US Patent 7287960 Titanium aluminide wheel and steel shaft connection thereto

Titanium aluminide (TiAl) rotor shaft assembly (10) of a type used in a turbocharger has a TiAl rotor (20) with an axially protruded portion (40) that is fixedly joined to a recessed portion (50) of a metal shaft (30) by the synergistic combination of an interference fit, such as a heat shrinkage fit, further supported by a brazed joint (60) in which a thin layer of a brazing material (110) is interposed between the surface of the protruded portion (120) and the recessed surface (130). Optionally, one or both of the jointed surfaces have braze channels (90) to facilitate braze flow within the joint. Methods for producing the rotor shaft assembly (10) and a turbocharger having the rotor shaft assembly (10) are provided.