The basic principles of alloying of aluminum alloys with scandium are: it is desirable to add scandium to aluminum alloys in a quantity from 0.1 to 0.3% together with zirconium (0.05–0.15%), which strengthens the positive influence of scandium on the structure and properties of alloys; the greatest effect (that is, the positive influence on mechanical properties and other characteristics) from addition of scandium together with zirconium is observed for alloys not containing alloy elements combining scandium in insoluble phases, specifically the Al−Mg, Al−Zn−Mg, and Al−Mg−Li systems; with a limited copper content alloying with scandium together with zirconium of Al−Zn−Mg−Cu and Al−Cu−Li system alloys is possible. At present on the basis of or taking into consideration the principles developed of alloying of aluminum alloys with scandium commercial aluminum alloys based on the Al−Mg−Sc−Sr (01570, 01571, 01523, 01505), Al−Zn−Mg−Sc−Zr (01970, 01975), and Al−Li−Mg−Sc−Zr (10421, 01423) systems have been developed.