HIGH-TEMPERATURE CREEP OF MICROCRYSTALLINE DISPERSION-STRENGTHENED COPPER-ALLOYS

High creep strength of dispersion strengthened alloys with microcrysta lline grain size can be obtained if the dispersoids are very small and located mainly on the grain boundaries, thus preventing grain boundar y sliding. For the creep investigations, TiC dispersion strengthened C u alloys or Cu-Ti alloys made by mechanical alloying were used The pro cessing technique used made it possible to produce TiC dispersoids of different sizes (10-50nm) formed by in-situ reactions and to localize them preferably an the grain boundaries. The matrix of the alloys is m icrocrystalline (100-500nm). The high temperature creep behavior of th e alloys is described in terms of ifs dependence on size, position and volume fraction (3-10v/o) of the dispersoids. The microstructure of t hese alloys is demonstrated by transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM) investiga tions.