Effect of Crystal Orientation on Creep Properties of DD6 Single Crystal Superalloy

Abstract:

In order to study the orientation sensitivity for creep life of aero-engine nickel-based single crystal turbine blades serving under high temperature， creep tests of DD6 single crystal superalloy were carried out with three typical orientations ［001］， ［011］ and ［111］ at 980^oC， indicated that the creep life and elongation of the single crystal alloy are both ［111］ > ［001］ > ［011］. By analyzing the microstructure evolution during the creep process and the fracture morphology after creep fracture， the creep failure mechanism of single crystal alloy with different orientations is revealed. Based on the crystal plasticity theory， the viscoplastic constitutive equation and damage equation considering the orientation sensitivity of DD6 single crystal were established， which could well fit the strain-time curve of single crystal with different crystal orientations， and provided a reference for the strength analysis and life prediction of single crystal blade.