Effects of Sc addition and increasing Zn content on mechanical properties, quenching sensitivity and corrosion resistance of 7085 aluminum alloy

doi:10.13251/j.issn.0254-6051.2023.04.032

Abstract

Abstract: Three kinds of hot-rolled sheet specimen with different compositions were prepared by adding Sc and increasing Zn content on the basis of the 7085 aluminum alloy. After being heated at 470 ℃ for 1 h, the specimens were quenched by force air-cooling (FC) and water-cooling (WC) respectively, and then artificially aged at 120 ℃ for 24 h. Then the effects of Sc and Zn elements on mechanical properties and corrosion resistance of the 7085 aluminum alloy were studied by room temperature tensile and intergranular corrosion tests, metallographic microscope observation and transmission electron microscope observation. The results show that the addition of Sc element can significantly refine the grain size, pin the dislocations, inhibit the recrystallization, increase the nucleation rate and reduce the width of the precipitation-free zone and the size of the precipitation phase on the grain boundary, thus contributing to the improvement of strength and corrosion resistance of the alloy, but the quenching sensitivity is increased. Further increase of Zn content on the basis of Sc addition will enhance the precipitated driving force of quench-induced phase, increase the number of intragranular and grain boundary precipitated phases, further improve the strength of the alloy after aging, significantly increase the quenching sensitivity and decrease the corrosion resistance.

Key words: 7085 aluminum alloy, Sc, mechanical properties, quenching sensitivity, intergranular corrosion

CLC Number:

TG146.21

Sun Haoming, Liu Chongyu, Shi Lei, Zhang Lei, Xiao Jijin. Effects of Sc addition and increasing Zn content on mechanical properties, quenching sensitivity and corrosion resistance of 7085 aluminum alloy[J]. Heat Treatment of Metals, 2023, 48(4): 196-203.

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