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Effect of heat treatment on corrosion behaviors of Mg-6Gd-3Y-0.5Zr alloy

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china Foundry 2024年第5期21卷 599-612页

作者： Fei Wang Bin-guo Fu Yu-feng Wang Tian-shun Dong Guo-lu Li Jin-hai Liu Hebei Key Laboratory of New Functional Materials School of Materials Science and EngineeringHebei University of TechnologyTianjin 300401China Tianjin Institute of Aerospace Mechanical and Electrical equipment Tianjin 300301China Tianjin Aerospace Long March Technology and equipment Co. Ltd.Tianjin 300462China

The microstructures and corrosion behaviors of as-cast,T4-treated,and T6-treated Mg-6Gd-3Y-0.5Zr alloys were systematically investigated by SEM,TEM,immersion test,and electrochemical corrosion *** results show that the microstructure of the as-cast alloy is composed ofα-Mg and Mg_(24)(Gd,Y)_(5) eutectic phase,and in T4-treated alloy,Mg_(24)(Gd,Y)_(5) phase dissolves into theα-Mg matrix,leading to an increase in the(Y,Gd)H_(2) *** T6 treatment,nanoscale Mg_(24)(Gd,Y)_(5) phase dispersedly precipitates from theα-Mg matrix,and exhibits a specific orientation relationship with the α-Mg:(332)Mg_((24)(Gd,Y)_(5))//(1011)_(α-Mg),[136]Mg_((24)(Gd,Y)_(5))//[1210]_(α-Mg).The corrosion resistance of the Mg-6Gd-3Y-0.5Zr alloys can be ranked in the following order:T6-treated alloy exhibits the highest corrosion resistance,followed by the T4-treated alloy,and finally,the as-cast *** corrosion products of the alloys are all composed of MgO,Mg(OH)_(2),Gd_(2)O_(3),Y_(2)O_(3),and MgCl_(2).The corrosion behavior of Mg-6Gd-3Y-0.5Zr alloy is closely related to the precipitated *** establishing the relationship between corrosion rate,hydrogen evolution rate,and corrosion potential,it is further demonstrated that during the micro galvanic corrosion process,the coarse Mg_(24)(Gd,Y)_(5)phase in the as-cast alloy undergoes extensive dissolution,and(Y,Gd)H_(2) phase promotes the dissolution of theα-Mg matrix in the T4-treated alloy,intensifying the hydrogen evolution *** T6-treated alloy,with dispersive precipitation of nanoscale Mg_(24)(Gd,Y)_(5) phase,exhibits better corrosion resistance performance.

关键词： Mg-6Gd-3Y-0.5Zr alloy heat treatment microstructure precipitated phase corrosion resistance

Revealing the Local Microstates of Fe–Mn–Al Medium Entropy Alloy:A Comprehensive First-principles Study

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Acta Metallurgica Sinica(English Letters) 2021年第11期34卷 1492-1502页

作者： Ying Zhang William Yi Wang Chengxiong Zou Rui Bai Yidong Wu Deye lin Jun Wang Xidong Hui Xiubing Liang Jinshan Li State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi'an 710072China State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China CAEP Software Center for High Performance Numerical Simulation Beijing 100088China Defense Innovation Institute Academy of Military Sciences of the PLA of ChinaBeijing 100071China

