单晶DD3与细晶GH4169 高温合金摩擦焊接界面表征

ue to high demand of welded turbine blisk, a fine grain superalloy, GH4169, has been widely used to make the disk and a single crystal superalloy, DD3, has been used for blades. In this work, the joint microstructureand the mechanism of friction welding between the GH4169 and DD3 have been investigated by using the SEM and TEM equipped with EDS. The research results show that there is a friction deformed band of the GH4169 in the weld zone. The heat and mechanical affected zones of the two alloys form dynamic recrystallization grains. The bonding interface is between their dynamic recrystallization grains. The two alloys bond with the common grains and the common grain boundaries. Their compositional change mainly occurs within the common grains and the common grain boundaries at bonding interface. The common grain (C2) at the viewpoint of TEM analysis and adjacent dynamic recrystallization grain (C3) of the GH4169 has a specific orientation relationship, [114]C2 [110]C3 , (220)C2 (220)C3 . With the friction welding thermal cycles and post weld heat treatment, the g' phase precipitates with tiny spherical distribution at the common grain and the two sides of dynamic recrystallization grains, and coherent with g matrix. But no g" phase precipitates.