Abstract: A high gas pressure material capable of producing 50-300 psi gas pressure at forming temperature is placed in an enclosed area surrounding and sealing the blanks to be superplastically formed, without the use of argon gas. The blanks are formed under tensile stress by the internal pressure produced by the high gas pressure material. The method can be performed concurrently with diffusion bonding to obtain a metallic structure from a plurality of workpieces, and also can be used to manufacture perfectly spherical hollow bodies by a dieless method.

Abstract: A gas management system for delivering forming gas under a controlled pressure through a first portion of a piping network to a region of a forming die between a die lid and a blank to be formed in a superplastic forming machine includes a gas pressure regulator in the piping network and two control loops. The first control loop has a first pressure transducer communicating with the piping network downstream of the gas pressure regulator and operatively with the gas pressure regulator. The second control loop includes a pulse controller downstream of the first pressure transducer and a second pressure transducer communicating with the piping network downstream of the pulse controller and operatively with the pulse controller. The gas pressure regulator receives signals from a controller to adjust the pressure at which the gas pressure regulator opens to release gas through the pressure regulator.

Abstract: A method for inducing superplasticity in a composite including a non-transforming phase and a transforming phase by cycling the composite material through a phase transformation of the transforming phase while applying an external stress to the composite material is provided as is a method for inducing superplasticity in a titanium/titanium carbide composite. Also provided is a method for forming a part from a composite material including a transforming phase and a non-transforming phase by cycling the composite through a phase transformation of the transforming phase and shaping the composite material by applying an external stress to the composite material while the transforming phase is undergoing a phase transformation to form a finished article.

Abstract: A method to superplastic form sandwich structures is provided. A series of worksheets are joined together at selected locations through the use of partial penetration welding. The worksheets are subsequently superplastic formed in order to form a sandwich structure. The method allows a different number of worksheets to be used at different points throughout the sandwich structure. This results in a sandwich structure with a different internal reinforcement at different locations in the sandwich structure. In the preferred embodiment, a wing is fabricated from a series of worksheets partial penetration welded together using a laser. The worksheets are superplastic formed to producing a wing with a different internal reinforcement at two or more locations in the wing.

Abstract: A method for producing a golf club head made of joined component pieces in which a mold black is split into separate first molds. Each of the first molds have a cavity patterned after one of the joined component pieces. In one embodiment, superplastic alloy plates are positioned within the first molds. The alloy plates are heated and pressurized fluid is simultaneously introduced into the cavities of the first mold for superplastic deformation of the plates. The alloy plates are then positioned within second molds and pressed to form the component pieces. The formed component pieces have shaped piece sections having small radii of curvature. The component pieces are joined to form the golf head. In another embodiment, one of the alloy plates is pressed by the second molds prior to being inserted within the first molds. The pressed alloy plate corresponds to one of the component pieces and has piece sections having a small radius of curvature.

Abstract: A forming die which includes a die cavity contains a forming blank composed of a metallic alloy having superplastic properties. The forming pressure in a pressurized space adjacent the forming blank is regulated by a pressure regulator. The volume of the die cavity is determined, as is the mass of gas initially contained in the die cavity at the beginning of the forming cycle. The total forming time is empirically determined. The average gas mass flow rate that will be exhausted from the die cavity is calculated by dividing the total mass of gas initially contained in the die cavity by the total forming time. A gas mass flow meter fluidly communicates with the die cavity and measures the mass flow rate of the gas displaced by the forming blank and exhausted from the die cavity. The gas mass flow meter is continuously monitored during the forming cycle or a gas mass flow rate signal is fed back to the pressure regulator.

Abstract: A method and apparatus for effecting superplastic forming of metal workpieces at temperatures greater than 1000.degree. C., wherein both oxidation and creep deformation of the tooling are minimized. The process is achieved by heating forming surfaces of ceramic forming dies to temperatures in excess of 1000.degree. C., and using metal housings to impart high loading conditions to seal the workpiece within a chamber for superplastic forming. More specifically, the metal housings are used not only for load bearing purposes, but also for creating an evacuated chamber within which superplastic forming can take place. The ceramic dies, on the other hand, are positioned on opposing sides of the workpiece region to be superplastically formed, and are insulated from, while being contained within, the metallic dies.

