Development of deformation processed copper-refractory metal composite alloys

The strength, electrical conductivity, and substructure of deformation processed Cu--15 vol.% X alloys have been studied where X included Nb, Ta, and Cr. One alloy of Cu--15Nb was studied in which 2% Ag was added to examine solid solution strengthening of the Cu matrix. The alloys were prepared by consumable arc melting and ingot diameters of 7.6 and 15.2 cm were examined. Deformation was carried out at room temperature by rolling, press forging, and axisymmetric modes. The results show that the strength/conductivity properties of the Nb, Ta, and Cr alloys are essentially the same and are slightly better than the Cu--20 vol.% Nb alloys previously measured. The Ag alloy was found to be stronger at a given deformation, but the solid solution Ag decreased the conductivity more than it increased strength so that the net effect was to reduce the strength at a given conductivity. TEM studies showed that the substructures of all the alloys were similar to each other and to previous results on Cu--20 vol.% Nb alloys. Deformation by both press forging and rolling are not as effective at increasing strength as is axisymmetric deformation. Graphs, Photomicrographs. 19 ref.--AA