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Microstructure and texture evolution in commercial-purity Zr 702 during cold rolling and annealing

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International Journal of Minerals,Metallurgy and Materials 2014年第8期21卷 785-795页

作者： Min Ma Ming-he Li yuan-biao tan Hui yuan Wen-chang Liu Key Laboratory of Metastable Materials Science and Technology College of Materials Science and Engineering Yanshan University

Microstructure and texture evolution in commercial-purity Zr 702 during cold rolling and annealing was investigated by optical microscopy, transmission electron microscopy, and X-ray diffraction. The results showed that crystallographic slip was the predominant deformation mechanism in the early stage of deformation. Deformation twins started to form when the rolling reduction was larger than 38.9%; both the dislocation density and the number of twins increased with increasing rolling reduction. The initial texture of the Zr 702 plate consisted of the basal fiber component. During cold rolling the strength of the basal fiber first decreased and then increased with increasing rolling reduction. The cold-rolled sheets were fully recrystallized after being annealed at 550℃. The recrystallization temperature and the size of recrystallized grains decreased with increasing rolling reduction. A larger rolling reduction resulted in a higher grain growth rate when the annealing temperature increased from 550℃ to 700℃. The recrystallization texture was characterized by a major basal fiber and a minor {0113}〈2110〉 component. The strength of the recrystallization texture increased with increasing rolling reduction.

关键词： zirconium cold rolling annealing microstrucmre texture recrystallization

Microstructure and texture evolution of TB8 titanium alloys during hot compression

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Rare Metals 2021年第10期40卷 2917-2926页

作者： Qiu-Yue Yang Min Ma yuan-biao tan Song Xiang Fei Zhao Yi-Long Liang College of Materials and Metallurgy Guizhou UniversityGuiyang 550025China College of Materials Science and Engineering Hunan University of Science and TechnologyXiangtan 411201China

In this study, microstructure and texture evolution of TB8 titanium alloys during hot deformation were investigated by using electron back-scattered diffraction(EBSD) analysis. The results showed that dynamic recrystallization(DRX) behavior of TB8 titanium alloys was drastically sensitive to the strain. As the true strain raised from 0.2 to 0.8, the degree of DRX gradually increased. The nucleation mechanism of recrystallization was observed, including discontinuous dynamic recrystallization(DDRX) resulting from the bulging of original boundaries. Furthermore, continuous dynamic recrystallization(CDRX) occurred because of the transformation of low-angle grain boundaries(LAGBs) to high-angle grain boundaries(HAGBs) in the interior of the original deformed grains. The texture evolution of TB8 titanium alloy during hot deformation process was analyzed in detail, and five texture components were observed,including{001}h100 i,{011}h100 i,{112}h110 i,{111}h110 i, and {111}h112 i. As the true strain increased,deformation textures were gradually weakened due to an increase in the volume fraction of DRX grains. When the true strain was 0.8, the main texture components consisted of the recrystallization texture components of the{001}h100 i and {011}h100 i textures.

关键词： TB8 titanium alloys Hot compression Microstructure Texture evolution

Variant selection of nanocrystalline a phase in metastableβTB8 titanium alloy via electric pulse treatment

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Rare Metals 2023年第8期42卷 2781-2794页

作者： Shan-Shan Wu Ya Yang yuan-biao tan Song Xiang Ya-Li Zhou Min Ma Fei Zhao Wei Shi Guizhou Key Laboratory of Materials Mechanical Behavior and Microstructure College of Materials and MetallurgyGuizhou UniversityGuiyang 550025China College of Materials Science and Engineering Hunan University of Science and TechnologyXiangtan 411201China

In this paper,the metastableβTB8 titanium alloy with nanocrystallineαphase is achieved by electric pulse *** morphology evolution and variant selection of nanocrystallineαphase in metastableβTB8titanium alloy were investigated by using scanning electron microscope(SEM),electron backscattered diffraction(EBSD)and transmission electron microscope(TEM)*** results indicated that the morphologies of the nanocrystallineαphase were mainly triangular clusters and needle-like at the pressure of 0 *** increasing pressure from 20 to 50 MPa,the volume fraction of needlelikeαphase decreased,and a large amount of V-shapedαphase formed in the interior ofβ*** on the EBSD data,the parentβphase was reconstructed by MTEX *** the interior of theβgrains,12 variants can form for the samples electric pulse treated at 0 and20 MPa,while only 3 and 6 variants can form for the samples electric pulse treated at 30 and 50 *** the grain boundary of theβgrains,one or more grain boundaryαvariants can be generated for the samples electric pulse treated at different pressures as long as one of the neighborβgrains follows the Burgers orientation relationship.

