Abstract: Disclosed is a method of making lithium-containing aluminum base alloy extrusion having at least a section thereof having a low aspect ratio or which is generally axisymmetrical, the extrusions having improved properties in sections thereof having the low aspect ratio or which are axisymmetrical. The method comprises providing a body of a lithium-containing aluminum alloy, pressing a portion of the body which is to form the axisymmetrical or low aspect ratio section through a tortuous path and extruding an axisymmetrical or a low aspect ratio extrusion section. The axisymmetrical or low aspect ratio section of the extrusion has a tensile strength of at least 60 ksi and an ultimate yield strength at least 4.5 ksi greater than the tensile yield strength.

Abstract: A dual aging treatment of aluminum-copper-lithium-scandium alloys allows preparation of alloys exhibiting superior physical properties as compared to the same alloys subjected to only a single aging. In particular, the difference between yield strength and ultimate tensile strength is markedly increased. The alloys are characterized by an array of fine T1 phase precipitates within the aluminum grain, leaving a substantially T1 phase precipitate-free zone along the grain boundaries, and an array of coarse .theta.' and .delta.' phase precipitates throughout the grains with little or no .theta.' and .delta.' phase-free zones.

Abstract: An Al material having an anodic oxidation film is provided that is excellent in gas and plasma corrosion resistance. By the present invention, a crack is not generated in the anodic oxidation film even in high temperature thermal cycles and corrosive gas or plasma environment. In the Al material having an Al alloy having on its surface an anodic oxidation film according to the invention, the anodic oxidation film has a porous layer and a barrier layer, and portions of cell triplet points, at which boundary faces of 3 cells in the porous layer melt, have secondary-pores.

Abstract: Age-hardened aluminum alloy sheet can be subjected to a shearing operation, such as trimming or piercing, with reduced sliver formation by first heating the region to be sheared to a temperature above about 250.degree. C., immediately quenching the heated region to soften the region, and then performing the shearing operation in the softened region before age-hardening occurs.

Abstract: In the stretch forming of aluminum alloys using a punch and a mating die cavity, the stretch formability of a sheet of age-hardened aluminum alloy is increased by selectively heat treating the sheet to soften at least a portion of the sheet that will underlie a punch surface but not be drawn over a radius of the punch.

Abstract: A method and apparatus for characterizing and controlling the heat treatment of a metal alloy employing non-contact sensors selectively positioned to minimize the effects of background temperature contributions. The sensors monitor the temperature of the part being treated at a location that is remote from the surface that is being irradiated directly. In preferred embodiments, the surface where the temperature measurements are taken are located within a black body source. The collected temperature information is used to control the heat treatment of the metal alloy.

Abstract: An improved method of forming a severe bend or a hem in a sheet of wrought aluminum age-hardened and age-hardenable alloy includes heating the region to be bent or hemmed to a temperature above about 250.degree. C. for a period of seconds and then quenching the heated region to remove the age-hardening effect and thereafter accomplishing the bend or hem before age hardening of the heated region occurs.

Abstract: Method and apparatus for simplified heat-treatment to harden aluminum castings made from heat-treatable aluminum alloys, especially with a copper content of up to 5%, such as the 300-T6 series, for example those cast aluminum parts utilized in the manufacture of automobile motors: cylinder heads, engine blocks and the like; whereby the castings are directly quenched before cooling below 400.degree. C. (and preferably immediately after demolding) without undergoing the conventional steps of natural cooling followed by a re-heating "solution" heat treatment (typically of at least 470.degree. C. for at least two hours, or for a shorter time at higher temperatures) which "solution" heat treatment requires excessive and expensive equipment, energy, and production time. This invention also has the unexpected beneficial effect of avoiding development of silicon spheroidization in the alloy matrix thereby resulting in improved machining properties.

Abstract: An aluminum-alloy article such as a fastener is prepared by providing an aluminum-alloy article precursor that is not in its final heat-treated state, and in one form is in its solution treated/annealed state. A curable organic coating material is also provided. The method includes anodizing the article precursor, preferably in chromic acid solution and without chemical sealing during anodizing, applying the organic coating material to the aluminum-alloy article precursor, and precipitation heat-treating the coated aluminum article precursor to its final heat-treated state, thereby simultaneously curing the organic coating. If the aluminum alloy temper is of the naturally aging type, it is optionally lightly deformed prior to precipitation treatment aging.

