Prediction of recrystallisation in single crystal nickel-based superalloys during investment casting

Chinnapat Panwisawas*, Harshal N. Mathur, Robert W. Broomfield, Duncan Putman, Catherine M F Rae, Roger C. Reed

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Citations (Scopus)

Abstract

Production of gas turbines for jet propulsion and power generation requires the manufacture of turbine blades from single crystal nickel-based superalloys, most typically using investment casting. During the necessary subsequent solution heat treatment, the formation of recrystallised grains can occur. The introduction of grain boundaries into a single crystal component is potentially detrimental to performance, and therefore manufacturing processes and/or component geometries should be designed to prevent their occurrence. If the boundaries have very low strength, they can degrade the creep and fatigue properties. The root cause for recrystallisation is microscale plasticity caused by differential thermal contraction of metal, mould and core; when the plastic deformation is sufficiently large, recrystallisation takes place. In this work, numerical and thermo-mechanical modelling is carried out, with the aim of establishing computational methods by which recrystallisation during the heat treatment of single crystal nickel-based superalloys can be predicted and prevented prior to their occurrence. Elasto-plastic law is used to predict the plastic strain necessary for recrystallisation. The modelling result shows that recrystallisation is most likely to occur following 1.5-2.5% plastic strain applied at temperatures between 1000 °C and 1300 °C; this is validated with tensile tests at these elevated temperatures. This emphasises that high temperature deformation is more damaging than low temperature deformation.

Original languageEnglish
Title of host publicationMATEC Web of Conferences
PublisherEDP Sciences
Volume14
DOIs
Publication statusPublished - 2014
Event2nd European Symposium on Superalloys and Their Applications, EUROSUPERALLOYS 2014 - Giens, France
Duration: 12 May 201416 May 2014

Conference

Conference2nd European Symposium on Superalloys and Their Applications, EUROSUPERALLOYS 2014
Country/TerritoryFrance
CityGiens
Period12/05/1416/05/14

ASJC Scopus subject areas

  • General Chemistry
  • General Engineering
  • General Materials Science

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