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, maximum melting depth, and ablation rate. Full solidification/epitaxial re-growth is observed within 60 ns for the laser fluence of 5 J/m2. Strong fluctuation is observed at the solid-liquid interface and surface of the molten pool. No visible super-heating 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 explosion.