中文摘要：

利用HRTEM，SEM和EBSD技术研究了固溶处理后镍基690合金在715℃时效时晶界处析出碳化物的形貌及与基体的取向关系．结果表明，碳化物在晶界处于高指数晶体学面的一侧晶粒中析出，并与此侧晶粒具有共格的取向关系．但是碳化物会向无共格取向关系一侧晶粒生长更快一些，碳化物向两侧晶粒生长速度的不同导致晶界附近Cr浓度曲线不对称，并且使晶界附近两侧晶粒的耐腐蚀能力不同．

英文摘要：

The morphology and orientation relationship between carbide precipitated at grain boundary and both side matrixes in nickel base alloy 690 aged at 715℃ for 2-200 h after solution treated were investigated by HRTEM, SEM and EBSD. The results show that the boundary carbide is easy to nucleate in the grain with high indexed crystal plane parallel to boundary, and the carbide has coherent orientation relationship （COR） with this grain. The carbide grows preferentially into the grain without COR between carbide and grain, which leads to lower chromium concentration in this side matrix near boundary. The asymmetry of chromium concentration profile leads to the different corrosion resistance of the two side grains nearby the grain boundary.