A novel synthesis pathway for oxide dispersion strengthened Fe−Cr alloys enabled by ultrasonic atomization

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This study presents a novel powder metallurgical route for an oxide dispersion strengthened (ODS) ferritic Fe–14Cr–0.4Ti–0.5Y (wt%) alloy using ultrasonic atomization (UA) as an alternative to conventional mechanical alloying. The key novelty lies in exploiting residual O inherent to the elemental Y feedstock and process atmosphere as an internal oxidant, driving in-situ formation of Y 42 Ti 10 O 45 dispersoids directly from the liquid during atomization without utilizing Y 2 O 3 powder. Diffusion length calculations and dispersoid spatial distributions confirm the liquid-phase nucleation and growth prior to matrix solidification. The dispersoids (20–100 nm) exhibit compositional stability during heat treatment at 1100 °C and field-assisted sintering at 1130 °C, though dispersoid density varies between powder particles due to non-uniform Y distribution in the melt pool. A microhardness of (282 ± 18) HV0.05 in high-dispersoid-density regions of consolidated samples is reached. This is comparable to mechanically alloyed counterparts, demonstrating UA as a promising alternative for ODS alloy fabrication.