Microstructure and mechanical properties of oxide dispersion strengthened ferritic steel prepared by a novel route

Abstract

Nanocrystalline oxide dispersion strengthened (ODS) ferritic steel powders with nominal composition of Fe–14Cr–3W–0.2Ti–0.3Y was synthesized using a sol–gel method combining with hydrogen reduction. X-ray diffraction patterns show that pure Fe–14Cr–3W–0.2Ti–0.3Y body-centered-cubic phase was obtained at a reduction temperature of 1200°C for 3h. Using such powders the ODS steel was produced by spark plasma sintering (SPS) technique. The energy dispersive spectrometry mapping and transmission electron microscopy results indicate that the oxide particles of Y2Ti2O7 with an average size of 55nm and particle number density of 3.2×1019m−3 are homogeneously dispersed in the steel matrix. The tensile strength and uniform elongation of the steel that was SPS sintered and mechanically–thermally treated at 1100°C under a uniaxial pressure reach 1070MPa and 15%, respectively.