Research on crack propagation behaviour of nickel-based superalloy under thermal shock load

Abstract

In this paper, the crack initiation and propagation laws of GH4169 under thermal-shock load were investigated. It was found that the development of main cracks experienced three stages: accelerated growth in the small crack stage, decelerated growth in the long crack stage and finally discontinued growth. With the increase of temperature, the crack initiation life decreases and the propagation rate increases, the crack initiation life at 600°C is six times to that at 700°C. A thermal fatigue crack growth model was proposed to character the whole crack growth process, and a comparison was drawn with the Paris and Z-H model. The results show that the model is applicable to predict the whole process growth rate of thermal fatigue cracks.

KEYWORDS:

• Thermal shock
• superalloy
• thermal fatigue crack growth model
• crack initiation and propagation

Acknowledgements

The author acknowledges the editors and reviewers for their valuable comments and suggestions, which is beneficial to improve the quality of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by National Major Science and Technology Project [grant number J2019-V-0009-0103]; Nanjing University of Aeronautics and Astronautics’ Graduate Open Laboratory Innovation Fund Project [grant number kfjj20200208].