Powder recycling effects on porosity development and mechanical properties of Hastelloy X alloy during laser powder bed fusion process

• Published in: Additive manufacturing Vol. 55; p. 102840
• Main Authors: He, Xing, Kong, Decheng, Zhou, Yiqi, Wang, Li, Ni, Xiaoqing, Zhang, Liang, Wu, Wenheng, Li, Ruixue, Li, Xiaogang, Dong, Chaofang
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.07.2022
• Subjects: Hastelloy X alloy; Laser powder bed fusion; Mechanical properties; Porosity; Recycled powder; Mechanical properties; Laser powder bed fusion; Hastelloy X alloy; Porosity; Recycled powder
• ISSN: 2214-8604; 2214-7810
• DOI: 10.1016/j.addma.2022.102840

This study compares and analyzes the morphology, size, oxygen content, and microstructure of virgin and recycled powders after six iterations to assess the mechanical properties of the Hastelloy X alloys fabricated via laser powder bed fusion (LPBF). Compared to the virgin powder, the average particle size and oxygen content for the recycled powder are increased by 22% and 48%, respectively, which promotes the laser absorptivity of the powder bed from 0.45 to 0.64, resulting in the rapid transitioning of the keyhole to a precarious state. The porosity of the LPBF Hastelloy X alloy manufactured using the recycled powder was 1.47%, which was significantly higher than that of the parts prepared using the virgin powder. However, only a slight difference in the grain size was observed in the LPBF Hastelloy X alloys manufactured from the virgin and recycled powders. A 20.8% reduction in the plasticity of the LPBF Hastelloy X manufactured from the recycled powder was observed after six iterations. The evolution of the printed defects evolution during the recycling process was revealed. Importantly, a printed defect diameter larger than 40 µm can significantly affect crack initiation and propagation in LPBF products.