Entropy-stabilized multi-component alloys have been considered to be prospective structural materials attributing to their impressive mechanical and functional *** local chemical complexions,microstates and configurational transformations are essential to reveal the structure–property relationship,thus,to promote the development of advanced multicomponent *** the present work,effects of local lattice distortion(LLD)and microstates of various configurations on the equilibrium volume(V0),total energy,Fermi energy,magnetic moment(μMag)and electron work function(Φ)and bonding structures of the Fe–Mn–Al medium entropy alloy(MEA)have been investigated comprehensively by first-principles *** is found that theΦandμMag of those MEA are proportional to the V 0,which is dominated by lattice *** terms of bonding charge density,both the strengthened clusters or the so-called short-range order structures and the weakly bonded spots or weak spots are *** the presence of weakly bonded Al atoms implies a large LLD/mismatch,the Fe–Mn bonding pairs result in the formation of strengthened clusters,which dominate the local microstates and the configurational *** variations ofμMag are associated with the enhancement of the nearest neighbor magnetic Fe and Mn atoms,attributing to the LLD caused by Al atoms,the local changes in the electronic *** work provides an atomic and electronic insight into the microstate-dominated solid-solution strengthening mechanism of Fe–Mn–Al MEA.

关键词： Medium entropy alloy Bonding charge density Magnetic moment Microstates

Remaining useful life prediction of aircraft lithium-ion batteries based on F-distribution particle filter and kernel smoothing algorithm

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Chinese Journal of Aeronautics 2020年第5期33卷 1517-1531页

作者： Kai ZHANG Peng ZHAO Canfei SUN Youren WANG Zewang CHEN College of Automation Engineering Nanjing University of Aeronautics and AstronauticsNanjing 211106China Aviation Industry Corporation Leihua Electronic Technology research Institute Wuxi 214000China Testing and Verification Center Aviation Key Laboratory of Science and Technology on Fault Diagnosis and Health ManagementShanghai 201601China

As an emergency and auxiliary power source for aircraft,lithium(Li)-ion batteries are important components of aerospace power *** Remaining Useful Life(RUL)prediction of Li-ion batteries is a key technology to ensure the reliable operation of aviation power *** Filter(PF)is an effective method to predict the RUL of Li-ion batteries because of its uncertainty representation and management ***,there are problems that particle weights cannot be updated in the prediction stage and particles *** settle these issues,an innovative technique of F-distribution PF and Kernel Smoothing(FPFKS)algorithm is *** the prediction stage,the weights of the particles are dynamically updated by the F kernel instead of being fixed all the ***,a first-order independent Markov capacity degradation model is ***,the kernel smoothing algorithm is integrated into PF,so that the variance of the parameters of capacity degradation model keeps *** based on NASA battery data sets show that FPFKS can be excellently applied to RUL prediction of Liion batteries.

关键词： F-distribution Kernel smoothing Lithium-ion batteries Markov model Particle filter prediction Remaining useful life

Contribution of ultrasonic surface rolling process to the fatigue properties of TB8 alloy with body-centered cubic structure

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Journal of Materials Science & Technology 2021年第2期61卷 63-74页

作者： Dan Liu Daoxin Liu Mario Guagliano Xingchen Xu Kaifa Fan Sara Bagherifard College of Civil Aviation Northwestern Polytechnical UniversityXi'an 710072China Department of Mechanical Engineering Politecnico di MilanoMilan 20156Italy

The effect of ultrasonic surface rolling process(USRP) as a severe plastic deformation technology was investigated on the evolution of microstructure, residual stress and surface morphology of TB8 alloys with body-centered cubic structure. Stress-controlled rotating-bending fatigue tests indicated increased fatigue strength in USRP samples prepared using different number of passes compared to the base material, which was attributed to the presence of gradient structure surface layers. Five subsequent USRP passes resulted in the highest fatigue strength, due to the optimal surface properties including higher extent of grain refinement, larger compressive residual stresses, "smoother" surface morphology and increased micro-hardness. However, the effect of USRP technology on improving fatigue strength of TB8 alloy was not significant in comparison with that of other titanium alloys(for example, Ti6 Al4 V), which was attributed to the notable surface residual stresses relaxation revealed from measurements on postfatigued USRP samples. Electron backscatter diffraction analysis confirmed that fatigue crack initiation occurred in the larger grains on the surface with high Schmid factor. Small cracks were found to propagate into the core material in a mixed transgranular and intergranular mode. Further analysis indicated that grain growth existed in post-fatigued USRP-treated TB8 samples and that the average geometrically necessary dislocations value reduced after fatigue loading.

