| About this Abstract |
| Meeting |
MS&T24: Materials Science & Technology
|
| Symposium
|
Austenite Formation and Decomposition V: A Symposium in Memory of Prof. Mats Hillert
|
| Presentation Title |
Bainite Formation Observed by In Situ Transmission Electron Microscopy |
| Author(s) |
Daniel dos Santos Avila, John Nutter, W. Mark Rainforth, S. Erik Offerman, Maria J. Santofimia |
| On-Site Speaker (Planned) |
Daniel dos Santos Avila |
| Abstract Scope |
The diffusional and diffusionless theories of bainite formation disagree on the growth mechanism of bainite sheaves. While the diffusional theory argues for a constant lengthening rate controlled by carbon diffusion in the austenite, the diffusionless theory argues for growth controlled by the successive nucleation of bainite plates. Real-time observations of bainite growth by laser confocal microscopy could not confirm either theory because the size of bainite sub-units is smaller than the spatial resolution of the technique. In this work, we observed bainite formation in higher resolution by in situ transmission electron microscopy (TEM). Our starting material is a steel with 1.24 wt.%C that retains around 40% of austenite after quenching to room temperature. The quenched samples were heated to 280 °C inside the TEM to observe the decomposition of retained austenite into bainite. The observed formation of bainite is then analyzed in light of the diffusional and diffusionless theories. |