Abstract: A sheet of Ti 6-2-2-2-2 alloy having a starting thickness of between approximately 0.040 inches and 0.187 inches is thermomechanically treated at a temperature of between approximately 1500 degrees F. and 1750 degrees F. at a mechanical strain rate in the range of between approximately 1.times.10.sup.-4 and 1.times.10.sup.-2 inch per inch per second to produce a formed part having a tensile strength which is approximately 33% greater than untreated rolled Ti 6-2-2-2-2 alloy sheet or plate.

Abstract: A vertically reciprocable lower chamber has a ceramic forming chamber surrounded by a steel reinforcing jacket. A fixed upper chamber includes a metal cover surrounded by ceramic insulator blocks and and an outer steel jacket. A horizontal foam ceramic platen inside the steel cover has a serpentine radiant heating coil attached to the flat underside thereof via inserted fasteners for more efficient heating of a metal sheet positioned horizontally between the upper and lower chambers. A plurality of foam ceramic insulator blocks have secondary heating coils attached to their inwardly facing surfaces for heating the peripheral edges of the metal sheet. This ensures a gas tight seal between the metal cover and the sheet.

Abstract: An SPF press is capable of forming large generally cylindrical structures from a sheet made of a first metal such as Titanium. The sheet is first rolled into a cylindrical or conical part blank. The press has a generally cylindrical ceramic die with a surface defining the contour of a part to be formed. The part is formed by pressing a first side of the part blank against the die utilizing high pressure gas. Generally cylindrical gas impervious seals overlie the opposite ends of the cylindrical part blank on a second side thereof opposite the first side. Each of these gas impervious seals includes a support member and a seal member which are spaced apart to define a gap therebetween. A generally cylindrical seal ring is seated in each gap and contacts the second side of the cylindrical part blank. The seal rings are made of a second metal that is softened at a temperature at which the first metal becomes superplastic.

Abstract: A method and apparatus for superplastic and diffusion bonding of hollow metal parts which are generally surfaces of rotation. A hollow frangible ceramic die having an interior shaping surface is provided. A metal part to be shaped is placed against the shaping surface (together with any other metal components to be diffusion bonded to the part during forming) and the remainder of the die is covered with sheet metal pieces, all of which are sealed together and to the part to form a gas-tight enclosure for the die. The enclosure is flushed with an inert gas and/or evacuated through an opening in the enclosure. The assembly is placed in an autoclave and exposed to an appropriate pressure and temperature to superplastic form the part outwardly against the shaping surface. The assembly is cooled and removed from the autoclave, then the enclosure is removed. The die is broken away, freeing the formed part.

Abstract: An apparatus and method for controlling the superplastic forming process by measuring and controlling the gas mass flow rate of the gas displacing the blank being formed.

Abstract: A process and apparatus for forming a sheet element with a contoured surface from a plane titanium or titanium alloy sheet by hot deep-drawing in a press. The plane sheet is preheated to a temperature of at least 730.degree. C. and transferred to a non-preheated deep drawing tool. The deep-drawing tool is placed in a press for a period of time sufficient for the temperature of the element to be at least 700.degree. C. at the end of the deep-drawing operation. The deep drawn element is transferred to a calibration tool and heated to at least 650.degree. C. for a sufficient time to assume a final shape and allowed to cool to room temperature.

Abstract: A method for producing a metallic material having an ultra-fine microstructure, the metallic material exhibiting a phase transformation of a low-temperature phase into a high-temperature phase is disclosed, the method comprising the steps of:preparing a metallic material which comprises at least a low-temperature phase;applying plastic deformation to the metallic material; andincreasing the temperature of the metallic material to a point beyond a transformation point while applying the plastic deformation to effect reverse transformation of the low-temperature phase into a high-temperature phase.

