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Effect of the Addition of High li Concentration on the Microstructure and Mechanical Properties of Al-Mg-Si Alloys with Different Mg Contents

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Acta Metallurgica Sinica(English Letters) 2021年第12期34卷 1721-1733页

作者： Xiao-Kun Yang Bai-Qing Xiong Xi-Wu li li-Zhen Yan zhi-hui li Yong-An Zhang Ya-Nan li Kai Wen State Key Laboratory of Nonferrous Metals and Processes GRINM Group Co.LtdBeijing 100088China GRIMAT Engineering Institute Co. LTDBeijing 101407China General Research Institute for Nonferrous Metals Beijing 100088China

In the present work,the microstructural characteristics and mechanical properties of Al-1.5 Mg-0.6Si and Al-3.0 Mg-0.6Si alloy containing 3 wt%li were investigated by optical microscopy(OM),X-ray diffraction analysis(XRD),scanning electron microscopy(SEM),time of flight-secondary ion mass spectrometry(SIMS),transmission electron microscopy(TEM),and mechanical performance *** addition of li reduces the density of the base alloy by up to 8.4%.The residual second phases contain Mg and Si in the hot-rolled condition,but the Mg/Si atomic ratio decreases after quenching,which means that li substitute some of the Mg and convert Mg_(2)Si into a(Mg,li)_(2)Si phase during solution *** results of SIMS observations confirm *** high Mg-containing alloy has a more rapid hardening response compared to the low Mg-containing *** observation reveals that theδ′-Al3li+β′′-Mg_(2)Si dual phases can be observed in the high Mg-containing alloy after aging for 100 h at 170°*** higher Mg content enhances the precipitation of theδ′phase,which results in the high Mg-containing alloy having a larger average diameter size ofδ′particles and widerδ′-precipitate-free zones(δ′-PFZs).The mechanical properties are significantly improved with the elastic modulus increasing by more than 16.5%.However,the existence of large second phases and wideδ′-PFZs in li-containing alloys is detrimental to their ductility;as a result,their elongation is much lower than that of the base alloy.

关键词： Al-Mg-Si alloy li addition Microstructure Aging behavior Mechanical properties Secondary ion mass spectrometer

Priori information analysis of optocoupler accelerated degradation experiment based on failure mechanism verification test

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Defence Technology（防务技术） 2020年第2期16卷 392-400页

作者： Xuan-gong Zhang Xi-hui Mu Jing Feng hui-zhi li Department of Ammunition Engineering Army Engineering University Shijiazhuang CampusShijiazhuang050000China Hunan Ginkgo Data Technology Co. Ltd.Luositang RoadChangshaHunan410100China

The optocoupler is a weak link in the inertial navigation platform of a kind of guided *** is necessary to use accelerated storage test to verify the storage life of long storage *** for small sample products,it is very important to obtain prior information for the design and implementation of accelerated degradation *** this paper,the optocoupler failure mechanism verification test is designed and the experimental results are analyzed and the prior information is *** results show that optocouplers have two failure modes,one is sudden failure and the other is degradation failure;the maximum temperature stress of optocoupler can’t exceed 140℃;the increase of leakage current of optocoupler is caused by movable ions contaminating the LED *** surface leakage current is proportional to the adsorption *** increase of leakage current makes p-n junction tunneling effect occur which LEDs the failure of the *** lifetime distribution model of the optocoupler is determined by the failure *** lifetime of the optocoupler is subject to the lognormal *** degeneracy orbit of the optocoupler leakage current is described by a power law *** estimated values of the orbital parameters are initially calculated and the parameters of its life distribution function are *** above information lays a good foundation for the optimization design and data processing of the accelerated degradation experiment.

关键词： Priori information Failure mechanism Failure mechanism verification test Accelerated degradation

Optimization of the S-band side-coupled cavities for proton acceleration

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Nuclear Science and Techniques 2020年第3期31卷 1-9页

作者： Hao-Yun li Xin-Miao Wan Wei Chen Chen-hui Shi zhi-hui li The Key Laboratory of Radiation Physics and Technology of Ministry of Education Institute of Nuclear Science and Technology Sichuan University

The proton beam with energy around 100 MeV has seen wide applications in modern scientific research and in various ***,proton sources in China fall short for meeting experimental needs owing to the vast size and expensive traditional proton *** Institute of Nuclear Science and Technology of Sichuan University proposed to build a 3 GHz side-coupled cavity linac(SCL)for re-accelerating a 26 MeV proton beam extracted from a CS-30 cyclotron to 120 *** carried out investigations into several vital factors of S-band SCL for proton acceleration,such as optimization of SCL cavity geometry,end cell tuning,and bridge coupler *** demonstrated that the effective shunt impedance per unit length ranged from 22.5 to 59.8 MX/m throughout the acceleration process,and the acceleration gradient changed from 11.5 to 15.7 MV/m when the maximum surface electric field was equivalent to Kilpatrick electric *** obtained equivalent circuit parameters of the biperiodic structures and applied them to the end cell tuning;results of the theoretical analysis agreed well with the 3D *** designed and optimized a bridge coupler based on the previously obtained biperiodic structure parameters,and the field distribution un-uniformness was\1.5%for a two-tank *** radio frequency power distribution system of the linac was obtained based on the preliminary beam dynamics design.

