Microstructures and mechanical properties of 9Cr oxide dispersion strengthened steel produced by spark plasma sintering

9Cr oxide dispersion strengthened (ODS) steel was fabricated by mechanical alloying (MA) and spark plasma sintering (SPS). The nano-sized particles, grain size distribution and mechanical properties of 9Cr-ODS steel sintered at 950 degrees C were studied by synchrotron radiation small angle X-ray scattering (SAXS), high-resolution transmission electron microscopy (HRTEM), electron backscatter diffraction (EBSD) and tensile experiment. The results showed that bimodal grain size distribution in the matrix is observed, which is attributed to the heterogeneous recrystallization process during the SPS. High-density nano sized Y2Ti2O7 and some large oxides of Cr2Mn(Ti)O-4 are formed in 9Cr-ODS steel. The number density and average size of Y2Ti2O7 obtained from SAXS are 4.72 x 10(22)/m(3) and 4.4nm, respectively. The yield strengths of 9Cr-ODS steel fabricated by SPS are compared with the typical 9Cr-ODS steel produced by HIP. (C) 2016 Elsevier B.V. All rights reserved.