A three dimensional cellular automaton-finite element model was developed to predict the solidification grain structures of DZ445 superalloy Ni-based single crystal

in which Gaussian distribution continuous nucleation model was adopted to describe the nucleation and the KGT model was extended to multi-component alloys to account for the growth kinetics of dendrite tip.Effects of slope angle and withdrawal rate on directional solidified microstructure evolution were investigated.The results reveal that slope wax-pattern can eliminate the stray grain formed at platform

however probably form new stray grain at other location.With increasing in the withdrawal rate

more stray grains are formed at platform.However sectional variable withdraw rate can eliminate the platform stray grain.Inaddition

the distance from airfoil where start change withdraw rate to platform should be keep a certain number

and which is determined through the size of blade and withdraw rate.