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The microstructure and LBE corrosion behavior of the irradiated (up to 110 dpa) Fe15Cr11Al0.5Y coatings were investigated. The surface roughness and hardness increased with the irradiation dose. Irradiation induces grain growth, and the grown grains contain many dislocations, but no segregation and voids. Irradiation accelerates the corrosion rate of the coating, and the irradiated coatings suffer from serious inward non-uniform growth of the Al 2 O 3 layer. The reaction of Al 2 O 3 with PbO promoted the formation of the outermost PbAl 2 O 4 of the irradiated coating. A "competitive mechanism" was proposed to explain the evolution of the corrosion behavior of the irradiated coatings. • The FeCrAlY coating irradiated with a damage level of up to 110 dpa. • Surface roughness and hardness increased with irradiation damage level. • Irradiation accelerates the corrosion rates of the FeCrAlY coating. • The reaction between Al 2 O 3 and PbO promoted the formation of PbAl 2 O 4. • A "competitive mechanism" was proposed to explain the evolution of corrosion behavior. [ABSTRACT FROM AUTHOR]

MAX phase ceramics attract increased attention for lead-cooled fast reactors due to their promising compatibility with lead-bismuth eutectic (LBE). This work systematically investigates the corrosion behaviors of five Ti 3 Al 1−x Si x C 2 MAXs with Al/Si complex A component in static LBE at 550 ºC up to 3000 h. Based on the lattice structure, mechanical properties, surface morphologies, and elemental composition during corrosion, a synergism of Al and Si during oxidation and diffusion is found, which contributes to a continuous and well-attached Al 2 O 3 layer with improved LBE corrosion resistance. Therefore, the multi-element design will bring a broad space for the applications of MAX ceramics. • Ti3Al1−xSixC2 presents an enhanced corrosion resistance in Pb-Bi eutectic. • The continuous Al2O3 layer is proven as the crucial anti-corrosion species. • Moderate amount of Si is beneficial for a thin and continuous Al2O3 layer. [ABSTRACT FROM AUTHOR]

FeCrAl(Y) coatings have excellent LBE corrosion resistance, but their actual performance could be predicted more accurately by simultaneous irradiation and corrosion experiments. Here two kinds of FeCrAl coatings were corroded at 550 ℃ while subjected to simultaneous proton irradiation. The results showed that irradiation did not change the three-layered structure of the surface oxide scale. Compared with the FeCrAl coating, the FeCrAlY coating has better corrosion resistance in the unirradiated-corroded area, while undergoing more serious accelerated corrosion in the simultaneous irradiation and corrosion area. The corrosion mechanism was discussed in detail and a corrosion model was proposed. • The FeCrAlY coating has better corrosion resistance in the unirradiated-corroded area. • The FeCrAlY coating undergoes more serious accelerated corrosion in the simultaneous irradiation and corrosion area. • The Al-rich segregation and holes appeared at the grain boundary of the coating. • The elemental diffusion accelerated by irradiation defects deteriorates the performance of the coating. [ABSTRACT FROM AUTHOR]

The effect of shot peening on microstructure and corrosion of 15–15Ti austenitic steel in liquid LBE at 550 ℃ was investigated. The nanocrystallization and preferential recrystallization were observed, improving the resistance to corrosion and intergranular cracking in LBE. The intensive grain boundaries and dislocations on steel surface improved the compactness and adhesion of the formed oxide scale, efficiently preventing LBE penetration into steel. The Cr-rich oxide formed in boundaries of the recrystallized grains is Fe-Cr spinel with porous structure, it significantly prohibited the counter diffusion of elements, suppressing the growth of outer magnetite layer and inner transgranular oxide. • The corrosion resistance of 15–15Ti steel in LBE is improved by shot peening. • The magnetite layer formed in shot-peened steel presents better stability and protection. • The preferential recrystallization occurs in subsurface of shot-peened steel. • The Cr-rich spinel formed in the boundaries of recrystallized grains is porous in structure. [ABSTRACT FROM AUTHOR]

The corrosion behavior of the FeCrAl coating with different Cr and Al contents before and after Au-ions irradiation was investigated in static LBE. The grain of the irradiated coating changed from nanocrystal to large columnar crystal. The irradiation accelerated the LBE corrosion rate, and the oxide scale changed from three layers to four layers. Nodular corrosion was found in the irradiated FeCrAl coating. The change of Cr and Al contents has a remarkable effect on the corrosion behavior of the irradiated coatings. • Large-sized columnar crystals appeared in the irradiated FeCrAl coatings. • Irradiation in the corrosion process is related to radiation-enhanced diffusion. • The oxide scale changed from three layers to four layers. • Nodular corrosion was found in the irradiated FeCrAl coating. • The change of Cr and Al contents affects the irradiation behavior of the irradiated coatings. [ABSTRACT FROM AUTHOR]

The corrosion mechanism of 15–15Ti and 316Ti austenitic stainless steels exposed to liquid lead-bismuth eutectic (LBE) at 550 ℃ with dissolved oxygen 5 × 10−7 mass% was investigated. The oxides formed on steels have a dual- or triplex-layered structure. The higher content of Cr in oxides, the better inhibiting effect on Ni diffusion. The local dissolution attack left a Ni-rich recrystallization area with fcc -phase fine grains. The preferential intergranular oxidation (PIO) in random GBs of 15–15Ti induced intergranular cracking while the annealing twin boundaries were more resistant to crack. The 316Ti with smaller grains presented higher resistance to corrosion and intergranular cracking. • The intergranular oxidation in 15–15Ti steel can induce the intergranular cracking. • The annealing twin boundaries presents higher resistance to intergranular cracking. • The TiN precipitates promote local preferential oxidation and cracking of oxide. • The Pb can preferentially diffuse along grain boundaries compared to the Bi. • The dissolution attack leaves a confined Ni-rich area with fcc phase fine grains. [ABSTRACT FROM AUTHOR]

The effect of Au-ions irradiation with different damage doses from 10 to 90 dpa on mechanical properties and LBE corrosion behavior of AlCrFeMoTi HEA coating was investigated. The fracture toughness and the interface bonding strength had been improved after irradiation. The Au-ions irradiation decelerated LBE corrosion rate of coating at low damage dose, which could be attributed to the formation of a more continuous Cr 2 O 3 layer adjacent to the coating surface. However, the element diffusion was intensified and the Cr 2 O 3 layer became more thick and porous at high damage dose, which resulted in the acceleration of LBE corrosion. • The amorphous AlCrFeMoTi HEA coatings were irradiated by Au-ions and then exposed to liquid LBE. • The fracture toughness and the interface bonding strength have been improved after Au-ions irradiation. • The Au-ions irradiation decelerated overall corrosion of coating at low irradiation damage dose. [ABSTRACT FROM AUTHOR]