Abstract
Dual-phase oxide dispersion strengthened (ODS) steels of Fe–12Cr–xY (x=0.1, 0.2 and 0.3 wt%) have been fabricated by casting, hot-forging and subsequent hot-rolling. Microstructure of the hot-rolled samples was carefully characterized by use of electron probe microanalysis (EPMA), electron backscatter diffraction (EBSD) and transmission electron microscope (TEM). The results show that all the samples consist of ferrite phase with coarse fiber grains (elongated along the rolling direction) and martensite phase in the form of fine block grains. As the Y addition increases, the ratio of ferrite to martensite and density of low-angle boundaries (LABs) within the martensite and ferrite grains do not change significantly. The Y2O3 particles introduced by self-oxidation during casting are survived without being dissolved or refined after hot-forging and hot-rolling. However, as the Y addition increases, the Y2O3 particles tend to aggregate with fine M23C6 and TaC carbides. The hardness of the sample with high Y additions is lower than that of the samples with none or low Y additions, which could be attributed to the aggregation coarsening of the yttria and TaC particles, resulting in a decrease in dispersion strengthening effect. The effect of Y additions on microtexture was also discussed.
Highlights
Nuclear energy is considered to be one of the clean and efficient energy sources and plays a significant role in addition to natural renewable energy sources (Saito, 2010)
Scenario 1: Dual-Phase Structure and Texture. It is well-known that the 12Cr oxide dispersion strengthened (ODS) is a typical ferriticmartensitic dual-phase steel (Chen et al, 2015, 2019; Yao et al, 2018)
It has been reported that the addition of alloys such as Al (Xu et al, 2019), Ti (Zhao et al, 2018b) can reduce the martensite lath in the ferritic/martensitic dual-phase ODS steels, and even obtain single-phase ferrite ODS steel
Summary
Nuclear energy is considered to be one of the clean and efficient energy sources and plays a significant role in addition to natural renewable energy sources (Saito, 2010). Oxide dispersion strengthened (ODS) steels have been considered as one of the most promising candidate materials due to their many advantages at high-temperature, such as low thermal. In the steel matrix during the MA processing, and the actual dispersion distribution particles are composite oxide clusters/particles, such as Y-Cr-O (YCrO3), YTi-O (Y2Ti2O3, Y2TiO5, Y2Ti2O7, etc.), and Y-Si-O (Y2Si2O), rather than Y2O3. Since the thermal stability of the composite oxide clusters/particles is not as good as that of the Y2O3 particles, resulting in the degradation of the high-temperature performance and the neutron radiation resistance (Zeybek et al, 2014). A ferritic/martensitic dual-phase ODS steel was fabricated by casting followed by hot-forging and hot-rolling. The electrolyte was 10% perchloric acid and 90% methanol, and the polishing temperature was about −30◦C
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