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Rare Metals 2023年第2期42卷 688-696页

作者： Xin-Bo Zhang Jin-Xu liu liu Wang shu-kui li School of Materials Science and Engineering Beijing Institute of TechnologyBeijing100081China

This paper aims at enhancing impact insensitivity of polytetrafluoroethylene(PTFE)-Mg-W without sacrificing bulk of energy released in the reaction and optimizing mechanical properties of PTFE-Mg-W by magnesium surface *** reaction energy results indicate that the reaction energy of PTFE-Mg-W(modified 1 min)in oxygen decreases slightly to 7905 J·g^(-1)compared with that of PTFE-Mg-W(unmodified)which is8533 J·g^(-1).Under impact condition(impact velocity between 16.232 and 17.726 m·s^(-1)),compared with PTFEMg-W(unmodified),the initiation time before ignition of PTFE-Mg-W(modified 1 min)delays 50μs;the absorbed energy needed for ignition of PTFE-Mg-W(modified1 min)increases by 67.9%.This increase in impact insensitivity of PTFE-Mg-W can be contributed to the formation of passivated layers of magnesium particles after modification which effectively weakens the total interface area among reactive components and partly contributes to the loss of released energy of PTFE-Mg-W after magnesium *** quasi-static and dynamic compression results show that PTFE-Mg-W(modified 1 min)possess the highest strength and the best ductility.

关键词： Pyrotechnic compositions Critical phenomena Thermal properties Impact insensitivity

Microstructure and mechanical properties of a Cr-Ni-W-Mo steel processedthermo-mechanical controlled processing

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Journal of Iron and Steel Research International 2021年第6期28卷 713-721页

作者： Jia-xin liang Ying-chun Wang Xing-wang Cheng Zhuang li Jin-ke Du shu-kui li School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China National Key Laboratory of Science and Technology on Materials Under Shock and Impact Beijing 100081China

Experiments were conducted to evaluate the microstructure and tensile properties of a medium carbon Cr-Ni-W-Mo steel processedthermo-mechanical controlled processing(TMCP)with cooling at different conditions in water,oil,air or lime followedlow *** to normal heat-treatment processing,TMCP with water-cooling after deformation enhances the yield strength and tensile strength of the steelabout 323 MPa and about 251 MPa,respectively,due to higher dislocation strengthening and grain boundary ***,it increases the elongation by ;about 1.76%attributed to the increase in volume percentage of the retained austenite and the refined laths of tempered *** the cooling rate after deformation during TMCP leads to a decrease in the *** results the coupling effectsthe reduction in dislocation density and volume fraction of tempered martensite together with the coarseness in martensite ***,cooling rate decreasing has less influences on ductility becathe improved elongation the increase in the volume fractions of both retained austenite and lower bainite together with dislocation density decreasing is compensatedthe reduced elongation coarsened grains.

关键词： Thermo-mechanical controlled processing Ultra-high strength steel Microstructure Bainite Tensile property

Bending mechanical property and failure mechanisms of woven carbon fiber-reinforced aluminum alloy composite

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Rare Metals 2016年第12期35卷 915-919页

作者： Qiu-Rong Yang Jin-Xu liu shu-kui li Teng-Teng Wu School of Materials Science and Engineering Beijing Institute of Technology

Copper-coated woven carbon fiber-reinforced aluminum alloy composite was prepared by spark plasma sintering （SPS）. Microstructure, three-point bending mechanical property, and the failure mechanisms of the composite were investigated. Microstructure observation shows that the carbon fibers bond compactly with matrix alloy. Compared with the matrix aluminum alloy, the bending strength, ductility, fracture energy, and cracking resistance of the composite are evidently improved. Microstructure analyses reveal that the high specific strength of carbon fibers and transfer of stress from matrix alloy to carbon fibers are responsible for the increase of the composite bending strength. The expanding of cracks is restrained, and cracking resistance of the composite is improved by adding woven carbon fiber. Attributed to the carbon fibers＇ debonding, cracks deflection, and multipath propagation mechanisms, the fracture energy of the composite increases.

关键词： Carbon fibers Aluminum alloy Composites Bending strength Mechanisms

An investigation on anti-impact and penetration performance of basalt fiber composites with different weave and lay-up modes

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Defence Technology（防务技术） 2020年第4期16卷 787-801页

作者： Hai-dong Fu Xin-ya Feng Jin-xu liu Zhi-ming Yang Chuan He shu-kui li School of Materials Science and Engineering Beijing Institute of TechnologyChina China National Key Laboratory of Science and Technology on Materials under Shock and Impact Beijing Institute of TechnologyChina State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyChina

The woven basalt fiber composites(WBFC) and the unidirectional [0°/90°/45°/-45°]s basalt fiber composites(UBFC) were prepared by ***-point bending test,low velocity impact test,and ballistic test were performed to the prepared *** the tests,the specimens were recovered and analyzed for ***-point bending tests show that both the bending strength and stiffness of the WBFC surpass those of the *** velocity impact test results show that the low velocity impact resistance to hemispherical impactor of the UBFC is higher than that of the WBFC,but the low velocity impact resistance to sharp impactor of the UBFC is lower than that of the *** the ballistic test,it can be found that the ballistic property of the UBFC is higher than that of the WBFC. After the tests,microscopic analysis of the specimens was applied,and their failure mechanism was *** main failure modes of the UBFC are delamination and fibers breakage under the above loading conditions while the main failure mode of the WBFC is fibers *** delamination damage can be found in the WBFC under the above loading conditions,the degree of delamination is far less than that of the UBFC.