关键词： TB8 titanium alloy Parentβgrain reconstruction Morphology ofαphase Variant selection

Effect of hot deformation on α→β phase transformation in 47Zr-45Ti-5Al-3V alloy

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Transactions of Nonferrous Metals Society of China 2018年第10期28卷 1947-1957页

作者： yuan-biao tan Li-yuan Ji Wen-chang LIU Song XIANG Fei ZHAO Yi-long LIANG Guizhou Key Laboratory of Materials Structure and Strength College of Materials and MetallurgyGuizhou UniversityGuiyang 550025China State Key Laboratory of Metastable Materials Science and Technology College of Materials Science and EngineeringYanshan UniversityQinhuangdao 066004China

The effect of strain rate and deformation temperature on theα→βphase transformation in 47Zr-45Ti-5Al-3V alloy with an initial widmanstattenαstructure was *** the deformation temperature of 550°C,the volume fraction ofαphase decreased with increasing strain *** 600 and 650°C,the volume fraction ofαphase firstly increased to a maximum value with increasing strain rate from 1×10-3 to 1×10-2 s-1,and then *** 700°C,the microstructure consisted of singleβ*** a given strain rate,the volume fraction ofαphase decreased with increasing deformation *** decreasing strain rate and increasing deformation temperature,the volume fraction and size of globularαphase *** 650°C and 1×10-3 s-1,the lamellarαphase was fully *** variation in the volume fraction and morphology ofαphase with strain rate and deformation temperature significantly affected the hardness of 47Zr-45Ti-5Al-3V alloy.

关键词： 47Zr-45Ti-5Al-3V alloy hot deformation phase transformation Vickers hardness microstructure

Specification and Verification of the Zab Protocol with TLA+

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Journal of Computer Science & Technology 2020年第6期35卷 1312-1323页

作者： Jia-Qi Yin Hui-biao Zhu yuan Fei Shanghai Key Laboratory of Trustworthy Computing East China Normal UniversityShanghai 200062China College of Information Mechanical and Electrical EngineeringShanghai Normal UniversityShanghai 200234China

ZooKeeper Atomic Broadcast (Zab) is an atomic broadcast protocol specially designed for ZooKeeper, which supports additional crash recovery. This protocol actually has been widely adopted by famous Internet companies, but there are few studies on the correctness and credibility of the Zab protocol, and thus we utilize formal methods to study the correctness. In this paper, Zab, Paxos and Raft are all analyzed and compared to help better understand the Zab protocol. Then we model the Zab protocol with TLA+ and verify three properties abstracted from the specification by the model checker TLC, including two liveness properties and one safety property. The final experimental results can prove that the design of the protocol conforms to the original requirements. This paper makes up for the analysis of formal methods in the Zab protocol.

关键词： Zab protocol TLA+ specification verification

Mainlobe jamming suppression via improved BSS method for rotated array radar

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Journal of Systems Engineering and Electronics 2022年第6期33卷 1151-1158页

作者： ZHANG Hailong ZHANG Gong XUE biao yuan Jiawen Key Laboratory of Radar Imaging and Microwave Photonics Ministry of EducationNanjing University of Aeronautics and AstronauticsNanjing 210016China Nanjing Marine Radar Institute Nanjing 211153China

This study deals with the problem of mainlobe jamming suppression for rotated array *** interference becomes spatially nonstationary while the radar array rotates,which causes the mismatch between the weight and the snapshots and thus the loss of target signal to noise ratio(SNR)of pulse *** this paper,we explore the spatial divergence of interference sources and consider the rotated array radar anti-mainlobe jamming problem as a generalized rotated array mixed signal(RAMS)model *** the corresponding algorithm improved blind source separation(BSS)using the frequency domain of robust principal component analysis(FDRPCA-BSS)is proposed based on the established rotating *** can eliminate the influence of the rotating parts and address the problem of loss of ***,the measured peakto-average power ratio(PAPR)of each separated channel is performed to identify the target echo channel among the separated *** results show that the proposed method is practically feasible and can suppress the mainlobe jamming with lower loss of SNR.

关键词： mainlobe jamming blind signal separation(BSS) robust principal component analysis(RPCA) peak to average power ratio(PAPR)

Accuracy Analysis and Design of A3 Parallel Spindle Head

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Chinese Journal of Mechanical Engineering 2016年第2期29卷 239-249页

作者： NI Yanbing ZHANG biao SUN Yupeng ZHANG yuan School of Mechanical Engineering Tianjin University Tianjin 300072 China China Faw Group Corporation R&D Center Changchun 130000 China

