Rockwell International Corporation

C Howard Hamilton

Neil E Paton

Leonard A Ascani, Jr

Murray W Mahoney

John M Curnow

Amit K Ghosh

Edward D Weisert

Paul R Puhaczewski

A composite is produced by placing a reinforcement between foils of a superplastic metal alloy to provide stack. The stack is then heated to a temperature at which the metal alloy exhibits its superplastic properties, and pressure is applied to the heated stack. This causes the foils to flow around the reinforcement and diffusion bond together in the solid state. A structural composite is thus formed comprising a reinforcement dispersed throughout a matrix of superplastic metal alloy.

Structural metal matrix composite and method for making same

A method is disclosed for removing a part from a die, the part having been produced by clamping a preform between first and second dies and forming at least a portion of the preform into a cavity of the first die. The method comprises the steps of drawing a vacuum from between at least a portion of the formed preform and the second die and separating the second die from the first die such that the part is withdrawn from the cavity of the first die. In a preferred embodiment, wherein the part is clamped abouts its periphery, the method involves the additional steps of providing a channel about at least a portion of the second die aligned with and in communication with the periphery of the preform, and providing sealing members to seal off the channel. The vacuum is then drawn from the channel.

Method of removing formed parts from a die

A method is provided to impart a fine grain structure to aluminum alloys which have precipitating constituents. The alloy is overaged to form coarse precipitates, and then plastically deformed at least 40%. Deformation is accomplished at a temperature and at a rate which are sufficient to retain strain energy in the alloy at the end of the deformation step. The alloy is subsequently heated at a rate of at least 0.02.degree. F..multidot.s.sup.-1 to a recrystallization temperature to form a new fine grain structure.

Method of imparting a fine grain structure to aluminum alloys having

A method is provided for eliminating internal voids in superplastically forming parts. A blank of material which is capable of being formed superplastically is held opposite a forming surface of a die. The blank is heated to the superplastic forming temperature and pressure is applied to both sides of the blank. This pressure is sufficient to prevent the formation of voids. The pressure on the side of the blank farthest from the die surface is then increased to superplastically form the material against the die surface. In a second embodiment, the pressure is applied after the blank has been formed either by maintaining the forming pressure to compreses the material between the forming pressure and the reaction of the die, or by applying a fluid pressure to both sides of the part, thereby removing voids by plastic deformation and diffusion.

Method for superplastic forming

A method and apparatus are provided for automatically controling the strain rate during superplastic forming of a blank of material into a part. The method and apparatus produce a part in a minimum time by deforming the material in its optimum superplastic conditions. A relationship is determined between time and the pressure required to form the blank against the configured surface of a die at a strain rate which causes the blank to flow superplastically. The blank is positioned in the die and held at a temperature at which the material exhibits superplasticity. Pressure is automatically applied across the thickness of the blank in accordance with the previously determined relationship between time and pressure until the part is formed. The apparatus comprises conduits connected to a die and to a high pressure gas. Valves in the conduits regulate the pressure applied to the blank. A controller receives command signals from a programmer which is programmed with the desired time vs pressure relationship. The controller operates the valves and receives feedback information from a pressure transducer in the conduit to maintain the programmed time vs pressure relationship during the forming operation.

Apparatus for superplastic forming

A method is provided for controlling the strain rate during superplastic forming of a blank of material into a part. The method produces a part in a minimum time by deforming the material under suitable-optimum superplastic conditions. A relationship is determined between time and the pressure required to form the blank against the configured surface of a die at a strain rate which causes the blank to flow superplastically. The blank is positioned in the die and held at a temperature at which the material exhibits superplasticity. Pressure is applied to the blank in accordance with the previously determined relationship between time and pressure until the part is formed.

A method is provided for imparting a fine grain structure to aluminum alloys which have precipitating constituents. The alloy is first heated to a solid solution temperature to dissolve the precipitating constituents in the alloy. The alloy is then cooled, preferably by water quenching, to below the solution temperature and then overaged to form precipitates by heating it above the precipitation hardening temperature for the alloy but below its solution treating temperature. Strain energy is introduced into the alloy by plastically deforming it in a temperature range of 380.degree. F. to 450.degree. F. to reduce its cross-sectional area a total of 40% minimum, at least 25% of the reduction in area being accomplished in a single continuous deformation operation. The alloy is then subsequently held at a recrystallization temperature so that new grains are nucleated by the overaged precipitates and the development of these grains results in a fine grain structure.

A method and apparatus are provided for automatically controlling the strain rate during superplastic forming of a blank of material into a part. The method and apparatus produce a part in a minimum time by deforming the material in its optimum superplastic conditions. A relationship is determined between time and the pressure required to form the blank against the configured surface of a die at a strain rate which causes the blank to flow superplastically. The blank is positioned in the die and held at a temperature at which the material exhibits superplasticity. Pressure is automatically applied across the thickness of the blank in accordance with the previously determined relationship between time and pressure until the part is formed. The apparatus comprises conduits connected to a die and to a high pressure gas. Valves in the conduits regulate the pressure applied to the blank. A controller receives command signals from a programmer which is programmed with the desired time vs pressure relationship. The controller operates the valves and receives feedback information from a pressure transducer in the conduit to maintain the programmed time vs pressure relationship during the forming operation.

A method for fabricating metallic structures, especially those having intricate shapes, utilizes a combination of flow forming and bonding. A metal preform having flow forming characteristics is positioned relative to a shaping member and a metal workpiece to be joined to the preform. The preform is heated to a temperature range suitable for flow forming. Pressure is applied to cause the preform to flow form against the shaping member and the workpiece. The preform and workpiece are maintained under coordinated temperature-pressure-time duration conditions to produce metallurgical bonding of the preform to the workpiece.

Method of making a metallic structure by combined flow forming and

A method for fabrication of honeycomb metallic structures combining superplastic forming and metallurgical bonding wherein a face sheet is formed and bonded to another face sheet and a core to form the desired structure. A metal honeycomb core is positioned between the first and second metal face sheets. The first face sheet, which has superplastic characteristics, is brought to within a temperature range suitable for superplastic forming. A pressure loading is applied to the first face sheet causing it to deform against the core and second metal face sheet. The face sheets and core are maintained under coordinated temperature-pressure-time duration conditions to produce metallurgical bonding to one another to form the desired honeycomb structure.

Method for fabrication of honeycomb structures

A method for making metallic structures especially those having a complex variable thickness, utilizing superplastic forming and forging. A metal preform having superplastic characteristics is positioned relative to a shaping member which substantially defines the final configuration of the preform. The preform is superplastically expanded and forged against the shaping member to produce the final structure.

Method of making a metallic structure by combined superplastic forming

A method is provided for imparting a fine grain structure to aluminum alloys which have precipitating constituents. The alloy is first heated to a solid solution temperature to dissolve the precipitating constituents in the alloy. The alloy is then cooled, preferably by water quenching, to below the solution temperature and then overaged to form precipitates by heating it above the precipitation hardening temperature for the alloy but below its solution treating temperature. Strain energy is introduced into the alloy by plastically deforming it at or below the overaging temperature used. The alloy is then subsequently held at a recrystallization temperature so that the new grains are nucleated by the overaged precipitates and the development of these grains results in a fine grain structure.

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Thousand Oaks, CA, United States of America

C Howard Hamilton