Magnesium alloying element

In addition to freshwater, seawater is also a source for sodium, magnesium, chlorides, iodine, bromine, and magnesium metal (see Sodium coLD>ouNDS Magnesium coLD>ouNDS Iodine Bromine Magnesiumand magnesium alloys). Many other elements are certain to be economically obtained from the ocean as technology for the recovery improves. 

No fewer than 14 pure metals have densities se4.5 Mg (see Table 10.1). Of these, titanium, aluminium and magnesium are in common use as structural materials. Beryllium is difficult to work and is toxic, but it is used in moderate quantities for heat shields and structural members in rockets. Lithium is used as an alloying element in aluminium to lower its density and save weight on airframes. Yttrium has an excellent set of properties and, although scarce, may eventually find applications in the nuclear-powered aircraft project. But the majority are unsuitable for structural use because they are chemically reactive or have low melting points." ... 

Finally, Table 10.4 shows that copper is not the only alloying element that can age-harden aluminium. Magnesium and titanium can be age hardened too, but not as much as aluminium. 

Knighton, J.B. Steunenberg, R.K. "Distribution of Transuranium Elements Between Magnesium Chloride and Zinc-Magnesium Alloy", J. of Inorganic and Nuc. Chem. 27 p.p. 1457-1462 (1965). 

Letters indicate ihc Iwo principal alloying elements A, Aluminum E, Rare-Earth H. Thorium K, Zirconium M, Manganese Q, Silver, S, Silicon T, Tin Z, Zinc. Thus HK signifies a thorium-zirconium magnesium alloy. 

Reactor fuel elements are contained in cans. In early British reactors, these were made of aluminium or aluminium/magnesium alloy to minimise capture of neutrons in the canning material. Nowadays, uranium fuel is enriched with respect to the 235U content, and the extra reactivity enables steel or zirconium cans to be used. In the original... 

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