Velocity field distributions of molten pool at moments of: 235 μs ((a), (e)), 470 μs ((b), (f)), 704 μs ((c), (g)), 939 μs ((d), (h)) for 304 SS ((a)–(d)) and aluminum ((e)–(h)) under 5.71 MW/cm² laser power density irradiation and 1 ms pulse duration. The white arrows indicate the material flowing directions. The unit of the color bar is m/s.