Application of Electron Microscopy to Investigation of Corrosion of Mg-Al Alloys in Various Electrolyte Solutions

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Abstract:

The Mg-Al alloys are the best-known and most commonly used magnesium alloys (especially AZ91 alloy). However, the AZ91 alloy offers insufficient corrosion resistance. Many investigations show that hydrogen is the main corrosive factor appearing during chemical reactions between magnesium and water in electrolyte solution. The main intermetallic phase in the AZ91alloy is the Mg17Al12 (β phase), which is a hydrogen trap. During corrosion, magnesium hydride forms inside the β phase, and this phase is brittle fractured when the inner stress caused by hydrogen pressure and expansion stress due to the formation of magnesium hydride is higher thanthe fracture strength. We examined the corrosion behaviour of AZ91 and AE44 magnesium alloysin 0.1M Na2SO4 solution and 3.5% NaCl solution. We analysed two Mg-Al alloys in order todetermine the various effects of hydrogen on these materials.

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Solid State Phenomena (Volume 231)

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41-47

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June 2015

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© 2015 Trans Tech Publications Ltd. All Rights Reserved

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[1] R. Zeng, J. Zhang, W. Huang, W. Dietzel, K.U. Kainer, C. Blawert, W. Ke, Review of studies on corrosion of magnesium alloys, Trans. Nonferrous Met. Soc. China 16 (2006) 763-771.

DOI: 10.1016/s1003-6326(06)60297-5

Google Scholar

[2] B. Chalmers, Physical Metallurgy, John Wiley and Sons, New York, (1959).

Google Scholar

[3] J. Chen, J. Dong, J. Wang, E. Han, W. Ke, Effect of magnesium hydride on the corrosion behavior of an AZ91 magnesium alloy in sodium chloride solution, Corros. Sci. 50 (2008) 3610-3614.

DOI: 10.1016/j.corsci.2008.09.013

Google Scholar

[4] R.B. Alvarez, H.J. Martin, M.F. Horstmeyer, M.Q. Chandler, N. Williams, P.T. Wang A. Ruiz, Corrosion relationships as a function of time and surface roughness on a structural AE44 magnesium alloy, Corros. Sci. 52 (2010) 1635-1648.

DOI: 10.1016/j.corsci.2010.01.018

Google Scholar

[5] N. Jacobson, B. Tegner, E. Schröder, P. Hyldgaard, B.I. Lundqvist, Hydrogen dynamics in magnesium and graphite, Appl. Phys. Rep. 35 (2001) 1-10.

Google Scholar

[6] M. Sato, T. Kuji, Thermodynamic Consideration on Multi-Step Hydrogenation of Mg17Al12 Assisted by Phase Separation, Mater. Trans. 52 (2011) 1773-1776.

DOI: 10.2320/matertrans.m2011123

Google Scholar

[7] M.B. Kannan, W. Dietzel, Pitting-induced hydrogen embrittlement of magnesium-aluminium alloy, Mater. Design 42 (2012) 321-326.

DOI: 10.1016/j.matdes.2012.06.007

Google Scholar

[8] M. Kappes, M. Iannuzzi, M.R. Carranza, Hydrogen embrittlement of magnesium and magnesium alloys: a review, J. Electrochem. Soc. 160 (2013) 168-178.

DOI: 10.1149/2.023304jes

Google Scholar

[9] T. Rzychoń, A. Kiełbus, J. Cwajna, J. Mizera, Microstructural stability and creep properties of die casting Mg-4Al-4RE magnesium alloy, Mater. Charact. 60 (2009) 1107-1113.

DOI: 10.1016/j.matchar.2009.05.014

Google Scholar

[10] W.L. Korst, J.C. Warf, Rare Earth-Hydrogen Systems. I. Structural and Thermodynamic Properties, Prop. Rare Earth-Hydr. Systems 50 (1966) 1719-1726.

DOI: 10.1021/ic50044a018

Google Scholar