关键词： Ultrasonic surface rolling process Gradient structure layers Fatigue crack Rotating-bending fatigue TB8 alloys

TDOA and track optimization of UAV swarm based on D-optimality

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Journal of Systems Engineering and Electronics 2020年第6期31卷 1140-1151页

作者： ZHOU Ronghua SUN Hemin LI Hao LUO Weilin Department of Intelligence Air Force Early Warning AcademyWuhan 430019China

To solve the problem of time difference of arrival(TDOA)positioning and tracking of targets by the unmanned aerial vehicles(UAV)swarm in future air combat,this paper adopts the TDOA positioning method and uses time difference sensors of the UAV swarm to locate target radiation ***,a TDOA model for the target is set up for the UAV swarm under the condition that the error variance varies with the received signal-to-noise *** accuracy of the positioning error is analyzed by geometric dilution of precision(GDOP).The D-optimality criterion of the positioning model is theoretically *** target is positioned and settled,and the maximum value of the Fisher information matrix determinant is used as the optimization objective function to optimize the track of the UAV in real *** results show that the track optimization improves the positioning accuracy and stability of the UAV swarm to the target.

关键词： time difference of arrival(TDOA) unmanned aerial vehicles(UAV)swarm D-optimality track optimization

Hybrid TDOA/FDOA and track optimization of UAV swarm based on A-optimality

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Journal of Systems Engineering and Electronics 2023年第1期34卷 149-159页

作者： LI Hao SUN Hemin ZHOU Ronghua ZHANG Huainian Department of Intelligence Air Force Early Warning AcademyWuhan 430019China

The source location based on the hybrid time difference of arrival(TDOA)/frequency difference of arrival(FDOA) is a basic problem in wireless sensor networks, and the layout of sensors in the hybrid TDOA/FDOA positioning will greatly affect the accuracy of positioning. Using unmanned aerial vehicle(UAV) as base stations, by optimizing the trajectory of the UAV swarm, an optimal positioning configuration is formed to improve the accuracy of the target position and velocity estimation. In this paper, a hybrid TDOA/FDOA positioning model is first established, and the positioning accuracy of the hybrid TDOA/FDOA under different positioning configurations and different measurement errors is simulated by the geometric dilution of precision(GDOP) factor. Second, the Cramer-Rao lower bound(CRLB) matrix of hybrid TDOA/FDOA location under different moving states of the target is derived theoretically, the objective function of the track optimization is obtained, and the track of the UAV swarm is optimized in real time. The simulation results show that the track optimization effectively improves the accuracy of the target position and velocity estimation.

关键词： unmanned aerial vehicle(UAV)swarm time difference of arrival(TDOA) frequency difference of arrival(FDOA) A-optimality track optimization

Fe3O4 nanoparticles as a saturable absorber for a tunable Q-switched dysprosium laser around 3μm

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Photonics research 2020年第1期8卷 70-77页

作者： JIAN YANG JIYI HU HONGYU LUO JIANFENG LI JISHU LIU XIAOHUI LI YONG LIU State Key Laboratory of Electronic Thin Films and Integrated Devices School of Optoelectronic Science and EngineeringUniversity of Electronic Science and Technology of China(UESTC)Chengdu 610054China School of Physics and Information Technology Shaanxi Normal UniversityXi'an 710119China

We demonstrate for the first time to our knowledge the use of Fe3O4 nanoparticles for Q-switching a tunable midinfrared(Mid-IR)Dy^3+-doped ZBLAN fiber laser around 3μ*** Q-switcher was fabricated by depositing the prepared Fe3O4 nanoparticles solution onto an Au *** nonlinear optical response was characterized using a mode locked Ho^3+/Pr^3+-codoped ZBLAN fiber laser at 2.87μm,and showed a modulation depth of 11.9%as well as a saturation intensity of 1.44 MW/cm^*** the device into a tunable Dy^3+-doped ZBLAN fiber laser,stable Q-switched pulses within the tunable range of 2812.4-3031.6 nm were *** tuning the wavelength to 2931.2 nm,a maximum Q-switching output power of 111.0 mW was achieved with a repetition rate of 123.0 kHz and a pulse width of 1.25μ*** corresponding pulse energy was 0.90μ*** demonstration suggests that Fe3O4 nanoparticles are a promising broadband saturable absorption material for mid-infrared operation.

