Influence of loading frequency on transient current behavior of Fe26Cr1Mo during low cycle corrosion fatigue in 1M H2SO4 and 0.6M NaCl solutions

Abstract

To understand the corrosion fatigue (CF) mechanism, in recent years many studies have been done on the transient current behavior of cyclic straining electrode for mild steel although there have been some studies on the transient current evolution under cyclic deformation, detailed information concerning the effect of loading frequency in corrosive solutions with different passivation characteristics is lacking. Crack initiation mechanisms are generally analyzed from the effect of surface dissolution, which is related to competition between the kinetics of depassivation by film rupture and repassivation by refilming of new metal surface. Two important factors should affect this surface reaction process: (1) surface dissolution behavior of metals which is dependent on the strain rate in the case of Fe-26Cr-1Mo stainless steel and gives a distribution of passive film damage; (2) repassivation kinetics, which are determined by the refilming ability of the corrosive medium. In the condition of CF, frequency is therefore an important factor which simultaneously determines both the material plastic deformation rate and the new surface repassivation time. On the other hand, the surface refilming process will be controlled by the characteristics of the selective medium. The main purpose of this paper is to study the effect of loading frequencymore » on the transient current behavior for Fe-26Cr-1Mo stainless steel under a low cycle CF condition, and to compare the difference of current response in 1M H[sub 2]SO[sub 4] solution.« less