Corrosion and mechanically assisted corrosion of Mg 9% Al alloy AZ91 /
Samah Mamdouh Mostafa Bekhet
Corrosion and mechanically assisted corrosion of Mg 9% Al alloy AZ91 / التآكل و التآكل الاجهادى لسبيكة مغنسيوم 9% ألومنيوم Samah Mamdouh Mostafa Bekhet ; Supervised Saad Megahed Elraghy , Hafiz Abdelazim Ahmed , Wafaa Abdelraouf Metwally - Cairo : Samah Mamdouh Mostafa Bekhet , 2016 - 87 P. : facsimiles , photographs ; 30cm
Thesis (M.Sc.) - Cairo University - Faculty of Engineering - Department of Metallurgical Engineering
In spite of a wide industrial market, already existing for Mg alloys and extending to more structural applications, poor corrosion resistance of these alloys continues to be an issue. In this study different corrosion testing methods and techniques were used to give some contribution in this respect. Immersion tests using hydrogen evolution and weight loss methods were used. Potentiodynamic polarization, OCP, cyclic polarization and impedance tests were carried out to examine the corrosion behavior of AZ91 Mg alloy in different microstructural forms; as cast, solution treated- T4 and artificially aged T6, and also in different electrolytes Cl⁻, SO₄⁻² and NO₃⁻ representing marine, industrial and rural atmospheres. Corrosion surface morphology was also examined. Mechanically-assisted corrosion behavior of AZ91-T6 was also studied. Erosion corrosion and SCC susceptibility of the alloy under different conditions were evaluated. The results showed that a combination of artificially aged-T6 structure and nitrate solution has an outstanding performance, whereas chloride ion has the most aggressive effect in all cases. Alkaline pHs are beneficial in reducing SCC susceptibility; whereas change in strain rates, within the effective range, has no significant effect. The results were explained on a basis of surface film integrity and/ or breakdown, whereas H ingress was the most effective parameter in SCC
Corrosion Mechanically assisted corrosion Mg 9% Al alloy AZ91
Corrosion and mechanically assisted corrosion of Mg 9% Al alloy AZ91 / التآكل و التآكل الاجهادى لسبيكة مغنسيوم 9% ألومنيوم Samah Mamdouh Mostafa Bekhet ; Supervised Saad Megahed Elraghy , Hafiz Abdelazim Ahmed , Wafaa Abdelraouf Metwally - Cairo : Samah Mamdouh Mostafa Bekhet , 2016 - 87 P. : facsimiles , photographs ; 30cm
Thesis (M.Sc.) - Cairo University - Faculty of Engineering - Department of Metallurgical Engineering
In spite of a wide industrial market, already existing for Mg alloys and extending to more structural applications, poor corrosion resistance of these alloys continues to be an issue. In this study different corrosion testing methods and techniques were used to give some contribution in this respect. Immersion tests using hydrogen evolution and weight loss methods were used. Potentiodynamic polarization, OCP, cyclic polarization and impedance tests were carried out to examine the corrosion behavior of AZ91 Mg alloy in different microstructural forms; as cast, solution treated- T4 and artificially aged T6, and also in different electrolytes Cl⁻, SO₄⁻² and NO₃⁻ representing marine, industrial and rural atmospheres. Corrosion surface morphology was also examined. Mechanically-assisted corrosion behavior of AZ91-T6 was also studied. Erosion corrosion and SCC susceptibility of the alloy under different conditions were evaluated. The results showed that a combination of artificially aged-T6 structure and nitrate solution has an outstanding performance, whereas chloride ion has the most aggressive effect in all cases. Alkaline pHs are beneficial in reducing SCC susceptibility; whereas change in strain rates, within the effective range, has no significant effect. The results were explained on a basis of surface film integrity and/ or breakdown, whereas H ingress was the most effective parameter in SCC
Corrosion Mechanically assisted corrosion Mg 9% Al alloy AZ91