Displacive

Diffusive or diffusionless transformations occur by some form of cooperative homogeneous movement of many atoms that results in a change in crystal structure. These movements are small (usually less than the interatomic distances) and the atoms maintain their relative relationships (to their neighbours). The ordered movement of large numbers of atoms lead some to refer to these as military transformations

The transformation involves, in this case, rows of many atoms moving cooperatively.

Diffusive

Diffusive or reconstructive transformations require the breaking and reforming of bonds. Reconstructive transitions are generally very slow (they require bond breaking/vacancy diffusion) and can result in a completely new atomic arrangement where the original neighbours are not maintained

Click "move vacancy" to move the vacancy manually, or use the run/stop buttons to run the simulation automatically