The Precipitated Particle Refinement in High-Cr ODS Steels by Microalloying Element Addition

Two oxide-dispersion-strengthened (ODS) steels with different compositions (14Cr-ODS and 14Cr-Zr-ODS) were investigated to reveal the influences of microalloying element addition on the microstructure and to clarify the refining mechanism of precipitated particles. TEM and HRTEM results indicated that precipitated particles in the Zr-containing ODS steel had finer sizes and dispersed more homogeneously within the grains. It was found that rhombohedral Y4Zr3O12 particles with complex lattice structures were formed and could pin the migration of the grain boundaries during heat treatment due to their high thermal stability. In addition, the Zr-containing ODS steel exhibited a finer and more uniform grain morphology. Tensile tests showed that microalloying element addition could significantly improve the comprehensive mechanical properties of 14Cr ODS steels at room temperature.

Automated summary

The study found that the ODS steel containing zirconium had finer and more uniformly dispersed precipitated particles with complex lattice structures, which could effectively inhibit the migration of grain boundaries. In addition, the zirconium-containing ODS steel exhibited a finer and more uniform grain morphology, significantly improving the mechanical properties of the steel at room temperature.