Corrosion-fatigue testing of Ni-based superalloy RR1000

Abstract

Operation of gas turbines at high temperatures can lead to corrosion of turbine materials. A programme was designed to understand the corrosion-fatigue behaviour of two grain size variants of RR1000 under cyclic loading at elevated.

Tests were conducted on cylindrical specimens under a range of loading conditions. Results indicated that salted specimens tested in air-SO_x had shorter fatigue lives than unsalted specimens tested in air, and this deficit was dependent on stress and/or test duration. Examination of specimens showed that the extent of corrosion was dependent on exposure time and stress. Additional salt loading resulted in faster initial pit growth which led to lower fatigue lives at higher stresses.

This paper is part of a thematic issue on the 9th International Charles Parsons Turbine and Generator Conference. All papers have been revised and extended before publication in Materials Science and Technology.

Keywords:

• Corrosion
• Corrosion-fatigue
• Ni-based superalloy
• Pitting
• Salt

Acknowledgements

The authors would like to acknowledge funding provided by the Technology Strategy Board (TSB – now Innovative UK) [TSB Project No. L8002D] and EPSRC through the Rolls-Royce plc. Strategic Partnership programme.

ORCID

D. J. Child http://orcid.org/0000-0002-8271-911X