Hybrid atomistic-macroscale modeling of long-time phase change in nanosecond laser–material interaction

In this work, large-scale hybrid atomistic-macroscale simulation is performed to study the long-time material behavior in nanosecond laser–material interaction. Different phase change phenomena are studied, including solid–liquid interface speed, temperature, maximummelting depth, and ablation rate. Full solidification/epitaxial re-growth is observed within 60 ns for the laser fluence of 5 J/m. Strong fluctuation is observed at the solid–liquid interface and surface of the molten pool. No visible superheating is observed at the solid–liquid interface. For the laser fluences studied in this work, an almost linear relationship is observed between the ablation yield and the laser fluence, indicating weak phase