PSI - Issue 74

Jaromír Brůža et al. / Procedia Structural Integrity 74 (2025) 1–8

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Jaromír Brůža / Structural Integrity Procedia 00 (2025 ) 000–000

Fig. 3 Grain boundary maps (a-c) and grain boundary misorientation distributions (d-f) as revealed using EBSD in EOS (a,d), SLM (b,e) and (c,f) Praxair L-PBF 316L stee ls. Black, green, red, and yellow represent HAGBs, LAGBs, and Σ 3 and Σ 9 TBs, respectively.

The size of grains was also evaluated as seen in Fig. 4. Still, instead of the usual equivalent circle diameter approach, the area-weighted maximum Feret diameter method was adopted, since the grains are elongated and, as such, the calculated diameter would not be optimal. The average maximum Feret diameter of SLM, Praxair, and EOS was found to be 42 ± 16 μm, 48 ± 18 μm, and 153 ± 51 μm, respectively. While the difference in grain size between SLM and Praxair steel was negligible, in comparison with the EOS microstructure, these steels show an average maximum Feret diameter three times smaller.

Fig. 4 Grain size distribution in L-PBF 316L steels manu-

Fig. 5 Vickers hardness of L -PBF 316L steels printed from

factured from various powders.

various powders.