Melting feasibility of oxide dispersion-strengthened tungsten W-Y2O3 via electron beam powder bed fusion

Oxide dispersion-strengthened tungsten (W-ODS) is a promising material for plasma-facing components (PFCs), but its fabrication via additive manufacturing (AM) remains challenging due to cracking, grain coarsening, and uncertain dispersoid stability. This study, for the first time, investigates the melting feasibility of tungsten reinforced with yttria (W-Y 2 O 3 ) processed via electron beam powder bed fusion ( E -PBF). A resonant acoustic mixing (RAM) approach was used to deposit nanoscale Y 2 O 3 onto tungsten powders, achieving an optimized partial coating at 0.5 wt% that balances dispersoid availability with electrical conductivity. To address powder smoking caused by the insulating oxide layer, a multi-pass, spot-based pre-heating strategy was developed to enable stable and defect-free melting. Direct microstructural observation reveals a nearly fivefold reduction in grain size in W-Y 2 O 3 compared to pure W, indicating surface grain refinement during solidification. Prolonged thermal exposure during E -PBF, nevertheless, leads to coalescence of nanoscale Y 2 O 3 into micrometer-scale aggregates, primarily distributed near melt-pool surfaces. Transmission electron microscopy (TEM) shows no detectable oxide particles or elemental segregation at cross-sectional grain boundaries, suggesting limited retention of nanoscale dispersions in the solidified material. This behavior likely results from particle coalescence, buoyancy, and convective transport within the melt pool during melting and subsequent cooling. The study demonstrates the successful melting of W-Y 2 O 3 via E -PBF with appropriate parameter control, while highlighting critical limitations in dispersoid stability that must be addressed to achieve sustained strengthening in additively manufactured W-ODS.