Effect of Alloying Elements on Zig-Zag Grain Boundary in Superalloy GH220

The formation mechanism of Zig-Zag grain boundary and the action of adding some W, Mo, C, Ce（minor） to alloy have been probed tentatively.The results show that gamma prime well induce the formation of Zig-Zag G. B. when alloy is cooled slowly, and the carbides are the same too when the alloy coolled quickly or the isothermal heat treatment method is used. The best content ranges of W, Mo, C, Ce are found out, which is useful for production.