Study On Effect Of Rare-Earth Element Erbium On The Al-Zn-Mg Alloy

How to improve the synthesis properties of the aluminum alloys by mean ofmicroalloying is one of the important basic research items. In our earlier studies,considerable efforts have been spent on the effects of the rare-earth element Erbiumon the aluminum and its alloys. The results show that Erbium is good for theproperty improvement of the aluminum and its alloys. For further study on theeffects of Er on the aluminum and its alloys, six different compositions of Al-Zn-Mgalloys containing Er were prepared by ingot metallurgy. The influence of differentcontents of Er addition on the mechanical properties under different states,microstructure, heat resistance and the aging properties of Al-Zn-Mg alloys has beenstudied by hardness test, tensile properties measurement, X-ray diffraction (XRD)analysis, optical microscopy, scanning electron microscopy (SEM), transmissionelectron microscopy(TEM) and energy dispersive x-ray spectroscopy(EDXS)analysis. The experimental results show that: the mechanical properties of theAl-Zn-Mg alloy can be obviously improved by Er addition. When the Er content is0.1wt%, the strength increment is the largest, that is about 15%. Then the incrementreduces when the Er content is over 0.4wt.%, though the strength continues toincrease compared to that of the Al-Zn-Mg alloy free of Er. With Er addition, therecrystallization of the Al-Zn-Mg alloy is suppressed, that is, the recrystallizationtemperature of Er-doped Al-Zn-Mg alloy increases about 50°C. Adding Er to theAl-Zn-Mg alloy, the time of getting to the hardness peak can be greatly shortenedand the value of the hardness peak can be increased remarkably.