The Effects of Nb As a Solid Solution Element on Mechanical and Electrical Properties of Cu

Abstract The effects of Nb as a solid solution element on the strengthening and conductivity of pure Cu were studied. Arc-melting was used to produce the alloys. Precipitation of Nb particles in local regions (islands) was observed in alloys with as little as 0.05 wt% Nb. In the Cu alloy with 23 wt% Nb, a thin layer of Nb was detected on the surface of the melted button, which could be an indication of the liquid immiscibility in the Cu-Nb system. The mechanical and electrical properties of Cu-0.1 wt% Nb at various stages of cold work were compared with that of pure Cu with a similar cold work path. The strength of Cu-0.1 wt% Nb was found to be 6% higher than that of Cu at various stages of cold work. Through the electrical resistivity measurements, room temperature solubility limit of Nb in Cu is determined to be 0.0086 at % (0.013 wt%Nb). It is then shown that this amount of Nb in solid solution form contributes only 0.19% to strengthening of Cu. The remaining strengthening is attributed to the dispersion and strain hardening mechanisms.