Influence of mechanical pre-deformation on the endurance life of directionally solidified superalloy DZ4

The endurance life and fracture behaviors of directionally solidified superalloy DZ4 after pre-deformation and heat treatment were tested and analyzed. The influence of recrystallization on endurance fracture mechanism was studied. The results show that recrystallizayion layer will form on the directionally solidified superalloy surface after pre-deformation and heat treatment. Recrystallizayion layer has strong effect on its endurance life. 33% of the endurance life will get decreased due to the surface recrystallizatron lay, 130 μm in depth. Lower strength of the recrystallizayion layer inharmonized deformation and the stress concentrated between recrystallizayion layer and based materials resulted in endurance life decreasing of the directionally solidified superalloy.