The formation mechanism of band-like microstructures in directionally solidified Cu-1.0%Cr hypoeutectic alloy
定向凝固Cu-1.0%Cr合金中带状组织及其形成机制

Band-like microstructures were observed in directionally solidified Cu-1.0%Cr hypoeutectic alloy at the growth rate ranging from 2 m/s to 10 m/s and the temperature gradient of 200K/cm in liquid. There are three kinds of band-like microstructures, which are the planar interface plus coupled eutectic, the planar interface plus cellular structure with the growth of coupled eutectic, and cellular interface structure plus coupled eutectic, respectively. The formation mechanism of band-like microstructures has been illustrated by discussing the solute distribution ahead of solid-liquid interface in which the growth rate and alloy composition are changed at the non-steady state in directional solidification. In addition, the density difference between Cu phase and Cr phase is also an available factor to cause the formation of band-like microstructures in directionally solidified Cu-1.0%Cr hypoeutectic alloy.