HIGH-TEMPERATURE STRENGTH OF INSITU FORMED CU-NB MULTIFILAMENTARY COMPOSITES

CuNb wire composites with 10.5 and 14.8 vol.% of submicron Nb filaments were produced in situ and their mechanical properties measured as a function of temperature (300-800 K) and wire diameter. The ultimate tensile strength increases both with niobium content and inverse wire diameter and is at all temperatures well above the values predicted by the rule of mixtures. The strengthening in these composites is attributed to the development of a stable cell-type substructure with copper-niobium interfaces acting as effective barriers to the motion of matrix dislocations. These results, combined with preliminary electrical resistivity measurements, indicate that the high temperature properties of the in situ formed copper-based composites are superior to other high-strength, high-conductivity materials. © 1979.