Patent ID: 7416105

Claim:
A superplastic forming method for manufacturing a structural assembly having a predetermined contoured configuration, the method comprising: providing a preform having a stack of first and second structural members, the stack abutting a third structural member and joined to the third structural member by a friction welded butt joint; and with the first and second structural members joined to the third structural member, superplastically forming at least one of the first and second structural members to a predetermined contoured configuration, wherein the providing step comprises: disposing the first and second structural members in the stacked configuration substantially parallel to the third structural member and with an edge of the first and second structural members abutting the third structural member, the third structural member having a thickness about equal to a combined thickness of the stacked first and second structural members, such that the first and third structural members define a substantially planar surface and the second and third structural members define a substantially planar surface; and friction stir welding the first, second, and third structural members to form the butt joint between the stacked first and second structural members and the third structural member.