EFFECT OF SCANDIUM ON THE STRUCTURE AND PROPERTIES OF ALLOY AL-5.5-PERCENT ZN-2.0-PERCENT MG

Commercial weldable aluminum alloys additionally containing scandium h ave recently been developed in Russia: thermally nonhardening alloys b ased on the system Al-Mg (01570, 01523, 01515), and thermally hardenin g alloys based on the systems Al-Zn-Mg (01970, 01975) and Al-Mg-Li (01 421, 01423). Compared with other weldable aluminum alloys these materi als exhibit improved operating properties. This is achieved as a resul t of a small addition of scandium which displays a high modifying effe ct and it promotes retention of an unrecrystallized structure for allo ys. Results are presented in this article for a study of the effect of scandium content on the structure and properties of pressed strips an d cold-rolled sheets of alloy Al-5.5% Zn-2.0% Mg.