zn, 0.5 wt. % max. Fe, 0.5 wt. % max. Si, the balance aluminum and incidental impurities.

Aluminum-lithium alloys

An aluminum based alloy useful in aircraft and airframe structures which has low density and consists essentially of the following formula:

Lithium aluminum alloy system

Disclosed is a method of producing an unrecrystallized Al-Zn-Mg thin gauge flat rolled product, e.g., plate or sheet, having improved levels of strength and fracture toughness. The method comprises the steps of providing a body of a Zn-Mg containing aluminum base alloy, heating and hot working the body to a first product. This is followed by reheating, cooling and heat treating the first product prior to further working it to a thin gauge, unrecrystallized plate or sheet product, for example.

Method of producing unrecrystallized thin gauge aluminum products by

An aluminum base alloy wrought product having improved corrosion resistance in addition to combinations of strength and toughness. The product comprises 0.2 to 5.0 wt. % Li, 0.05 to 6.0 wt. % Mg, at least 2.45 wt. % Cu, 0.05 to 0.16 wt. % Zr, 0.05 to 12 wt. % Zn, 0.5 wt. % max. Fe, 0.5 wt. % max. Si, the balance aluminum and incidental impurities and has the ability to develop improved combinations of strength and toughness in response to an aging treatment. Prior to an aging step, the product having imparted thereto a working effect equivalent to stretching so that after an aging step it has improved combinations of strength and toughness.

Aluminum-lithium alloys having improved corrosion resistance containing

Disclosed is a method of producing an unrecrystallized A1-Zn-Mg thin gauge flat rolled product having improved levels of strength and fracture toughness. The method comprising the steps of providing a body of a Zn-Mg containing aluminum base alloy, working the body to a flat rolled product and then subjecting the product to a ramp anneal followed by solution heat treating, quenching and aging.

Unrecrystallized aluminum plate product by ramp annealing

Disclosed is a method of producing an unrecrystallized aluminum base, wrought product having improved levels of strength and fracture toughness. The method comprises providing a body of the aluminum base alloy, hot working the body to a wrought product and then subjecting it to an isothermal soak followed by a ramp anneal.

Growing community of inventors

Richmond, VA, United States of America

Alex Cho