Review―Importance of Atmospheric Gas Selection in Metal Additive Manufacturing: Effects on Spatter, Microstructure, and Mechanical Properties

In metal additive manufacturing, it is possible to control the microstructure and the associated mechanical and chemical properties of metal products over a wide range. For example, in laser powder bed fusion (L-PBF), the laser process parameters are considered critical for the fabrication of functional parts. However, the effect of atmospheric gas on L-PBF has not yet been comprehensively documented. In L-PBF, gas flow is used to remove spatter and fumes, preventing degradation of quality due to laser attenuation and spatter contamination of the fabricated product. Thus, the use of atmospheric gas is inevitable in fabrication via L-PBF. In this review, we focus on the use of atmospheric gas in L-PBF, explain the effects of atmospheric gas on the microstructure and mechanical properties of fabricated products, and describe the importance of selecting the right atmospheric gas.