About this Abstract |
| Meeting |
MS&T25: Materials Science & Technology
|
| Symposium
|
Phasing Out Carbon: Phase Transformation Challenges in Decarbonization Technologies
|
| Presentation Title |
Anomalous Behavior of Dilute Phosphorus Alloying on Phase Transformations in the Fe-Ni System |
| Author(s) |
Ugochukwu Philip Ochieze, Matthew A Steiner |
| On-Site Speaker (Planned) |
Ugochukwu Philip Ochieze |
| Abstract Scope |
While the equilibrium phase diagram of Fe-Ni is well established due to unique behavior around the 36% Ni “Invar” composition, the effects of non-metal impurities have received less attention due to their typically deleterious impact on the stability of Invar-type alloys. As part of an effort to develop processing routes for Fe-Ni-P magnetic materials, a potential replacement for rare-earth permanent magnets, it is important to understand the impact of dilute (< 1at%) P additions on the equilibria and phase transformations of the Fe-Ni system. Highly anomalous dilatation behavior of Fe-x%Ni-0.5%P is observed near 900°C, hypothesized to be related to P-vacancy pair dissolution in an unexpectedly rapid, local reordering process inconsistent with long-range diffusion. The effect is compositionally dependent, suggesting an interplay with Fe-Ni local chemical ordering, relevant to explaining the kinetics of L10 ordered Fe-Ni meteoric phases (known to have P precipitates) that are difficult to reproduce terrestrially. |