Spatter oxidation during laser powder bed fusion of Alloy 718: Dependence on oxygen content in the process atmosphere

Influence of part geometry on spatter formation in laser powder bed fusion of Inconel 718 alloy revealed by optical tomography

“…It is necessary to clarify that the oxygen level in the process chamber can have significant impact on the oxidation of the spatter and the correlation found in this study is only applicable to the condition where a 1000 ppm oxygen level control is applied. As reported by Raza et al [9], stricter control of the oxygen level in the process chamber under 20 ppm can mitigate the surface oxidation of the IN718 powder but would not prevent spattering. It is recommended for future work to apply the proposed methodology in this paper to investigate the influence of oxygen level in the build chamber on spattering and powder degradation.…”

“…Firstly, in a commercial L-PBF system, the oxygen level is typically controlled at a level lower than 1000 ppm, which is not sufficiently low to prevent surface oxidation [8,9]. Based on simulations, in L-PBF process the powder in close proximity of the part is heated to elevated temperatures due to the heat conduction from the printed part [10].…”

A Review of Spatter in Laser Powder Bed Fusion Additive Manufacturing: In Situ Detection, Generation, Effects, and Countermeasures

“…As shown in Figure 9, 60% of the ejection was due to hot entrainment ejection at velocities ranging from 6 m/s to 20 m/s: 25% was cold entrainment ejection, which occurred at a velocity of 2 m/s to 4 m/s, and 15% was droplet breakup ejection from the melt pool as a result of the recoil pressure applied at a velocity of 3 to 8 m/s. Raza et al [65] also found that spatter from the melt pool was less than that due to vapor-induced entrainment. According to Ref.…”

“…As shown in Figure 9, 60% of the ejection was due to hot entrainment ejection at velocities ranging from 6 m/s to 20 m/s: 25% was cold entrainment ejection, which occurred at a velocity of 2 m/s to 4 m/s, and 15% was droplet breakup ejection from the melt pool as a result of the recoil pressure applied at a velocity of 3 to 8 m/s. Raza et al [65] also found that spatter from the melt pool was less than that due to vapor-induced entrainment. Young et al [56] showed the characteristics and generation mechanisms of five unique types of spatter during L-PBF by in situ high-speed, high-energy X-ray video imaging: solid spatter, metallic ejected spatter, agglomeration spatter, entrainment melting spatter, and defect-induced spatter.…”

Residual oxygen content and powder recycling: effects on microstructure and mechanical properties of additively manufactured Ti-6Al-4V parts

“…These are caused by heat influences and oxidation during processing leading to a changed chemical composition, as well as spattering and sintering resulting in larger particles [20][21][22][23][24]. For example, an increased oxygen content could be seen in recycled powder [25][26][27][28]. Moreover, Carrion et al investigated the effect of powder reuse on the microstructure for a fixed parameter setting but no significant influence could be detected [26].…”