Abstrait

Responses to indentation and to impedance spectroscopy of plastically compressed steels. Part 1: Case of pure iron

Adrien Frigerio, Pierre-Yves Girardin, Patrice Berthod

The consequences of plastic deformation of alloys on their electrochemical behaviour may be usefully known to anticipate changes in corrosion resistance. Stationarymethods of corrosion characterization can be helped by transitory methods to complete the knowledge about the hardening – corrosion dependence. Impedance spectroscopy was used in this work to study the effect of several compression plastic deformations on the corrosion behaviour of a model metallic material – pure iron – for the two main orientations of surface with respect to the deformation axis. It appeared here that the electrochemical behaviour of crystalline iron after plastic deformation immersed in an acid sulphuric aqueous solution can be still described by the same electro-kinetic model as usually considered for the not-deformed iron, independently from the deformation rate and from the orientation of the surface versus the compression axis. In addition it varies with these two but not really monotonously, except for two of the three studied deformation rates. Indeed, in this case it appeared for example that the charge transfert resistance tends to be higher for the parallel orientation than for the perpendicular one and increases for both orientations with the deformation rate.