Abstract: A method of heat treating an aluminum--lithium alloy is provided. The method includes carrying out a succession of at least two artificial aging steps. The first such step is carried out within a first temperature range and one or more further steps are carried out within successively reduced temperature ranges to promote the precipitation of the .delta.' phase of the alloy.

Abstract: An aluminum-alloy article such as a fastener is prepared by providing an aluminum-alloy article precursor that is not in its final heat-treated state, and in one form is in its solution treated/annealed state. A curable organic coating material is also provided. The method includes anodizing the article precursor, preferably in chromic acid solution and without chemical sealing during anodizing, applying the organic coating material to the aluminum-alloy article precursor, and precipitation heat-treating the coated aluminum article precursor to its final heat-treated state, thereby simultaneously curing the organic coating. If the aluminum alloy temper is of the naturally aging type, it is optionally lightly deformed prior to precipitation treatment aging.

Abstract: The invention relates to an aluminum alloy sheet heat treated by natural aging, quenching and possibly tempering so as to obtain a yield strength greater than 320 MPa, for use in mechanical, naval, aircraft, or spacecraft construction, with a composition (by weight) of:Si: 6.5 to 11%Mg: 0.5 to 1.0%Cu: <0.8%Fe: <0.

Abstract: A method is disclosed for treating an aluminum alloy product in order to impart a fine grain structure and thereby improve formability and surface finish characteristics. According to this method, the product is first heated to a first temperature high enough to dissolve soluble constituent phase particles into solid solution. The product is maintained at this first temperature long enough to dissolve a major portion of the soluble constituent phase particles. Thereafter, the product is subjected to a controlled cooling process. The product is first cooled from the first temperature, at a first rate that is rapid enough to minimize the precipitation of coarse-grained constituent phase particles, to a second temperature that is below the temperature at which such coarse-grained constituent phase particles will precipitate out. Then, the product is cooled from the second temperature, at a second rate that is within a range of about 1-300 degrees F. per hour, to a third temperature that is at least 50 degrees F.

Abstract: A method of producing an AA7000 series aluminum alloy wrought product or plate includes a two step solution heat treating sequence wherein the aluminum plate is subjected to a first solution heat treatment at a first elevated temperature or temperatures for a first period of time, followed by a second solution heat treatment at a lower temperature or temperatures for a second period of time. The two step solution heat treating sequence results in vastly improved exfoliation corrosion resistance in the final aluminum wrought or plate product. An improved process for making aluminum alloy products in the T7751 Temper also is disclosed.

Abstract: A method of fabricating an alloy sputtering target having fine precipitates of the second phase material and small, randomly oriented and uniform grains. The new method includes solution treatment to minimize second-phase precipitate size, cryo-deformation to prevent the formation of cubic structures and recrystallization to generate fine uniform grain sizes having a random orientation.

Abstract: An alloy suitable for manufacturing components out of a hollow body by high internal pressure forming contains, in wt. %,______________________________________ Silicon 0.3 to 1.6 Magnesium 0.3 to 1.3 Iron max. 0.5 Copper max. 0.9 Manganese max. 0.5 Vanadium 0.05 to 0.3 Cobalt max. 0.3 Chromium max. 0.3 Nickel max.0.8 Zirconium max. 0.3 ______________________________________and other alloying elements, individually at most 0.05, in total at most 0.15, the remainder aluminum.

Abstract: A continuously cast and rolled aluminum alloy substrate for an electrolytically grainable lithographic printing plate, consisting of 0.20 to 0.80 wt. % of Fe and the balance of Al, grain-refining elements and unavoidable impurities including 0.3 wt. % or less of Si and 0.05 wt. % or less of Cu, the amount of Fe present in solid solution being not more than 250 ppm, the amount of Si present in solid solution being not more than 150 ppm, and the amount of Cu present in solid solution being not more than 120 ppm.

Abstract: An aluminum alloy containing magnesium (Mg) between 3.0 and 4.0 wt. %, manganese (Mn) between 0.5 and 1.0 wt. %, copper (Cu) between 0.2 and 0.6 wt. %, iron (Fe) between 0.05 and 0.4 wt. % and remaining obligatory trace elements, has an electrical conductivity after baking of 30 to 32% IACS, a yield strength of 320 MPa or more and a ratio of decrease in buckling strength after retort-treatment to that immediately after manufacturing the can end of less than 10%. This an aluminum alloy sheet for can ends has an excellent corrosion resistance, complete lack of stress corrosion cracking, or age softening resistance, maintains the a high buckling strength obtained subsequent to the manufacture of a can, even after retort treatment and storage at room temperature. The aluminum alloy sheet of this invention is particularly suitable for use as a can end for non-carbonated beverages and has the potential for even thinner aluminum alloy sheet formation.

