About this Abstract |
| Meeting |
2027 TMS Annual Meeting & Exhibition
|
| Symposium
|
Phase Stability, Phase Transformations, and Reactive Phase Formation in Electronic Materials XXVI
|
| Presentation Title |
A strain-driven compositional detour in an in situ TCP precipitation |
| Author(s) |
Yu-ning Chiu, Tsai-fu Chung, Shih-kang Lin |
| On-Site Speaker (Planned) |
Yu-ning Chiu |
| Abstract Scope |
Topologically close-packed (TCP) phases strengthen advanced alloys, yet their atomic-scale transformations remain poorly understood because these transitions are short-lived. Here, by combining 4D-STEM strain mapping with Monte Carlo/molecular dynamics simulations, we tracked a prototypical TCP transition in Al-Zn-Mg alloys. During in situ precipitation, we discovered a highly counterintuitive phenomenon: a striking “compositional detour”. Instead of moving directly toward its final state, the precipitate initially absorbs the very solute (Mg) it must ultimately expel. We show that elastic strain, rather than the chemical endpoint, drives this route. As the lattice constant shifts during precipitation, temporarily taking in oversized Mg atoms to relieve the building compressive strain actually serves as the minimum energy path. Ultimately, this reveals that structural and compositional changes are inextricably linked, challenging the widespread assumption of a fixed composition during structural evolution and unveiling a uniquely dynamic behavior of in situ TCP precipitates. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Computational Materials Science & Engineering, Phase Transformations, Other |