Zinc Containing Eral - 6.0% - 2.0% Cu Mg - 1.5% - 1.5% Zr Alloy Thermal Deformation And Organizational Performance Research

In this thesis, on the basis of the Al-Zn-Mg-Cu alloy with0.15%wt Zr, four kinds of Al-6.0%of Zn-2.0%Mg-1.5%Cu-0.15%Zr alloys with different Er were prepared by traditional ingot metallurgy. First selected the Al-6.0%Zn-2.0%Mg-1.5%Cu-0.15%Zr-0.4%Er alloy as the research object. The established constitutive equations and processing maps were obtained by using hot compression simulation test alloy at high temperature. The influence of Er addition on the mechanical properties and microstructure of Al-6.0%Zn-2.0%Mg-1.5%Cu-0.15%Zr alloy under different states has been studied by hardness test, tensile properties measurement, X-ray diffraction (XRD) analysis, optical microscopy, scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDXS) analysis. The existing forms of Er in alloy, the influence of casting process and the strengthening mechanism of Al-6.0%Zn-2.0%Mg-1.5%Cu-0.15%Zr alloys were all discussed in this paper. The results can be summarized as follows.(1) The softening mechanism of alloy transformed from dynamic recovery to dynamic recrystallization with increasing of deformation temperature of the Al-6.0%Zn-2.0%Mg-1.5%Cu-0.4%Er-0.15%Zr alloy.(2) The microstructure demonstrated the obvious feature of dynamic recrystallization at the strain rate of10s-1. The hot deformation behavior of the alloy can be obtained by Arrhenius function revised by Arrhenius function revised by hyperbolic sine with an activation energy of219.990kJ/mol: ε=2.98383×1016[sinh(0.008104×σ)]7639828exp(-219.990×103/RT)An optimal parameter can be obtained according to the processing map as follows:T=420～450℃,ε=0.01～0.1s-1.(3)The microstructure of alloy under cast and homogenization showed that:the a(Al) grains was obviously refined with the addition of Er; the alloy was fully homogenized under460℃/24h and the MgZn2dissolved completely in the matrix. (4)Tensile test results of the Al-6.0%Zn-2.0%Mg-1.5%Cu-0.15%Zr alloy at room temperature showed that:microscale addition of rare earth Er element improved mechanical properties of the alloy. The optimal mechanical properties was obtained in Al-6.0%Zn-2.0%Mg-1.5%Cu-0.15%Zr alloy with0.4%wt Er. The tensile strength, yield the strength and elongation were560.6MPa,491.6MPa,15.62%respectively.