On the solidification microstructure of copper-rich niobium alloys

The microstructure of copper-rich niobium alloys has been studied as a function of cooling rate. The main alloy composition investigated was Cu-7 wt% Nb. The cooling rate was varied from 40° C sec^–1 to approximately 7×10^4° C sec^–1. The microstructure as observed in the scanning electron microscope changes from well-dispersed niobium spheres for fast-cooling to an heterogeneous distribution of niobium flowers for slow-cooling.