| About this Abstract |
| Meeting |
2022 TMS Annual Meeting & Exhibition
|
| Symposium
|
Phase Transformations and Microstructural Evolution
|
| Presentation Title |
Phase Transformation upon Low Temperature Nitriding of Co-Cr Alloys |
| Author(s) |
Maryam Akhlaghi, Stefan Martin, Johannes Dallmann, Rainer Hock, Carolin Körner, Andreas Leineweber |
| On-Site Speaker (Planned) |
Maryam Akhlaghi |
| Abstract Scope |
Nitriding of Co- 15 at.% Cr alloy with an initial hexagonal close-packed (hcp) crystal structure was applied using gaseous nitriding medium at low temperatures of 400 °C and 450 °C. By diffusion of atomic nitrogen into the hcp lattice of substrate at low nitriding temperature of 400 °C, nitrogen supersaturated hcp phase has been developed. Formation of this expanded hcp phase results in the development of self-equilibrating residual macrostress throughout the nitrided layer and the corresponding substrate. Upon further diffusion of nitrogen, transformation from hcp to face-centered cubic (fcc) lattice is favored within the nitrided layer. However, owing to the developed macrostress, the progress of this phase transformation dependents on the initial orientation of hcp variants with respect to nitriding direction. The expanded phase takes up around 20 at.% N at the surface, which has a significant impact on enhancement of hardness in nitrided layer. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Phase Transformations, Characterization, Surface Modification and Coatings |