Speaker
Description
Wrought γ’-strengthened Ni-based superalloys are commonly used in aircraft engine disk applications. The required high strength and temperature resistance is achieved by a high alloying content and, thus, resulting complex microstructures. This high alloying content makes these alloys prone to segregation which, in combination with the high inherent strength, leads to cracking during manufacturing and allows for a narrow processing window only.
Carbon is usually added to wrought superalloys, to form discrete carbides on grain boundaries which prevent grain boundary sliding and significantly improve their creep resistance. However, certain heat treatments can lead to unfavourable microstructures where those carbides are not discrete entities but occur as brittle, continuous film decorating the grain boundaries. To prevent this and optimise the final microstructure, comprehensive knowledge of the stability regime and kinetics of the present phases is necessary.
In this study heat treatments and electron microscope techniques are used to characterise the formation of grain boundary phases in Ni-based superalloys with different chemical compositions. The collected data are utilised to improve and update the thermodynamic database for the commercially available simulation software package MatCalc. This will help to avoid unfavourable temperature regimes during the processing of wrought Ni-based superalloys and help to achieve microstructures with optimised mechanical properties.
| Speaker Country | Australia |
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