Abstract: A method of friction stir welding joints with shims and an associated structural assembly is provided. The structural assembly includes one or more skin members that are disposed and friction stir welded to a substructure. A shim is disposed in a space defined by the other members of the assembly, e.g., between adjacent skin members or between a skin member and the substructure. The shim can be friction stir welded to the other members. That is, the adjacent skin members can be connected via the shim, and/or the skin members can be connected to the substructure via the shim. In some cases, the skin members and the substructure are relatively stiff, and the shim substantially fills the space to reduce flexing of the members during the friction stir welding operation.

Abstract: A combination pneumatic and electro-pneumatic gas valve positioning system comprising a pneumatic positioner and an electro-pneumatic positioner in parallel. The apparatus also includes at least one solenoid to control gas flow between the electro-pneumatic positioner and the pneumatic positioner.

Abstract: A method of holding a billet of material (70) to a machining table (106) includes determining a first set of outer dimensions of a component (72) to be machined. The billet of material (70) is selected in response to the first set of outer dimensions to have a second set of outer dimensions. Dimensions of the second set of outer dimensions are approximately equal to or greater than corresponding dimensions of the first set of outer dimensions. Multiple tabs (76) are attached to the billet of material (70). The tabs (76) are rigidly fixed to the machining table (106). A machining system (50) includes a controller (52) that determines a first set of outer dimensions of a component (72) to be machined. A tab-forming mechanism (54) generates multiple tabs (76) that are configured to be rigidly fixed to a machining table (106).

Abstract: The machined-sandwich structural assembly has two components joined together with a joint of substantially the same strength as the weakest base material. More specifically, the structural assembly includes a first structural member and a second structural member. The first structural member is spaced from the second structural member through a plurality of intermediate members which extend between the first structural member and the second structural member. The plurality of intermediate members are friction stir welded to the first structural member. The resultant assembly requires less stock material, takes less time to machine and has a joint of improved strength.

Abstract: A method for forming a gas-filled consolidated metal billet, involving preparing a metallic shell container, filling the shell with a metal core material and pressurized gas, and consolidating the shell and its contents to form the billet. The consolidated billet is further formed in the same manner as solid metal components by conventional wrought mill working technologies. After thus forming a shaped billet having a predetermined, desired geometry, it is subjected to a heat treatment that expands the gas trapped within the core, to produce in situ a metal body having an integral sandwich-type structure with a solid metal facing and a porous metal core.

Abstract: Powder metallurgy techniques are disclosed for fabricating gamma titanium alloy articles (TiAl type alloys) from mixture of powder wherein one species is based on Al.sub.3 Ti and the other Ti.sub.3 Al. Mixtures of these powders in the proper ratio can be compacted, worked, and heat treated to form the desired gamma TiAl alloy.

Abstract: A method of inhibiting grain growth and restricting grain size during heat-treatment and hot-working of metallic materials. A small volume of inert gas is added to a metallic material so that the inert gas is dispersed throughout the metallic material. The metallic material is then heated sufficiently high so that the inert gas forms micropores within the metallic material; the micropores interact with grain boundaries to inhibit grain growth. If desired, all or part of the residual microporosity may be eliminated from the metallic material during the final step of a deformation processing cycle.