The prolonged thermal exposure with centrifugal load results in microstructural degradation,which ultimately leads to a reduction in the fatigue and creep resistance of the turbine blades.The present work proposes a m...The prolonged thermal exposure with centrifugal load results in microstructural degradation,which ultimately leads to a reduction in the fatigue and creep resistance of the turbine blades.The present work proposes a multi-scale framework to estimate the life reduction of turbine blades,which combines a microstructural degradation model,a two-phase constitutive model,and a microstructure-dependent fatigue and creep life reduction model.The framework with multi-scale models is validated by a Single Crystal(SC)Ni-based superalloy at the microstructural length-scale and is then applied to calculate the microstructural degradation and the fatigue and creep life reduction of turbine blades under two specific service conditions.The simulation results and quantitative analysis show that the microstructural degradation and fatigue and creep life reduction of the turbine blade are heavily influenced by the variations in the proportion of the intermediate state,namely,the maximum rotor speed status,in the two specific service conditions.The intermediate state accelerates the microstructural degradation and leads to a reduction of the life,especially the effective fatigue life reserve due to the higher temperature and rotational speed than that of the 93%maximum rotor speed status marked as the reference state.The proposed multi-scale framework provides a capable approach to analyze the reduction of the fatigue and creep life for turbine blade induced by microstructural degradation,which can assist to determine a reasonable Time Between Overhaul(TBO)of the engine.展开更多
Aero-engine turbine blades may suffer overheating during service,which can result in severe microstructural and mechanical degradation within tens of seconds.In this study,the thermal cycling creep under(950℃/15 min+...Aero-engine turbine blades may suffer overheating during service,which can result in severe microstructural and mechanical degradation within tens of seconds.In this study,the thermal cycling creep under(950℃/15 min+1100℃/1 min)-100 MPa was performed on a directionally solidified superalloy,DZ125.The effects of overheating and thermal cycling on the creep properties were evaluated in terms of creep behavior and microstructural evolution against isothermally crept specimens under 950℃/100 MPa,950℃/270 MPa,and 1100℃/100 MPa.The results indicated that the thermal cycling creep life was reduced dramatically compared to the isothermal creep under 950℃/100 MPa.The plastic creep deformation mainly occurred during the overheating stage during the thermal cycling creep.The thermal cycling creep curve exhibited three stages,similar to the 1100℃isothermal creep,but its minimum creep rate occurred at a lower creep strain.The overheating events caused severe microstructural degradation,such as substantial dissolution ofγ'phase,earlier formation of raftedγ'microstructure,widening of theγchannels,and instability of the interfacial dislocation networks.This microstructural degradation was the main reason for the dramatic decrease in thermal cycling creep life,as the thermal cycling promoted more dislocations to cut intoγ'phase and more cracks to initiate at grain boundaries,carbides,and residual eutectic pools.This study underlines the importance of evaluating the thermal cycling creep properties of superalloys to be used as turbine blades and provides insights into the effect of thermal cycling on directionally solidified superalloys for component design.展开更多
Flower shaped antimony oxide (Sb2O3) microstructures were synthesized in a large quantity via simple solution method using aqueous mixtures of antimony chloride and hexamethylene diamine (HMDA). The morphological char...Flower shaped antimony oxide (Sb2O3) microstructures were synthesized in a large quantity via simple solution method using aqueous mixtures of antimony chloride and hexamethylene diamine (HMDA). The morphological characterizations were done by field emission scanning electron microscopy (FESEM), which revealed that the synthesized products possess flower-shaped microstructures. The detailed structural characterizations performed by X-ray diffraction (XRD), Fourier transform infrared spectrophotometer (FT-IR) and Raman spectrophotometer confirmed that the synthesized microstructures are well-crystalline antimony oxide. The Energy dispersive spectroscopy (EDS) shows that the grown products are composed of Sb and O. Optical properties of the synthesized products were characterized by UV-Visible spectrophotometer which exhibits a well defined peak at ~ 291.0 nm. The photo-catalytic activity of the Sb2O3 microstructures was evaluated by degradation of acridine orange (AO), which mineralized almost 63.0% in 150 min. The chemical sensing properties of Sb2O3 microstructures was also studied by I-V technique using chloroform as a detecting solvent. The fabricated chloroform sensor demonstrates good sensitivity of 0.1154 μA cm–2 mM–1, lower-detection limit (~0.1 mM), large-linear dynamic range (LDR, 0.122 mM to 1.22 M) with linearity (R = 0.7898) in short response time (10.0 sec).展开更多
