Numerical Simulation of Blade Arrangement on Stray Grains in a Fourth-Generation Single Crystal Superalloy Blade

For the problem of stray grain caused by uneven temperature field in the module production of fourth-generation single crystal blades, the finite element simulation software ProCAST was used to simulate the temperature field and grain structure during the solidification process when the blades were arranged in different ways and analyzed the influence of adding crystal guide rod on the stray grain. The results show that transverse temperature field is uneven for the small heat preservation effect of the center pillar in the module production. So when the blades are arranged at 0°, the edge corner of the platform is close to the center pillar, and the temperature drops rapidly during the solidification process, resulting in large undercooling at the edge corner. At the same time, the temperature gradient is small, the dendrites grow slowly, so the formation tendency of stray grain is the largest. With the increase of the angle, the non-uniformity of the transverse temperature field is improved, but due to the low degree of nucleation undercooling of the fourth-generation alloy, there will be stray grain formation at the platform position. The stray grain can be eliminated by adding the crystal guide rod, however when the blades are arranged at 0°, due to the inlet edge of the blades near the center pillar, there will be stray grain in the crystal guide rod. When the blades are arranged at 90°, the transverse temperature field is more uniform, there is no stray grain in the crystal guide rod, and the module diameter is small, which can reduce the size requirements of the furnace body, and is expected to become the optimal arrangement for the production of high-generation single crystal blades.