Solid state bonding in superplastic Ti-6Al-4V

AbstractThe time taken to produce a bond between two sheets of superplastic Ti-6Al-4V has been calculated using existing theories of high temperature cavity growth and of sintering. The predicted conditions for bonding have been compared with those determined experimentally, and a theory based on the Chen and Argon model of creep cavity growth has been developed to take into account the effect of a material grain size which can be substantially smaller than either the cavity size or the original surface roughness. It has been found that high integrity bonds can be produced at 927°C with pressures between 0.7 and 2 MPa (100–300 lb in−2), and within a time scale of the order of 0.5–4 h.