Tensile Deformation and Fracture Behavior of Nickel-Based Superalloy DZ951G

DZ951G is a novel developed nickel-based directional solidified superalloy with an incipient high melting point and low density. Compared with DZ417G superalloy, DZ951G superalloy has a higher ultimate tensile strength. At intermediate temperatures, the plasticity and strength were both markedly improved, and an obviously anomalous yield behavior could be observed where the yield strength reached its maximum at 760 degrees C. Below 600 degrees C, two competitive modes of dislocations shearing gamma ' particles existed, in which one was the formation of stacking faults and another was a/2 dislocations shearing. At intermediate temperatures, a transitional phase between shearing gamma ' particles and bypassing appeared, and the fracture translated from brittle fracture into ductile fracture. Exceeding 900 degrees C, bypassing of dislocations was operated under thermal activation. Moreover, short continuous stacking faults still existed at 760 degrees C. Finally, the various dislocation configurations were rationally illuminated and explained with the intrinsic connection of mechanical properties.