TABLE OF CONTENTS The selection of aluminium alloys for use in engineering has often been difficult because specification and alloy designations have differed from country to country. Moreover, in some countries, the system used has been simply to number alloys in the historical sequence of their development rather than in a more logical arrangement. For these reasons, the introduction of an International Alloy Designation System (IADS) for wrought products in 1970 and its gradual acceptance by most countries is to be welcomed. The system is based on the classification used for many years by the Aluminium Association of the United States and it is used when describing alloys in this book.
The IADS gives each wrought alloy a four digit number of which the first digit is assigned on the basis of the major alloying element(s) (Fig. 3.16). Hence there are the 1xxx series alloys which are unalloyed aluminium (with 99% aluminium minimum), the 2xxx series with copper as the major alloying element, 3xxx series with manganese, 4xxx series with silicon, 5xxx series with magnesium, 6xxx with magnesium and silicon and 7xxx series with zinc (and magnesium) as the major alloying elements. The 8xxx series is used for compositions not covered by the above designations and several different alloys are mentioned in some other sections of Chapter 3. It should also be noted that wrought Al Si alloys of the 4xxx series are used mainly for welding and brazing electrodes and brazing...
