The effects of stress on corrosion behavior of SIMP martensitic steel in static liquid lead-bismuth eutectic

摘要

As for a newly developed tempered martensitic steel, SIMP with 1.4 wt.% Si, used in the Chinese Initiative Accelerator Driven System (CiADS), so it is worth investigating the stress corrosion property of SIMP steel in liquid lead-bismuth eutectic at the system operating temperature. The compatibility of the structural materials with the proposed operational conditions was investigated by performing corrosion-mechanical testing. The stress corrosion was performed in static lead-bismuth eutectic at 300 degrees C, 450 degrees C, and 500 degrees C with different loading stresses. The effect of stress on corrosion rate at different temperatures was investigated by scanning electron microscopy and transmission electron microscopy. The testing of SIMP steel showed that the corrosion rate in the presence of LBE was strongly temperature-dependent. At 300 degrees C, only a very thin oxide scale was formed which inhibits the Pb and O from penetrating inside matrix steel, and hence keeps it ductile (no crack). On the other hand, at 450 and 500 degrees C, the stress can significantly enhance the corrosion rate at 450 degrees C and 500 degrees C, but not at 300 degrees C. Reasons are investigated and discussed based on the available space model.