The object of this paper is to present some of the user experience with the high strength aluminium alloys. The somewhat tarnished reputation of the Aluminium-Zinc-Magnesium alloys is undoubtedly due to their premature introduction; the very substantial weight savings offered by the relatively high static strength values proving too strong an attraction at the end of the war-time era dominated by short term considerations.

It will be appreciated that there is a wide range of alloys in this family. Table I lists the composition ranges of typical French, American and British specifications together with a proprietary alloy, of German origin, which is of particular interest. Manufacturers have their own favoured compositions within the permitted ranges. Fig. 1 shows diagrammatically the wide variation in percentage of the principal alloying elements zinc, magnesium and copper.