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采用“熔-浸”热还原法,制备了具有优良组织结构的镁锶系列(Mg-Sr、Mg-Sr-Y、Mg-Sr-Zn、Mg-Sr-Zn-Y)镁合金。借助OM、SEM和XRD等测试技术,研究了工艺与合金元素对镁锶系合金微观组织结构的影响。结果表明:较低温下加入SrO有助于镁锶合金中Mg17Sr2相的形成;随镁锶合金冷却速度的增大,晶界处长条状Mg17Sr2相变成颗粒状和短条状;锶、钇和锌的加入均细化了镁锶合金的显微组织,多种元素的复合效果优于添加单一元素的作用;在镁锶形成共晶组织的基础上,Mg-Sr-Y合金在枝晶内和枝晶间形成了Mg24Y5相,在Mg-Sr-Zn-Y合金中形成了Mg12YZn相。
Magnesium-strontium (Mg-Sr, Mg-Sr-Y, Mg-Sr-Zn, Mg-Sr-Zn-Y) magnesium alloys with excellent microstructures were prepared by the “melt- immersion” thermal reduction method. With OM, SEM and XRD and other testing techniques, the effects of alloying elements on microstructure of Mg-Sr-strontium alloy were studied. The results show that the addition of SrO at lower temperature contributes to the formation of Mg17Sr2 phase in magnesium-strontium alloy. With the cooling rate of magnesium-strontium alloy increasing, the elongated Mg17Sr2 phase changes into granular and short stripe at the grain boundary. And the addition of zinc all refined the microstructure of magnesium-strontium alloy, and the composite effect of multiple elements was better than the effect of adding single element. Based on the formation of eutectic microstructure of magnesium-strontium, Mg24Y5 phase is formed between the inner and dendrites, and Mg12YZn phase is formed in the Mg-Sr-Zn-Y alloy.