Abstract: A method is set forth for forming a unitary structure having a plurality of deformable foils having first and second sides stacked one upon another with the first sides facing in one direction and the second sides in an opposite direction, each of the foils having an undulating cross-section, adjacent of the foils having their undulations orthogonal to one another and every other one of the foils having parallel orientations. The method comprises positioning a first plurality of parallel rods against the first side of a respective one of the foils and positioning a second plurality of parallel rods against the second side of the same foil with the rods of the second plurality of rods between and parallel to the rods of the first plurality of rods. Thereafter the aforementioned steps are repeated with each next adjacent foil having the rods defining the undulating cross-section thereof at a non-zero angle to the rods of the next adjacent foil.

Abstract: A process is set forth for making a structure formed of at least two metallic workpiece sections each formed of a reactive metal. A mandrel having a nonreactive surface is sandwiched between the workpiece sections thereby preventing them from being in contact over a first selected area and allowing them to be in facing relation over a second selected area. A reactive metal contact is formed of the workpiece sections over the second selected area. The workpiece sections are maintained under coordinated temperature-pressure-time duration conditions to diffusion bond them at the second selected area. A gas pressure differential is applied between intermediate the workpiece sections and external of the workpiece sections to cause breakthrough at the first selected area and superplastic forming of at least one of the workpiece sections causing it to stretch in excess of its original surface area. The mandrel is removed from between the workpiece sections.