Internal oxidation as a pathway to fabrication of ODS-like 316LY stainless steel by laser powder directed energy deposition

Oxide-dispersion-strengthened (ODS) stainless steels offer high-temperature strength but typically require costly mechanical alloying. However, direct additive manufacturing routes for forming Y-containing oxide particles without ex situ oxide addition remain insufficiently established. This study evaluates internal oxidation of pre-alloyed Y during laser powder directed energy deposition of 316L as a route to ODS-like 316LY. Gas-atomized 316L + 0.14 wt% Y powder was deposited to >99% relative density at 600–700 W and 600 mm min −1 and aged at 1000 °C for 100 h. Electron backscatter diffraction, scanning transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy, hardness testing, and room-temperature tensile testing compared the as-printed and aged conditions. The as-printed alloy contained a cellular austenitic matrix and amorphous Y–Si–Mn–O-rich oxide particles averaging 118 ± 25 nm. Aging produced recovery-dominated microstructural evolution with negligible recrystallization and promoted oxide coarsening and nanocrystallization toward Y 2 O 3 -rich particles averaging 152 ± 15 nm. Ultimate tensile strength decreased from 760–774 to 592–623 MPa, while elongation increased from 22–36% to 42–67%. First-order calculations estimated dispersion-hardening contributions of only 14.7 and 11.9 MPa before and after aging, respectively. These results demonstrate a proof-of-concept route for ODS-like 316LY while highlighting oxide refinement and quantitative oxygen-potential control as priorities.