Crystallographic relations between Ti3SiC2 and TiC

Ti3SiC2 is a so-called not-so-brittle ceramic that combines the merits of both metals and ceramics. However, many previous works demonstrated that its bonding nature and properties were strongly related to TiC. In this paper the crystallographic relations between Ti3SiC2 and TiC were established and described based on the transmission electron microscopy investigation on the Ti3SiC2/TiC interface in Ti3SiC2 based material. At Ti3SiC2/TiC interface, the following crystallographic relationships were identified: (111)TiC//(001)Ti3SiC2, (002) TiC//(104)Ti3SiC2, and [1 (1) over bar 0]TiC//[110]Ti3SiC2. Based on the above interfacial relations an interfacial structure model was established. The structure of Ti3SiC2 could be considered as two-dimensional closed packed layers of Si periodically intercalated into the (111) twin boundary of TiC0.67 (Ti3C2). The intercalation resulted in the transformation From cubic TiC0.67 to hexagonal Ti3SiC2. In the opposite case, de-intercalation of Si from Ti3SiC2 caused the transformation from hexagonal Ti3SiC2 to cubic TiC0.67. Understanding the crystallographic relations between Ti3SiC2 and TiC is of vital importance in both understanding the properties and optimizing the processing route for preparing pure Ti3SiC2.