Effect of Al Content Addition on Microstructure of Mg-9Zn-xAl Alloy

Microstructure of Mg-9Zn-xAl (x=2,4,6) magnesium alloy was prepared by traditional casting, SIM casting and isolated treatment. The effect of Al content addition on microstructure of Mg-9Zn-xAl was investigated. Results show that Compared with traditional casting, grain size is refined by self-inoculation method casting. Grain size of Mg-9Zn-xAl (x=2,4,6) is 88μm,76μm and 69μm respectively at traditional casting, and is 49.5μm,42μm,35.6μm respectively at SIM casting. With Al content increase, the isolated island-like secondary phase change into semi-continuous network and continuous network, and combination between Magnesium and alloy element decrease accumulation of magnesium atom on the primary phase, so that the growth of the primary phase is prevented.