Abstract:

The weight percentages of δ phase and γ″ phase in Inconel 718 cold rolled to different reductions and then treated at 860℃ for different times were measured by the X ray diffraction method, and the effect of cold rolling on the precipitation behavior of δ phase and γ″ phase was investigated. The results show that cold rolling affects the morphology of δ phase. As cold rolling amount increases, the shape of δ phase changes gradually from needle to spheroid. The relationship between the weight percentage of δ phase and annealing time follows the Avrami equation. As cold rolling amount increases, the value of n decreases, whereas the value of α increases. In the case of 860℃ for 15 minutes, the γ″ phase has been precipitated in austenite matrix. With the increasing time, the weight percentage of γ″ phase increases to a maximum value, and then decreases. For a given time in this experiment, as cold rolling amount increases, the weight percentage of γ″ phase decreases, whereas the weight percentage of δ phase increases.

Key words: Inconel 718, co ld ro lling, p recip itates