TABLE OF CONTENTS Today more than several dozens of aluminum alloys are used in different areas of manufacturing and technology (e.g., automotive, aerospace, etc.) [1 13]. Patents have been issued for thousands of alloy compositions. However, most of them contain a relatively limited number of alloying elements. This is illustrated by Appendix 1, which provides information on the most widely used US casting aluminum alloys.
All alloying elements that are used for aluminum alloy design can be classified into three principal groups: basic alloying elements, ancillary additions (or dopants), and impurities. Depending upon the nature of an alloy, the same elements could play different roles.
In the overwhelming majority of all cases only four alloying elements are used: metals magnesium, zinc, and copper; and semiconductor silicon. We call these chemical elements basic , or principal , because they are introduced into aluminum alloys in (relatively) large amounts and define their microstructure and properties. For example, the Mg content in Al Si casting alloys with 7%Si or 9%Si is only ~0.3%, but it is this small amount that defines the alloy s strength. In this sense, Mg is the principal alloying element in these alloys. On the other hand, Mn in similar alloys can be present in the amounts 0.5% and even more, but should be considered a small addition since its principal role is auxiliary, to neutralize the harmful influence of iron. Another example: in alloys on the basis of the Al Cu system containing less than 1%Mn,...
