Distinct impact behaviors of liquid metals featured by diffusion and microstructure on different substrates: Insights from molecular dynamics simulation

Abstract Molecular dynamics (MD) simulations are performed to study the impact behaviors of liquid metal drops on different carbon-based substrates, which are greatly affected by surface structure and roughness. Simulation results validate that, the nanotube surface can generate a strip-like shape of the Pb drop because of the non-synchronized spreading behavior caused by different diffusion speed. For surfaces with higher roughness, due to the weak wettability of metal drops and their distinguished feature of penetrating into the valleys between surface protrusions, the spreading area and time are both reduced on the pillared surface. By contrast, the spreading ability of the Al drop is weak because of its large viscosity. The investigation of the liquid Al Pb alloy suggests that adding other elements can control the impact process. Moreover, it is the first time in this paper to discuss the microstructure of liquid drops on different surfaces after impact, which may affect the solid microstructure in material fabrication. Besides, the effect of the impact velocity is also considered. These results would provide guidance in controlling the liquid impact behaviors for some technologies, such as 3D printing, plasma spraying and so on.