Abstract: A process of producing solution heat treated aluminum alloy sheet material comprises subjecting hot- or cold-rolled aluminum alloy sheet to solution heat treatment followed by quenching and, before substantial age hardening has taken place, subjecting the alloy sheet material to one or more subsequent heat treatments involving heating the material to a peak temperature in the range of 100.degree. to 300.degree. C. (preferably 130.degree.-270.degree. C.), holding the material at the peak temperature for a period of time less than about 1 minute, and cooling the alloy from the peak temperature to a temperature of 85.degree. C. or less. The sheet material treated in this way can by used for automotive panels and has good a good "paint bake response", i.e. an increase in yield strength from the T4 temper to the T8X temper upon painting and baking of the panels.

Abstract: A friction boring process creates a corrosion resistant fine grain microstructure in the wall surfaces of holes bored in aluminum alloy materials. A rotating tool is inserted directly into the aluminum material, or into a pre-drilled pilot hole, at a sufficient rotational velocity and feed rate to cause working that extends beyond the diameter of the tool, frictional heating, and extraction of aluminum material by metal deformation rather than cutting action as with a conventional drill bit. Burring, smoothing, and otherwise removing aluminum material extracted from the hole may be performed by a finishing segment that limits insertion depth of the tool. Frictional heating generates a temperature sufficient for rapid recrystallization of the remaining worked metal to form a fine grain microstructure to a depth of about 2.5 mm in the hole surfaces. Corrosion protection is retained even if some fine grain material is removed during a subsequent reaming operation.

Abstract: The invention relates to a fabrication process to obtain aluminum alloy sheet having high formability. In this process, an alloy obtained by alloying Al with Si, Mg, Cu, Mn and Fe, and one or more elements taken from the group of Cr, Zn, Zr and Ti, is subjected to a continuous solution treatment for at least 3 seconds at a temperature higher than 450.degree. C., followed by cooling to a temperature between 60.degree. and 250.degree. C., at a rate higher than 100.degree. C./min, followed by a coiling at the same temperature in the 60.degree. C.-250.degree. C. range and a preaging between 1 minute and 10 hours at the same cooling temperature of 60.degree. to 250.degree. C.

Abstract: An improvement to a process for treating an aluminum alloy for the series AA 2000 or AA 6000 comprising solution heat treating, quenching and natural or artificial aging, in which conventional heat solution heat treating is defined as solution heat treating the alloy at a temperature which is 5.degree. to 10.degree. C. below a known eutectics melting temperature for the alloy. The improvement comprises solution heat treating at a temperature which is 10.degree. to 100.degree. C. below the conventional solution heat treating temperature in order to desensitize the alloy to intercrystalline corrosion.

Abstract: An aluminum-alloy article such as a fastener is prepared by providing an aluminum-alloy article that is not in its final heat-treated state, and is preferably in its annealed state. A curable organic coating material is also provided. The method includes applying the organic coating material to the aluminum-alloy article, and heat-treating the coated aluminum article to its final heat-treated state, thereby simultaneously curing the organic coating.

Abstract: The present invention provides a high strength aluminum alloy suitable for use in the manufacture of a fin, said aluminum alloy containing at most 0.1% by weight of Si, 0.10 to 1.0% by weight of Fe, 0.1 to 0.50% by weight of Mn, 0.01 to 0.15% by weight of Ti, and the balance of Al and unavoidable impurities, intermetallic compounds having a diameter not larger than 0.1 .mu.m being distributed within the metal texture of the alloy in a number density of at least 10/.mu.m.sup.3. The present invention also provides a method of manufacturing a high strength aluminum alloy suitable for use in the manufacture of a fin, comprising the steps of heating to 430.degree. to 580.degree. C. an aluminum alloy ingot of the composition noted above, applying a hot rolling treatment to said aluminum alloy ingot to obtain a plate material before the temperature of the aluminum alloy ingot is lowered by at most 50.degree. C.

Abstract: A planar sheet of structurally hardened aluminum alloy, having, after quenching and aging, mechanical strength which varies continuously in a particularly defined direction of the planar sheet. The planar sheet is produced in a process comprising quenching and final aging, where the final aging comprises heating for a defined period of time a first portion of the plate or sheet including a first edge to a first temperature T and a second portion of the plate or sheet including an opposite edge to a second temperature t<T.

