Computer simulation on the dynamic solidification process of super-alloy turbine blade

Microstructure simulation of a super-alloy turbine blade casting was carried out by coupled simulation based on micro cellular automaton model and macro temperature field calculation. In this model, thermal enthalpy method was used to calculate temperature field with crystal latent heat in 2-D unstable thermal conductive equation, continuous nucleation model was used to describe heterogeneous nucleation of the liquid metal, gauss distribution function was employed to describe the relation between the density of nucleation sites and the temperature which was integrated to get the grain density at a given under-cooling, and dendrite tip growth kinetics and preferential <100> crystallographic orientation were also taken into account. Therefore, not only the stochastic nature of nucleation process but also the deterministic of dendrite growth was considered in the calculation. Simulation results showed that the obtained grain size increases with increasing of average nucleate under constant cooling, which agreed very well with experiments' ones.