Microstructure and mechanical properties of an oxide dispersion strengthened ferritic steel by a new fabrication route

A reduced activation oxide dispersion strengthened (ODS) ferritic steel with nominal composition of Fe–12Cr–2.5W–0.25Ti–0.2V–0.4Y2O3 (designated 12Cr-ODS) was produced by using EDTA–citrate complex method to synthesize and add Y2O3 particles to an argon atomized steel powder, followed by hot isostatic pressing at 1160 °C for 3 h under the pressure of 130 MPa, forging at 1150 °C, and heat treatment at 1050 °C for 2 h. The microstructure, tensile, and Charpy impact properties of the 12Cr-ODS steel were investigated. Transmission electron microscopy studies indicate that the 12Cr-ODS steel exhibits the characteristic ferritic structure containing few dislocations. Tensile characterization has shown that the 12Cr-ODS steel has superior tensile strength accompanied by good elongation at room temperature and 550 °C. The material exhibits very attractive Charpy impact properties with upper shelf energy of 22 J and a ductile-to-brittle transition temperature (DBTT) of about −15 °C. The formation of small, equiaxed grains and fine dispersion of oxide particles are the main reasons for the good compromise between tensile strength and impact properties.