| About this Abstract |
| Meeting |
2025 TMS Annual Meeting & Exhibition
|
| Symposium
|
Phase Transformations and Microstructural Evolution
|
| Presentation Title |
Diffusional-displacive mixed-mode transformation from ferrite parent phase to form an intermetallic nanocomposite in a Fe-Mo alloy |
| Author(s) |
Rama Srinivas Varanasi, Srikakulapu Kiranbabu, Reina Utsumi, Hiroyuki Saitoh, Ronald Schnitzer, Eiji Akiyama, Motomichi Koyama |
| On-Site Speaker (Planned) |
Rama Srinivas Varanasi |
| Abstract Scope |
Solid-state phase transformations are typically classified into diffusional and displacive transformations. There exist transformations exhibiting both diffusional and displacive traits (such as bainitic transformation); these are referred to as diffusional-displacive mixed-mode transformations (MMT). In ferrous alloys, the MMT is not limited to the austenite parent phase and interstitial alloying. Herein, we report a novel MMT from the ferrite parent phase in a Fe0.78Mo0.22 alloy (arc melted and quenched). We performed scanning electron microscopy, X-ray diffraction, and electron-backscattered diffraction studies. We observed two transformations: (i) Allotriomorphic μ-phase formation at the parent ferrite grain boundaries. (ii) Formation of basket-weave Widmanstätten laths (μ-phase) at the parent ferrite grain interior. Site-specific atom probe tomography studies revealed Mo partitioning across ~800 nm wide Fe2Mo Widmanstätten laths. Based on ferrite chemistry, we estimated the Mo partitioning temperature to be ~865°C. Widmanstätten lath formation is clarified based on thermodynamic considerations using a shear-assisted diffusional transformation model. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Phase Transformations, Characterization, High-Temperature Materials |