Oxide Dispersion Strengthened Ferritic Steels (ODS FS) are candidate materials for structural components in future fusion reactors. Their high strength and creep resistance at elevated temperatures and their good resistance to neutron radiation damage is obtained through extremely fine microstructures containing a high density of nanometric precipitates, generally yttrium and titanium oxides.

This work shows transmission electron microscopy (TEM) and extended X-ray absorption fine structure (EXAFS) characterization of Fe-14Cr-2W-0.3Ti-0.24Y ODS FS obtained by the STARS route (Surface Treatment of gas Atomized powder followed by Reactive Synthesis), an alternative method to obtain ODS alloys that avoids the mechanical alloying to introduce Y₂O₃ powder particles. In this route, FS powders already containing Ti and Y, precursors of the nanometric oxides, are obtained by gas atomization. Then, a metastable Cr- and Fe-rich oxide layer is formed on the surface of the powder particles. During consolidation by HIP at elevated temperatures, and post-HIP heat treatments above the HIP temperature, this oxide layer at Prior Particle Boundaries (PPBs) dissociates, the oxygen diffuses, and Y-Ti-O nano-oxides precipitate in the ferritic matrix.

TEM characterization combined with XAFS and XANES analyses have proven to be suitable tools to follow the evolution of the nature of the different oxides present in the material during the whole processing route and select appropriate HIP and post-HIP parameters to promote profuse and fine Y-Ti-O nanometric precipitates.

氧化物弥散强化铁素体钢（ODS FS）是未来聚变反应堆中结构组件的候选材料。它们的高温强度高，抗蠕变性能好，并且对中子辐射损害具有良好的抗性，这是通过包含高密度纳米沉淀物（通常为钇和二氧化钛）的极细微结构获得的。

这项工作显示了通过STARS途径获得的Fe-14Cr-2W-0.3Ti-0.24Y ODS FS的透射电子显微镜（TEM）和扩展的X射线吸收精细结构（EXAFS）表征（气体雾化粉末的表面处理，然后进行反应性合成），这是获得ODS合金的另一种方法，该方法避免了机械合金化而引入Y ₂ O _3的情况粉末颗粒。通过这种途径，通过气体雾化获得已经包含Ti和Y的纳米级氧化物的FS粉末。然后，在粉末颗粒的表面上形成亚稳的富含Cr和Fe的氧化物层。在高温下通过HIP进行固结以及在HIP温度以上进行HIP后热处理期间，先验颗粒边界（PPB）处的该氧化物层解离，氧扩散，Y-Ti-O纳米氧化物沉淀在铁素体基体中。

TEM表征与XAFS和XANES分析相结合已被证明是跟踪整个加工过程中材料中存在的不同氧化物的性质演变并选择合适的HIP和HIP后参数以促进大量和精细Y-反应的合适工具。 Ti-O纳米沉淀。