AbstractDiffusion welding of titanium cylinders to an alumina cylinder (Ti/Al2O3/Ti) was carried out at temperatures above theα–βtransition temperature of titanium. Titanium and alumina were welded under the following conditions: maximum heating temperature greater than 1400 K, holding time of 30 s, heating (cooling) rate of 1–10 K s−1, welding pressure of 1·6 MPa, and an air atmosphere. The shear strength of Ti/Al2O3/Ti welds was very low because of the residual stress at the welded interface. Alumina cylinders were welded using titanium foil as an insert (AI2O3/Ti foil/Al2O3). The shear strength of Al2O3/Ti foil/Al2O3welds increased slightly with the decrease of foil thickness, and attained a maximum value of 82 MN m−2. When the foil thickness was less than 10μm, the welds failed at the welded interface, but the welds with foil of 100μm thickness failed in alumina close to the interface.MST/1114