Abstract: The specification describes a ternary alloy of aluminium. The alloy described comprises from 80 to 96% by weight of aluminium and from 4 to 20% by weight of titanium and a third element selected from the group consisting of cobalt, chromium, copper, magnesium, nickel and iron. The weight ratio of titanium to ternary alloying element lies in the range from 1:1 to 6:1. The alloy can be aged at a temperature in the range from 300.degree. to 450.degree. C.

Abstract: A method for heat treating a metal component uses a first heating system having a first high intensity heating portion to rapidly heat the component to a desired temperature and a second heating portion to maintain the component temperature for solution heat treatment. The heating system is an indexing-type system which includes a plurality of individual heating stations to effect solution heat treatment of the component. Following quenching, a second heating system having a first high intensity heating portion to rapidly heat the component to a desired temperature and a second heating portion to maintain the component temperature artificially ages the component.

Abstract: Thin wall lightweight panels which are subjected to high temperature solutioning and rapid quenching to impart high strength properties without distortion, warping or oil-canning. The panels are produced by casting in a mold cavity having an interconnected recess network which surrounds thin wall-forming areas and distributes molten metal uniformly thereto. The recess network forms a waffle pattern reinforcing rib network surrounding the thin-wall areas, lending strength and dimensional stability thereto during the heat treatment and quenching steps, to prevent distortion, warping and oil-canning.

Abstract: A composition and method for producing a low density, high stiffness aluminum alloy which is capable of being processed into structural components having a desired combination of tensile strength, fracture toughness and ductility. The method includes the steps of forming, by spray deposition, a solid Al-Li alloy workpiece consisting essentially of the formula Al.sub.bal Li.sub.a Zr.sub.b wherein "a" ranges from greater than about 2.5 to 7 wt %, and "b" ranges from greater than about 0.13 to 0.6 wt %, the balance being aluminum, said alloy having been solidified at a cooling rate of about 10.sup.2 to 10.sup.4 K/sec. The method further includes several variations of selected thermomechanical process steps for: (1) eliminating any residual porosity which may be present in the workpiece as a result of the spray deposition step; and (2) producing components for a wide range of applications.

Abstract: A case nitrided aluminum product is produced by contacting an aluminum product with a nitriding agent at a part of a surface thereof at least, and by nitriding the aluminum product at the surface with an ambient gas at a temperature of a melting point of the aluminum product or less while keeping the aforementioned contact. The nitriding agent includes an aluminum powder, and the ambient gas virtually includes a nitrogen gas. The resulting nitriding layer has a depth of 5 micrometers or more, and it exhibits a case hardness of from 250 to 1,200 mHv. Thus, it is possible to form the deep and hard nitriding layer on the aluminum product with ease under the conditions where it has been said to be too difficult to nitride aluminum products. The case nitrided aluminum product can appropriately make sliding parts which require high wear resistance.

Abstract: A process for producing an aluminum alloy in the form of mass includes: preparing as a material to be formed a mixed powder of aluminum and at least one kind of metal or non-metallic substance selected from the elements belonging to Groups 4a, 4b, 5a, 6a, 7a and 8a of the periodic table and boron, or a compact or a cast material formed of the mixed powder; placing the material to be formed in a die, and performing plastic deformation repeatedly on the material to be formed at 100.degree. to 400.degree. in an inert atmosphere while retaining at least part of the material to be formed in a confined state, so as to cause diffusion reaction between phases constituting the material to be formed, thereby forming the quasi-stable phase composed mainly of amorphous phases and/or supersaturated solid solution phases.

Abstract: A method of producing aluminum alloy sheet product includes casting a slab, homogenizing the cast slab, and hot rolling the homogenized slab to provide an intermediate gauge product. The temperature and other operating parameters of the hot rolling process are controlled so that the temperature of the intermediate gauge product exiting the hot rolling step is between about 500.degree. F. and 650.degree. F. Preferably, the temperature does not exceed 575.degree. F. The intermediate gauge product is then subjected to a cold reduction of 45% to 70%, annealed, and cold rolled to final gauge. The combination of controlling the hot rolling to provide a desired exit temperature of the intermediate gauge product and annealing prior to cold rolling to final gauge minimizes or eliminates the appearance of ridging or roping line defects in the aluminum sheet product when subjected to further straining in a forming or stamping operation.

