The Structure and Properties of Wrought Al-Mg-Sc Aluminum Alloys with Different Scandium Content

Round ingots 110 mm in diameter and cold-rolled sheets 2 mm in thickness, which were made of experimental Al-Mg-Sc alloys containing with different scandium content (0.07, 0.20 wt %), have been studied. Transmission electron microscopy and thermodynamic simulation have been used to investigate the peculiarities of the structural-phase state of the material. A reduction in scandium content from 0.20 to 0.07% has been found to result in a twofold increase in the grain size in ingots, a 46% drop in hardening of ingots after homogenization, and a 10-20% decrease in the strength of annealed sheets, which has been caused by a smaller amount of the key phase, Al-3(Sc, Zr). A good level of strength characteristics of experimental annealed sheets made of alloy with low scandium content 0.07 wt % (sigma(u) > 400 MPa, sigma(0.2) > 300 MPa) has been achieved and it is higher than that of the traditional AMg6 alloy (sigma(u) > 350 MPa, sigma(0.2) > 150 MPa).