Influence of gas atmosphere (Ar or He) on the laser powder bed fusion of a Ni-based alloy

The gaseous atmosphere plays a major role in the quality of manufactured parts Laser Powder Bed Fusion (L-PBF) by protecting metal from high temperature oxidation. If argon and nitrogen are most commonly used gases, helium has almost never been considered as possible candidate chemically inert shielding gas. To provide better understanding influence gas on process stability, comparative study L-PBF manufacturing under atmospheres carried out, considering nickel-based alloy Inconel® 625 single bead configuration. this end, in-situ measurements were out dedicated experimental setup. melt pool behaviour, expansion vapour plume amount spatters evaluated with high-speed imaging for two gases considered, together final dimensions. Results also compared to fusion beads an industrial machine comparable range volume energy densities. was follows: (1) dimensions shown be constant whatever gas; (2) fewer smaller produced atmosphere, especially Physical mechanisms then discussed understand those specific effects.