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Effects of Shot Peening Process on Thermal Cycling Lifetime of TBCs Prepared by EB-PVD

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Chinese Journal of aeronautics 2007年第2期20卷 145-147页

作者： ZHOU Zhao-hui GONG Sheng-kai LI He-fei XU Hui-bin ZHANG Chun-gang WANG Lu School of Materials Science and engineering Beij＇ing University of Aeronautics and Astronautics Beij＇ing 100083 China shenyang liming.4ero-engine Group corporation Shenyang 110043 China

Conventional two-layered thermal barrier coatings （TBCs） are prepared by electron beam physical vapor deposition （EB-PVD） with ZrO2-8 wt% Y2O3 （8YSZ） as top coat and CoCrAlY as bond coat on disk-shaped Ni based super-alloy. In this paper, three kinds of shot peening process with different lengths of operating time were adopted for bond coating. As a result, changes took place in its surface roughness and the surface micro-hardness. A thermal cycling test at 1 273 Kx55 rain and another at room temperature for 5 min were performed to study the effects of shot peening process on the thermal cycling lifetime of TBCs. It is found that a moderate shot peening process will be able to prolong the life time. The oxidation dynamic of the as-processed TBCs basically accords with the parabolic rule, and the oxidation test also attests to the spallation between YSZ and thermal growth oxide （TGO） responsible mainly for the failure of TBCs.

关键词： thermal cycling lifetime shot peening thermal barrier coatings (TBCs)

Creep Behavior of Fusion Zone and Base Metal of the Electron Beam Weldments of a Near-alpha Titanium Alloy

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Journal of Materials Science & Technology 2010年第6期26卷 564-571页

作者： Zhiyong Chen Jinwei Li Jie Liu Qingjiang Wang Jianrong Liu Rui Fang Division of Titanium alloys Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China Research Department of High Energy Density Beam Processing Technology Beijing Aeronautical Manufacturing Technology Research Institute Beijing 100024 China AVIC shenyang liming aero-engine (Group) corporation LTD Shenyang 110043 China

The high temperature creep behavior of fusion zone （FZ） and of a near-alpha titanium alloy Ti-60 has been investigated. base metal （BM） of the electron beam weldments While the BM shows a fully transformed, coarse primary β grains with large colonies consisting of aligned α lamellar, the FZ exhibits thin martensitic α′ platelets in the columnar β grains. The creep results show that the steady state creep rates of FZ follow the power-law creep, with the stress exponents obtained in the range from 5.6 （550℃） to 5.9 （600℃）, and corrected activation energies of 309-352 kJ/mol; the stress exponents of BM exhibit different values when the creep testing stress and temperature alternate. The values of 2.4-3.2 are obtained when the stresses are under 220 MPa or the temperature is 550℃, also an exponent of 6.6 is achieved at stresses above 220 MPa at 600℃. The corrected activation energies of BM corresponding to the stress exponents are 123-161 kJ/mol （n=2.4-3.2） and 344 kJ/mol （n=6.6）. The creep mechanisms of FZ and BM have been discussed in light of the creep microstructures, activation energies and the stress exponents. The creep mechanisms of FZ is the diffusion controlled dislocation climb, the creep of BM is controlled by ＇solute drag＇ creep and dislocation climb when the stress and temperature are different. Transmission electron microscopy （TEM） observations of the dislocation structures of crept specimens are presented to give some supports for the creep behavior of FZ and BM. In addition to the creep mechanism of dislocation movement, the interface sliding has been found to play an important role during creep of FZ.

关键词： Steady state creep Stress exponent Activation energy Electron beam welding Near-alpha titanium alloy

Laser cladding of Al+Ir powders on ZM5 magnesium base alloy

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Rare Metals 2007年第5期26卷 420-425页

作者： CHEN Changjun WANG Maocai WANG Dongsheng JIN Ren LIU Yiming State Key Laboratory for Corrosion and Protection Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education College of Materials ＆ Metallurgy Wuhan University of Science ＆ Technology Wuhan 430081 China shenyang liming aero-engine corporation Shenyang 110043 China

Laser cladding of preplaced Al ＋ Ir powders on a ZM5 magnesium alloy was performed to enhance the corrosion resistance of the ZM5 magnesium alloy. A metallurgical bond was obtained at the coating/substrate interface. The corrosion potential （Ecorr） of the laser cladded sample was 169 mV positive to that of the untreated ZM5 substrate,while the corrosion current （Icorr） was some one order of magnitude lower. The laser cladded sample,unlike the untreated ZM5 substrate,showed a passive region in the polarization plot. Immersion tests confirmed that the corrosion resistance of the laser cladded ZM5 sample was significantly enhanced in 3.5 wt.% NaCl solution. The Al-rich phases of AlIr,Mg17Al12,and Al formed in the cladding layer and the rapid solid characteristics were contributed to the improved corrosion behavior of the coating.

