Method and apparatus for superplastic forming and diffusion bonding of hollow parts

A method for superplastic forming and diffusion bonding of hollow metal parts which comprises the steps of:

• preparing a pair of concentric metal parts which are surfaces of revolution;
• placing selected discrete metal parts between said parts intermediate the axial ends thereof;
• closing the spaces between the axial ends of said parts to produce a part assembly;
• inserting a hollow tool into said part assembly, the exterior surface of said tool being in uniform contact with the interior surface of the inner concentric part;
• placing said part assembly and tool in a pressure chamber;
• placing a heater inside said hollow tool;
• closing said chamber;
• evacuating the interior of said part assembly;
• activating said heater to heat said part assembly to the diffusion bonding temperature of the part metals;
• pressurizing the interior of said chamber;
• and
• whereby the outer concentric metal part is forced into contact with said discrete parts and said inner concentric part and all parts comprising the part assembly are diffusion bonded to form a unitary product.