SwissMech Seminar: The austenite/martensite interface: structure, kinetics, transformation strain. Toughening: theory and experiment
Event details
| Date | 10.11.2022 |
| Hour | 16:00 › 17:00 |
| Speaker | Prof. William Curtin Laboratory for Multiscale Mechanics Modeling, EPFL Lausanne |
| Location | Online |
| Category | Conferences - Seminars |
| Event Language | English |
SWISSMECH SEMINAR
Abstract: In next-generation high-strength/high-toughness steels, the austenite/martensite (fcc/bcc) interface is the dominant microstructural feature controlling important properties. In spite of decades of research, the fundamental structure, mechanism of motion, and transformation strain due to this interface have remained uncertain. Here, an atomistic fcc-bcc iron interface is constructed that completely matches experimental observations and reveals a defect structure differing from longstanding theory assumptions while also violating conditions believed essential for a glissile interface. Based on this interface, we develop a new crystallographic double-shear theory of lath martensites that provides predictions in near-perfect agreement with both simulations and experiments. In a classic Fe-Ni-Mn alloy, we then use in-situ high resolution digital image correlation to measure the transformation strain and confirm the parameter-free theory. The theory predicts increasing the fcc/bcc lattice parameter ratio increases the transformation strain, which is validated with literature data and then provides a new path for developing tougher high-strength steels.
A. Curtin, F. Maresca, E. Polatidis, M. Smid, H. Van Swygenhoven
Abstract: In next-generation high-strength/high-toughness steels, the austenite/martensite (fcc/bcc) interface is the dominant microstructural feature controlling important properties. In spite of decades of research, the fundamental structure, mechanism of motion, and transformation strain due to this interface have remained uncertain. Here, an atomistic fcc-bcc iron interface is constructed that completely matches experimental observations and reveals a defect structure differing from longstanding theory assumptions while also violating conditions believed essential for a glissile interface. Based on this interface, we develop a new crystallographic double-shear theory of lath martensites that provides predictions in near-perfect agreement with both simulations and experiments. In a classic Fe-Ni-Mn alloy, we then use in-situ high resolution digital image correlation to measure the transformation strain and confirm the parameter-free theory. The theory predicts increasing the fcc/bcc lattice parameter ratio increases the transformation strain, which is validated with literature data and then provides a new path for developing tougher high-strength steels.
A. Curtin, F. Maresca, E. Polatidis, M. Smid, H. Van Swygenhoven
Practical information
- General public
- Registration required
- This event is internal
Organizer
- EPFL-ETHZ
Contact
- ETHZ : Prof. George Haller, [email protected] EPFL : Prof. John Kolinski, [email protected]