BRAZE JOINTS OF DISPERSION-STRENGTHENED COPPER

Prior attempts to join alumina dispersion strengthened alloys (GlidCop ) to itself, stainless steel (SS) and other materials have been less t han successful. Typically these joints show low strength and poor duct ility due to the segregation of alumina particles at the braze interfa ce. This paper presents the results of a study undertaken to develop l ow activation brazing alloys, fluxes and processes for vacuum, argon a nd air environments to join alumina dispersion strengthened copper all oys to 304 SS. Vacuum and argon experiments were conducted using a Gle eble resistance heated system. Air brazing experiments were conducted in a resistance heated furnace with active fluxes. A reactive braze al loy composition has been developed which eliminates the segregation of Al2O3 particles at the braze interface and produces joints with excel lent strength and ductility. Wetting and mechanical properties of the braze alloys were measured. Tensile properties, microstructure, microh ardness and measurements of the compositional segregation across the b raze joint are discussed.