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The need to drive down the operating cost of aero-engines has led to increased
interest in failure prediction and life extension of components in gas turbines. The
aim of this paper is to present a generic microstructure-based remnant life
assessment method for nickel-based superalloys, built upon an understanding of
the dominant damage micromechanisms. Mechanical testing has been carried out
on two superalloys (conventionally cast IN738LC and the single crystal CMSX4)
to asses the effects of strain and thermally-induced damage. The microstructural
re-arrangements accompanying creep and fracture have been studied using FEGSEM
and the results obtained have been used to develop a microstructure-explicit
deformation model that links microstructural evolution to the macroscopic
behaviour. The model predictions are in good agreement with experiment in terms
of the strain accumulation and microstructural changes. Thus, the proposed
approach provides a potential framework for developing a valuable tool in
undertaking remnant life assessment.