| About this Abstract |
| Meeting |
2023 TMS Annual Meeting & Exhibition
|
| Symposium
|
Phase Transformations and Microstructural Evolution
|
| Presentation Title |
Nucleation of Coupled Body-centered-cubic and Closed-packed Structures in Liquid Ni-Cr Alloys: A Molecular Dynamics Study |
| Author(s) |
Deep Choudhuri |
| On-Site Speaker (Planned) |
Deep Choudhuri |
| Abstract Scope |
In the last four decades, the structure of pre-critical solid nuclei within a liquid phase of single-component face-centered-cubic (FCC) materials has been extensively investigated. These studies demonstrated that formation of equilibrium-FCC is mediated by metastable-body-centered-cubic (BCC) structured pre-critical nucleus. However, it is unknown if such nucleation mechanism is applicable to multi-component structural alloys that forms FCC and BCC structures as equilibrium phases. We have investigated this matter using Ni-35at.\%Cr and Ni-50at.\%Cr binary alloys via molecular-dynamics simulations. Our results indicated that the pre-critical and critical nucleus comprised coupled Cr-rich BCC and Ni-rich closed-packed (FCC and hexagonal-closed-packed) structures. Formation of such multi-structured pre-critical nucleus was facilitated by prior phase-separation of alloy-melt into Cr-rich and Ni-rich liquid-pockets. BCC and closed-packed regions inside the nucleus formed with non-equilibrium compositions that evolved over time. Thus, a non-conventional nucleation mechanism in concentrated Ni-Cr alloys allows them to solidify into FCC-BCC microstructures. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Computational Materials Science & Engineering, Modeling and Simulation, Solidification |