Microstructure, mechanical properties andcorrosion behavior of commercial 7N01 alloys
(1. Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, China;
2. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;
3. Jiangsu Key Laboratory for Clad Materials, Yin Bang Clad Material Co., Ltd., Wuxi 214145, China;
4. Metal & Chemistry Institute, China Academy of Railway Sciences Corporation Limited, Beijing 100081, China)
2. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;
3. Jiangsu Key Laboratory for Clad Materials, Yin Bang Clad Material Co., Ltd., Wuxi 214145, China;
4. Metal & Chemistry Institute, China Academy of Railway Sciences Corporation Limited, Beijing 100081, China)
Abstract: The effect of grain morphology and precipitates on mechanical properties and corrosion behavior of two commercial 7N01 alloys was studied using transmission electron microscopy (TEM) and scanning electron microscopy (SEM) equipped with electron backscatter diffraction (EBSD). Results showed that the recrystallization degree of the outer surface of 7N01-I alloy was lower than that of 7N01-II alloy. The main strengthening precipitates of two alloys were mainly η'''' phases. The grain boundary precipitates (GBPs) of 7N01-I alloy distributed discontinuously, while those of 7N01-II alloy distributed continuously. The strength of two 7N01 alloys was similar, but the maximum corrosion depth of 7N01-I alloy was less than that of 7N01-II alloy,because the discontinuous GBPs and the lower recrystallization degree of outer surface of 7N01-I alloy were favorable for improving corrosion behavior. Different models of strengthening mechanism were discussed, and the corrosion behavior was correlated with microstructure.
Key words: 7N01 alloys; microstructure; mechanical properties; corrosion behavior