【摘要】 对SiO2 与Mg反应的热力学分析计算 ,在Mg的熔化温度范围内 ,Mg与SiO2 反应生成MgO和Mg2 Si。通过真空感应炉中氩气保护 ,在纯Mg熔体中加入SiO2 原位反应自生MgO/Mg2 Si增强镁基复合材料 ,并采用XRD、OM、ESEM、EDAX等对反应生成相的种类、形态、大小和分布等进行研究。结果表明 :80 0℃在Mg中加入SiO2 可原位反应生成Mg2 Si和MgO增强相 ,Mg2 Si为多角形和细条状 ,在Mg基体中分布均匀 ;MgO为细小的粒子状 ,在熔体中分布不均匀 ,大多则是聚集在坩埚底部 ;机械搅拌可有效削弱反应添加物SiO2 的动力学沉降过程 ,改善原位反应的动力学条件 ,促使反应生成的MgO在熔体中分布均匀。初步建立起SiO2 与Mg反应的宏观动力学模型更多还原

【Abstract】 According to thermodynamic calculation, MgO/Mg 2Si can be formed in situ through the reaction of SiO 2 and Mg under experimental condition. In situ MgO/Mg 2Si reinforced magnesium matrix composite was fabricated by adding SiO 2 into the molten magnesium under the protection of Ar gas atmosphere in vacuum induction furnace. The effect of mechanical stir on the microstructure of in situ MgO/Mg 2Si reinforced magnesium matrix composite was investigated by means of OM, ESEM, EDAX, XRD etc. It is found that the morphology of Mg 2Si particles is a rough granular and fineplate. The morphology of MgO is particles that segregate without mechanical stir. MgO particles distributes uniformly with a maximum size of about 1 μm by using mechanical stir. The mechanism of in situ reaction of SiO 2 and Mg is also discussed.更多还原