The Analysis of Contact Fatigue Behavior in Ni-Base Single Crystal Superalloy Turbine Blade Rabbet

Abstract

Based on the dislocation pile-up theory and the crystal plastic theory, a rate-dependent crystallographic plastic finite element method (FEM) was used to analyze the stress distribution in the contact zone of single crystal turbine blade rabbet. The FEM results show that the maximum stress and the maximum resolved shear stress location are in the upper edge of the first tooth contact area of the rabbet. The surface crack initiates in the edge and grows as the zigzag wave. The deflected angle of the plane defined by maximum resolved shear stress gradient direction and the upper edge of the first tooth contact area of the rabbet with respect to the Z axis is 35°. The fracture occurs along the {-1-11} plane. Fracture behavior of rabbet/groove modeling specimens made of nickel-based single crystal superalloys was studied by corresponding contact fatigue experiments. The initial place and developing direction of the fatigue crack observed from experiments are found to be in good agreement with the predicted results based FEM.