Abstract: A monitor is provided for measuring and controlling the strain rate of a blank during forming. A light source directs light against the blank and a video camera is positioned and focused to view the light reflected from the blank while it is being formed. A video monitor and an image processor receive the signal from the camera. This signal is used to determine the strain rate based upon the dimensional change in reference marks on the blank. The image processor provides an output signal which can be used to control the strain rate in accordance with a predetermined strain rate profile for the particular part being formed.

Abstract: A method is provided for achieving predetermined thickness requirements throughout a superplastically formed structure having extreme contours. A laminate assembly of sheets of a metal capable of exhibiting superplasticity, such as titanium alloy, is formed by a combination of superplastic forming and diffusion bonding. The shapes and positioning of the sheets is selected to provide extra metal where the greatest degree of stretching is necessary, such as around the lobes of an exhaust mixer for a turbofan aircraft engine. The gauge can thus be controlled throughout the structure while avoiding weak points and undue weight.

Abstract: An apparatus for superplastric forming of metallic workpieces and, more particularly, aluminum workpieces is disclosed. The apparatus includes a mechanism for ejecting the workpiece from the die upon completion of the superplastic forming process. A steel liner covers the surface of the die cavity, and the workpiece is formed against the liner (which acts as a die surface). The steel liner has high temperature resistance at superplastic forming temperatures providing it with sufficient rigidity to enable it to be removed from the cavity at or near superplastic forming temperatures while still retaining its shape and that of the formed worpiece which it supports. In one embodiment, a cam operated ejection mechanism pushes the liner from the die cavity surface as desired at the end of the superplastic forming process. In another embodiment, the die is provided with apertures through which pressurized gas is directed toward the liner pushing the liner away from the die cavity surface.

Abstract: A method and apparatus for the superplastic forming of a workpiece are disclosed. The invention comprises securing the workpiece within a die assembly located within an autoclave. The die assembly is of a type suitable for use in the superplastic fabrication of workpieces. The die assembly includes a lid, a die and first and second sealing mechanisms. The first sealing mechanism seals a first volume formed between the lid and the workpiece from a main volume of the autoclave. The second sealing mechanism is for sealing a second volume formed between the workpiece and the die from the main volume of the autoclave. The second volume has a backpressure, P.sub.b. The first volume has a pressure P.sub.f +P.sub.b where P.sub.f is the forming pressure for achieving superplastic forming of the workpiece. The main volume of the autoclave has a pressure, P.sub.m. The back pressure, P.sub.b is established so as to minimize grain boundary cavitation. A minimal pressure differential .DELTA.P=P.sub.m -P.sub.

Abstract: A method of superplastically forming a part from a blank of material. The blank is placed between opposed die structures and heated to a superplastic forming temperature. Positive fluid pressure is supplied at an increasing rate against a front surface of a blank to stretch the same into a cavity of one of the dies to begin formation of the part. A positive fluid pressure is also applied against the back surface of the blank, and acoustical energy emitted by the material of blank resulting from the occurrence of cavitation in the material is sensed. The sensing of acoustical energy is employed to control one or more of the above parameters until the formation of the cavities substantially reduces or ceases altogether.

Abstract: Methods of making superplastically formed and diffusion bonded articles are disclosed as well as the articles made from such methods. Metal sheets are superplastically formed and diffusion bonded in a manner such that pillows are formed on respective outer surfaces thereof, providing a cellular structure interconnected by channels permitting control of gas pressure with the cells. The cellular structure can, in one embodiment, be twisted and the cells can be inflated through superplastic forming. The twisted cellular structure is particularly useful as an intermediate stiffener for an airfoil.

Abstract: The process for forming a metallic sandwich structure having a curved surface, particularly a surface curving about more than one axis, such as a quadric surface partially by direct displacement and partially by a fluid interface. Additionally, means to restrain the work sheets being formed with respect to the shaping fixture which allow a portion of the work sheets to flow into the forming cavity before absolute restraint is applied and the restraining means function independently of the clamping force of the press.

