The effect of deformation on low temperature sensitized metastable austenite stainless steel
LI Hong-dou1, LUO Hong-yun*1, Lü Jin-long1, XIE Jin-peng2
1.Beihang University, School of Material Science and Engineering, Beijing 100191, China; 2.China Iron & Steel Research Institute, Beijing 100081, China
Abstract：The microstructure of metastable austenite stainless steel (AISI 304) at different deformation level after low temperature sensitization (vacuum treatment at 380 ℃ for 240 h ) were investigated by scanning electron microscope (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). Double loop electrochemical potentiokinetic reactivation (DL-EPR) method was used to test the samples’ degree of sensitization (DOS). And the corrosion resistance of these samples was characterized by electrochemical impedance spectroscopy (EIS). The results indicated that the DOS value increases with the increasing deformation level as well as the corrosion resistance of the samples decreases. The DOS value of samples with 40% deformation level can reach to 71%. The morphology of the specimen surface after the measurement of DL-EPR showed that the martensite region was corroded obviously while the austenite region was corroded slightly. Transgranular corrosion happened at this condition. The carbides were easily nucleated at the martensite lath and the slip band in the matrix.
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