レーザを用いた粉末床溶融結合法でのScを含むアルミニウム合金粉末造形時の最適雰囲気酸素濃度

抄録

In this paper, the influence of oxygen concentration in the building chamber on the melt pool behavior and the mechanical properties of the built part obtained via a metal-based powder bed fusion with a laser beam (PBF-LB/M), which is one of an additive manufacturing (AM) method, was experimentally investigated. The metal powders used were two types of aluminum alloy powders; Al-Si-Mg and Al-Mg-Sc. The amount of fumes and spatter particles scattered from laser-irradiated area was calculated when the oxygen concentration was varied from 10 to 10000 ppm, and their chemical composition was evaluated. In addition, the mechanical properties of the built part obtained in different oxygen concentration and their chemical composition were also evaluated. The results showed that the amount of oxygen in the building chamber was one of the principal factor affecting the melt pool behavior. The amount of fumes scattered during the building of Al-Mg-Sc powder was significantly increased when the oxygen concentration in the building chamber was below 5000 ppm, and the amount of Mg composition included in fumes was extremely larger than the virgin powder. Aluminum alloy powders are oxygen-active, so fume generation must be minimized. It was noted that the suitable oxygen concentration during the building of Al-Mg-Sc powder in the PBF-LB/M was ranged from 3000 to 5000 ppm in order to obtain the excellent mechanical properties such as high relative density and elongation while minimizing the amount of fume generation.