About this Abstract |
| Meeting |
2026 TMS Annual Meeting & Exhibition
|
| Symposium
|
Vacancy Engineering in Metals and Alloys
|
| Presentation Title |
Influence of thermo-mechanical processing on ordering kinetics in 18 karat red gold alloy |
| Author(s) |
Steven Van Petegem |
| On-Site Speaker (Planned) |
Steven Van Petegem |
| Abstract Scope |
We investigate the ordering transformation in an 18K Au-Cu-Ag red gold alloy using operando synchrotron X-ray diffraction during controlled heating and cooling. The disordered FCC solid solution evolves into an ordered tetragonal AuCu-type phase, marked by the appearance of superstructure reflections. Prior to long-range order, we observe tweed-like diffuse scattering, indicating local symmetry breaking and strain heterogeneity. A key finding is that the kinetics of ordering are significantly influenced by the presence of lattice defects. Vacancies, retained from processing, enhance atomic mobility, while dislocations provide fast diffusion pathways that facilitate ordering. Regions with higher dislocation density show more rapid development of order. The presence of silver slows but does not suppress the transformation. These results demonstrate that the ordering pathway in noble metal alloys is strongly governed by the interaction between vacancies and dislocations, and highlight the power of operando diffraction for resolving early-stage transformation mechanisms. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Phase Transformations, Characterization, |