【摘要】 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,Mg2Si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,经超声波辅助电搅拌混料获得的试样,反应所生成的MgO在Mg2Si表面形成了一层致密的团聚体壳层,其与基体之间结合紧密。力学性能测试结果表明,超声波辅助电搅拌混料所获得的试样维氏硬度比电搅拌混料所获得的试样的维氏硬度提高近40%。对体系中自组织反应的反应机理进行了讨论。更多还原

【Abstract】 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.更多还原