Microstructure Evolution of the Cu-Cr Hypereutectic Alloys During Directional Solidification

摘要

The effects of directional solidification velocity, temperature and alloy composition on the microstructure evolution of Cu-Cr alloys were investigated systematically. The microstructure observations showed that the halo α-Cu phase formed from the Cu-rich solute neighbor to primary Cr-rich phase, and followed by the growth of rod-like coupled eutectic. The Cr-rich phase coarsened and the eutectic spacing increased with the decreasing growth velocity and the increasing solidification temperature. Further, the eutectic and the primary phase transformation temperatures in hypereutectic alloys were determined by the DSC tests. The eutectic temperature has been established to be 1079 ± 0.5 °C.