a b s t r a c t Solid state diffusion bonding has been successfully employed to join -TiAl alloys. Processed in vacuum, at high temperature and pressure, the thin interfaces and the lack of structural discontinuity across the interface are the main advantage of this joining technique. An interlayer made of alternated Ti and Al nanometric layers that increases the diffusivity at the joint interface, was used in order to assist the bond-ing process of -TiAl alloys. The use of Ti/Al interlayer has efficiently reduced the joining temperature. Sound joints have been achieved at a temperature of 900 • C under a pressure of 50 MPa in vacuum. In the present work Cu was added as third element to the Ti/Al multilayers and its effect improved the bonding quality. The interface microstructure was studied by scanning and transmission electron microscopy.