Temperature magnesium alloys

Silver, brass, aluminium, steel, copper, nickel can cause decomposition at elevated temperatures. Magnesium alloys and aluminium containing >2% magnesium. Natural rubber... 

Betties C.J., Forwood C.T., StJohn D., et al. (2003a), AMC-SCl an elevated temperature magnesium alloy suitable for precision sand casting of powertrain components , in H. Kaplan (ed.). Magnesium Technology, TMS, pp 223-226. 

Very small quantities of bismuthine are obtained when a bismuth-magnesium alloy, BijMgj, is dissolved in hydrochloric acid. As would be expected, it is extremely unstable, decomposing at room temperature to bismuth and hydrogen. Alkyl and aryl derivatives, for example trimethylbismuthine, Bi(CHj)3, are more stable. 

Mg yA1 2> or P-(MgAl). Thus aluminum occurs in magnesium alloys both in soHd solution and as the intermediary intermetaUic phase. The latter is clear white and in slight rehef in poHshed and etched samples. In as-cast alloys, the hard phase occurs in massive form, but when precipitated from sohd solution a lamellar stmcture is formed similar to peadite in steel. When produced by aging at low temperatures, it appears as fine particles. 

In the area of superconductivity, tetravalent thorium is used to replace trivalent lanthanides in n-ty e doped superconductors, R2 Th Cu0 g, where R = Pr, Nd, or Sm, producing a higher T superconductor. Thorium also forms alloys with a wide variety of metals. In particular, thorium is used in magnesium alloys to extend the temperature range over which stmctural properties are exhibited that are useful for the aircraft industry. More detailed discussions on thorium alloys are available (8,19). 

Tensile strength diminishes rapidly with increasing temperature above 200°C. The high-magnesium alloys N5, N6 and N8 should not be used above 65°C because higher temperatures make them susceptible to stress corrosion cracking. 

They are widely employed in the manufacture, storage and distribution of liquified gases, particularly on sea and road tankers. The most popular alloy for cryogenic applications is 4.5% magnesium alloy (N8). Table 3.33 gives the boiling points of the most common cryogenic liquids and the minimum temperatures at which various materials can be used. 

In considering the corrosion behaviour of magnesium alloys, therefore, it is of the utmost importance to know the nature of the medium to which the metal is to be exposed. In general, atmospheric attack in damp conditions is largely superficial aqueous solutions bring about attack which varies not only with the solute but with the volume, movement and temperature... 

Improved Protection of Magnesium Alloys Against Synthetic Aviation Lubrications at Elevated Temperatures, Rendu, Tawil SAE Paper 880869... 

King, J. F., Adamson, K. G. and Unsworth, W., Impregnation of Anodic Films for the Protection of Magnesium Alloys, Ministry of Defence D.Mat. Report No. 193, February (1973) Adamson, K. G., King, J. F. and Unsworth, W., Evaluation of High Temperature Resistant Coatings for the Protection of Magnesium Alloys, Ministry of Detence D.Mat. Report No. 196, July (1973)... 

The Stability of the natural oxide film reinforced by the chromate ion determines the conditions of pH, ratio of activating anion to chromate, and temperature at which the oxide is broken down and a chromate film deposited. Thus magnesium alloys can be chromate-treated in nearly neutral solutions, whereas aluminium alloys can be treated only in solutions of appreciable acidity or alkalinity. 

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