机械预变形对定向凝固DZ4合金持久寿命的影响

Influence of Mechanical Pre-Deformation on the Endurance Life of Directionally Solidified Superalloy DZ4

对定向凝固DZ4合金机械预变形和热处理后的持久寿命与断裂行为进行了测试与分析,研究了再结晶对定向凝固DZ4合金持久行为的影响机制。结果表明,定向凝固DZ4合金机械预变形和热处理后在其表面形成再结晶层。再结晶层对定向凝固DZ4合金持久寿命的影响很大,表面130μm的再结晶使其持久寿命下降33%。再结晶层本身的强度极低、再结晶层与基体的变形不协调以及界面所具有的缺口效应导致了定向凝固DZ4合金机械预变形和热处理后持久强度的下降。

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 gin 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.