原位合成MoSi2/SiC复合材料的组织缺陷

TEM和HREM研究表明，原位合成MoSi2基复合材料的组织中，基体MoSi2中存在较多的位错，而且尤以MoSi2与SiC的界面处位错最为集中，SiC颗粒的内部缺陷的主要形式为孪晶和层错，纳米力学探讨分析表明，MoSi/SiC界面附近存在明显的硬度梯度，在材料制备冷却过程中，因MoSi2基体与SiC颗粒之间的热膨胀系数（CTE）的差别而导致的其中的残余热应力是造成上述组织特征的原因。

Microstructure Defects of MoSi2-SiC Composite Synthesized in Situ

TEM and HREM observations of the MoSi2-SiC composite synthesised in situ reveal that large amounts of dislocations exist in the MoSi2 matrix specially near the interfaces between MoSi2 math and the SiC particles, and the SiC particles typically contain defects including twins and stacking faults. Nanoinden- tation investigation shows that there exists a gradient distribution of microhardness near the interface of MoSi2/ SiC. The microstructurd characters above can be attributed to the residue heat stress due to the CTE discrep- ancy between MoSi2/SiC generated in the cooling process of the production.