Recrystallization of Single Crystal Nickel-Based Superalloy

A series of experiments of investigating the recrystallization of single crystal DD3 superalloy were carried out. The threshold temperature for recrystallization and the effect of annealing temperature on recrystallization were studied. The results show that the threshold temperature for recrystallization of the shot-peened DD3 samples is between 1 000 degrees C and 1 050 degrees C under the condition of annealing for 2 h, and the recrystallization depth increases with the rise of the annealing temperature. Below 1 150 degrees C, the recrystallization depth increases slowly with the temperature climbing while above 1 150 degrees C, the recrystallization depth increases quickly with the rise of the temperature. The solution of the gamma' phase is a critical factor of the recrystallization behavior of DD3 superalloy. In addition, the kinetics and microstructural evolution of recrystallization at 1 200 degrees C were also studied. It is found that the recrystallization progresses rapidly at 1 200 degrees C through the growth of fully developed recrystallized grains, and the recrystallization process on the shot-peened surface is similar to that of wrought materials, including nucleation of recrystallization, growth of new grains into the matrix, and growth of new grains by swallowing up each other.