Lockheed Martin Corporation

Other

William J Arbegast

Brian J Dracup

Joseph H Armstrong

Timothy Dennis Iwanczyk

Brian J Maclean

Timothy E Hatten

Paula J Hartley

The present invention provides an improved method and apparatus for joining aluminum allow panels (eg. 2090-T83 aluminum lithium alloy). The method preliminarily positions two panels and skin panels next to each other so that a stringer panel overlaps a skin panel. A friction stir weld pin tool penetrates through one panel and at least partially into another panel. The panel material around the pin tool is frictionally heated, plasticized and joined until the faying surface is substantially consumed. In another embodiment, a tee-shaped structure is formed using friction stir welding to join three panels together. A projecting part of one panel (center, vertical) provides material that becomes a contoured corner panel below two side, horizontal panels after friction stir welding is completed (FIGS.)

Friction stir welding as a rivet replacement technology

The present invention provides an improved method and apparatus for joining aluminum allow panels (eg. 2090-T83 aluminum lithium alloy). The method preliminarily positions two panels and skin panels next to each other so that a stringer panel overlaps a skin panel. A friction stir weld pin tool penetrates through one panel and at least partially into another panel. The panel material around the pin tool is frictionally heated.

A method for fabrication or production of composite structures, which has particular advantages when fabricating large structures, includes the steps of procuring a composite panel, such as carbon-fiber-reinforced resin. The edge of the composite panel its adhesively fixed in the slot of a bifurcated metallic piece. After the composite panel is adhesively fixed to the metallic piece, the metallic piece is stir-friction welded to another metal piece. The stir-friction welding occurs at a lower temperature than fusion welding, and so the adhesive bond between the metallic element and the composite panel is less affected. When two composite panels are each adhesively fastened to a metallic element, the two metallic elements can, in turn, be stir-friction welded. Thus, large panels can be fabricated.

Method for making large composite structures without use of an autoclave

A friction stir welding tool includes a body having an upper surface defining an entrance opening and a lower surface, and a pin having a lower surface defining an exit opening, wherein the pin extends from the lower surface of the body. The friction stir welding tool further includes a passageway defined by the body and the pin from the entrance opening to the exit opening and is capable of allowing a filler material to pass therethrough. A friction stir welding method includes applying a frictional heating source to a workpiece to plasticize a volume of the workpiece and applying the frictional heating source to a filler material to plasticize the filler material. The method further includes introducing the filler material into the volume of the workpiece and incorporating the filler material into the volume of the workpiece.

Apparatus and method for friction stir welding using filler material

A method of using friction stir welding to repair weld defects and to help avoid weld defects in intersecting welds and crack-sensitive material, such as 2195 Al&mdash;Cu&mdash;Li. Intersecting fusion welds in 2195 Al&mdash;Cu&mdash;Li have shown a propensity to crack both during welding and during proof testing. These cracks have generally been associated with a particular metallurgical structure present in the fusion zone ofVPPA/SPA weldments. HYBRID Friction Stir Overwelding of the initial VPPA/SPA weld from the penetration side is shown to convert the cast microstructure of these VPPA/SPA weldments into a fine grained, dynamically recrystallized microstructure showing higher strength, ductility, toughness, and resistance to intersection weld cracking.

Method of using friction stir welding to repair weld defects and to help avoid weld defects in intersecting welds

A seam (,) between juxtaposed workpieces (,) is welded or heat-treated by friction-stir using a pin tool (,) driven by an apparatus (,) which controllably positions the pin tool (,) in the vertical direction (,). The workpiece (,) is supported by an anvil (,). The joint is heated by rotation of the pin tool (,) inserted into the joint from the obverse side. In order to provide a good weld through the thickness of the workpiece, a sensor (,) senses electrical characteristics near the heated or welded region, and generates a control signal which tends to control the position of the pin tool near the reverse side of the weld. The sensor is located adjacent the weld (,) on the obverse side, and is preferably protected by mounting in a depression (,) in the anvil (,). In one embodiment, the sensor (,) senses magnetic characteristics near the weld. In another embodiment, the sensor (,) senses conduction, conductivity, or eddy currents in the vicinity of the weld.

Friction stir conduction controller

A fastener having an elongated shank formed of a shape memory alloy, a head at the upper end of the shank, and an annular segment at the lower end of said shank having a deformed cross-sectional shape suitable for insertion into an opening extending through adjacent workpieces. The annular segment has a frusto-conical trained shape that is larger than this opening. The annular segment radially flares from the deformed shape to an approximation of the trained shape when heated above a critical transformation temperature, thereby securing the fastener in place with respect to the workpieces. Alternatively, a sleeve made of a different material (e.g. aluminum) extending over a portion or the entire length of the fastener can be added for improved deformational characteristics, by providing the same frusto-conical shape through axial contraction of the shank.

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Rapid City, SD, United States of America

William J Arbegast