Abstract: A sintered Al-alloy, which has a composition of 0.2 to 2.0% of Mg, 10.0 to 35.0% of Si, from 0.2 to 4.0% of Cu, and Al and unavoidable impurities in balance, is produced by using a mixture of the main powder (10.0-35.0% of Si, 0.2-2.0% of Cu, and Al and unavoidable impurities in balance) and at least one metal or mother-alloy powder selected from (a)-(i): (a) Mg powder; (b) Al--Mg powder; (c) Al--Cu powder; (d) Al--Mg--Si powder; (e) Al--Cu--Si powder; (f) Al--Mg--Cu powder; (g) Al--Mg--Cu--Si powder; (h) Mg--Cu powder; and, (i) Mg--Cu--Si powder.

Abstract: A method is disclosed for the production of aluminum-copper-lithium alloys that exhibit improved strength and fracture toughness at cryogenic temperatures. Improved cryogenic properties are achieved by controlling the composition of the alloy, along with processing parameters such as the amount of cold-work and artificial aging. The ability to attain substantially equal or greater strength and fracture toughness at cryogenic temperature in comparison to room temperature allows for use of the alloys in cryogenic tanks for space launch vehicles and the like.

Abstract: 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.

Abstract: Cooling of a workpiece is conducted at selected workpiece locations in accordance with predetermined heat flux, at the locations, required to result in a desired workpiece cooling rate for workpiece integrity, microstructure and mechanical properties. A cooling fluid is controlled to follow the workpiece surface according to preselected cooling fluid convective cooling parameters including, but not limited to, cooling fluid direction, mass flow rate, and velocity at the selected locations.

Abstract: 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.

Abstract: A method of producing aluminum can sheet having low earing characteristics. An aluminum alloy ingot is provided and is heated to a temperature between about 527.degree. to 571.degree. C. (980.degree. to 1060.degree. F.). After this, the ingot is hot rolled in a single-stand reversible hot mill to produce an intermediate gauge sheet. The intermediate gauge sheet is then cold rolled to produce a final gauge aluminum can sheet having low eating characteristics.

Abstract: A method for producing a cast aluminum vehicle wheel uses a high intensity electric infrared heating system to heat treat the wheel. The infrared heating system is an indexing-type system which includes a plurality of individual heating stations. A first group of heating stations effects solution heat treating of the wheel, while a second group effects artificial aging. The infrared system enables the solution heat treating and aging to be completed in less than 15 minutes.

Abstract: An infrared radiation element and a process for producing the same. An aluminum alloy material consists essentially of 0.3 to 4.3 weight % of Mn, balance Al, and impurities. The alluminum alloy material is heated for dispersing a precipitate of an Al--Mn intermetallic compound at a density of at a minimum 1.times.10.sup.5 /mm.sup.3 for a size of 0.1 .mu.m to 3 .mu.m. The heated aluminum alloy material is anodized to form an anodic oxide layer thereon.

Abstract: A method for producing a cast aluminum vehicle wheel uses a high intensity electric infrared heating system to heat treat the wheel. The infrared heating system is an indexing-type system which includes a plurality of individual heating stations. A first group of heating stations effects solution heat treating of the wheel, while a second group effects artificial aging. The infrared system enables the solution heat treating and aging to be completed in less than 15 minutes.

Abstract: A method of producing an aluminum-based alloy product having improved exfoliation resistance and fracture toughness which comprises providing an aluminum-based alloy composition consisting essentially of about 5.5-10.0% by weight of zinc, about 1.75-2.6% by weight of magnesium, about 1.8-2.75% by weight of copper with the balance aluminum and other elements. The aluminum-based alloy is worked, heat treated, quenched and aged to produce a product having improved corrosion resistance and mechanical properties. The amounts of zinc, magnesium and copper are stoichiometrically balanced such that after precipitation is essentially complete as a result of the aging process, no excess elements are present. The method of producing the aluminum-based alloy product utilizes either a one- or two-step aging process in conjunction with the stoichiometrically balancing of copper, magnesium and zinc.

Abstract: A process for producing an aluminum alloy with high strength and toughness includes the steps of: preparing an alloy blank having a primary structure which is one selected from a single-phase structure comprised of a solid-solution phase, a single-phase structure comprised of an amorphous phase, and a mixed-phase structure comprised of a solid-solution phase and an amorphous phase, and subjecting the alloy blank to a thermal treatment to provide an aluminum alloy which has a secondary structure containing 20% or more by volume fraction Vf of chrysanthemum-like patterned phases each having a diameter of at most 5 .mu.m and comprising a solid-solution phase and an intermetallic compound phase arranged radiately.

