Effects of trace Er addition on the mechanical properties

microstructure

age-hardening characteristics and recrystallization behavior of the high strength Al-6Zn-2Mg alloy have been investigated by tensile property measurement

optical microscope （OM）

X-ray diffraction analysis （XRD）

scanning electron microscope （SEM）

transmission electron microscope （TEM） and energy spectrum analysis （EDS）. The results show that Er can greatly refine the grain size of the alloy

which is attributed to primary Al

3

Er as heterogeneous substrate to sharply improve nuclei rate. Tensile strength of the alloy has been significantly improved with Er addition as a result of fine grain strengthening and precipitated strengthening. Meanwhile

Er addition can improve age-hardening effects by accelerating ageing process of the alloy. In addition

Er can inhibit the recrystallization of the alloy and raise the recrystallized temperature

resulting from the pinning effects of the secondary fine Al

3

Er phase on dislocation and sub-boundary.