Journal of Materials Science

, Volume 48, Issue 1, pp 348–358 | Cite as

Effect of high pressure and high temperature on the microstructural evolution of a single crystal Ni-based superalloy

  • Inmaculada Lopez-Galilea
  • Stephan Huth
  • Werner Theisen
  • Thomas Fockenberg
  • Sumit Chakraborty
Article

Abstract

The application of high nearly hydrostatic pressures at elevated temperatures on the LEK94 single crystal (SX) nickel-based superalloy directly affects its microstructure. This is due to a combination of the effect of pressure on the Gibbs free energy, on the diffusion coefficients of the alloying elements, on the internal coherent stresses, and on the porosity distribution. The last effect depends at least on the first three. Therefore, based on the theoretical influences of the pressure, the main objective of this work is to understand, by means of an experimental work, the effect of high pressure at elevated temperature during annealing on the evolution of the phases morphology, and porosity of the high-temperature material LEK94. Specifically, pressures up to 4 GPa, temperatures up to 1180 °C, and holding times up to 100 h were investigated. The main findings are that, porosity can be considerably reduced without affecting significantly the γ/γ′ microstructure by high pressure annealing and the verification that increasing the external pressure stabilizes the γ′-phase.

Notes

Acknowledgements

The authors acknowledge support by the Deutsche Forschungsgemeinschaft (DFG) through project B4 of SFB/Transregio 103 (Single Crystal Superalloys) as well as by the state of North Rhine-Westphalia through the Materials Research Department.

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Copyright information

© Springer Science+Business Media, LLC 2012

Authors and Affiliations

  • Inmaculada Lopez-Galilea
    • 1
  • Stephan Huth
    • 1
  • Werner Theisen
    • 1
  • Thomas Fockenberg
    • 2
  • Sumit Chakraborty
    • 2
  1. 1.Lehrstuhl WerkstofftechnikRuhr-Universität BochumBochumGermany
  2. 2.Institut für Geologie, Mineralogie und GeophysikRuhr-Universität BochumBochumGermany

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