Fabrication and characterization of ODS austenitic steels

Pure Fe, Cr, Ni, W, Ti elemental powders and nano-Y2O3 powders (the compositions of the mixed powders are Fe–18Cr–8Ni–2W–1Ti–0.35Y2O3) were processed by high energy mechanical milling. The as milled powders were consolidated by hot isostatic pressing for 3 h at 1423 K under a pressure of 200 MPa. The microstructure of the fabricated ODS austenitic steels and chemical composition of the oxide particles were examined by field emission scanning electron microscopy with energy dispersive spectrometry. The dispersed fine oxides were determined to be Y–Ti–O oxides. The tensile properties were improved significantly by oxide dispersion strengthening but the ductility deteriorated.