Fabrication Routes, Microstructural Evolution, and Creep Performance of Oxide Dispersion Strengthened Austenitic Steels: A Review.

Oxide dispersion strengthened (ODS) austenitic steels exhibit superior high-temperature stability and mechanical properties, which are attributed to the strong pinning effect of nano-oxide particles on dislocations and grain boundaries. The microstructure and properties of ODS steels are intrinsically governed by their fabrication techniques. While powder metallurgy (PM) serves as the predominant synthesis route, the fabrication of austenitic ODS steels faces distinct technical challenges compared to their ferritic counterparts, primarily due to issues such as powder sticking to the milling media. Conversely, although traditional melting processes often lead to oxide agglomeration, coarsening, or flotation, which makes it difficult to achieve a uniform dispersion, they remain of significant interest because of their scalability and cost-effectiveness. Furthermore, emerging technologies such as additive manufacturing (AM) have also been employed for the preparation of ODS steels. This review provides a systematic and comprehensive overview of the recent progress in the fabrication technologies of ODS austenitic steels. The scope encompasses a critical analysis of the merits and limitations of techniques including PM, in situ internal oxidation, melting, and AM, alongside an examination of the potential impacts of adding process control agents (PCA) to mitigate powder sticking during mechanical alloying. Additionally, the microstructural characteristics resulting from different processing routes are discussed in detail, followed by a consolidated evaluation of their mechanical properties.