Effects of plastic straining on the corrosion resistance of TRIP-aided lean duplex stainless steels
In the present paper, the effects of plastic deformation on the corrosion resistance of strip cast TRIP (transformation-induced plasticity)-aided stainless steel (19Cr-DSS) and conventional lean duplex stainless steel (LDX2101) were studied by observations of deformed microstructure and electrochemical experiments. The electrochemical results indicate that the corrosion susceptibility of experimental steels in 3.5% NaCl solution is increased with increasing deformation amounts. The Mott–Schottky analysis revealed that the passive films formed on both 19Cr-DSS and LDX2101 exhibit the n-type and p-type semiconducting behaviors regardless of strains. With the increase in true strain, the acceptor and donor densities are both continuously increased. The total density of acceptor and donor in 19Cr-DSS is increased more rapidly with increasing strain than that of LDX2101, indicating that the corrosion resistance of 19Cr-DSS is more sensitive to plastic deformation compared to that of LDX2101. For the TRIP-aided 19Cr-DSS, the deterioration of corrosion resistance after plastic deformation may have been caused by the decrease in low-Σ CSL boundaries especially the twin (Σ3) boundaries, the increase in dislocations, and the formation of strain-induced martensite during plastic deformation.
This work was supported by the National Natural Science Foundation of China with contracts of U1460204 together with Baosteel Co., Fundamental Research Funds for Central Universities (N150704002), and National Natural Science Foundation of China (51774083).
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Conflict of interest
The authors declare that they have no conflict of interest.