关键词： The woven basalt fiber composites The[0°/90°/45°/-45°]_s basalt fiber composites Low velocity impact Ballistic test Delamination

Preparation and properties of W–Cu–Zn alloy with low W–W contiguity

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Rare Metals 2016年第3期35卷 242-248页

作者： ling-ling Zheng Jin-Xu liu shu-kui li shuang liu Qing-He Zou Xing-Wang Cheng School of Materials Science and Engineering Beijing Institute of Technology Mudanjiang North Alloy Tool Co. Ltd

The W–Cu–Zn alloy with a-brass matrix and low W–W contiguity was prepared by method of electroless copper plating combined with spark plasma sintering（SPS） *** effects of process and parameters on the microstructure and mechanical properties of the alloy were *** W–Cu–Zn alloy with a relative density of 96 % and a W–W contiguity of about 10 % was prepared by original fine tungsten particles combined with wet mixing method and SPS solid-state sintering method at 800℃ for 10 *** microstructure analysis shows that Cu–Zn matrix consists of nano-sized a-brass grains,and the main composition is Cu3Zn *** nano-sized Cu was coated on the surface of tungsten particles by electroless copper plating method,and the fairly low consolidation temperature and short solid-state sintering time result in the nano-sized matrix *** dynamic compressive strength of the W–Cu–Zn alloy achieves to1000 MPa,but the alloy shows poor ductility due to the formation of the hard and brittle Cu3Zn *** fine-grain strengthening and the solution strengthening of the Cu–Zn matrix phase are responsible for the high Vickers microhardness of about 300 MPa for W–Cu–Zn alloy.

关键词： W–Cu–Zn alloy Spark plasma sintering Microstructure Mechanical properties Microhardness

Adiabatic shear banding of hot-rolling Ti–6Al–4V alloy subjected to dynamic shearing and uniaxial dynamic compression

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Rare Metals 2015年第9期34卷 632-637页

作者： Yu-Meng Luo Jin-Xu liu Xing-Wang Cheng shu-kui li Fu-Chi Wang Wen-Wen Guo China National Key Laboratory of Science and Technology on Materials Under Shock and Impact School of Materials Science and Engineering Beijing Institute of Technology

Effect of stress state including dynamic shearing and uniaxial dynamic compression on adiabatic shear banding(ASBing) of hot-rolling Ti–6Al–4V(TC4) alloy was investigated. The absorbed energy of specimen before failure was calculated to evaluate the susceptibility to adiabatic shear band(ASB) of TC4 alloy *** show that the susceptibility to ASB of hot-rolling TC4 alloy exhibits obvious anisotropy under both dynamic shearing and uniaxial dynamic compression conditions, but the anisotropy of susceptibility to ASB under dynamic shearing condition exhibits an opposite tendency with that under uniaxial dynamic compression condition. Under the condition of uniaxial dynamic compression, material shows the highest susceptibility to ASB when loaded along transverse direction(TD) of the hot-rolling TC4, while the lowest susceptibility when loaded along rolling direction(RD). However, under the condition of dynamic shearing,the material behaves in the opposite way, demonstrating the lowest susceptibility when loaded along TD of the hotrolling TC4, while the highest susceptibility when loaded along RD.

关键词： Adiabatic shear banding Ti alloy Dynamic compressi

Penetration performance of W/Cu double-layer shaped charge liners

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Rare Metals 2016年第2期35卷 184-191页

作者： Wen-Jian Dong Jin-Xu liu Xing-Wang Cheng shu-kui li Qing-He Zou Wen-Qi Guo School of Materials Science and Engineering Beijing Institute of Technology Mudanjiang North Alloy Tool Co. Ltd.

Two kinds of W/Cu double-layer shaped charge liner（SCL） were prepared by chemical vapor deposition（CVD） combined with electroforming technique： A SCL with W inner layer and Cu outer layer, B SCL with Cu inner layer and W outer layer. The penetration properties of A and B SCLs were researched. The results show that the two SCLs can form continuous jet and the tip velocities of A and B jets are 7.4 and 6.3 km s^（-1）, respectively. The kinetic energy density（5.3 9 1011 J m-3） of A jet tip increases by 194.4 %compared with that（1.8 9 1011 J m-3） of B jet tip. B jet,however, exhibits deeper penetration depth at the same experimental conditions. The chemical component and microstructure of the area nearby the ballistic perforation were researched. Component analysis shows that both the jets are formed only from inner layer metal. Microstructure analysis shows that martensite and intermetallic form around ballistic perforation penetrated by A SCL due to the intensive interaction between W jet and steel target. The two kinds of newly formed ultrahard phases also hinder the jet from penetrating target further. As a result of relatively alleviative interaction between Cu jet and target, only solid solution rather than ultrahard phases forms around ballistic perforation penetrated by B SCL.

