Immune crack in the alloy of the finite element simulation

By means of measuring creep curves, microstructure observation and FEM analysis of the stress field near the hole, an investigation has been made into the influence of the defects on creep behaviors and microstructure evolution of single crystal nickel-based superalloys. Results show that the creep lifetimes and plasticity of the single crystal nickel based superalloys are obviously decreased by microstructure defects. During high temperature creep, the stress isoline near the holes region displays the feature of the acetabuliform distribution, and possesses the bigger stress value at 45° angle direction relative to the applied stress axis. That results in the γ′ phase transformed into the rafted structure at 45° angle direction relative to the applied stress axis, and the circular holes defects are elongated into the ellipse in shape along the direction parallel to the applied stress axis. During creep, a smaller value of the stress distribution displays in the up and down regions of the circular holes, and the maximum value of the stress distribution exhibits the apices region in the sides of the hole. In the further, the fact that the max value of the stress distribution increases as creep goes on results in the germination and expanding of the cracks, which is a main reason of damaging creep lifetimes of the alloys.