Microstructure and Creep Property of DZ125 Nickel-Based Superalloy

By means of creep property measurement and microstructure observation, an investigation has been made into the creep behaviors of DZ125 superalloy at high temperature and low stress. Results showed that the superalloy under the applied stress of 137MPa at 1293 K displayed a better creep resistance, and the apparent creep activation energy of the alloy during steady state creep was measured to be Q = 325.57 kJ/mol. The various microstructures were displayed in different regions of the sample, thereinto, the rafted γ phase was uniformly distributed in the regions far away from the fracture, but the twisted and coarser rafted γ phase appeared in the region near the fracture. The deformation mechanism of the alloy during steady state creep was the dislocations climbing over the rafted γ phase. In the later stage of creep, significant amount of dislocations shearing into the rafted γ-phase promoted the initiation and propagation of the cracks along the boundaries up to the occurrence of fracture, which was though to the fracture mechanism of the alloy during creep.