基金funded by the National Science and Technology Major Project of China(No.2019-IV-0017-0085)the Science Center for Gas Turbine Project,China(No.P2022-Ⅲ-003-002)+1 种基金the National Natural Science Foundation of China(Nos.12172021,52205139 and 52105137)the Project funded by China Postdoctoral Science Foundation(No.2022M710288)。
文摘The prolonged thermal exposure with centrifugal load results in microstructural degradation,which ultimately leads to a reduction in the fatigue and creep resistance of the turbine blades.The present work proposes a multi-scale framework to estimate the life reduction of turbine blades,which combines a microstructural degradation model,a two-phase constitutive model,and a microstructure-dependent fatigue and creep life reduction model.The framework with multi-scale models is validated by a Single Crystal(SC)Ni-based superalloy at the microstructural length-scale and is then applied to calculate the microstructural degradation and the fatigue and creep life reduction of turbine blades under two specific service conditions.The simulation results and quantitative analysis show that the microstructural degradation and fatigue and creep life reduction of the turbine blade are heavily influenced by the variations in the proportion of the intermediate state,namely,the maximum rotor speed status,in the two specific service conditions.The intermediate state accelerates the microstructural degradation and leads to a reduction of the life,especially the effective fatigue life reserve due to the higher temperature and rotational speed than that of the 93%maximum rotor speed status marked as the reference state.The proposed multi-scale framework provides a capable approach to analyze the reduction of the fatigue and creep life for turbine blade induced by microstructural degradation,which can assist to determine a reasonable Time Between Overhaul(TBO)of the engine.
基金supported by the“National Key Research and Development Program of China(Grant No.2016YFB0701403)”the“National Natural Science Foundation of China(Grant Nos.51631008 and 91860201)”+1 种基金the“111 Project(No.B170003)”financial support to the reported work.Stoichko Antonov would like to acknowledge financial support from the Alexander von Humboldt Foundation。
文摘Aero-engine turbine blades may suffer overheating during service,which can result in severe microstructural and mechanical degradation within tens of seconds.In this study,the thermal cycling creep under(950℃/15 min+1100℃/1 min)-100 MPa was performed on a directionally solidified superalloy,DZ125.The effects of overheating and thermal cycling on the creep properties were evaluated in terms of creep behavior and microstructural evolution against isothermally crept specimens under 950℃/100 MPa,950℃/270 MPa,and 1100℃/100 MPa.The results indicated that the thermal cycling creep life was reduced dramatically compared to the isothermal creep under 950℃/100 MPa.The plastic creep deformation mainly occurred during the overheating stage during the thermal cycling creep.The thermal cycling creep curve exhibited three stages,similar to the 1100℃isothermal creep,but its minimum creep rate occurred at a lower creep strain.The overheating events caused severe microstructural degradation,such as substantial dissolution ofγ'phase,earlier formation of raftedγ'microstructure,widening of theγchannels,and instability of the interfacial dislocation networks.This microstructural degradation was the main reason for the dramatic decrease in thermal cycling creep life,as the thermal cycling promoted more dislocations to cut intoγ'phase and more cracks to initiate at grain boundaries,carbides,and residual eutectic pools.This study underlines the importance of evaluating the thermal cycling creep properties of superalloys to be used as turbine blades and provides insights into the effect of thermal cycling on directionally solidified superalloys for component design.
文摘Flower shaped antimony oxide (Sb2O3) microstructures were synthesized in a large quantity via simple solution method using aqueous mixtures of antimony chloride and hexamethylene diamine (HMDA). The morphological characterizations were done by field emission scanning electron microscopy (FESEM), which revealed that the synthesized products possess flower-shaped microstructures. The detailed structural characterizations performed by X-ray diffraction (XRD), Fourier transform infrared spectrophotometer (FT-IR) and Raman spectrophotometer confirmed that the synthesized microstructures are well-crystalline antimony oxide. The Energy dispersive spectroscopy (EDS) shows that the grown products are composed of Sb and O. Optical properties of the synthesized products were characterized by UV-Visible spectrophotometer which exhibits a well defined peak at ~ 291.0 nm. The photo-catalytic activity of the Sb2O3 microstructures was evaluated by degradation of acridine orange (AO), which mineralized almost 63.0% in 150 min. The chemical sensing properties of Sb2O3 microstructures was also studied by I-V technique using chloroform as a detecting solvent. The fabricated chloroform sensor demonstrates good sensitivity of 0.1154 μA cm–2 mM–1, lower-detection limit (~0.1 mM), large-linear dynamic range (LDR, 0.122 mM to 1.22 M) with linearity (R = 0.7898) in short response time (10.0 sec).
