Microstructure evolution in Cu–1.54 wt% Cr alloy during directional solidification

The effect of the growth velocity on the microstructure evolution of Cu–1.54 wt% Cr alloy under directional solidification was investigated. The cellular eutectic structure was observed at 50 μm/s. However, a centered Cr-rich β dendritic structure surrounded by a layer of Cu-rich α phase and a eutectic structure between Cu-rich α phase and Cr-rich β phase were observed when a sample solidified at a rate faster than 50 μm/s. A microstructure of a centered Cr-rich β equiaxed dendritic structure covered by a Cu-rich α phase grew at temperatures higher than the eutectic interface temperature. This paper explains the mechanism of the microstructure formation as a function of growth velocity.

► Directional solidification experiments were carried out for the Cu–1.54 wt%Cr alloy. ► Eutectic planar was shown in a low growth velocity. ► Cr-rich β equiaxed dendritic structure was presented for velocities>50 μm/s. ► A centered Cr-rich β dendritic structure surrounded by a layer of Cu-rich α phase. ► The mechanism of the microstructure formation as a function of velocity was explained.