AbstractIsostatic diffusion bonds were produced between Ti–6Al–4V and Super Alpha-2 sheet materials at temperatures of 920–940°C and pressures of 6–10 MPa. The diffusion bonds were evaluated using optical microscopy, lap shear testing, and scanning electron microscopy of the lap shear fracture faces. The results of X-ray microanalysis carried out on the bond interface region showed that substantial diffusion of niobium and molybdenum had occurred from the Super Alpha-2 to the Ti–6Al–4V. This caused a local suppression of theβtransus in the Ti–6Al–4V alloy and on subsequent cooling theβphase decomposed to give a microstructure of fine acicularαphase and retainedβphase in the bond region.MST/3421