Influence of Al addition on the microstructure and mechanical properties of Zr-containing 9Cr-ODS steel

Abstract

Two oxide dispersion strengthened (ODS) steels with compositions of 9Cr-ODS (9Cr-ODS) and 9Cr-3Al-ODS (9Cr-ODS-Al) were fabricated by hot isostatic pressing (HIP). The microstructures and precipitates of the ODS samples were characterized by scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM). The results showed that the addition of Al could reduce the precipitation of coarse M23C6 and optimized the size of carbides in ODS steels. Furthermore, it was found that the mean size of nanoparticles in 9Cr-ODS-Al is larger than that in 9Cr-ODS due to the formation of large-size Y–Al–O nanoparticles with Al addition. The tensile test results indicated that the addition of Al slightly decreased the strength of ODS steels, but substantially increased the ductility.

Keywords

• ODS steels
• Carbides
• Oxides
• Mechanical properties