Interface morphology and microstructure evolution of Cu-0.5Cr alloy in directional solidification

Effects of directional growth rate on solidification structure of Cu-0.5Cr alloy have been described in directional solidification. It is found that the solidification structure of the alloy is evolved from planar to cellular to coarse dendrite to hexagon cellular, and then to fine plate-like structure with varying solidified growth rate from 2 μm/s to 500 μm/s in the condition of 200 K/cm temperature gradient. The presence of eutectic phase from non-equilibrium solidification can be observed in directional solidification structure of the alloy with the solidification rate more than 10μm/s, whose volume fraction is reduced with the increase of the solidification rate. The value of primary dendritic arm spacing in Cu-0.5Cr alloy is located between the calculated results of the KF model and the Hunt-Lu model.