Towards enhancing ODS composites in laser powder bed fusion: Investigating the incorporation of laser-generated zirconia nanoparticles in a model iron–chromium alloy

Oxide dispersion-strengthened (ODS) steel is a sought-after composite material known for its high demand in high-temperature and corrosive environments. Achieving the desired ODS steel properties requires specific conditions for the size and nanoparticles (NP) distribution in the printed part. Laser ablation in liquid (LAL) enables precise NP size adjustment. At the same time, the dynamic melt pool solidification in the Laser Powder Bed Fusion (PBF-LB/M) process complements this by creating favorable conditions for successful ODS processing. In this study, ZrO₂ NP with a small and narrow particle size distribution (d₅₀ = 3.8 nm; d₉₀ = 10 nm) is produced by LAL. Dielectrophoretic deposition achieves the homogeneous, deformation-free coating of the binary Fe20Cr (wt.-%) matrix powder with NP. PBF-LB/M printed parts out of the oxide-additivated powder exhibit a crack-free structure and a density of up to 98%. Expectedly, the metal matrix grain sizes and room temperature microhardness (~ 220 HV) are not affected by NP addition. NP tracing by 2D simulation indicates a homogeneous NP distribution and less than 10% NP to be agglomerated in the solidified part. Thus, a promising perspective for a complete laser-based process chain for generating and processing ODS alloys is outlined.