Joining of Gamma Titanium Aluminides

This report summarizes, interprets and comparatively discusses the results of research and development performed on the joining of gamma titanium aluminides during the past two decades. Although organized and presented by joining process, many of the observations made and relationships developed, particularly those regarding the weldability and welding metallurgy of gamma titanium aluminides, are broadly applicable. Generally, the basic welding processes and techniques utilized in the fusion and solid -state friction welding of conventional titanium alloys can also be applied to the welding of gamma titanium aluminides. However, the welding process parameters must be optimized, and in some instances the welding system significantly modified, to provide a comparatively slow weld cooling rate that minimize the potential for solid-state weld cracking, and that promotes the formation of a weld zone micro structure that exhibits suitable mechanical properties. Control of the weld cooling rate and the application of a postweld heat treatment can be used to generate a wide range of crack-free weld zone microstructures that correspondingly offer a range of mechanical property combinations. Gamma titanium aluminides can also be effectively joined using diffusion welding and conventional and diffusion brazing techniques.Air Force Research Lab Wright-Patterson AFB OH Materials and Manufacturing Directorate is the author of 'Joining of Gamma Titanium Aluminides', published 2002 under ISBN 9781423504535 and ISBN 1423504534.