Influence of deformation level on microstructure and creep behavior of GH4169 alloy

By means of the creep properties measurement and microstructure observation, the influence of the deforming techniques on the microstructure and creep behavior of GH4169 alloy has been investigated. Results show that, compared to the isothermal forged (ITF), the hot continuous rolled (HCR) may increase the deformed quantity of alloy. During HCR, significant amount of dislocations and twinning are activated in the alloy, which is favorable for the multi-systems slipping of dislocation, during creep, for releasing the stress concentration to improve the creep resistance and prolong the creep lifetime of the alloy. In the later period of creep, the micro-cracks are initiated along the grain boundaries vertical to the applied stress axis, and propagated along the grain boundary to occur the cleavage fracture, which is a main mechanism of creep fracture for the alloys prepared by two deformed techniques.