Microstructure of friction welded joint between single crystal superalloy DD3 and fine grain superalloy FGH4095

The microstructure and composition of weld zone in friction welded joint between single crystal superalloy D and powder fine grain superalloy FG095 were analyzed by metallographic microscope and SEM-EDS. The results indicate that the dynamic recrystallization grains form on both sides of the bonding interface, which had distinct boundary. In bonding zone, the alloying elements in single crystal superalloy and fine grain superalloy diffused to each other. The dynamic recrystallization grains of the dissimilar rnalerials grew to each other by how shape, and the tendency of FG095 dynamic recrystallization grain growing up to D alloy was more than the opposite tendency. Through mutual grains, these two dissimilar materials were bonded. During friction welding, the friction interface transformed from the interface of D and FG095 to the interior of D friction band. The c hange of microstructure gradient in the joint was great.