Abstract: A method for heat treating an aluminum part is provided. The method includes heat treating the aluminum alloy part with direct radiation from a source of infrared energy until the part attains a desired state of heat treatment. The method and apparatus further include monitoring of the part and controlling the intensity of the radiation source through proportional control in response to the measured temperature.

Abstract: Disclosed are an aluminum alloy casting having a high strength and a high toughness, and a production process for the same. The aluminum alloy casting comprises silicon (Si) in an amount of 2.5 to 4.4% by weight, copper (Cu) in an amount of 1.5 to 2.5% by weight, magnesium (Mg) in an amount of 0.2 to 0.5% by weight and the balance of aluminum (Al), and a matrix thereof includes a dendrite which has a size of 30 micrometers or less. Since the Si addition amount is suppressed as less as possible and since the size of the dendrite is micro-fined in the aluminum alloy casting, the toughness is improved remarkably. Further, since the Cu and Mg are added in the predetermined addition amounts, the strength is enhanced in the aluminum alloy casting. In addition, a solution treatment which is employed in the production process can further enhance the strength of the aluminum alloy casting.

Abstract: In order to achieve damage-tolerant properties and sufficient isotropy of aluminum alloys, particularly of type AlLi 8090, subsequent especially to hot-forming of a bar of said aluminum alloy there is interposed a solution heat treatment and quenching, followed by working and subsequent intermediate annealing within a temperature range of from 250.degree. to 475.degree. C. for a period of from 1 to 85 hours. The intermediate annealing is followed by cold forming and subsequent solution heat treatment with the additional purpose of recrystallization, whereupon the recrystallized material is especially cold-formed to a degree of deformation of only up to 8%. Thereafter the sheets having a sheet thickness of from 0.5 to 10 mm are subjected to artificial aging.

Abstract: The present invention provides a method for improving aluminum alloy plate product properties by delaying final stretching of the plate product. During processing of the product, a time interval or intentional delay is provided between the final cold rolling step and the final stretching step. By delaying the final stretching procedure, an aluminum alloy plate product is provided with an improved fracture toughness without significant decrease in strength values. The method of intentionally delaying final stretching is particularly adapted for 2000 series aluminum alloys.

Abstract: A process for producing a high strength and high toughness aluminum alloy comprises a first step of preparing an alloy material which has a primary metallographic structure with a volume fraction Vf of a single-phase structure of at least 90%, said single-phase structure is comprised of crystal particles having a particle size of less than 30 nm and an fcc structure (face-centered cubic structure), the alloy having a composition represented by a chemical formula:Al .sub.a T .sub.b X.sub.cwherein T is at least one element selected from a first group including Y, La, Ce, Mm (misch metal) and Ca; X is at least one element selected from a second group including Fe, Co and Ni (but at least one element of Co and Ni, if only Y is selected from the first group); and each of a, b and c represents an atom %, with the proviso that 85.ltoreq.a.ltoreq.97, 1.ltoreq.b.ltoreq.10, and 2.ltoreq.c.ltoreq.15, and a second step of subjecting the alloy material to a thermal treatment at a temperature in a range .+-.100.degree. C.

Abstract: Optimum strengthening of a superplastically formed aluminum-lithium alloy structure is achieved via a thermal processing technique which eliminates the conventional step of solution heat-treating immediately following the step of superplastic forming of the structure. The thermal processing technique involves quenching of the superplastically formed structure using static air, forced air or water quenching.

Abstract: A process of producing solution heat treated aluminum alloy sheet material comprises subjecting hot- or cold-rolled aluminum alloy sheet to solution heat treatment followed by quenching and, before substantial age hardening has taken place, subjecting the alloy sheet material to one or more subsequent heat treatments involving heating the material to a peak temperature in the range of 100.degree. to 300.degree. C. (preferably 130.degree.-270.degree. C.), holding the material at the peak temperature for a period of time less than about 1 minute, and cooling the alloy from the peak temperature to a temperature of 85.degree. C. or less. The sheet material treated in this way can be used for automotive panels and has good a good "paint bake response", i.e. an increase in yield strength from the T4 temper to the T8X temper upon painting and baking of the panels.