Fabrication of titanium parts by massive diffusion bonding

Massive diffusion bonding (MDB) is an innovative manufacturing method to produce heavy titanium parts with solid-state bonding of multi-sheets by applying low pressure of inert gas. Massive solid-state bonding is different from conventional diffusion bonding, which is utilized for sandwich panels during superplastic forming of two or three thin-sheets. The advantages of MDB are its ability to produce heavy titanium sections with less materials waste relative to conventional method such as mechanical machining from solid bulk. It is also possible to produce closed sections, which could not be manufactured by extrusion or forging. In this study massive diffusion bonding process of titanium sheets was developed in an inert gas environment. Massive diffusion bonding of 40 sheets with thickness of 2 mm was completed in a furnace at 1173 K, pressure of 4 MPa for 1 h in inert gas environment. Using gas pressure as a loading medium prevents bonding area from the non-uniform pressure application. From pre-sized multi-sheets of titanium, near net shape forming was possible with this process so that significant weight and cost saving was possible.