2、Mg7Zn3、Mg2Sn相、MgSnGd相組成。MgSnGd相為高溫相，在合金凝固過程中最先形成，改變了凝固過程，使晶界處半連續(xù)第二相轉(zhuǎn)變?yōu)閿嗑W(wǎng)狀。MgSnGd相與α-Mg基體存在共格位向關(guān)系，能作為異質(zhì)形核核心細(xì)化合金晶粒。Mg-8Zn-1Mn-3Sn-0.5Gd合金的綜合力學(xué)性能最佳，合金力學(xué)性能得到顯著提高的機(jī)制為通過添加Gd元素細(xì)化晶粒組織、MgSnGd相釘扎晶界阻礙位錯運(yùn)動以及晶界第二相形貌轉(zhuǎn)變。;The effect of minor Gd element on the microstructure and properties of Mg-8Zn-1Mn-3Sn alloy was studied. The results show that Mg-8Zn-1Mn-3Sn-xGd is mainly composed of α-Mg matrix, MgZn2, MgZn, Mg7Zn3, Mg2Sn phase and MgSnGd phase. The MgSnGd phase is a high temperature phase, which is formed firstly during the solidification and changes the solidification process, causing the semi-continuous second phase at the grain boundary to transform into a discontinuous network. The MgSnGd phase has a coherent orientation relationship with the α-Mg matrix, which can be used as a heterogeneous nucleation core to refine grains. The Mg-8Zn-1Mn-3Sn-0.5Gd alloy has the best comprehensive mechanical properties. The mechanical properties of the alloy are significantly improved by adding Gd elements to refine the grains, and the MgSnGd phase pins the grain boundary to hinder the movement of dislocations and the transformation of the second phase of the grain boundary."/>