Mg-Mg2Si-MgO复合材料的反应自组织合成机理

以纯Mg粉,SiO2粉为原料,采用反应自组织生长的方法制备了以MgO,Mg2 Si为增强相的镁基复合材料.通过对试样的差热分析发现,Mg与SiO2在510～600℃之间发生原位化学反应,生成MgO与Si,被还原的Si继而与过量的Mg反应生成Mg2Si.采用扫描电镜和能谱分析对烧结后试样的微观形态进行分析,结果表明,经超...

Reaction Mechanism in Self-assembly Growth Formation of Mg-Mg2Si-MgO Composites

With pure Mg and SiO2 powders as raw materials,an Mg-based metal matrix composite reinforced by MgO ceramic and Mg2Si intermetallic was formed through self-assembly growth method.The differential thermal analysis(DTA) was performed on the samples and it was revealed that the in-situ reaction between Mg and SiO2 took place from 510℃ to 600℃.As a result of reaction,the MgO was formed,and the reduced Si continually reacted with excess Mg,forming Mg2Si.The observation of scanning electron micrograph and energy dispersive spectrometry indicated that,in the sample made by ultrasonic assisted stirring,the in-situ formed MgO covered the Mg2Si intermetallic as a compact aggregate layer which had a strong bonding strength with the matrix.What’s more,the Vickers hardness tests showed that the Vickers hardness of ultrasonic assisted stirring sample was 40 percent higher than that of the sample made by generally stirring.The reaction mechanism between Mg and SiO2 was concretely discussed.