Influence of Plastic Deformation on the Corrosion Behaviour of As-Cast AlMg2 and AlCu4Mg1 Aluminium Alloys in NaCl Solution

The influence of plastic deformation on the corrosion behavior of as-cast AlMg2 and AlCu4Mg1 aluminum alloys was studied at the microscale using the Electrochemical Microcell Technique and surface microgauges. It was shown that large strain gradients develop locally. The corrosion behavior of both alloys was affected by plastic deformation. The most active sites contain large strain gradients in AlMg2 and cracks with damage in the matrix in AlCu4Mg1.

Application of the Electrochemical Microcell Technique in Solid State Surface Analysis

In the two last decades, the Electrochemical Microcell Technique (EMT) was used in various electrochemical surface investigations. The diameter of microcapillaries was in the range between few and few hundred microns. This technique was commonly used in corrosion research. Indeed, metallic alloys exhibit a complex microstructure consisting of different metallic and intermetallic phases, inclusions, precipitates... The use of microcapillaries based techniques like EMT makes possible to perform local electrochemical measurements in individual phases. Therefore, it was possible to get information about the behavior of a single grain, inclusion, precipitate... From these information, precursor sites can be identified and criteria leading to corrosion can be proposed.

Advances in local mechanoelectrochemistry for detecting pitting corrosion in duplex steels

The goal of this study was to demonstrate that a relationship exists between surface stress and pitting corrosion. The surface stress field generated by polishing was first calculated using a thermomechanical model and a finite element code. Pitting corrosion tests performed at the microscale along the austenite/ferrite interface using the electrochemical microcell technique were then analyzed considering the microstructure, and the residual surface stress field calculated numerically under the microcapillary. Mechanical criteria are proposed leading to an enhancement of pitting corrosion of duplex steels.