Effects of the Coordinates Planes Crystal Orientation on the Structural Strength of Single-Crystal Turbine Vanes and Blades

Abstract

The effects of crystal orientation (θ) on the structural strength of single crystal trubine vanes and blades calculated with the finite element method (FEM) are discussed in this paper. TMS-75, a 3^rd generation single-crystal Ni-base superalloy, is chosen as the model material for turbine vanes and blades. It became clear that, (1) the elastic constant matrix changes were equivalence for each of three coordinate due to the orientation variation (0°<θ<90°), and the strength of the turbine vane and blade were strongly related to θ, and also depended on the load and model shape. (2) The strength dependence of the turbine vane on the crystal orientation was depended on coordinate plane : there are lower Mises stress in XY plane and maximum Mises stress in near the θ=45°at both YZ and ZX Planes. (3) In the case of a blade, the influence is similar to the vane on blade tip, but the converse holds for the blade root. It is clear that the creep rupture time can be extended, when the <100> crystallographic axes is the Y or X axis of the blade under higher revolution speed.