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The crack growth behavior and fracture feature of superalloy GH2132 (equivalent to A286) under creep-fatigue conditions have been studied in the present paper. The tests were carried out at 550℃ under various cyclic freqencies (hold time) and load levels,and the fracture surfaces were examined by using a scanning electron microscope. It is shown that the fracture mode of creep-fatigue and the effect of cyclic loading on crack growth change with the growth of crack and the increase of net-section stress,and both are reversed when the net-section stress is up to the yield stress of material.When σn <σ0.2, cracking is predominantly cycle-dependent transgranular and cyclic loading accelerates creep crack growth, whereas when σm>σ0.2, the case is reversed.
The crack growth behavior and fracture feature of superalloy GH2132 (equivalent to A286) under creep-fatigue conditions have been studied in the present paper. The tests were carried out at 550 ° C under various cyclic freqencies (hold time) and load levels, and the fracture surfaces were examined by using a scanning electron microscope. It shows the fracture mode of creep-fatigue and the effect of cyclic loading on crack growth change with the growth of crack and the increase of net-section stress, and both are when the net-section stress is up to the yield stress of material. When σn <σ0.2, cracking is predominantly cycle-dependent transgranular and cyclic loading accelerates creep crack growth, while when σm> σ0.2, the case is reversed.