  This paper reviews the status of molecular dynamics as a method in describing
solid-solid phase transitions, and its relationship to continuum approaches.
Simulation work done in NiTi and Zr using first principles and semi-empirical
potentials is presented. This shows failures of extending equilibrium
thermodynamics to the nanoscale, and the crucial importance of system-specific
details to the dynamics of martensite formation. The inconsistency between
experimental and theoretical crystal structures in NiTi is described, together
with its possible resolution in terms of nanoscale effects.
