British Aerospace Plc

British Aerospace Public Limited Company

John Norton

Martin H Mansbridge

Sidney J Swadling

Dennis J Payne

David J Irwin

David Stephen

Paul W Beazley-Long

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 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 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.

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Bristol, United Kingdom

John Norton