Enhanced corrosion resistance of 15-15Ti austenitic steel in liquid lead-bismuth eutectic at 550 ℃ by shot peening processing

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.