A series of Al-Mg armour plates were cast in a metallic mold with Mg content varying from l% to 5% Mg. The effect of Mg content on the mechanical properties and microstructure was investigated. Tensile,Impact toughness,and Hardness tests were carried out on specimens machined from the 35 mm thickness cast armour plates. Penetration resistance tests were carried out on 200 x 200 x 32 mm plates using 7.62 x 39 mm projectiles. Energy consumed during penetration was evaluat-ed and taken as a measure of penetration resistance.
The following relationship between penetration resistance and Mg content was deduced using the obtained results :
P.R. = 1366 + 58 (Mg % ) .
where P.R. = Penetration Resistance ( Joules ).