The control of in-process nanoparticle behaviors, including but not limited to migration and agglomeration, during the fabrication of oxide dispersion-strengthened (ODS) steels, is a key factor in maximizing their mechanical and high-temperature reinforcement properties [1,2]. Accompanied by the thriving growth of Additive Manufacturing (AM) technologies, the idea of designing optimized ODS steels via AM has been vastly adopted in recent works [3]. However, challenges exist in achieving the optimum nanoparticle dispersion, which is required by the Orowan mechanism for strengthening, mainly due to the complex interactions among nanoparticles, melt flow, and other underlying physics (like rapid solidification). Since the nanoparticles are not accessible during processing to perform in-situ measurements, the combination of simulations with the experimental characterization presents a promising approach to tailor the properties of the AM-produced ODS steels.

Joining the heat-melt-microstructure (HMM) coupled phase-field model with nanoparticle kinematics, we present the studies on the nanoparticle behaviors in the melt pool during the AM process of the ODS steels. Taking laser powder bed fusion as the AM technique, numerical simulations have been conducted for manufactured nanoparticle-additivated Fe-Cr powder with various nanoparticle characteristics considered, including the nanoparticle composition, size distribution, and additivation weight fraction. This study is aimed to demonstrate the chronological and spatial trace of the nanoparticles that enables graphical and statistical analysis on the nanoparticle behaviors, such as migration, agglomeration, capture and enrichment around the interfaces. Influences on the nanoparticle behaviors from the processing parameters, notably the beam power and scan speed, are also presented and discussed.