Transition from intergranular to pitting corrosion in fine grained aluminum processed by equal channel angular pressing

Oussama Jilani (1) , Nabil Njah (1) , Pierre Ponthiaux (2)

1 Université de Sfax - University of Sfax
2 LGPM - Laboratoire de Génie des Procédés et Matériaux - EA 4038

Equal Channel Angular Pressing (ECAP) is used to improve the strength of metallic materials by grain refinement. Moreover, extensive applications become possible by combining high strength with good surface properties. In the present work, the effect of ECAP on the corrosion behavior of aluminum was investigated in a 3% NaCl medium. From electrochemical experiments, microscopic and topographic observations, we have shown that, corrosion is mainly intergranular in the coarse grained material. After ECAP, a clear pitting is observed. We related this to a destruction of the preexisting grain boundaries and to the homogenization of the microstructure achieved by ECAP.

Mots clés: A. Aluminum; B. Polarization; B. SEM; C. Pitting corrosion; C. Repassivation

Domaines: Matériaux

Oussama Jilani, Nabil Njah, Pierre Ponthiaux. Transition from intergranular to pitting corrosion in fine grained aluminum processed by equal channel angular pressing. Corrosion Engineering, Science and Technology, 2014, 87, pp.259 - 264. ⟨10.1016/j.corsci.2014.06.031⟩. ⟨hal-01237729⟩