High Temperature Creep Fatigue Life Prediction of GH3536 Superalloy

Strain-controlled creep fatigue tests were conducted on GH3536 superalloy for combustion liner materials at 600, 800, 900, 1 000 ℃, and the high temperature creep fatigue behavior of the alloy was studied. The Coffin-Manson equation considering the influence of temperature and load holding was developed. The creep fatigue life was predicted by the model, and was compared with the test results. The results show that GH3536 alloy exhibited varying degrees of cyclic hardening between 600 ℃ and 900 ℃, and the hardening degree decreased with increasing temperature. At 1 000 ℃, slight cyclic softening occurred during initial cycles, and then the peak stress remained stable until the alloy failed. During the creep fatigue half-life load holding stage at 800–1 000 ℃, GH3536 alloy showed a significant stress relaxation phenomenon. With the increase of temperature, the creep fatigue life of the alloy decreased. The maximum strain holding stage had basically no effect on fatigue life at 600 ℃, and resulted in the obviouse decrease of creep fatigue life at temperatures ranging from 800 ℃ to 1 000 ℃. The creep fatigue life predicted by the fatigue life prediction model considering temperature and load holding effect at different temperatures was mostly within the double scatter band. This model could accurately predict the creep fatigue life of GH3536 alloy.