Properties of Magnesium Alloys

Two-code letter that corresponds to the two major alloying elements ordered by mass fraction 

Rounded percentage by mass of the two major alloying elements arranged in the order defined for the first code 

One-letter code for distinguishing two different alloys having the same first and second code. All the letters of the Roman alphabet can be used except 1 andO 

One-letter, one-number code that corresponds to the tempering of the alloy 

H11 = slightly strain hardened H23, H24 = strain hardened and partially annealed T4 = solution heat treated T5 = artificially aged T6 = solution heat treated T8 = solution heat treated, cold worked, and artificially aged 

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Table 6-4 Composition (wt.%) and properties of magnesium alloys for anodes...

A. Yonkeu, I.P. Swainson, J. Dufour, J. Huot, Kinetic investigation of the catalytic effect of a body centered cubic-alloy 1iV1, Mn0) (BCC) on hydriding/dehydriding properties of magnesium, . /. Alloys Compd. 460 (2008) 559-564. 

The Behavior of High-Magnesium-Content Aluminum Alloys at Room and Liquid-Nitrogen Temperatures (5) 385 Some Mechanical Properties of Magnesium Alloys at Low Temperatures (5) 397 MAGNETIC LOSSES... 

Mechanical Properties of Insulating Plastic Foams at Low Temperatures (4) 132 Some Mechanical Properties of Magnesium Alloys at Low Temperatures (5) 397 Mechanical Properties of High-Strength 301 Stainless Steel Sheet at 70, -320, and -423 F in the Base Metal and Welded Joint Configurations (5) 406 The Low Temperature Mechanical Properties of Some Selected Austenitic Manganese Steels (5) 421... 

Magnesium usage has been limited because of the poor corrosion properties of magnesium alloys (Makar et al., 1988). Corrosion resistance is especially poor when a magnesium alloy contains specific metallic impurities or when the magnesium alloy is exposed to aggressive electrolyte species such as Cl" ions. 

SOME MECHANICAL PROPERTIES OF MAGNESIUM ALLOYS AT LOW TEMPERATURES... 

Table 4. Chemical Compositions and Physical Properties of Magnesium Cast and Wrought Alloys ...

Table 5. Mechanical Properties of Magnesium Casting Alloys ...

Magnesium anodes usually consist of alloys with additions of Al, Zn and Mn. The content of Ni, Fe and Cu must be kept very low because they favor selfcorrosion. Ni contents of >0.001% impair properties and should not be exceeded. The influence of Cu is not clear. Cu certainly increases self-corrosion but amounts up to 0.05% are not detrimental if the Mn content is over 0.3%. Amounts of Fe up to about 0.01% do not influence self-corrosion if the Mn content is above 0.3%. With additions of Mn, Fe is precipitated from the melt which on solidification is rendered harmless by the formation of Fe crystals with a coating of manganese. The addition of zinc renders the corrosive attack uniform. In addition, the sensitivity to other impurities is depressed. The most important magnesium alloy for galvanic anodes is AZ63, which corresponds to the claims in Ref. 22. Alloys AZ31 and M2 are still used. The most important properties of these alloys are... 

Z.G. Huang, Z.P. Guo, A. Calka, D. Wexler, H.K. Liu, Effect of carbon black, graphite and carbon nanotubes additives on hydrogen storage properties of magnesium, J. Alloys Compd. 427 (2007) 94-100. 

M. Mamatha, B. Bogdanoviq M. Felderhoff, A. Pommerin, W. Schmidt, F. Schiith, C. Weidenthaler, Mechanochemical preparation and investigation of properties of magnesium, calcium and hthium-magnesium alanates , J. Alloys Compd. 407 (2006) 78-86. 

Magnesium and zinc are the predominantly used galvanic anodes for the cathodic protection of pipelines [13—16]. The corrosion potential difference of magnesium with respect to steel is 1 V, which Umits the length of the pipeline that can be protected by one anode. Economic considerations have led to the use of aluminum and its alloys as anodes. However, aluminum passivates easily, decreasing current output. To avoid passivation, aluminum is alloyed with tin, indium, mercury, or gallium. The electrochemical properties of these alloys, such as theoretical and actual output, consumption rate, efficiency, and open circuit (corrosion) potential, are given in Table 15.1. 

Sun J, Howlett PC, MacFarlane DR, Lin J, Forsyth M (2008) Synthesis and physical property characterisation of phosphonium ionic liquids based on P(0)2(0R)2— and P(0)2(R)2— anions with potential application for corrosion mitigation of magnesium alloys. Electrochim Acta 54 (2) 254-260. doi 10.1016/j.electacta.2008.08.020... 

Structural The mechanical properties of magnesium improve when it is alloyed with small... 

The effect of applied current, testing time and microstructure on the electrochemical properties of magnesium-based sacrificial anode in potable water was evaluated by Andrei et al. (2003). The Al-Zn Mg alloy AZ63 alloy was utilized as the Mg sacrificial anode for use in potable water considered as a high-resistivity electrolyte. The anodes were tested in order to evaluate the main anode properties such as efficiency, current capacity and charge... 

Kim J-G and Koo S-J (2000), Effect of Alloying Elements on Electrochemical Properties of Magnesium-based Sacrificial Anodes Corrosion Science Section, NACE International, Houston, Texas, 380-388. 

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