中文摘要：

利用扫描电子显微镜（SEM）、电子背散射衍射（EBSD）技术和取向成像显微（OIM）软件研究了Ni基690合金中不同类型晶界处碳化物的形貌。不同类型晶界处析出碳化物的形貌有很大区别,在孪晶的非共格界面（Σ3i）附近,棒状碳化物向两侧晶粒内部生长,而类似的棒状碳化物只向Σ9晶界一侧的晶粒内部生长。Σ3i与Σ9晶界附近的棒状碳化物的生长方向与基体晶粒的{111}面平行。晶界上析出的碳化物尺寸随着Σ值的升高而明显增大。在相同的腐蚀条件下,晶间腐蚀的痕迹随着Σ值的升高变得严重。

英文摘要：

The morphology of carbide precipitated at grain boundaries with various characters in nickel based Alloy 690 were investigated by scanning electron microscopy（SEM）,electron backscatter diffraction（EBSD） technical and orientation imaging microscopy（OIM）.The morphology of carbides precipitated at grain boundaries with different characters is distinct.The bar-like carbide precipitated near both side of Σ3_i boundary,while similar carbides precipitated only near one side of Σ9 boundary.The bar-like carbide near Σ3_i and Σ9 grows on the {111} planes of the matrix grain.The size of carbide grain boundary on increases with the increasing of Σ value of the boundary.The intergranular corrosion increases with the increasing of Σ value of the boundary.