Page 82 - MSAM-4-1

Materials Science in Additive Manufacturing SLM of ODS steel: Process and properties

Figure 1. SEM-BSE images of the mixed ODS-steel powder. Magnification: 2000×, 5000×, 20000×
Abbreviations: BSE: Backscattered electrons; SEM: Scanning electron microscopy.

Figure 2. Effect of laser power (P) and scanning speed (V) on the density of as-built SLM material
Abbreviation: SLM: Selective laser melting

at 300°C to reduce the temperature gradient during
printing.
In Figure 3, the effect of VED of the SLM process on
relative density is shown. When pre-heating was applied,
the trends of influence of laser power and scanning speed
on the density of as-built SLM material were the same as
it was observed without pre-heating. However, density
depending on these parameters, did not exhibit very
pronounced variations. The lowest density was obtained
with the VED lower than 70 J/mm . It can be attributed to a
3
lack-of-fusion defect formation. This type of defect can be
seen in Figure 4, which resulted in a significant reduction
in material density. Conversely, samples produced at
high energy densities (higher than 110 J/mm ) exhibited
3
spherical pores as a result of changing melting from
conduction to key-hole mode and attributed to material
overheating. Figure 3. Effect of VED on the relative density of as-built SLM material
with and without platform pre-heating
Platform pre-heating not only resolved the surface Abbreviations: SLM: Selective laser melting; VED: Volumetric energy
cracking issue but also enhanced the material density, density

Volume 4 Issue 1 (2025) 5 doi: 10.36922/MSAM025060004