Effect of Interface Wettability on Additively Manufactured Metal Matrix Composites: A Case Study of 316L-Y2O3 Oxide Dispersion-Strengthened Steel

Laser powder bed fusion (LPBF) is a fusion-based additive manufacturing process. It has the advantage of allowing the manufacturing of metal matrix composites. This advantage arises from its small melting zone and rapid cooling rate, which minimize the risk of reinforcement segregation. In this work, 0.3 wt% and 1.0 wt% Y2O3 nanoparticles were added to 316L to fabricate oxide dispersion-strengthened (ODS) steels using the LPBF process. Notably, Y2O3 agglomerates were identified in the LPBF-fabricated 316L ODS steels, without inducing grain refinement, while the impact on tensile strength of Y2O3 addition proved negligible. Tensile elongation was decreased due to the poor bonding of the Y2O3 agglomerations to the matrix. The crucial role of the wettability of the reinforcement and the matrix in facilitating grain refinement and strength enhancement is discussed. The poor wettability of the Y2O3 particles and 316L emerged as the primary cause for Y2O3 agglomeration. This finding highlights the importance of addressing wettability issues to optimize the manufacturing process and enhance the overall performance of LPBF-fabricated metal matrix composites.