Very high temperature creep behavior of a single crystal Ni-based superalloy under complex thermal cycling conditions

Abstract

Very high temperature thermal cycling has been performed on the single crystal superalloy MC2 to evaluate the effect of periodic overheating on creep behavior. The experiments consist of alternately performing 1 min dwell time at 1100°C and 1150°C for every 15 min during creep test at 1050°C/120 MPa. Both thermal cycling and prior γ′-rafting appear to be deleterious to the cyclic creep properties. The observed non-isothermal creep behavior is correlated with γ′-dissolution/coalescence processes, especially during overheatings where γ′ micro-rafts seem to play a significant role.

Keywords:

• superalloy
• creep
• microstructure evolutions
• thermal cycling

Acknowledgements

The authors are grateful to Turbomeca–SAFRAN group for providing the material. They are also grateful to Said Jouiad for English suggestions. Dr José Mendez is also acknowledged for valuable and fruitful discussions.