NSUF 25-5356: Effect of ion irradiation and dose rates on 316L oxide-dispersion-strengthened steel additively manufactured by wire-powder laser-directed energy deposition

The oxide dispersion strengthened (ODS) alloys have emerged as promising candidates due to their strong high-temperature performance and resistance to radiation damage. These ODS alloys are characterized by a high density of fine oxide particles, such as yttrium oxides, uniformly dispersed within a metallic matrix, which serves to stabilize the microstructure and restrict dislocation movement. However, conventional manufacturing of ODS alloys is costly and limited in terms of shaping flexibility, as it involves multiple complex steps, including prolonged mechanical alloying (MA), canning, degassing, and either hot extrusion or hot isostatic pressing. Consequently, despite their advantageous properties, ODS steels are not yet widely available or commercially utilized, largely due to the challenges and expenses associated with traditional manufacturing processes. This has spurred interest in exploring alternative fabrication techniques, including additive manufacturing (AM) through laser powder bed fusion (L-PBF) and laser directed energy deposition (LDED), to achieve both scalability and consistent material properties. For AM materials to be effectively used in nuclear environments, accelerated irradiation testing, such as ion irradiation, is essential. With a growing body of irradiation studies on AM materials, discrepancies have emerged, mainly concerning how cellular dislocation structures impact radiation resistance. Notably, some studies suggest that these cellular dislocations may enhance void swelling, highlighting the need for a deeper understanding of microstructure evolution in AM materials under irradiation. Our preliminary results indicate that (1) AM ODS alloys show improved radiation tolerance, as oxide particles stabilize cellular dislocation structures, which act as defect sinks; (2) cellular dislocation structures tend to increase void swelling at higher dose rates but may reduce swelling at lower rates. Gaining insights into how ODS influences dislocation stability and the dose-rate dependency of radiation response is vital for advancing AM-based nuclear materials and assessing radiation performance.

Additional Info

Field	Value
Awarded Institution	Oregon State University
DOI	10.46936/NSUF/60015368
Embargo End Date	2027-09-03
Facility Tech Lead	Lin Shao, Mukesh Bachhav
Irradiation Facilities	Accelerator Laboratory
NSUF Call	FY 2025 RTE 2nd Call
PI	Somayeh Pasebani
PIE Facilities	Microscopy and Characterization Suite
Prep Facilities	Microscopy and Characterization Suite
Project Member	Professor Lin Shao, Professor - Texas A&M University (https://orcid.org/0000-0002-5703-1153)
Project Member	Dr. Tianyi Chen, Assistant Professor - Oregon State University (https://orcid.org/0000-0003-2880-824X)
Project Member	Dr. Somayeh Pasebani, Assistant Professor - Oregon State University (https://orcid.org/0000-0001-8744-6598)
Project Type	RTE