关键词： Proton beam Side-coupled cavity linac Accelerating cavity Biperiodic structure Bridge coupler

Fracture mechanism of a laminated aluminum alloy plate during ballistic impact

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Rare Metals 2017年第9期36卷 737-745页

作者： Ming-Yuan li Bai-Qing Xiong Guo-Jun Wang You-zhi Tong Xi-Wu li Shu-hui Huang zhi-hui li Yong-An Zhang State Key Laboratory of Nonferrous Metals and Processes General Research Institute for Nonferrous MetalsBeijing 100088China Northeast light Alloy Co. Ltd.Harbin 150060China

The multilayered 7XXX series aluminum alloy was impacted by 7.62 mm ogival projectiles at velocities ranging from 787 to 851m·s^（-1）. The deformed microstructure under various impacting velocities and fracture surfaces of different sections were investigated at different physical scales to determine the process of *** microscopy（OM）,electron back-scattered diffraction（EBSD） and scanning electron microscopy（SEM） were used in the investigation. The results show that crater is constrained in the 7B52 front layer and two types of adiabatic shear bands which are transformed bands and deformed bands and different types of cracks are *** fracture is the significant failure mode of 7B52 front layer, and the resulting delamination leads to the presence of bending tensile fracture instead of the shear *** ductile 7A01 layer blunts and deflects the spall crack tips, preventing the targets from full spall, and induces a constraint of 7A52 rear layer. The level of the constraint determines different fracture modes of 7A52 layer,accounting for the asymmetry of damage.

关键词： Laminate Aluminum Ballistic impact Spallfracture Adiabatic shear bands

As-cast microstructure of Al-Zn-Mg-Cu-Zr alloy containing trace amount of Sc

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Rare Metals 2019年第4期38卷 343-349页

作者： Yu Wang Bai-Qing Xiong zhi-hui li Shu-hui Huang Kai Wen Xi-Wu li Yong-An Zhang State Key Laboratory of Nonferrous Metals and Processes General Research Institute for Nonferrous Metals

It has been reported that the element scandium (Sc) is the most effective modificator which can significantly refine the grain size,prohibit recrystallization process and increase the *** trace of Sc in 7000 series aluminum alloys is considered to be an effective way to modify its microstructure and promote mechanical *** order to study the effect of Sc element on ascast microstructure of Al-Zn-Mg-Cu-Zr alloy,ingots containing different amounts of Sc were prepared by ferrous-mold *** were characterized by means of differential scanning calorimeter (DSC),X-ray diffraction (XRD),optical microscope (OM) and scanning electrical microscope (SEM).The results indicate that when the Sc level exceeds a critical concentration,A13(Sc,Zr) primary phase would form in the melt and act as an efficient nucleant,resulting in very refined grain and an equiaxed grain *** element reduces the number of eutectic phases formed during solidification,coupled with an increase in the concentration of major alloying elements retained in the *** behavior suggests possible benefits in improving the integrated properties of terminal products.

关键词： Scandium Aluminum alloy As-cast Microstructure Nucleant

Quantum state manipulation of single-Cesium-atom qubit in a micro-optical trap

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Frontiers of physics 2014年第5期9卷 634-639页

作者： zhi-hui Wang Gang li Ya-li Tian Tian-Cai Zhang State Key Laboratory of Quantum Optics and Quantum Optics Devices Institute of Opto-Electronics Shanxi University Taiyuan 030006 China

Based on single Cesium atoims trapped in a 1064 nm microscopic optical trap we have exhibited a single qubit encoded in the Cesium ＂clock states＂. The single qubit initialization, detection and the fast state rotation with high efficiencies are demonstrated and this state manipulation is crucial for quantmn information processing. The ground ~ates Rabi flopping rate of 229.0 ± 0.6 kHz is realized hy a two-photon Raman process. A clock states dephasing time of 3.0 ± 0.7 ms is measured, while all irreversible homogeneous dephasing time of 124 ± 17 ms is achieved by using the spin-echo technique. This well-controlled single atom provides an ideal quantmn qubit and quantmn node for quantum information processing.

