Corrosion behavior of T91 steel in liquid lead-bismuth eutectic at 550 ℃ under different tensile stresses

To efficiently evaluate the corrosion behavior of T91 steel in lead-bismuth eutectic (LBE) under different stresses, a corrosion experiment of small tapered conical specimen of T91 in LBE with an oxygen concentration of 1×10-6 wt% at 550 ℃ under 0~180 MPa was carried out. The results showed that the (Fe,Cr)3O4 and internal oxidation zone always exist, but the Fe3O4 peels off severely under tensile stress, and its fragments become smaller with the increase of stress; (Fe,Cr)3O4 has two sub-layers, which is caused by different Cr enrichments; As the tensile stress increases, the cracks increase in number and size, extending continuously to the matrix direction, running through the whole (Fe,Cr)3O4 by the time the tensile stress reaches 180 MPa. Moreover, with the tensile stress increasing, the thickness of each oxide layer increases, but the rate of incrassation decreases constantly.