Dégradation de l’acier inoxydable soumis à la contrainte : L’influence des contraintes sur la cinétique de passivation, et la cristallographie de la fissuration dans des milieux acides

Abstract : : A multidisciplinary experimental approach of electrochemical and mechanical techniques was employed to study the corrosion of different stress states of 304L stainless steel in acidic electrolytes (0.5-5 M H2SO4) with and without chloride additives. Stress corrosion cracking (SCC) conditions were applied to evidence cracking crystallographical and propagation aspects. Scanning electron microscopy of SCC revealed clear traces of successive slipping planes and consequent dissolutions on the crack facets, and nonlinear crack propagation kinetics. A method was proposed to access cracking crystallography using electron back scattered diffraction. It demonstrated {111} and {110} preferential cracking planes in proportion of about 75% and 25% respectively, which supports recent SCC models such as corrosion enhanced localized plasticity. The profiles of (applied/residual) stress evolution measured by X-ray diffraction before and after SCC were used as an introduction to develop a micro-mechanical cracking model. During optimized potentiodynamic corrosion tests, elemental dissolution rates and total current transients were measured by combining electrochemical flow cell and downstream solution analysis by inductively coupled plasma atomic emission spectroscopy. The results were used to separate the current portion spent on passive film formation from the total current. The high field ion conduction model was upgraded to calculate the constructed passive film thickness and passivation rate. The applied stress caused a measurable difference in passive film growth kinetics and its thickness.
Document type :
Theses
Complete list of metadatas

https://pastel.archives-ouvertes.fr/tel-01562914
Contributor : Abes Star <>
Submitted on : Monday, July 17, 2017 - 11:05:10 AM
Last modification on : Tuesday, January 16, 2018 - 4:12:20 AM
Long-term archiving on : Saturday, January 27, 2018 - 3:21:28 AM

File

MUBARAK.pdf
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-01562914, version 1

Collections

Citation

Hazem Mubarak. Dégradation de l’acier inoxydable soumis à la contrainte : L’influence des contraintes sur la cinétique de passivation, et la cristallographie de la fissuration dans des milieux acides. Matériaux. Ecole nationale supérieure d'arts et métiers - ENSAM, 2016. Français. ⟨NNT : 2016ENAM0069⟩. ⟨tel-01562914⟩

Share

Metrics

Record views

578

Files downloads

163