A preferred method to prepare a single crystal blade by a downward directional solidification

DWDS (Downward Directional Solidification) is a novel directional solidification process that allows solidification to proceed from top to bottom by using an anchor-type mold shell, thereby avoiding freckle issues. The longer sprue of DWDS makes heat field control more challenging, thus making it more susceptible to the influence of stray grains. In this study, a method of increasing temperature gradients by adding insulating baffles in the hot-cold zone was proposed and validated through corresponding DWDS experiments. The control effects of different baffle thicknesses and surface emissivities on stray grains of different shapes were verified. Experimental results indicate that adding baffles is effective in maintaining high-temperature gradients in DWDS, and when improving gradients through baffles, consideration should be given to radiative heat exchange issues.