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

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.