Tracking meta-dynamic recrystallization in a Ni-based superalloy using timeresolved synchrotron X-ray diffraction
Publicerad
Författare
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Program
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
The drive towards more sustainable aviation has gained traction as the global aviation
industry expands alongside increasing demands to reduce carbon emissions.
This drive has pushed research in materials science aimed at developing alloys capable
of withstanding high operating temperatures while maintaining metallurgical
stability. The nickel-based superalloy Haynes 282 has emerged as a promising material
for use in aero-engine applications. Recrystallization plays a critical role in
determining the final microstructure and, consequently, the mechanical properties of
metallic materials. This project aims to develop computational methods for studying
the dynamics of meta-dynamic recrystallization in Haynes 282, to gain a deeper
understanding of how the recrystallization process evolves.
The superalloy samples were first deformed at elevated temperatures. Right after
the deformation stopped, in situ synchrotron X-ray diffraction (XRD) measurements
were performed while maintaining the constant deformation temperature. Diffraction
patterns were recorded as a function of time. A method was developed to
separate the signal into contributions from the deformed and recrystallized grains.
This enabled the calculation of the recrystallized fraction, and the tracking of recrystallized
grain evolution over time. These analyses were applied to samples deformed
at different temperatures. For the sample deformed at 1100 °C, the recrystallized
fraction increased rapidly, from an initial average of approximately 5% to 90%
within 120 seconds. Higher deformation temperatures resulted in faster recrystallization
kinetics and higher final fractions. The progression of new grains and their
size distribution was also studied, showing an increase in both the number of grains
and their average size over time.
The results were compared to previous experimental measurements of Haynes 282,
where electron backscatter diffraction was used to quantify the recrystallization
and grain growth. The findings of this project align with conclusions previously
drawn. The methodology developed in this work demonstrates that time-resolved
synchrotron XRD data can be used to effectively study recrystallization, enabling
high temporal resolution and potentially greater sensitivity to small grains.
Beskrivning
Ämne/nyckelord
Dynamic recrystallization, meta-dynamic recrystallization, Ni-base superalloys, synchrotron, XRD