Influence of Temperature on the Microstructural Evolution of SIMP and T91 Steels in Liquid Lead-Bismuth Eutectic: Experiments and Molecular Dynamics Simulations

The microstructural evolution of ferritic/martensitic steels SIMP and T91 in oxygen-saturated liquid LBE at different temperatures (400, 470, 550 and 620 degrees C) has been studied by experiments and molecular dynamics simulations. It is shown that the SIMP steel offers better oxidation resistance at 400-550 degrees C due to the formation of protective SiO2 particles and bands. At 620 degrees C, both the SIMP and T91 steels undergo dissolution corrosion with similar dissolved layer thicknesses. Molecular dynamics simulations reveal that the number of Fe-O pairs decreases with increasing temperatures and the enhanced dissolution of Fe makes the surfaces of the steel difficult to oxidize at 620 degrees C.