关键词： tunable switched laser

Inverse aerodynamic design for distributed propulsion wing with expected circulation distribution

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Chinese Journal of Aeronautics 2024年第9期37卷 206-223页

作者： Pengbo SUN Zhou ZHOU Xu LI Kelei WANG School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China

Distributed Propulsion Wing(DPW)technology offers significant advantages in terms of flight energy savings,but the strong aerodynamic coupling between the propulsive internal flow and aerodynamic external flow brings significant design *** the primary DPW profile design is of great significance,this paper proposes a hybrid method to solve the inverse problem mainly based on the formula relationship between the required aerodynamic loads and the profile shape,which is more direct and instructive compared with traditional parametric iterative *** aerodynamic characteristics are described by the circulation distribution in the Fourier series form,then the mean camber line of the profile is solved through the re-derived airfoil theory considering disk's *** CFD correction methods are also *** validate the effectiveness and feasibility of the proposed hybrid inverse method,several DPW profile design tests are then ***,the relationship between 2D and realistic 3D unit shape is also *** results show that the proposed inverse design method has great accuracy and convergence speed in the design tests,and shows good robustness against changes of the design *** 2D profile shape and the actual 3D shape of DPW unit can establish an aerodynamic-propulsion equivalent relationship based on the same internal mass fluxes.

关键词： Propulsion Inverse problem Aerodynamic load Fourier series Flux

Si对625合金激光熔覆层高温氧化特性的影响

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稀有金属材料与工程 2022年第10期51卷 3602-3610页

作者：张剑刘宗德马荷蓉李悦李家璇华北电力大学电站能量传递转化与系统教育部重点实验室北京102206

利用循环氧化法,研究了不同Si含量(0%,1%,3%,质量分数)的625合金熔覆层在700、800、900℃下氧化144 h后的高温氧化行为。用XRD分析了氧化物相。通过SEM/EDS研究了氧化物表面和截面的形貌、元素组成和氧化膜的厚度。结果表明,不同温度下... 详细信息

利用循环氧化法,研究了不同Si含量(0%,1%,3%,质量分数)的625合金熔覆层在700、800、900℃下氧化144 h后的高温氧化行为。用XRD分析了氧化物相。通过SEM/EDS研究了氧化物表面和截面的形貌、元素组成和氧化膜的厚度。结果表明,不同温度下试样的氧化动力学都保持抛物线规律,随着温度的升高,氧化增重逐渐增加。通过观察,在900℃时,0%Si含量的625合金熔覆层出现了氧化膜大面积剥落的情况,3%Si含量的合金熔覆层氧化膜保持完整。在700℃时,随着Si含量增加,氧化膜表面的氧化颗粒尺寸减小且更加致密,同时促进了Cr_(2)O_(3)氧化物的生成。在700℃下,0%Si含量的试样出现了大片的内氧化区域;1%Si含量的试样基体部分出现了2处条状的含Ni,Cr,Mo的氧化物相区;而3%Si含量的试样氧化后由于生成了富Si的内氧化层,这阻止了内氧化的发生。外层Cr_(2)O_(3)氧化膜和内层SiO_(2)的联合作用既阻止了O阴离子的渗入也抑制了Fe等金属离子的扩散,提高了合金熔覆层的抗氧化性。

关键词：激光熔覆 625合金氧化动力学氧化膜扩散