Abstract:Oxide dispersion-strengthened materials are reinforced by a (Y, Ti, O) nano-oxide dispersion and thus can be considered as nanostructured materials. In this alloy, most of the nanoprecipitates are (Y, Ti, O) nano-oxides exhibiting a Y2Ti2O7 pyrochlore-like structure. However, the lattice structure of the smallest oxides is difficult to determine, but it is likely to be close to the atomic structure of the host matrix. Designed to serve in extreme environments—i.e., a nuclear power plant—the challenge for ODS s… Show more
“…Figure 6e shows the microstructure of a TiC particle in 0. [36,37,44]. These Y-Ti oxides could promote the solidification of materials and lead to the evolution of TiC morphology from bar-shape to short-bar-shape or sphere.…”
Section: Phase Composition and Microstructures Of Composite Coatingmentioning
In order to prevent the lead-bismuth eutectic (LBE) corrosion of stainless-steel components used in nuclear reactors, the FeCrAlTiC-xY2O3 coatings were prepared on 304 stainless steel (304SS) by laser cladding. After adding Y2O3, Y2TiO5 and Y2Ti2O7 formed, which have a combined strengthening effect on improving hardness. The 0.2 wt.% Y2O3 coating showed the highest hardness as ~489 HV. In the 400 °C wear test, the weight loss of coating samples was less than ~5.2 mg, while the weight loss of 304SS samples was ~35.5 mg. The 0 wt.% Y2O3 coating showed the highest wear resistance, indicating that adding Y2O3 could result in the decrease of wear resistance. The LBE corrosion behaviors of coatings at 500 °C were investigated. The results showed that a uniform and dense oxide scale with a low growth rate was obtained on the coating surface, and no penetration of LBE into the coating was observed. After 1000 h of corrosion, the oxide scale of coatings grew to merely a ~0.3 μm thickness. The corrosion resistance mechanism of the coating in oxygen-saturated LBE at 500 °C was proposed based on experimental results along with a thermodynamic and kinetic analysis.
“…Figure 6e shows the microstructure of a TiC particle in 0. [36,37,44]. These Y-Ti oxides could promote the solidification of materials and lead to the evolution of TiC morphology from bar-shape to short-bar-shape or sphere.…”
Section: Phase Composition and Microstructures Of Composite Coatingmentioning
In order to prevent the lead-bismuth eutectic (LBE) corrosion of stainless-steel components used in nuclear reactors, the FeCrAlTiC-xY2O3 coatings were prepared on 304 stainless steel (304SS) by laser cladding. After adding Y2O3, Y2TiO5 and Y2Ti2O7 formed, which have a combined strengthening effect on improving hardness. The 0.2 wt.% Y2O3 coating showed the highest hardness as ~489 HV. In the 400 °C wear test, the weight loss of coating samples was less than ~5.2 mg, while the weight loss of 304SS samples was ~35.5 mg. The 0 wt.% Y2O3 coating showed the highest wear resistance, indicating that adding Y2O3 could result in the decrease of wear resistance. The LBE corrosion behaviors of coatings at 500 °C were investigated. The results showed that a uniform and dense oxide scale with a low growth rate was obtained on the coating surface, and no penetration of LBE into the coating was observed. After 1000 h of corrosion, the oxide scale of coatings grew to merely a ~0.3 μm thickness. The corrosion resistance mechanism of the coating in oxygen-saturated LBE at 500 °C was proposed based on experimental results along with a thermodynamic and kinetic analysis.
“…Enhanced properties of ODS alloys greatly depend on their nanostructure characteristics: the chemical composition, size, and spatial distribution of disperse inclusions. The nanostructure of ODS alloys consists of stoichiometric oxide particles detected by TEM [ 14 , 15 , 16 , 17 , 18 , 19 ] and nanoclusters detected by APT (see, e.g., articles [ 20 , 21 , 22 ] and reviews [ 23 , 24 , 25 , 26 ].…”
In this work, the nanostructure of oxide dispersion-strengthened steels was studied by small-angle neutron scattering (SANS), transmission electron microscopy (TEM), and atomic probe tomography (APT). The steels under study have different alloying systems differing in their contents of Cr, V, Ti, Al, and Zr. The methods of local analysis of TEM and APT revealed a significant number of nanosized oxide particles and clusters. Their sizes, number densities, and compositions were determined. A calculation of hardness from SANS data collected without an external magnetic field, or under a 1.1 T field, showed good agreement with the microhardness of the materials. The importance of taking into account two types of inclusions (oxides and clusters) and both nuclear and magnetic scattering was shown by the analysis of the scattering data.
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