Investigating enhancement areas in the L-PBF additive manufacturing process / additive manufactured parts. Investigating the effect of manufacturing processes on the fatigue behaviour of metallic parts.
Abstract
Despite the great success of the metal additive manufacturing process by Laser Fusion on Powder Bed (L-PBF), this technique still lacks maturity in several areas. Among its major challenges, the low fatigue strength of the L-PBF parts [3] caused, among other things, by two main types of defects. Firstly, a high surface roughness, mainly linked to the phenomenon of partial powder melting on the part surface [1]. Secondly, internal defects are created during the building process and are randomly distributed in the material [2]. The present study aims to investigate the effect of a second lasing [4][5] on the improvements of the characteristics of L-PBF parts. Based on preliminary experiments, two relasing strategies were selected. A high cycle fatigue campaign was subsequently carried out with a stress ratio of R=-1 on samples with or without relasing, in the as-built state or after polishing. Specimens printed in Net-Shape showed even after relasing and polishing, a much lower fatigue strength than those machined in the bulk after additive manufacturing [6]. In addition, preliminary results show that the tested relasing conditions has a slight beneficial effect on the quasi-static and fatigue strength of the 316L obtained by L-PBF.[1] E. Santecchia, S. Spigarelli and M. Cabibbo, Material Reuse in Laser Powder Bed Fusion: Side Effects of the Laser—Metal Powder Interaction, Metals 2020, 10, 341.
[2] B. Zhang, Y. Li, Q. Bai, Defect Formation Mechanisms in Selective Laser Melting: A Review, Chin. J. Mech. Eng. (2017) 30:515–527.
[3] M. Zhang, C.N. Sun, X. Zhang, P.C. Goh, J. Wei, D. Hardacre, H. Li, Fatigue and fracture behaviour of laser powder bed fusion stainless steel 316L: influence of processing parameters, Mater. Sci. Eng. 703 (2017) 251–261.
[4] Liang, A., Hamilton, A., Polcar, T., & Pey, K. S. (2022). Effects of rescanning parameters on densification and microstructural refinement of 316L stainless steel fabricated by laser powder bed fusion. Journal of Materials Processing Technology.
[5] Yasa, E., & Kruth, J. P. (2011). Microstructural investigation of Selective Laser Melting 316L stainless steel parts exposed to laser re-melting. Procedia Engineering, 19, 389-395.
[6] Merot, P., Morel, F., Mayorga, L. G., Pessard, E., Buttin, P., & Baffie, T. (2022). Observations on the influence of process and corrosion related defects on the fatigue strength of 316L stainless steel manufactured by Laser Powder Bed Fusion (L-PBF). IJF, 155, 106552.
Session
| Room | Date | Hour | Subject |
|---|---|---|---|
| Room 6 | Thursday 30th November | 09:30-10:00 | Foued Abroug S01-3 Additive Manufacturing 125 - Effect of re-lasing on the fatigue properties of 316L Stainless Steel Produced by laser powder bed fusion |
