Structure simulation in unidirectionally solidified turbine blade by dendrite envelope tracking model (II): model validation and defects prediction

The developed model was validated by the checking of grain preferential growth orientation and the solidification experiment with low melting point alloy of Sn-21%Bi(mole fraction). It was also applied to predict the structure defects (e.g. stray grain) of unidirectionally solidified turbine blade. The results show that the developed model is reliable and has the following abilities: 1) reduce the misorientation caused by the orthogonal mesh used in simulation; 2) well reproduce the growth competition among the different-preferential-direction grains with less than 10% relative error; 3) predict the structure defect of stray grain with the accuracy over 80%; 4) optimize the grain selector to better obtain a single crystal avoiding the multigrain defect; 5) simulate the structure evolution (nucleation and growth) of the directional and single crystal turbine blade.