Microstructure of Carbides at Grain Boundaries in Nickel Based Superalloys

• Published in: Journal of materials science & technology Vol. 28; no. 11; pp. 1031 - 1038
• Main Authors: Dong, Xiaoming, Zhang, Xiaoli, Du, Kui, Zhou, Yizhou, Jin, Tao, Ye, Hengqiang
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.11.2012
• Subjects: Bicrystals; Carbides; Electron microscopy; Fluctuation; Grain boundaries; M23C6; MC型碳化物; MC碳化物; Mechanical properties; Microstructure; Ni based superalloys; Nickel base alloys; Orientation relationship; Superalloys; 化学组合物; 微观结构; 晶界碳化物; 机械性能; 镍基高温合金; Grain boundaries; Ni based superalloys; Orientation relationship; Electron microscopy
• ISSN: 1005-0302; 1941-1162
• DOI: 10.1016/S1005-0302(12)60169-8

It is well known that carbides at grain boundaries play an nickel based superalloys. In order to deeply understand the mportant role in affecting mechanical properties of relationship between grain boundary structures and properties, in this work, we have investigated the microstructure of grain boundaries with different misorienta- tion angles in bicrystals of nickel based superalloys. It is found that the bicrystals with smaller misorientation angles contain denser M23C6 but sparse MC particles at grain boundaries, and this kind of bicrystals presents longer stress rupture lives. It was observed that MC carbides were decorated by M23C6 and M6C particles at grain boundaries. The formation of these carbide particles, therefore, is likely due to the local fluctuation of chemical composition around MC carbides. In addition, the orientation relationships between MC carbides and γ/γ1 matrix were also determined.