Numerical Simulation on Directional Solidification of DD4 Alloy Airplane Engine Blade

The recrystallization in directional solidification of airplane engine blade, made of nickel-based single crystalline DD4 super-alloy was mathematically modeled and numerically simulated with Procast software and CAFE module. The influence of the pulling speed on the temperature field profile, secondary dendritic arm spacing (SDAS) distribution and mushy zone was investigated. The simulated results show that the pulling speed has a major impact. To be specific, as the pulling speed increases, the temperature of the blade, held at the same furnace position, is higher, distributing with a smaller temperature gradient; the mushy zone width increases, accompanied by an increasing bending; and the surface SDAS distribution changes in a decrease-increase manner. We suggest that an optimized pulling speed may result in the engine blade with finest grains and the densest micro-dendritic structure.