British Aerospace Public Limited Company

British Aerospace Plc

Martin H Mansbridge

John Norton

David J Irwin

David Stephen

Sidney J Swadling

Dennis J Payne

Alan W Highnam

Paul W Beazley-Long

A method of forming a diffusion bonded joint during superplastic forming of a hollow metal structure (43) from sheet material (15, 16, 17, 18) using a two-piece die (1) having opposed clenching faces (9, 10) disposed along a split line (2) thereof, the structure 43 being formed with a joint at the split line, the method including placing the sheets (15, 16, 17, 18) between the faces (9, 10) clenching the sheets with a pressure sufficient to locate same during superplastic forming while being insufficient to deform the metal and prevent superplastic flow in the sheets between the clenching faces (9, 10), heating the sheets to a superplastic forming temperature and applying a gas pressure between the sheets to commence superplastic forming, when superplastic metal flow between the clenching faces substantially ceases upset forging metal from between the faces towards the interior of the die to increase wall thickness at the joint upon trimming off a flange formed by that part of the sheets trapped between the clenching faces. A die to carry out the above method, a die and sheet assembly and a structure manufactured according to the method are also provided.

Forming of diffusion bonded joints in superplastically formed metal

A method of superplastically forming a metal article and an article formed by such a method are provided. The method includes the steps of placing sheet material including at least one sheet of superplastically formable material (2, 3) and a sheet of reinforcing material (10) adjacent a said sheet (2) of superplastically formable material within a mold tool having a male former (18) protruding from the tool surface positioned to contact the sheet of reinforcing material during forming and causing the at least one superplastically formable sheet (2, 3) adjacent the reinforcing sheet (10) to be superplastically formed into conformation with the surface (28) of the mold tool and simultaneously to urge the sheet of reinforcing material (10) against the male former (18). The method is characterised by thinning at least one selected area (14, 15, 16, 17) of the sheet of reinforcing material (10), the at least one area being adapted to form around at least one region of high curvature (19, 20, 21, 22) of the male former (18) whereby to promote controlled folding of the reinforcing sheet (10) about the former.

Forming of metal articles

The present invention provides a method of making a domed structure using superplastic forming and diffusion bonding techniques. The dome is of a deep and/or irregular shape that cannot be achieved by creep forming. The method includes the step of forming a stack of two or more sheets made of superplastic material and the sheets of the stack being joined together in face to face contact by metallic bonds such that no sheet in the stack is bonded to more than one of its neighbouring sheets; the metallic bonds preferably lie on lines extending radially from and/or circumferentially around the said peak. The resulting stack is heated to superplastic termperatures and a pressure differential is established across the stack to form it into a domed shape. The resulting dome is placed in a mould and heated; an inert gas is injected between the sheets to inflate the stack superplastically thereby forming a space between the sheets which is divided into cells by webs formed from two of the said sheets that have been superplastically formed by the inflation process.

Domed structures and a method of making them by superplastic forming and

A structural box beam of the type formed by a method using superplastic forming and diffusion bonding techniques (SPF/DB). The basis is a SPF/DB four sheet cellular structure box beam, for particular application to a flap track beam for aircraft, said box beam including integrally formed flap track flanges and corrugated shear webs. The corrugations serve the dual purpose of reacting local track bending moments. Internal shear webs are integrally formed as part of the cellular structure. The box beam is designed to be manufactured from a flat blank assembly consisting of four chemically-etched sheets with local reinforcements placed between the core and skin sheets providing a low cost means of tailoring the beam to minimum thickness requirements.

Structural box beams

A method of forming a stiffened panel from first and second metal sheets, at least the first sheet being capable of both superplastic deformation and diffusion bonding, and also provided with at least one control region of different thickness compared with other regions of the sheet, includes the steps of:

Forming of stiffened panels

A method of making a stiffened panel including subjecting two metal sheets, at least one capable of superplastic deformation and diffusion bonding, which are positioned face to face, to a bonding and deforming process during which the sheets are joined to one another at a series of spaced joint lines across their faces, the joint lines being interrupted by non-joined regions along their lengths but being otherwise substantially continuous, and during which parts of at least said one sheet between the joint lines and the non-joined regions thereof are superplastically deformed in a mould to form a series of cavities between the two sheets, portions of at least said one sheet on respective sides of each of the joint lines and the non-joined regions thereof being moved to form sidewalls of two neighboring cavities, these sidewalls being urged to lie adjacent one another over substantial parts of their areas, so that they become diffusion bonded, one to another, to form a common sidewall of neighboring cavities, the non-joined regions of the joint lines each forming a generally circular or part-circular aperture in each sidewall of a diameter similar to the length of the non-joined region.

Stiffened panel with apertures

A stiffened panel of the type formed by a method including subjecting two metal sheets, both capable of superplastic deformation and diffusion bonding, which are positioned face to face, to a bending and deforming process during which the sheets are joined to one another at a series of spaced substantially continuous joint lines across their faces, and during which parts of said sheets between the joint lines are superplastically deformed in a mould to form a series of cavities between the two sheets, portions of said sheets on respective sides of a joint line being moved to form sidewalls of two neighboring cavities, these sidewalls being urged to lie adjacent one another over substantial parts of their areas, so that they become diffusion bonded one to another to form a common sidewall of neighboring cavities, and having formed spaced-apart regions where the sheets have contacted opposite mould faces is further formed with an outer lip region in which an edged region of one sheet remains generally aligned with that spaced-apart region which it forms, while an edge region of the other sheet is deformed out of alignment with that spaced-apart region which it forms to lie, firstly, generally transverse to the spaced-apart regions and, secondly, to be generally aligned with, and be attached to, said region of said one sheet.

Stiffened panel

A method of forming metal articles comprises placing a pair of sheet members 1, 2 or superplastically deformable material in opposed, spaced apart relationship, (conveniently by means of a reinforced member 3), heating them to the temperature range within which superplastic deformation can take place, and urging portions of the sheets toward each other until they lie one against the other thereby to effect bonding. The bonding is preferably by means of diffusion bonding.

Forming metal articles

Two face-to-face metal sheets, one or each of which is superplastically deformable, are subjected to a bonding and pressure deformation process in which the sheets are bonded together at a series of spaced positions thereon and the areas of the or each superplastically deformable sheet between these positions move away from the other sheet so that there is formed a series of cavities between the sheets, the sides of neighboring cavities being substantially adjacent to one another over substantial parts of their areas. These sides of the cavities, which are preferably substantially rectangular may come directly into contact with one another and be diffusion bonded together either directly or via reinforcing members.

Growing community of inventors

Bristol, United Kingdom

Martin H Mansbridge