去应力退火对DZ125合金再结晶行为的影响

为了获得具有优异高温力学性能的定向凝固高温合金,减少定向凝固叶片在生产过程中产生再结晶的现象,对经过喷丸后的DZ125合金进行了去应力退火处理,随后对其进行了不同温度下的热处理.利用扫描电子显微镜观察了DZ125合金的微观组织.结果表明,当表征喷丸强度的Almen值为0.25 mm时,依次进行870℃/500 h去应力退火与1 000℃/4 h热处理后,DZ125合金中仍存在少量胞状再结晶.经过1 150℃/4 h热处理后,胞状再结晶层厚度约降低30%;经过1 230℃/4 h热处理后,等轴状再结晶层厚度总体约降低了30%.当Almen值为0.17 mm时,在870℃下进行不同时间的去应力退火处理与1 230℃/4 h热处理后发现,随着退火时间的增加,再结晶层厚度逐渐降低,当退火时间为500 h时,再结晶层厚度约降低50%.

Effect of stress relief annealing on recrystallization behavior of DZ125 alloy

In order to obtain the directional solidification superalloy with excellent mechanical properties at high temperature and reduce the recrystallization phenomenon of directional solidification blade in the production process, the stress relief annealing treatment was conducted for the DZ125 alloy after shot blasting, and then the heat treatments at different temperatures were performed for the DZ125 alloy. In addition, the microstructures of DZ125 alloy were observed with scanning electron microscope(SEM). The results show that when the Almen value which characterizes the shot blasting strength is 0.25 mm, a small amount of cellular recrystallization still exists in the DZ125 alloy after the stress relief annealing at 870 ℃ for 500 h and the heat treatment at 1 000 ℃ for 4 h are successively performed. After the heat treatment at 1 150 ℃ for 4 h, the depth of cellular recrystallized layer decreases by about 30%. After the heat treatment at 1 230 ℃ for 4 h, the depth of equiaxed recrystallized layer decreases by about 30%. When the Almen value is 0.17 mm and after the stress relief annealing at 870 ℃ for different time and the heat treatment at 1 230 ℃ for 4 h are successively performed, it is found that with increasing the annealing time, the depth of recrystallized layer gradually decreases. When the annealing time is 500 h, the depth of recrystallized layer decreases by about 50%.