B_4C_p+SiC_w/MB15Mg基复合材料的界面微结构

THE INTERFACE MICROSTRUCTURE OF A B_4C_p +SiC_w/MB15 MAGNESIUM BASED COMPOSITE

采用真空压力浸渍法和热挤压法制备了碳化硼颗粒和碳化硅晶须混杂增强MB15Mg合金复合材料．通过配备能量色散谱仪（EDS）和电子能量损失谱仪（EELS）的分析型电镜研究了这种复合材料的界面微结构.研究结果表明，碳化硼颗粒表面的玻璃态氧化硼和Mg发生界面反应4Mg（1）＋B2O3（1）＝MgB2（s）＋3MgO（S）；液态Mg对碳化朋颗粒发生润湿，加强了界面结合，使复合材料具有优异的力学性能由于高温时氧化硼的可流动性，在碳化硼颗粒附近的碳化硅晶须和基体的界面区域也发生了类似的反应而远离碳化硼颗粒的碳化硅品须和Mg基体成平直界面，界面上有β（MgZn2）相析出.

The magnesium alloy (MB15) matrix composites reinforced by the hybrid ofthe boron carbide particle and the silicon carbide whisker were fabricated with vacuum pressure infiltration and hot extrusion techniques. The interface microstructure of the composite has been studied using analytical electron microscope (equipped with EDS, EELS). Experimental results showed that the chemical reaction 4Mg(1)+B2O3(1)=MgB2(s)+3MgO(s) took place during infiltration, and produced magnesium diboride (MgB2) phase and MgO microcrystallites. Due to this interface reaction, liquid magnesium wetted boron carbide particle. Moreover, the surface of boron carbide particle had a serrated periphery, thus a strong interfacial bonding was formed,which resulted in excellent mechanical properties of the composite. Because of the flowabilityof boron chide, the same interfacial reaction also took place at the SiCw/Mg interface region,where the SiC whisker is near a boron carbide particle. When the SiC whisker is far from a boroncarbide particle, the SiCw/Mg interface is straight with β' (MgZn2) precipitates on it.