关键词： qubit single atom Rabi flopping spin-echo dephasing time

Transformation behavior of precipitates during artificial aging at 170℃in Al-Mg-Si-Cu alloys with and without Zn addition

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Rare Metals 2021年第7期40卷 1907-1914页

作者： Shang Zhu zhi-hui li li-Zhen Yan Xi-Wu li Shu-hui Huang Hong-Wei Yan Yong-An Zhang Bai-Qing Xiong State Key Laboratory of Nonferrous Metals and Processes GRIMAT Engineering Institute Co..LtdBeijing 101407China

The transformation behavior of precipitates in Al-Mg-Si-Cu alloys with and without Zn addition during artificial aging at 170℃was investigated in this *** Al-Mg-Si-Cu alloys with and without Zn addition,two types of precipitates,needle-likeβ″and lath-like L,are formed with the aging time increasing from 8 to 34 *** needle-likeβ″precipitate exhibits a Mg-to-Si atomic ratio of 1.31 which is in agreement with the theoretical ratio of1.25 forβ″(Mg5 Al2 Si4).In addition,theβ″precipitate is supposed to contain Al and *** further partitioning of Mg,Si and Cu and release of Al,the needle-likeβ″precipitate can transform to lath-like L *** L phase has significantly higher concentrations of Mg,Si and Cu and lower concentration of Al,with a higher Mg-to-Si atomic ratio(1.41)deviated from theoretical ratio ofβ″.However,the major of Zn has a random distribution in Al matrix and exhibits no significant partitioning into *** remained in matrix can enhance the transformation ofβ″precipitates to L precipitates.

关键词： Al-Mg-Si-Cu alloys Zn addition Precipitates Transformation

Mechanical properties,microstructure and surface quality of Al-1.2Mg-0.6Si-0.2Cu alloy after solution heat treatment

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Rare Metals 2017年第7期36卷 550-555页

作者： li-Zhen Yan Yong-An Zhang Bai-Qing Xiong Xi-Wu li zhi-hui li Hong-Wei liu Shu-hui Huang Gang Zhao State Key Laboratory for Nonferrous Metals and Processes General Research Institute for Nonferrous Metals Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education) Northeastern University

The effect of solution heat treatment （SHT） on mechanical properties, microstructure and surface quality of Al-1.2Mg-0.6Si-0.2Cu-0.6Zn alloy was investigated by tensile test, Erichsen test, surface topography, scanning electron microscope （SEM） and electron back-scattered diffraction （EBSD）. The results indicate that with the increase in SHT temperature, yield strength and cupping test value （IE） of the sheets increase greatly and reach a peak value, then decrease. Meanwhile, intermetallic com- pounds dissolve into matrix gradually. The grains grow up as SHT temperature increases, and abnormal grain growth leads to the surface defects after solution-treated above 560 ~C. Considering mechanical properties, IE value, residual phases, grain size and surface quality of the sheets, SHT temperature for the alloy should not be higher than 550 ℃.

关键词： AI-Mg-Si alloy Solution heat treatment Surface defects Mechanical properties Microstructure

Microstructural characterization of as-cast and homogenized 2D70 aluminum alloy

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International Journal of Minerals,Metallurgy and Materials 2009年第4期16卷 427-431页

作者： Guo-jun Wang Bai-qing Xiong Yong-an Zhang zhi-hui li Pei-yue li State Key Laboratory for Fabrication and Processing of Nonferrous Metals General Research Institute for Nonferrous Metals Beijing 100088 China Northeast light Alloy Co. Ltd. Harbin 150060 China

The microstructure of the as-cast 2D70 aluminum alloy and its evolution during homogenization were investigated by means of optical microscopy （OM）, scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS）, X-ray diffraction （XRD）, and differential scanning calorimetry （DSC） analysis. The results indicate that the microstructure of the as-cast 2D70 aluminum alloy mainly consists of the dendritic network of aluminum solid solution and intermetallic compounds （Al2CuMg, Al2Cu, Al9FeNi, Cu2FeAl7, and Al7Cu4Ni）. After conventional homogenization, Al/Al2CuMg eutectic phases are dissolved into the matrix, and a small amount of high melting-point eutectic Al/Al2Cu phases exist in the matrix, resulting in an increase in the starting melting temperature. Under double homogenization, the high melting point Al/Al2Cu phases are dissolved, and no obvious change is observed for the size and morphology of Al9FeNi, Cu2FeAl7, and Al7CuaNi compounds.

关键词： aluminum alloys microstructure homogenization intermetallics