Measurements of liquidus temperatures in the Cu-Nb and Cu-Cr systems

The Cu-Nb and Cu-Cr alloys at compositions ranging from 5 to 86 wt% Nb (89 wt% Cr) were processed in a clean environment and solidified at relatively low cooling rates of 50 to 75 °C/s to determine liquidus temperatures. In this study, both temperature measurements and microstructural observations confirmed the equilibrium phase diagram having an S-shaped, nearly flat liquidus, rather than that with a monotectic reaction in the liquid state. However, a metastable liquid miscibility gap exists in the two systems.