Authors:
Jonas Koob (1), Markus Mirz (1), Marie Luise Scheck (2), Anke Kaletsch (1), Christoph Broeckmann (1)
1- Institute for Materials Applications in Mechanical Engineering (IWM), RWTH Aachen University, Aachen, Germany
2- Institute for Applied Powder Metallurgy and Ceramics (IAPK) at RWTH Aachen e. V., Aachen, Germany
Abstract:
Duplex stainless steels (DSSs) exhibit excellent mechanical properties due to their austenitic-ferritic microstructure, which, for example, leads to higher impact toughness compared to fully ferritic steels. The phase equilibrium is dependent on solidification conditions and chemical composition, with elemental nitrogen stabilizing the austenitic phase. To better understand the influence of pro-cess gases during processing by laser-based powder bed fusion (PBF-LB) on microstructure and mechanical properties, in this study, DSS AISI 318LN was processed with PBF-LB with different shielding atmospheres (argon and nitrogen) and subsequently, some of the samples were hot-isostatically post-densified before final heat treatment. The impact toughness of the different condi-tions was tested and complemented by microstructural and fractographic analysis. To completely exclude the influence of process gases, samples were also built up by electron-beam powder bed fusion (PBF-EB) under vacuum as a reference and subjected to the same post-processing strategies for comparison with the samples produced by PBF-LB.
DOI:
https://doi.org/10.59499/EP246282914
