Commerical aluminium always contains some magnesium, name two such allous of aluminium. What properties are imparted by the addition of magnesium to these alloys?

Explanation

The two alloys of aluminium are:
(a). Duralium: `AI = 92.5%`
`Ni =4%`
`Cu = 2%`
`Mg = 1.5%`
(b). Magnalium: `AI =95%`
`Mg = 5%`
It is used in the construction of aeroplane, motors and light instruments.
By the addition of magnesium to aluminium the alloy becomes `(i)` malleable and rust free, `(ii)` it increases the durability of the alloys and `(iii)` it makes alloy more hard and strong.