Recently, researchers from the Hefei Institutes of Physical Science of the Chinese Academy of Sciences elucidated the effect of Cerium (Ce) and Praseodymium (Pr) enriched oxides on microstructure and properties of China Low Activation Martensitic (CLAM) steel.
The related results were published in Journal of Nuclear Materials.
CLAM steel has been selected as one of the main candidate structural materials for fusion reactor blanket due to its good mechanical properties and relatively mature fabrication technology in China. However, its strength and creep resistance at elevated temperatures require further improvement. The Oxide Dispersion Strengthening (ODS) is an effective strategy to enhance the performance of materials at the elevated temperature.
In the study, two types of ODS-CLAM samples were fabricated—one containing Ce-enriched oxides and the other Pr-enriched oxides. The results revealed that adding these rare-earth oxides significantly refined the grain structure and generated a high density of nanoscale particles within the steel matrix. These nanoparticles exhibited specific orientation relationships and coherent interfaces with the matrix, contributing to the overall strengthening effect.
The Pr-enriched oxide exhibited a better strengthening effect, the Ce-enriched oxide showed a good synergistic strengthening effect of strength and ductility. The results demonstrate that Ce- and Pr-enriched oxides, as effective oxide strengthening phases, have potential to be used in fabrication of ODS steel with high strength and ductility.
This study provides a reference for the research and development of high-performance structural materials for nuclear reactors.
Interface relationship between nanoparticles and the matrix: (a-d) Ce4.67O13Si3; (e-f) Pr4.67O13Si3 (Image by HUANG Tingjun)
Strengthening mechanism and performance advantages:
(a) Comparison of calculated and measured yield stresses;
(b) Ultimate tensile strength versus total elongation compared with those of 9Cr-ODS steels in references (Image by HUANG Tingjun)
