Stability of damping capacity and mechanical properties of high-Zn-concentration Al–Zn–Mg–Sc alloy

Abstract

The microstructure, damping capacity, mechanical properties, and the performance stability of high-Zn-concentration Al–Zn–Mg–Sc alloys after annealing treatment were studied. The Al–20Zn–0.5 Mg–0.5Sc alloy contained fine grains, a high number of solution atoms, Zn phases, Al 3 Sc phases, and high-density fine η and η' phases. Decreasing the Zn content led to the disappearance of the Zn phases and the decrease of intragranular η phases density and solution atom number. Increasing the Mg content did not increase the number of solution atoms but increased the size of the intragranular η phases. The Al–20Zn–0.5 Mg–0.5Sc alloy exhibited higher internal friction value and higher strength than the other two alloys because of its satisfactory grain boundaries and Al/Zn interface sliding ability at high temperature, as well as its high solid solution and second phase strengthening effects at room temperature. All annealed Al–Zn–Mg–Sc alloys exhibited excellent damping capacity and mechanical properties stability during the DMA test at the highest temperature of 360 °C due to their high structural stability. • A novel Al alloy with excellent damping capacity, mechanical properties, and performances stability was obtained. • The satisfactory GB and Al/Zn interface sliding ability led to the Al–Zn–Mg–Sc alloy exhibited well damping capacity. • The high solid solution and second phase strengthening effects led to the Al–Zn–Mg–Sc alloy exhibited high strength. • Sc addition and annealing led to the Al–Zn–Mg–Sc alloy exhibited excellent structural and properties stabilit.