Discontinuous Precipitation Reaction Front of Cellular Recrystallization for a Single-Crystal Superalloy Studied by Electron Microscopy*Supported by the Scientific Research Foundation of Xi'an University of Technology under Grant No 101-451115007, the National Natural Science Foundation of China under Grant No 51174161, and the Pivot Innovation Team of Shaanxi Electric Materials and Infiltration Technique under Grant No 2012KCT-25. (July 2015) - Zhuo, Long-Chao
Abstract Combining analytical transmission electron microscopy systematic tilting, scanning transmission electron microscopy mapping and nano-beam electron diffraction operations, we obtain direct experimental proofs on the boundary type, elemental distribution and structure of the cellular recrystallization reaction front for a single-crystal superalloy. It is demonstrated that the cellular recrystallization reaction front usually corresponds to coincidence site lattice boundaries, and a thin layer of γ-forming elements such as Re, Cr, Mo and Co invariably exists in the direct reaction front. Furthermore, the thin layer with γ-forming elements is proved to be γ phase, with the same orientation as the neighboring original matrix.