关键词： Shaped charge liner Jet Penetration performance Chemical vapor deposition Electroforming technique

Enhanced thermal- and impact-initiated reactions of PTFE/Al energetic materials through ultrasonic-assisted core-shell construction

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Defence Technology（防务技术） 2022年第8期18卷 1362-1368页

作者： Zhou-yang Wu Jin-xu liu Song Zhang Xian-qing liu Xiao Xu Wei-zhe Ma shu-kui li Chuan He School of Materials Science and Engineering Beijing Institute of TechnologyBeijing100081China Science and Technology on Transient Impact Laboratory No.208 Research Institute of China Ordnance Industries102202China Department of Materials Science and Engineering Shenzhen MSU-BIT UniversityShenzhen518172China

A facile and economical approach was developed for the large-scale production of powdered core-shell structured PTFE/Al (CS-PA) energetic materials through ultrasonic-assisted mixing. The low-cost micrometer-sized PTFE and Al particles were used as starting materials. Under high-power ultrasonic waves, the PTFE powder was dispersed into nano-to sub-micrometer-sized particles and then encapsulated the Al microparticles to form the core-shell structure. The heat of combustion, burning rate, and pressurization rate of the powdered CS-PA were measured. The thermal-initiated reaction behavior was further evaluated using thermogravimetry-differential scanning calorimetry. Subsequently, the bulk CS-PA with a uniform microstructure was obtained via cold isostatic pressing of the powdered CS-PA followed by vacuum sintering. For the bulk CS-PA, the quasi-static compression behavior was characterized, and the impact-initiated reaction processes were conducted using the Split Hopkinson Pressure Bar (SHPB) and evaluated by a high-speed camera. Compared to physically mixed PTFE/Al materials, the powdered and bulk CS-PA demonstrated enhanced thermal- and impact-initiated reaction characteristics respectively, proving the effectiveness of our approach for constructing core-shell structures.

关键词： PTFE/Al Core-shell structure Energetic materials Ultrasonic-assisted mixing

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苏云金芽胞杆菌—开放的基因组与多种功能

植物保护 2017年第4期43卷 1-8,35页

作者：王奎束长龙李一梅张杰中国农业科学院植物保护研究所植物病虫害生物学国家重点实验室北京100193 东北农业大学生命科学学院哈尔滨150030

苏云金芽胞杆菌Bacillus thuringiensis(Bt)作为微生物杀虫剂,被广泛应用于农业、林业和卫生害虫的防治;而利用Bt杀虫基因研制的转基因植物,也在全球植物害虫防治中发挥了重要作用。近年来,随着科学技术的发展与社会需求的拓展,Bt新的... 详细信息

苏云金芽胞杆菌Bacillus thuringiensis(Bt)作为微生物杀虫剂,被广泛应用于农业、林业和卫生害虫的防治;而利用Bt杀虫基因研制的转基因植物,也在全球植物害虫防治中发挥了重要作用。近年来,随着科学技术的发展与社会需求的拓展,Bt新的功能被不断发掘出来。这些新的功能包括抗线虫、抗病杀菌、促进植物生长、环境修复等。本文从Bt的泛基因组结构及其遗传学特性分析入手,在详细介绍了近来Bt杀虫基因发掘进展的同时,分析了泛基因组与Bt新的功能之间可能存在的关系,旨在为我国Bt资源的研究与应用提供参考。

关键词：苏云金芽胞杆菌泛基因组杀虫基因抗菌作用促进植物生长环境修复

Microstructure characteristics and mechanical properties of TiB/Ti-1.5Fe-2.25Mo composites synthesized in situ using SPS process

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Transactions of Nonferrous Metals Society of China 2013年第9期23卷 2598-2604页

作者：张朝晖神祥博王富耻魏赛李树奎才鸿年北京理工大学材料学院北京100081

TiB/Ti-1.5Fe-2.25Mo composites were synthesized in situ using the spark plasma sintering （SPS） method at temperatures of 850-1150 °C. The effect of the sintering temperature on microstructure and mechanical properties of the composites was investigated. The results indicate that the aspect ratio of the in situ synthesized TiB whiskers in Ti alloy matrix decreases rapidly with an increase in sintering temperature. However, both the relative density of the sintered specimens and the volume content of TiB whiskers in composites increase with increasing sintering temperature. Thus, the bending strength of the composites synthesized using SPS process increases slowly with increasing the sintering temperature from 850 to 1150 °C. TiB/Ti-1.5Fe-2.25Mo composite synthesized at 1150 °C using SPS method exhibits the highest bending strength of 1596 MPa due to the formation of fine TiB whiskers in Ti alloy matrix and the dense microstructure of the composite.

关键词： titanium boride (TiB) titanium matrix composites (TMCs) spark plasma sintering (SPS) microstructure mechanicalproperties