J. Phys. IV France 12 (2002) Pr8-203
Resistance to corrosion an embrittlement of T91 steel in stagnant Pb-Bi of eutectic compositionJ.-L. Pastol1, P. Plaindoux1, C. Leroux1, S. Guerin1, S.B. Goryachev1, D. Gorse1, F. Gamaoun2, M. Dupeux2 and V. Ghetta2
1 CNRS-CECM, 15 rue Georges Urbain, 94407 Vitry-sur-Seine cedex, France
2 LTPCM, ENSEEG, INP/Grenoble, 38402 Saint-Martin-d'Hères cedex, France
The resistance to corrosion and embrittlement of T91 steel in stagnant Pb-Bi eutectic was studied in the temperature interval 150-650°C. The degradation of the corrosion resistance manifested itself above 350°C, with Pb-Bi sticking at surface inclusions at 600°C and with localized corrosion effects visible at 650°C. Nevertheless, the specimens aged in Pb-Bi did not exhibit any degradation of mechanical properties during ex situ testing in air at room temperature. On the contrary, a liquid metal embrittlement (LME) effect was observed, when the tensile tests were camed out in situ in Pb-Bi in the temperature interval 300-400°C. The LME effect depends on temperature, strain rate, existence of stress concentrators and especially on the chemical composition of the cover gas. This effect was observed in Pb-Bi under He-4% H 2 cover gas, whereas almost no LME effect was detected in Ph-Bi under vacuum. A maximum reduction in energy to rupture (around 30%) was found for notched specimens tested in Pb-Bi under He-4% H 2 cover gas at a crosshead displacement rate of 6x10 -4 mm/s at 350°C.
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