三维网络SiC_n/20Cr钢复合材料的界面固相反应及显微组织

Solid-Phase Reaction and Microstructure of Interface of 3D Meshy SiC_n/20Cr Steel Composite

采用真空-气铸法制备了SiCn/20Cr钢复合材料,并对SiC/20Cr钢复合材料的界面进行了研究.结果表明:SiC和20Cr在复合材料的界面产生较强固相反应,SiC分解出的Si与Fe结合生成Fe-Si化合物,SiC分解出的C以石墨态沉积下来.固相反应的区域由碳化硅反应区、金属反应区和碳沉积区组成.碳元素在碳沉积区的沉积形态与沉积点到SiC的距离有关.TEM证实了金属反应区的产物为(Cr,Fe)23C6及Fe3Si,其中Fe3Si的形成为SiC的分解提供了热力学驱动力.

The interface of the SiCn/20Cr steel composite material fabricated via vacuum-gas casting process was investigated with XRD and EDS （energy-dispersive spectroscopy analyzer） attached to SEM. The result revealed that an intensive solid-phase reaction occurs on the composite＇s interface between SiC and 20Cr steel, then SiC decomposed into Si that forms Fe-Si compound with Fe and C that precipitated in graphite form. The solid-phase reaction zone is composed of three zones, i.e. the metal, silicon carbide and carbon precipitation zones. The precipitating form of C in carbon precipitation zone relates to the distance between the precipitation position and silicon carbide. The （Cr, Fe）23C6 and Fe3Si is the products from metal reaction zone are verified by transmission electron microscope（TEM）, of which the formation of Fe3Si provides thermodynamically the driving force for the decomposition of SiC.