High Temperature Low Cycle Fatigue Behavior of GH4742 Alloy

• Published in: Journal of iron and steel research, international international, 2015-06, Vol.22 (6), p.551-556
• Main Authors: QIN, He-yong, CHEN, Gang, ZHU, Qiang, WANG, Chuan-jie, ZHANG, Peng
• Format: Article
• Language: English
• Subjects: Applied and Technical Physics; cyclic hardening; cyclic softening; dislocation structure; Engineering; fracture morphology; low cycle fatigue; Machines; Manufacturing; Material; Materials Engineering; Materials Science; Metallic Materials; Physical Chemistry; Processes; superalloy; 不均匀变形; 低周; 低循环疲劳试验; 合金; 扫描电子显微镜; 电子显微镜观察; 疲劳行为; 高温
• ISSN: 1006-706X; 2210-3988
• DOI: 10.1016/S1006-706X(15)30039-X

High temperature low cycle fatigue tests on GH4742 superalloy were studied under the total strain-con- trolled 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 mi- croscopy. The results showed that fatigue life and fatigue resistance of GH4742 alloy decreased significantly with in- creasing total strain amplitude. The cyclic hardening, cyclic softening and cyclic stability phenomena of the alloy oc- curred during the low cycle fatigue process. The increasing total strain amplitude is conducive to the formation of γ1 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.