Phase transition in Zirconia

Dear LAMMPS developers and users

I want to simulate the primary cascades in (1) hcp (800 K), (2) partially hcp and partially bcc (920 K), and (3) bcc (1300 K) Zr.

Based on the eam/fs potential I use (which clearly states that the potential file is fitted for phase transition simulation), I tried to simulate the phase transition using LAMMPS (with fix nvt command, and raising the box temperature to the desired value), but unfortunately my structure did not transform from hcp to bcc even at 1400 K (which is physically meaningless). So, I believe that the potential file is only fitted to reproduce the thermodynamics for structures with a known lattice.

Now I have a question:

Can I create a simulation box using LAMMPS, which is “partially hcp & bcc”? (The status of the material during the phase transition; neither prefect hcp nor prefect bcc)

Phase transitions in bulk are rare events. This makes them poorly suited to be simulated via bare bones MD. The fact that you employed a fixed-volume technique while raising the temperature may have turned the process even more challenging as you artificially kept the density of your system constant. You should look into alternative techniques to simulate phase transitions some of which are already implemented in Lammps. Additionally, what is the need to simulate the transition of your goal is just to shot cascades at the given structures?