Influence of Different Minor Additions on Structure and Properties of High-Strength Al-Zn-Mg-Cu Alloy Sheets

The effect of Zr, Cr, Mn, Sc transition elements on the microstructure evolution and properties of high-strength aluminum alloy sheets is reviewed. The grain size and morphology, degree of recrystallization, aging precipitation, and fracture surfaces were examined using TEM, SEM, optical microscopy, and X-ray diffraction. Maximum hardening, good exfoliation corrosion resistance, and superplasticity were achieved by Zr and Sc alloying and optimization of composition and processing. (Author)