Assessment of Ferritic ODS Steels Obtained by Laser Additive Manufacturing

Area of Science:

• Materials Science
• Metallurgy
• Additive Manufacturing

Background:

• Oxide Dispersion Strengthened (ODS) steels are typically produced via mechanical alloying and hot consolidation.
• Laser Additive Manufacturing (LAM) offers a novel approach for fabricating advanced materials.
• Ferritic/Martensitic (F/M) ODS steels are crucial for high-temperature applications.

Purpose of the Study:

• To evaluate the feasibility of using Laser Powder Bed Fusion (LPBF), a type of LAM, for ODS steel production.
• To compare ODS steels fabricated by LAM with conventionally produced ODS steels and non-ODS materials.
• To investigate the influence of different powder types on LAM-processed ODS steels.

Main Methods:

• Utilized Laser Powder Bed Fusion (LPBF) to process two types of Fe-14Cr-1W ODS powders.
• One powder was produced by mechanical alloying, the other by soft mixing with yttria nanoparticles.
• Compared microstructural and mechanical properties with non-ODS powder and Hot Isostatic Pressing (HIP) consolidated ODS steel.

Main Results:

• Nano-oxides were formed in LAM-processed ODS steels, but their density was lower than in HIP ODS steels.
• Mechanical properties of LAM-produced ODS steels were modest compared to conventional ODS materials.
• The powder melting stage in LPBF limited the formation of fine, dense nano-oxide precipitation.

Conclusions:

• Achieving desired characteristics in F/M ODS steels using LAM remains challenging.
• Current LAM techniques face limitations in achieving the necessary nano-oxide precipitation density.
• Further advancements in LAM processes are needed to enhance ODS steel properties.