Quantitative correlation between nano/micro-scale structure and high-temperature strength of 9Cr-ODS steel, 1; Nano/micro-scale structure quantitative analysis using X-ray and neutron small angle scattering technique

Onuma, Masato*; Suzuki, Junichi; Otsuka, Satoshi   ; Kaito, Takeji ; Kim, S.-W.; Inoue, Masaki ; Asayama, Tai 

This study discussed the interrelation between chemical composition and nano-scale oxide particle dispersion of the 9Cr-ODS steel for fast reactor fuel cladding application using small angle scattering (SAS) analysis, which is viewed as a strong tool for quantitative evaluation of nano-structure such as particle diameter and number density. Decreasing excess oxygen as well as increasing titanium is shown to provide the considerable increase of nano-scale particle population as well as the reduction of particle diameter. The type of these particles are identified to be YTiO and the number density is evaluated to be in the range between 1E17 and 1E19 (cm). The elevation of hot-extrusion temperature from 1150 C to 1200 C reduced 20% of nano-scale oxide particle number density.