Microstructural evolution and its effect on corrosion behavior and mechanism of an austenite-based low-density steel during aging

The microstructural evolution during aging and its influence on corrosion behavior and mechanism of the Fe-19Mn-9Al-0.8 C-5Ni low-density steel (LDS) were studied. The results showed that the morphology, chemical property and proportion of the B2 phase in the LDS changed with aging time. These changes effectively inhibited the microgalvanic effect between different phases at the initial corrosion and the local acidification at the late stage. Accordingly, the corrosion resistance of the aged LDSs continually increased as the aging time extended. Moreover, the corrosion mechanism and the properties of corrosion product film of the Fe-19Mn-9Al-0.8 C-5Ni LDS during aging were revealed in detail.