About this Abstract |
Meeting |
2022 TMS Annual Meeting & Exhibition
|
Symposium
|
Computational Thermodynamics and Kinetics
|
Presentation Title |
Understanding the Role of Anharmonic Phonons in Diffusion of bcc Metal |
Author(s) |
Seyyedfaridoddin Fattahpour, Sara Kadkhodaei |
On-Site Speaker (Planned) |
Seyyedfaridoddin Fattahpour |
Abstract Scope |
Diffusion in high-temperature bcc phase of IIIB and IVB metals such as Zr or Ti is orders of magnitude higher than that of the mechanically stable bcc metals, e.g. bcc Cr, Mo, and W. The underlying reason for this anomalously higher diffusion is still poorly understood. We hypothesize that the strong anharmonicity of lattice vibrations along the soft phonon modes promotes the monovacancy diffusive jumps in these mechanically unstable but dynamically stabilized phases and is the likely reason for their anomalously higher diffusion.
Here, we present a method that locates the saddle point under two scenarios: First, using a mere geometrical interpolation of the initial and final states of diffusion to locate the saddle point. Second, we implement a finite temperature stochastic sampling of the effective energy surface confined to high energy ridges. We employ this method to calculate the diffusion coefficient for bcc Ti, Zr, and dilute Zr-Sn alloys. |
Proceedings Inclusion? |
Planned: |
Keywords |
Computational Materials Science & Engineering, Other, Titanium |