Development of oxide dispersion strengthened ferritic steel prepared by chemical reduction and mechanical milling

Abstract

The oxide dispersion strengthened ferritic steel with a nominal composition of Fe–14Cr–2W–0.5Ti–0.06Si–0.2V–0.1Mn–0.05Ta–0.03C–0.3Y2O3 (14Cr–ODS) was fabricated by sol–gel method in combination with hydrogen reduction, mechanical alloying (MA) and hot isostatic pressing (HIP) techniques. Pure Fe–1.5Y2O3 precursor was obtained by a sol–gel process and a reduction process at 650°C for 3h and pure 14Cr–ODS alloy powders were obtained from this precursor and the alloying metallic powders by mechanical alloying. The microstructure analysis investigated by transmission electron microscopy (TEM) and energy dispersive spectrometry (EDS) reveal that Y–Ti–O complexes and V–Ti–O complexes with a main particle size of 8nm are formed in the 14Cr–ODS steel matrix. After HIP sintering the weight and the relative density of the compacted ingots are about 0.8kg and 99.7%. The uniform elongation and ultimate tensile strength of the ODS steel obtained by HIP after annealing at 1100°C for 5h are about 13% and 840MPa, respectively.