ZHAO Zuo-peng 1 , HU Xu-teng 2,3 , GUO Zhi-wei 4 , WEN Wei-dong 2,3.Fatigue Small Crack Propagation Test of FGH96 Turbine Disc Structure Simulation Specimen[J].航空发动机,2024,50(2):83-87
Fatigue Small Crack Propagation Test of FGH96 Turbine Disc Structure Simulation Specimen
DOI:
Key Words:FGH96 superalloy  simulation specimen  small fatigue crack  crack initiation  crack propagation  turbine disc
Author NameAffiliation
ZHAO Zuo-peng 1 , HU Xu-teng 2,3 , GUO Zhi-wei 4 , WEN Wei-dong 2,3 1. College of Mechanical and Electrical Engineering Sanjiang University Nanjing 210012 China 2. College of Energy and Power Engineering Nanjing University of Aeronautics and Astronautics 3. Key Laboratory of Aero-Engine Thermal Environment and Structure Ministry of Industry and Information Technology: Nanjing 210016 China 4. AECC Shenyang Engine Research Institute Shenyang 110015 China 
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Abstract:In order to analyze the influence of geometric discontinuities (mortise and groove, etc.) of turbine disk rim on fatigue crack initiation and small crack propagation behavior, a structure characteristics simulation specimens were designed based on the actual configuration of an FGH96 powder disc, naturally-initiated small crack propagation tests of the specimens were carried out under high- temperature conditions. The fatigue crack initiation and small crack propagation behaviors of the mortise and groove and bolt-hole structure simulation specimens at 500℃ were observed and analyzed by fatigue interruption tests and surface replication techniques. The results show that there are multi-site crack initiation phenomena on the notch surface of the two structural simulation specimens. With the stress level decreases, the location of crack initiation changes from surface grain boundaries to near-surface specific crystallographic facets and non-metallic inclusions. The crack initiation life accounts for about 36% to 73% of the total predicted fatigue life for the two kinds of structure simulation specimens, and increases with the decrease of stress level. The crack initiation life is about 82% to 96% of the total predicted fatigue life when the crack propagates to the detectable size, and the influence of stress level is relatively small. High-level plastic deformation near the notch leads to the disappearance of the segmented characteristics in the small crack propagation rate, and delays coalescence behavior during crack propagation, extending the crack propagation life.
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