High temperature low cycle fatigue tests on GH4742 superalloy were studied under the total strain-controlled conditions at 650℃.Combined with fatigue test data,fatigue properties of the alloy were analyzed.Fracture m...High temperature low cycle fatigue tests on GH4742 superalloy were studied under the total strain-controlled conditions at 650℃.Combined with fatigue test data,fatigue properties of the alloy were analyzed.Fracture morphology and dislocation structure were observed by scanning electron microscopy and transmission electron microscopy.The results showed that fatigue life and fatigue resistance of GH4742 alloy decreased significantly with increasing total strain amplitude.The cyclic hardening,cyclic softening and cyclic stability phenomena of the alloy occurred during the low cycle fatigue process.The increasing total strain amplitude is conducive to the formation ofγ′phase.Fatigue crack propagation is controlled jointly by ductile and brittle fracture.Inhomogeneous deformation and deformation restricted in slip bands are the main reasons for the reduction of fatigue life of GH4742 alloy.展开更多
基金Sponsored by Major National Science and Technology Project of High-end CNC Machine Tools and Basic Manufacturing Equipments of China(2012ZX04010081)
文摘High temperature low cycle fatigue tests on GH4742 superalloy were studied under the total strain-controlled conditions at 650℃.Combined with fatigue test data,fatigue properties of the alloy were analyzed.Fracture morphology and dislocation structure were observed by scanning electron microscopy and transmission electron microscopy.The results showed that fatigue life and fatigue resistance of GH4742 alloy decreased significantly with increasing total strain amplitude.The cyclic hardening,cyclic softening and cyclic stability phenomena of the alloy occurred during the low cycle fatigue process.The increasing total strain amplitude is conducive to the formation ofγ′phase.Fatigue crack propagation is controlled jointly by ductile and brittle fracture.Inhomogeneous deformation and deformation restricted in slip bands are the main reasons for the reduction of fatigue life of GH4742 alloy.
