Powder dynamics and molten pool characteristics in laser powder bed fusion of a CuSn10 alloy revealed by multi-dimensional in situ observations

The laser powder bed fusion (LPBF) of CuSn10 alloy parts with high metallurgical quality remains challenging due to its low laser absorption and high thermal conductivity. The laser-matter interaction in the LPBF of CuSn10 alloy has not yet been fully explored. Here, through multidimensional in situ observations, combining high-speed and infrared thermal imaging, we studied the impact of various laser energy inputs on the powder dynamics and molten pool characteristics during LPBF of CuSn10 alloy. An increase in laser energies facilitates the formation of laser-induced vapor jet and inward ambient gas flow, resulting in an increase in the amount of powder entrainment and the molten pool size. The stability of the molten pool has a significant impact on the spatter features, including average spatter ejection angle, average spatter ejection velocity, and the number of spatters. The presented methods and results are beneficial for a deeper understanding of laser-matter interaction in LPBF process, particularly for materials with low laser absorption or high thermal conductivity, which are critical for the prevention of defects in the manufactured components.