Creep life prediction for a nickel-based single crystal turbine blade

Abstract

The life of turbine blades often determines the life of the aero-engine, and creep rupture is one of the main fracture forms of turbine blades in high temperature environments. In order to accurately predict the life of turbine blades, creep tensile tests of smooth specimens were carried out according to typical loads of 760 °C/800 MPa, 900 °C/445 MPa, 980 °C/400 MPa, 1000 °C/283 MPa and 1050 °C/210 MPa. With the help of crystal plasticity theory, creep constitutive equations with temperature interpolation were constructed. The FSI heat transfer analysis was performed to obtain the creep life of the turbine blades,. The temperature difference on the blade had reached 300 °C. With creep constitutive model and temperature boundary, the creep analysis of the blade was carried out and the creep process was revealed. The dangerous section of the global-model was obtained, and the sub-model was used to re-analyze the dangerous area. This paper reveals the deformation of the blade after creep failure: the middle part of the blade shrinks which is also the potential damage area, the top part expands, and the trailing edge of the blade tip produces a radial displacement of 0.313 mm after creep failure. The creep life of the turbine blades is determined to be 91 h. Finally, a method to determine the creep life of turbine blades was given based on skeletal point stress method.

Keywords:

• Nickel-based single crystal superalloys
• crystal plasticity theory
• creep damage model
• skeletal points stress
• turbine blade temperature field
• turbine blade creep life prediction

Additional information

Funding

We are grateful for the financial support by the China's Post-doctoral Science Fund (2020M682698).