关键词： laser cladding magnesium alloys Ir corrosion

Modeling of Large-Scale Hydrogen Storage System Considering Capacity Attenuation and Analysis of Its Efficiency Characteristics

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Energy engineering 2024年第2期121卷 291-313页

作者： Junhui Li Haotian Zhang Cuiping Li Xingxu Zhu Ruitong Liu Fangwei Duan Yongming Peng Key Laboratory of Modern Power System Simulation and Control&Renewable Energy Technology Ministry of Education(Northeast Electric Power University)Jilin132012China Ministry of Science and Technology Electric Power Research Institute of State Grid Liaoning Electric Power Co.Ltd.Shenyang110006China Northeast Electric Power Dispatching Control Center Northeast Branch of State Grid Corporation of ChinaShenyang110180China

In the existing power system with a large-scale hydrogen storage system,there are problems such as low efficiency of electric-hydrogen-electricity conversion and single modeling of the hydrogen storage *** order to improve the hydrogen utilization rate of hydrogen storage system in the process of participating in the power grid operation,and speed up the process of electric-hydrogen-electricity *** article provides a detailed introduction to the mathematical and electrical models of various components of the hydrogen storage unit,and also establishes a charging and discharging efficiency model that considers the temperature and internal gas partial pressure of the hydrogen storage *** models are of great significance for studying and optimizing gas storage *** these models,the performance of gas storage units can be better understood and *** studies are very helpful for improving energy storage efficiency and sustainable *** factors affecting the charge-discharge efficiency of hydrogen storage units are *** integrating the models of each unit and considering the capacity degradation of the hydrogen storage system,we can construct an efficiency model for a large hydrogen storage system and power conversion *** addition,the simulation models of the hydrogen production system and hydrogen consumption system were established in MATLAB/*** accuracy and effectiveness of the simulation model were proved by comparing the output voltage variation curve of the simulation with the polarization curve of the typical hydrogen production system and hydrogen consumption *** results show that the charge-discharge efficiency of the hydrogen storage unit increases with the increase of operating temperature,and H2 and O2 partial voltage have little influence on the charge-discharge *** the process of power conversion system converter rectification operation,its efficiency decreases wi

关键词： Hydrogen storage system simulation modeling electrolyzer fuel cell capacity loss

A novel method for chemistry tabulation of strained premixed/stratified flames based on principal component analysis

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Applied Mathematics and Mechanics(English Edition) 2018年第6期39卷 855-866页

作者： Peng TANG Hongda ZHANG Taohong YE Zhou YU Zhaoyang XIA Department of Thermal Science and Energy engineering University of Science and Technology of China School of Mechatronics engineering Chizhou University shenyang engine Research Institute Aero Engine(Group) Corporation of China

The principal component analysis （PCA） is used to analyze the high dimen- sional chemistry data of laminar premixed/stratified flames under strain effects. The first few principal components （PCs） with larger contribution ratios axe chosen as the tabu- lated scalars to build the look-up chemistry table. Prior tests show that strained premixed flame structure can be well reconstructed. To highlight the physical meanings of the tabu- lated scalars in stratified flames, a modified PCA method is developed, where the mixture fraction is used to replace one of the PCs with the highest correlation coefficient. The other two tabulated scalars are then modified with the Schmidt orthogonalization. The modified tabulated scalars not only have clear physical meanings, but also contain passive scalars. The PCA method has good commonality, and can be extended for building the thermo-chemistry table including strain rate effects when different fuels are used.

关键词： premixed flame stratified flame strain rate principal component analysis(PCA) chemistry table

Corundum dissolution in concentrated sodium hydroxide solution

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China Foundry 2016年第6期13卷 422-426页

作者： Yu-sheng Wu Hong-liang Li Feng-ling Shi xiao-fu Liu Gui-qao Su Yan-ping Qu School of Materials Science and engineering Shenyang University of Technology Shenyang 110870 China shenyang Research Institute of Foundry Shenyang 110022 China shenyang liming aero engine (Group) Co. Ltd. Shenyang 110043 China

The corundum(α-alumina) core has been considered as a suitable candidate for investment casting of hollow, high pressure turbine engine airfoils due to its excellent properties. However, the efficiency of removing alumina cores in concentrated caustic solution cannot meet the needs of industrial production. In this paper, the effects of temperature and initial solution concentration on dissolution of α-alumina were studied by the classical weight-loss method. The fractal kinetic model was developed in order to describe α-alumina dissolution, assuming that the nonporous particles shrank during reaction process. The results show that the dissolution rate increases with increasing reaction temperature and initial solution concentration. Especially, the initial solution concentration has a significant influence on α-alumina dissolution rate at a higher reaction temperature. The activation energies decrease with increasing initial solution concentration, and the chemical reaction is the rate-controlling step.

