Molecular Dynamics Simulation of Structural Evolution in Crystal and Amorphous CuZr Alloys under Ultrafast Laser Irradiation
Résumé
Surface structuring of amorphous and crystals materials may find interest in many leading technological applications. The one we target is related to laser-driven surface topography modification, however, so far, no exhaustive study was made to really give a clear picture of the different mechanisms involved in this complex process. The main originality of this work is to investigate the ultrafast phenomena and the subsequent structural modifications triggered by
femtosecond laser pulses. In this context, classical molecular dynamics approach is proposed to capture solid-solid phase transformations in alloys. To manage our investigations, we have used LAMMPS to lead atomistic simulation, which is adapted to catch phenomena occurring at a picosecond scale. To model this laser-matter interaction a suitable hybrid simulation combining Molecular Dynamics and Two Temperature Model is used to predict the involved dynamics of the electrons and ions. This combination allows us the control of laser most important processing parameters, namely the fluence and pulse duration. We have to highlight that this work deals with metallic and amorphous based alloys structures. Dealing with such structures is motivated
by two reasons, the experimental evidence that this alloys compositions are stable and the availability of a robust Embedded Atomic Method potential which faithfully reproduces the properties required to determine the thermodynamic path for laser-induced polymorphic phase
transition.