Krishnan, P. S. S. R., Vas, J. V., Mishra, S. R., Xu, X., Davidson, K. P., Padhy, S. P., Duchamp, M., & Ramanujan, R. V. (2024). In Situ Operando Investigations of the Thermal Instability Mechanisms of a Deformed Ti‐48Al Alloy. Crystal Research and Technology, 60(1). Portico. https://doi.org/10.1002/crat.202400177
Abstract:
TiAl based alloys are currently deployed in extreme service environments, such as jet engine turbine blades. The microstructure of these alloys is a two‐phase lamellar structure, comprising of the majority γ‐TiAl and the minority α2‐Ti3Al phases. Understanding the microstructural evolution at high stresses and elevated temperatures is a key requirement to develop the next generation of these alloys. In situ hot stage TEM studies are reported of the mechanisms of lamellar instability and changes in phase fraction of both cold worked and undeformed Ti‐48Al alloys. The effect of cold working on the kinetics of this instability has also been determined. Cross‐sectional TEM samples are prepared on custom designed MEMS chips and in situ heating studies carried out. These results show that neck formation, break‐up of lamellae, and spheroidization are the dominant mechanisms of microstructural instability. An increase in γ‐TiAl phase content is also observed. The strain energy present in the α2 and γ lamellae in cold worked samples results in microstructural instabilities occurring at lower temperatures in cold worked samples. These findings can be used to design new alloys with improved high temperature stability.
License type:
Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)
Funding Info:
This research / project is supported by the Agency for Science, Technology and Research - Structural Metal Alloys Programme
Grant Reference no. : A18B1b0061
This research / project is supported by the National Research Foundation, Singapore - Competitive Research Programme (CRP)
Grant Reference no. : NRF-CRP29-2022-0002
Description:
This is the peer reviewed version of the following article: Krishnan, P. S. S. R., Vas, J. V., Mishra, S. R., Xu, X., Davidson, K. P., Padhy, S. P., Duchamp, M., & Ramanujan, R. V. (2024). In Situ Operando Investigations of the Thermal Instability Mechanisms of a Deformed Ti‐48Al Alloy. Crystal Research and Technology, 60(1). Portico, which has been published in final form at https://doi.org/10.1002/crat.202400177. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.