Melt dynamics and solidification in surface processing with laser radiation

2- and 3-dimensional self consistent modelling calculations of the surface-tension driven melt dynamics with flat and free surfaces are presented as a function of processing variables for surface processing with laser radiation. A model is described to relate the evolution of length scales in microscopic solidification to the macroscopic thermal temperature distribution fields, in particular considering melt flow effects as well as the shape and the moment of the solid liquid phase front as the driving boundary condition of solidification. The numerical results are related to experimental ones from optical microscopy, electron microscopy and high- speed photography giving information on the geometry of the molten pool, on the structure and phases of the resolidified material, on the surface dynamics of the melt as well as on the developing surface morphologly of the melt.