As functional components of machine tools, parallel mechanisms are widely used in high efficiency machining of aviation components, and accuracy is one of the critical technical indexes. Lots of researchers have focused on the accuracy problem of parallel mechanisms, but in terms of controlling the errors and improving the accuracy in the stage of design and manufacturing, further efforts are required. Aiming at the accuracy design of a 3-DOF parallel spindle head（A3 head）, its error model, sensitivity analysis and tolerance allocation are investigated. Based on the inverse kinematic analysis, the error model of A3 head is established by using the first-order perturbation theory and vector chain method. According to the mapping property of motion and constraint Jacobian matrix, the compensatable and uncompensatable error sources which affect the accuracy in the end-effector are separated. Furthermore, sensitivity analysis is performed on the uncompensatable error sources. The sensitivity probabilistic model is established and the global sensitivity index is proposed to analyze the influence of the uncompensatable error sources on the accuracy in the end-effector of the mechanism. The results show that orientation error sources have bigger effect on the accuracy in the end-effector. Based upon the sensitivity analysis results, the tolerance design is converted into the issue of nonlinearly constrained optimization with the manufacturing cost minimum being the optimization objective. By utilizing the genetic algorithm, the allocation of the tolerances on each component is finally determined. According to the tolerance allocation results, the tolerance ranges of ten kinds of geometric error sources are obtained. These research achievements can provide fundamental guidelines for component manufacturing and assembly of this kind of parallel mechanisms.

关键词： A3 head error model sensitivity analysis tolerance allocation

Infrared radiation characteristics of a hypersonic vehicle under time-varying angles of attack

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Chinese Journal of Aeronautics 2019年第4期32卷 861-874页

作者： Qinglin NIU Zhichao yuan biao CHEN Shikui DONG School of Energy Science and Engineering Harbin Institute of Technology Key Laboratory of Aerospace Thermophysics of Ministry of Industry and Information Technology Harbin Institute of Technology Key Laboratory of Chemical Laser Dalian Institute of Chemical Physics Chinese Academy of Sciences

Hypersonic vehicles emit strong infrared(IR) radiation signatures that can be treated as a detecting source for object identification and routine diagnosis. This paper is aimed at examining the intrinsic radiation characteristics of a Boost-Glide Vehicle(BGV) under the condition of various Angles of Attack(AOAs). A two-temperature model considering the thermal and chemical nonequilibrium effects is coupled with Navier-Stokes equations solved by the finite volume technique.A gas–solid conjunction heat transfer model is also added into the fluid solver to simulate the surface temperature of the vehicle. The radiative transfer equation is solved with Line of Sight(LOS)algorithm. The computational results for a Hypersonic Technology Vehicle-2(HTV-2) type vehicle show that radiances of the vehicle are strongly dependent on the surface temperature. The presence of AOA results in the significant difference of the surface temperature. Infrared radiation characteristics are also changed in intensity and spectral band due to the AOA. Simulations are performed with two time-varying AOAs. Transient results indicate that the variation of AOA does have a great effect on the infrared radiance and is closely related to observation angle, spectral band, angle size,angular velocity and time history.

关键词： Angle of attack Fluid-thermal interaction HTV-2 Hypersonic vehicle IR radiation Surface temperature

Tuning the Johari-Goldstein β-Relaxation and Its Separation from α-Relaxation of Poly(n-alkyl methacrylate)s by Small Molecule-bridged Hydrogen Bonds

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Chinese Journal of Polymer Science 2021年第11期39卷 1459-1469页

作者： yuan-biao Liu Gao-Peng Shi Guo-Zhang Wu Shanghai Key Laboratory of Advanced Polymeric Materials School of Materials Science&EngineeringEast China University of Science&TechnologyShanghai 200237China

Introducing small molecule-bridged hydrogen bonds(HBs)between polymer chains has been reported to effectively reduce the interchain cooperativity despite of strengthening the intermolecular ***,a systematic investigation on tuning the Johari-Goldsteinβ(βJG)relaxation by adding various low-molecular-weight phenols in poly(n-alkyl methacrylate)s is carried out to further clarify the anomalous *** these small molecules capable of coupling the motion with pendent groups of host polymers due to forming at least two HBs per molecule,poly(n-alkyl methacrylate)mixtures exhibit rich dynamic changes in theβJG-properties andα,βJG *** increased loading of phenols with a small size and strong inter-HB strength(Δυi)clearly benefits for significant retardation and suppression of theβJG-relaxation,narrows theα,βJG separation and converges theβJG-peak with theα-peak,which demonstrates the alleviation of inter-chain topological ***,small molecules with a relatively big size and weakΔυi are found to amplify the magnitude of theα,βJG separation of poly(butyl methacrylate),even though experimental results of changes inα-dispersion and dynamic fragility confirm a reduction of the coupling factor n in all of these *** counterintuitive phenomenon suggests that the crossover time tc in the Coupling Model is no longer a universal quantity if the inter-chain interaction of polymers is strengthened by *** compelling findings shed vital insights into the HBinduced anomalous dynamics,and provide essential guidance for tailoring theβJG behavior and designing glassy polymeric materials.

关键词： Johari-Goldsteinβ-relaxation Hydrogen bond Glass transition Poly(n-alkyl methacrylate) Small molecule