Additive Manufacturing of Large-scale Metallic Components: Poster Session
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS: Additive Manufacturing Committee
Program Organizers: Sougata Roy, Iowa State University; Sneha Prabha Narra, Carnegie Mellon University; Andrzej Nycz, Oak Ridge National Laboratory; Yousub Lee, Oak Ridge National Laboratory; Chantal Sudbrack, National Energy Technology Laboratory; Albert To, University of Pittsburgh; Yashwanth Bandari, AddiTec Technologies LLC
Monday 5:30 PM
March 20, 2023
Room: Exhibit Hall G
Location: SDCC
Controlling Heterogeneity of Inconel 625 and 316L Interface by Functionally Gradient Method Using L-PBF Process: Seong Gyu Chung1; Jung Wook Cho1; 1Postech, Graduate Institute of Technology
Welding or joining between two different materials is a critical issue in conventional manufacturing criteria. The interface instability of two different components leads to catastrophic failures such as crack propagation and undesirable intermetallic formation. Functionally graded material (FGM) method in AM is a suitable application for incidents that require multiple properties simultaneously, such as high corrosion resistivity via high-temperature durability. The earlier solutions of FGM in the gradient interface were only given by the addition of alloying elements. Hence, controlling in-situ gas content alteration leads not only to detouring undesirable phases but also form beneficial inclusions toward the boundary. In-situ gas control method application in Inconel series and 316L stainless steel degraded creation of intermetallic phases and solidification crack. Microstructural assessment and mechanical property comparison determined; the reduction and oxidation behavior in the melt pool and inclusion (Nitride and oxide) formation mechanism in-situ atmosphere control will be majorly discussed.
A-9: Inclusion Modification in AISI 316L by Addition of AlN via Laser Powder Bed Fusion: Seung Hoon Lee1; Jung-Wook Cho1; 1Graduate Institute of Ferrous and Energy Materials Technology
In Laser Powder Bed Fusion(L-PBF) process, oxide inclusion dispersed in the matrix has been studied to achieve comparative mechanical properties. However, there are few trials that have been explored; the oxide inclusion modification and utilization of nitride particles. In this work, the 316L specimen was manufactured with the addition of alloying element; 1wt. % of Aluminum nitride (AlN) powder with 316L powder. Powder mixing led to a diminishment of the oxygen content from 489ppm (powder) to 244ppm (as-built). The melt pool’s reduction behavior was accelerated due to aluminum. The inclusions were observed to be alumina. The larger epitaxial grains were observed within the change in texture orientation, which correlated to the melt pool stability and temperature distribution. Improvement in strength was measured considering Orowan strengthening, Hall-Patch equation, and the dislocation density. The results show that variation of the oxygen content in the melt pool results in mechanical properties change.
A-10: Influence of Exposure Strategy on Part Quality in Multi-Laser-Powder-Bed-Fusion (M-LPBF): Tino Pfalz1; Astrid Rota1; 1EOS GmbH
When printing large-scale metallic parts using the LPBF-process, systems with big building envelops are required. Thus, it is favorable to use systems with multiple lasers to increase productivity. Depending on the size of the scan field, it is necessary to split the exposure area and use multiple lasers to expose the respective layers.To investigate the influence of different exposure strategies on part quality in M-LPBF, porosity and tensile tests were conducted on Ti6Al4V samples, that were built by two lasers using an EOS M400-4. While the mechanical properties only showed minor differences between single- and dual-laser exposure, a significant increase in porosity for the dual-laser samples was observed. By using CT- and optical topography analysis we were able to identify the underlying defect forming mechanism. These findings help to optimize the exposure strategy in such a way that the formation of additional porosity in M-LPBF can be significantly reduced.