Abstract: A superplastic forming apparatus is described in which a blank of superplastic material is formed onto a die located in a pressure cavity. The die, which is preferably made of ceramic material, is removable from the cavity and requires no special connections for gas or vacuums ducts and therefore is cheap to manufacture. The use of a separate die also allows accurate monitoring and control of the pressure on the die side of the superplastic blank.

Abstract: In a method for transmitting force from one piston to another piston, a superplastic alloy is used between the pistons as a pressure transmitting medium. An apparatus adopting the method serves as a force multiplication apparatus.

Abstract: The process for forming a metallic sandwich structure having a curved surface, particularly a surface curving about more than one axis, such as a quadric surface partially by direct displacement and partially by a fluid interface. Additionally, means to restrain the work sheets being formed with respect to the shaping fixture which allow a portion of the work sheets to flow into the forming cavity before absolute restraint is applied and the restraining means function independently of the clamping force of the press.

Abstract: A superplastic hot working method for a duplex-phase, nitrogen-containing ferrous alloy and stainless steel, and a superplastic duplex-phase ferrous alloy are disclosed. The ferrous alloy comprises: at least one of Si and Mn in an amount of not less than 0.5 % and not less than 1.7%, respectively; and N: at least 0.01% in solid solution, wherein Si eq and Mn eq which are defined as: Si eq=Si+(2/3) (Cr+Mo), and Mn eq=Mn+2Ni+60C+50N, satisfy the formula:(5/6) (Si eq)-15/2.ltoreq.Mn eq.ltoreq.(11/5)(Si eq)-77/5,and its superplastic hot working is carried out by deforming the alloy heated to 700.degree.-1200.degree. C. at a strain rate of 1.times.10.sup.-6 S.sup.-1 to 1.times.10.sup.0 S.sup.-1. In another aspect, superplastic hot working of a duplex-phase stainless steel comprising Cr: 10.0-35.0%, Ni: 2.0-18.0%; Mo: 0-6.0%, and N: 0.005-0.3% and having the values of Si eq and Mn eq as above is carried out by deforming the steel at a strain rate of from 1.times.10.sup.-6 S.sup.-1 to 1.times.10.sup.1 S.sup.

Abstract: A method of superplastically forming a part over period of a forming cycle in which a blank of the material is provided and heated to within a certain range of temperatures. An analytical model is provided that determines locations of the blank that will deform most rapidly when forming pressure is applied. As the forming pressure is applied, the displacements are monitored at such locations while the blank is being deformed. The strain rate is then calculated and feedback control is provided to affect the strain rate at such locations that will reduce the tendency of the blank or part to cavitate.

Abstract: A hollow sphere is made of a superplastic material and blown to a large size, unrestricted or with restriction in one or two directions. The unrestricted hollow sphere may be rotated while being blown.

Abstract: Heated superplastic material is deformed using gas pressure which forces the material into a die cavity. Improved three dimensional models for deforming superplastic materials are based upon spherical shapes penetrating the die cavity which is approximated by one of two different rectangular box models. The three dimensional and box models produced radius and thickness equations from which an accelerated gas pressure versus time profile and a minimum thickness value are calculated. The gas pressure deforms the superplastic material at the maximum possible strain rate without rupturing thereby reducing the speed at which parts are formed. Die frictional effects and variable flow stress phenomena are included into the pressure versus time profile computation and thickness equations so as to improve the speed and accuracy of the superplastic forming process.

Abstract: An apparatus and method for controlling the superplastic forming process by measuring and controlling the volume displaced by the blank being formed so as to measure total strain or surface area increase of the blank.

Abstract: A method and apparatus are disclosed for the drawing of wire-like elements, such as, wires, rods, tubes, and the like. The method employs the use of macrosonics for deformation of the wire. The use of hydrodynamic lubrication together with the macrosonic drawing process substantially increases the permissible drawing speeds. Apparatus for performing the method includes a horn having a drawing die and a properly dimensioned channel for permitting hydrodynamic lubrication disposed therein.