Manufacturing method for hollow metal airfoil type structure

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. The process provides structures such as airfoils having leading edges and trailing edges of controlled weight and internal radii.

Dependencies are inferred from the claim text.