Cracking and exfoliation behavior of oxide scale on T91 steel under different tensile stresses in oxygen-controlled lead-bismuth eutectic at 550 °C

The effect of different tensile stresses (0-180 MPa) on cracking and exfoliation behavior of oxide scale for T91 steel was studied in lead-bismuth eutectic containing 10-6 wt% oxygen concentration at 550 ?C. The results demonstrate that the exfoliation area of magnetite increased with stress. When tensile stress reached about 180 MPa, only a little magnetite remained; the outer sub-layer of spinel began to crack and locally exfoliated, exposing the inner sub-layer of spinel. The cracks with four different morphologies originated at the outer sublayer of spinel and propagated inward. A model was proposed to explain these phenomena.

Automated summary

The study investigated the effect of different tensile stresses on cracking and exfoliation behavior of oxide scale for T91 steel in a lead-bismuth eutectic environment. Results showed that the exfoliation area of magnetite increased with stress, with cracks originating at the outer sublayer of spinel and propagating inward. A model was proposed to explain these phenomena, providing insights into the material behavior under different stress conditions.