| 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 |
Ferrite and Austenite Transformations in Fe-N Based Alloys |
| Author(s) |
Tadashi Furuhara, Mitsutaka Sato, Goro Miyamoto |
| On-Site Speaker (Planned) |
Tadashi Furuhara |
| Abstract Scope |
Microstructures formed during ferrite transformation and austenite reversion are analyzed in Fe-0.3mass%N based alloys prepared by gaseous nitriding and quenching. By isothermal holding in the ferrite+austenite two-phase region, two morphologies of allotriomorphic ferrite and Widmanstatten ferrite are formed at austenite matrix grain boundary. At 500°C, on the other hand, nitride-free bainitic ferrite was formed at the beginning, and later changed to bainite accompanied with γ’ precipitation. In reverse transformation by intercritical annealing of initial nitrogen martensite, two morphologies of acicular and globular austenite are formed. These phase transformation behaviors are similar to those of carbon-containing steels. Non-equilibrium partitioning of nitrogen and third alloying elements are observed in general. In the presentation, various factors causing energy dissipation in ferrite/austenite boundary migration will be discussed in comparison to carbon-containing steels. |