Atomistic simulation of the kinetics of phase transformations
The research group focuses on the development and application of methods for long time-scale atomistic simulations. The two main research areas are the diffusion of impurities in the presence point and extended defects (e.g. diffusion of d-band elements in Ni-based superalloys), and the kinetics of phase transformations (e.g. formation of topologically close-packed phases, martensitic transformation in high-temperature shape memory alloys, nucleation during solidification).
Atomistic processes dominating the long-time dynamics of impurity diffusion, solid-solid phase transformations or nucleation belong to the class of so-called rare events. In this context, rare events comprise processes that require transitions between local minima of the potential energy surface that are separated by sizeable energy barriers. This leads to a separation of time scales between the short-time dynamics within each local minimum (e.g. lattice vibrations) and the long-time dynamics between the minima (e.g. diffusion, structural rearrangements), which makes it impossible to study such problems with classic molecular dynamics simulations. If the dynamics of the rare events can be described correctly based on the underlying atomistic processes, it is possible to follow the time evolution of a system over an extended time scale.
Within the group, various techniques such as accelerated molecular dynamics, kinetic Monte Carlo, or transition path sampling are utilised to investigate rare events.
- Dr. Yaojun Du
- Dr. Ari Harjunmaa
- Marco Rozgic
- Dr. Sergej Shuwalow
- nucleation and phase transformation
- (adaptive) kinetic Monte Carlo
- transition path sampling
- (accelerated) molecular dynamics
G. Díaz Leines, J. Rogal. Maximum likelihood analysis of reaction coordinates during solidification in Ni The Journal of Physical Chemistry B, 122, 10934-10942, (2018)
A. Ferrari, A. Paulsen, J. Frenzel, J. Rogal et al. Unusual composition dependence of transformation temperatures in Ti-Ta-X shape memory alloys Physical Review Materials, 2, 073609, (2018)
T. Chakraborty. Atomistic modelling of phase transitions in Ti-Ta high-temperature shape memory alloys PhD Thesis, Ruhr-Universität Bochum (2017)
H. Alvaro Galue, G. Díaz Leines. Origin of spectral band patterns in the cosmic unidentified infrared emission Physical Review Letters, 119, 171102, (2017)
Y. Liang. Nucleation in Ni-Al alloys - an atomistic study Master Thesis, Ruhr-Universität Bochum (2017)
Dr. Jutta Rogal
Tel: +49 234 32 29317
Fax: +49 234 32 14977