Hot deformation behavior of a new Al-Zn-Mg-Sc-Er-Zr alloy

Abstract

The hot deformation behavior of Al-8.9Zn-1.3Mg-0.1Sc-0.1Er-0.1Zr aluminum alloy was studied by Gleeble-3800 thermal simulator. The hot processing map of the alloy in the temperature range of 380-440 ℃ and strain rate range of 0.01-10 s-1 was established.The phase in the alloy was analyzed by XRD, SAED and EDS. The microstructure after hot deformation was observed by OM and TEM. The optimum range of hot working parameters is as follows: 400 ℃ < T < 440 ℃, 0.01 s-1 < $\rm{\dot \varepsilon }$ < 0.1 s-1. The main phase group of the alloy after deformation is α-Al and Al3(Sc, Er); The results show that the stress required for plastic deformation decreases with the increase of temperature and the decrease of strain rate, which is mainly due to the recrystallization and the decrease of pinning force of Al3 (Sc, Er) particles; the tendency of dynamic softening is greater at low strain rate, and the softening mechanism is changed from dynamic recovery to dynamic recrystallization; the formation of adiabatic shear band and dislocation stacking is the main reason for the instability of the alloy.

Keywords

• al-zn-mg-sc-er-zr
• hot deformation
• constitutive equation
• hot processing map
• micro-structure evolution