单晶DD3与细晶DAIn718高温合金摩擦焊接性分析

Friction Weldability of Single Crystal Superalloy DD3 and Fine Grain Superalloy DAIn718

整体叶盘是发展高推重比航空发动机的关键技术 ,整体涡轮叶盘的叶片和轮盘分别由单晶高温合金和细晶 (或粉末 )高温合金制造。文中分析了单晶 DD3与细晶 DAIn71 8高温合金摩擦焊接头组织 ,测试了室温及高温下接头的强度与持久性能。结果表明 ,摩擦焊接工艺对单晶高温合金的“定向”及“单晶”特征 ,以及细晶高温合金的“细晶”特征均无明显改变 ;异种材料摩擦焊接头的力学性能可以达到母材性能。摩擦焊接是连接单晶材料与细晶材料的有效方法。

Blisk (integrally bladed disk) is a key technology for improving performance of aeroengine. The single crystal superalloy DD3 is always used as the blade material of blisk and fine grain superalloy DAIn718 is used as disk material of blisk. There is not any report about the friction weldability between DD3 and DAIn718 in the open literature. We examined the microstructure of the welding joint with an optical microscope. The tensile tests were carried out at room temperature and 650℃ to measure the mechanical properties at room temperature and elevated temperature. The stress rupture tests were made under 690MPa and at 650℃ to detect the rupture time. The results show that the friction welding process has no effect on the directional and single crystal characteristics of the single crystal superalloy DD3 and that the grains near the weld are finer than those of the base metal of superalloy DAIn718. The heat mechanical affected zone at the side of DAIn718 is divided into dynamic recrystallization zone, partial dynamic recrystallization zone, deformation zone and solid solution softening zone. The tensile strengths at room temperature and 650℃ of the joints are the same as the base material. The rupture times of the joints are longer than that of the base material. These results indicate that the friction welding process is an effective way for connecting the DD3 blade to DAIn718 disk.