Microstructure evolution of Cu-1.0% Cr hypoeutectic alloy during directional solidification

Directionally solidified microstructures were investigated based on the calculation and comparison of interface growth temperatures of different phases in Cu-1.0% Cr hypoeutectic alloy at various growth velocities. The results show that the entirely coupled eutectics could not be obtained at the growth rate higher than 5 μm/s and the α-Cu phase will be the primary phase solidified ahead of the coupled eutectics, which agrees with the experiment results. In addition, the primary dendritic arm spacing, dendritic radius of α-Cu phase and the volume fraction of eutectics decrease with the increase of the growth rate. The value of primary dendritic arm spacing of Cu-1.0% Cr alloy measured in the experiment is very close to the calculation results of KF model.