Achieving high-density oxides and superior high-temperature properties in additively manufactured superalloys via precise oxygen control

To further increase dispersoid number density in oxide dispersion strengthened (ODS) alloys fabricated by laser powder bed fusion (L-PBF), this study employs a precise oxygen-controlled treatment of Y-alloyed Hastelloy X powders, eliminating the need for direct addition of Y₂O₃. In situ precipitation during L-PBF, followed by secondary precipitation during heat treatment, markedly increased dispersoid density. The heat-treated alloy contained Y₂O₃ particles averaging 16.8 nm in size with a number density of 4.93 × 10²¹ m⁻³. These ultrafine dispersoids delivered superior tensile and creep performance, demonstrating strong potential for the development of L-PBF ODS superalloys.