关键词： kinetics corundum sodium hydroxide solution dissolution core

Double oxide film defects in Ni-based super-alloy castings

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China Foundry 2008年第1期5卷 16-19页

作者： Huang Aihua Cui Shusen Lou Yanchun shenyang liming aero-engine Group Corp. Ltd. Shenyang 110043 P. R. China shenyang Research Institute of Foundry Shenyang 110022 P. R. China

A new class of defects has been recently discovered, which are regarded as double oxide film defects. In this study, a number of Ni-based vacuum-cast test bars were investigated. The fractures in the broken test bars were observed by Scanning Electron Microscopy （SEM）. Energy Dispersive Spectroscopy （EDS）, as well as Wavelength Dispersive Spectroscopy （WDS） were used to characterize the chemical elements of the fracture＇s surface. Observation by SEM revealed the presence of inclusions identified as films that appeared to have initiated the growth of carbides. This study has added to the evidence that oxide film defects do exist in Ni-based super-alloy in certain vacuum casting conditions. It provides a reference for researchers＇ further study on the defects, and provides a possible direction for researchers to improve casting technology so as to remove these defects.

关键词： double oxide film vacuum casting Ni-based super-alloy

Low-cycle fatigue behavior of DZ125 superalloy under prior exposure conditions

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Rare Metals 2023年第6期42卷 2028-2036页

作者： Hong-Yu Qi Xiao-Lei Zheng Li-Qiang Ma Shao-Lin Li Xiao-Guang Yang Duo-Qi Shi School of Energy and Power engineering Beihang UniversityBeijing100191China Collaborative Innovation Center of Advanced aero-engine Beijing100191China shenyang engine Design and Research Institute Aviation Industry Corporation of ChinaShenyang110015China

Low-cycle fatigue(LCF) behavior of the directionally solidified(DS) nickel-based DZ125 superalloy was studied at elevated temperature(980 ℃).Specimens were,respectively,exposed for 0,2,25,50,and 100 h in *** fatigue life of pre-exposed specimens is lower than that of unexposed *** result is closely associated with fatigue crack initiation and propagation due to oxygen embrittlement and cycle *** fractographic evaluations indicate the fatigue life is closely related to the surface microstructural *** resulting changes in microstructure cause the decrease in the effective area and the increase in actual stress.A methodology based on the continuum damage mechanics is developed to describe the correlation between the residual LCF life and pre-exposed time.

关键词： Nickel-based superalloy Oxidation Prior exposure Low-cycle fatigue Continuum damage mechanics

Global stability coefficient of large underground caverns under static loading and earthquake wave condition

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Journal of Central South University 2024年第8期31卷 2826-2843页

作者： Chen, Peng-fei Jiang, Quan Liu, Jian Li, Shao-jun Chen, Tao He, Ben-guo State Key Laboratory of Geomechanics and Geotechnical engineering Institute of Rock and Soil Mechanics Chinese Academy of Sciences Wuhan China University of Chinese Academy of Sciences Beijing China Power China Chengdu engineering corporation Limited Chengdu China Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines Northeastern University Shenyang China

Underground energy and resource development, deep underground energy storage and other projects involve the global stability of multiple interconnected cavern groups under internal and external dynamic disturbances. An evaluation method of the global stability coefficient of underground caverns based on static overload and dynamic overload was proposed. Firstly, the global failure criterion for caverns was defined based on its band connection of plastic-strain between multi-caverns. Then, overloading calculation of the boundary geostress and seismic intensity on the caverns model was carried out, and the critical unstable state of multi-caverns can be identified, if the plastic-strain band appeared between caverns during these overloading processes. Thus, the global stability coefficient for the multi-caverns under static loading and earthquake was obtained based on the corresponding overloading coefficient. Practical analysis for the Yingliangbao (YLB) hydraulic caverns indicated that this method can not only effectively obtain the global stability coefficient of caverns under static and dynamic earthquake conditions, but also identify the caverns’ high-risk zone of local instability through localized plastic strain of surrounding rock. This study can provide some reference for the layout design and seismic optimization of underground cavern group.

关键词： underground caverns global stability coefficient static-dynamic overload local instability