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Microstructures and mechanical properties of friction stir processed Mge2.0Nde0.3Zne1.0Zr magnesium alloy

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Journal of Magnesium and Alloys 2013年第2期1卷 122-127页

作者： F.y.Zheng y.J.Wu L.M.peng x.W.Li P.H.Fu W.J.Ding National Engineering Research Center of Light Alloy Net Forming Shanghai Jiao Tong University800 Dongchuan RoadShanghai 200240PR China The State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University800 Dongchuan RoadShanghai 200240PR China

The effect of Friction stir process(FSP)parameters on the microstructure and mechanical properties of an extruded Mge2.0Nde0.3Zne1.0Zr(wt.%)alloy was investigated in this *** alloy was friction stir processed with different passes:single-pass,three-pass and five-pass,under a tool rotation rate of 800μm and a traverse speed of 200 mm min^(-1).FSP results in remarkable grain refinement of the extruded alloy(average grain size w3.8 mm as 3 passes)and almost complete dissolution of the Mg_(12)Nd phase in the *** the increase of pass,the average grain size in the stir zone(SZ)is decreased firstly and then *** Vikers hardness of SZs in all FSPed samples is higher than that of the parent material(PM).Tensile tests at room-temperature show that the tensile strengths of the stir zones along the FSP advancing direction are slightly lower than those of ***,the elongations are remarkably improved from 13.0%for PM to 24.5%for SZ FSPed with *** improved tensile properties are attributed to the microstructure refinement,dynamic recrystallization and dissolution of the Mg_(12)Nd phase.

关键词： Mg-Nd-Zn-Zr alloy Friction stir processing Grain refinement Dynamic recrystallization

CARBAZOLE-CONTAINING HyPERBRANCHED POLy(ARyLENEETHyNyLENE)S:SyNTHESIS,CHARACTERIZATION,ANDPROPERTIES

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Chinese Journal of Polymer Science 2007年第6期25卷 641-649页

作者： Han peng xiu-wen Zheng Jacky W. y. Lam Ben-zhong Tang Institute of Material Science and Engineering South China University of Technology Guangzhou 510640 China Department of Chemistry Hong Kong University of Science ＆ Technology Clear Water Bay Kowloon Hong Kong China

New hyperbranched poly（aryleneethynylene）s containing carbazole moieties are synthesized in high yields （up to 87%） by polycyclotrimerization of 3,6-bis（4-ethynylphenyl）-9-octylcarbazole and its copolymerization with 1-octyne catalyzed by CpCo（CO）2 in THF. The structures and properties of the polymers are characterized and evaluated by IR, NMR, TGA, UV, photoluminescence, and cyclic voltammetry analyses. All the polymers are soluble in common organic solvents and show outstanding thermal stability （≥ 430℃）. They graphitize in high yields （up to 79%） when pyrolyzed at 800℃. Upon photoexcitation, the polymers emit a strong deep blue light of ca. 400 nm with quantum yields larger than 60%.

关键词： Acetylenes Carbazole Cyclopolymerization Hyperbranched Luminescence.

EFFECT OF RARE EARTH ON VANADIZATION PROCESS IN BORAx BATH

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Acta Metallurgica Sinica(English Letters) 1999年第5期12卷 968-973页

作者： x.K. Tao, x.Cong, R.S. peng, J.Liu and Z.y. Liu Tianjin Institute of Technology, Tianjin 300191, China

This paper investigates the effect of rare earth elements on the kinetic process, microstructure and mechanical properties of vanadization in borax bath. The results show that addition of rare earth elements to vanadizing agent has obvious catalytic effect on the rate of vanadization, which has been enchanced by 30%. The wear and corrosion resistance of vanadium carbide layer were prompted by the addition of rare earth to the agent. Through increasing vanadium potential of the agent, activating the surface of workpieces and decreasing the activation energy of diffusion of carbon, rare earth elements accelerate the rate of vanadization process.

关键词： rare earth elements vanadization in borax bath activation energy of diffusion

Ship maneuvering prediction based on virtual captive model test and system dynamics approaches

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Journal of Hydrodynamics 2022年第2期34卷 259-276页

作者： peng Du Lu Cheng Zi-jian Tang A.Ouahsine Hai-bao Hu y.Hoarau Research and Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen518057China School of Marine Science and Technology Northwestern Polytechnical UniversityXi’an710072China Laboratoire Roberval UT Compiègne-Sorbonne UniversitéCompiègneFrance ICUBE Laboratory University of StrasbourgStrasbourgFrance

The maneuvering simulation is carried out through the continuous captive model test and the system dynamics *** mathematical maneuvering group(MMG)model is implemented in the virtual captive model tests by using the computational fluid dynamics(CFD)*** oblique towing test(OTT),the circular motion test(CMT),the rudder force test and the open water test are performed to obtain the hydrodynamic derivatives of the hull,the rudder and the propeller,and the results are validated by experimental *** designing the tests,the number of cases is reduced to a low level,to allow us to evaluate the maneuverability with a low cost and in a short *** these obtained coefficients,the system-based maneuvering simulations are conducted to calculate the position and the attitude of the ship,with results in agreement with the free running test *** procedure can also be used for other hull forms,with reduced workload and with convenience for maneuvering simulation tasks.

关键词： Maneuvering simulation captive model test(CMT) system dynamics computational fluid dynamics(CFD) Hydrodynamic derivatives

Synergistic effects of Nb and Mo on hydrogen-induced cracking of pipeline steels:A combined experimental and numerical study

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Journal of Materials Science & Technology 2023年第27期158卷 156-170页

作者： Shiqi Zhang Luming Qi Shilong Liu Zhixian peng y.Frank Cheng Feng Huang Jing Liu The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081China Institute of Advanced Steels and Materials School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China Department of Mechanical Engineering University of CalgaryCalgaryAB T2N 1N4Canada Hubei Engineering Technology Research Centre of Marine Materials and Service Safety Wuhan University of Science and TechnologyWuhan 430081China

The synergistic effects of Nb and Mo on hydrogen-induced cracking(HIC)of pipeline steels were studied experimentally and *** results showed that Mo was primarily segregated at grain-boundaries(GBs)or solid-dissolved in the matrix,while most Nb and a small amount of Mo formed dis-persed(Nb,Mo)C nano-precipitates and refined the *** with Nb alloying,the multi-ple additions of Nb-Mo played dual roles in affecting H diffusion:primarily,the H-traps densities such as GBs,precipitates,and solute Mo atoms increased,providing an advantage;however,Mo slightly reduced the H-trapping capacity of precipitates,playing an adverse ***,the beneficial effects far outweighed the adverse effects,thereby reducing H diffusivity and inhibiting crack ***-ally,Nb and Mo hindered crack propagation synergistically as follows:(i)Mo enhanced GB cohesion by repelling H,impeding intergranular cracking and hydrogen-enhanced decohesion(HEDE);(ii)Nb reduced the proportion of3/high-angle grain boundaries,increasing cracking resistance;(iii)(Nb,Mo)C precip-itates impeded H-dislocation interactions,reducing the hydrogen-enhanced localized plasticity(HELP).

关键词： Hydrogen-induced cracking Nb-Mo microalloying Hydrogen permeation Precipitate Pipeline steel

STUDy ON CONSTITUTIVE RELATIONSHIP OF Ti-5Al-2Sn-2Zr-4Cr-4Mo ALLOy AND SIMULATION OF HOT FORMING PROCESSES

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Acta Metallurgica Sinica(English Letters) 2000年第1期13卷 342-348页

作者： x. Q. Zhang y. H. peng M. Q. Li and x. y. Ruan( 1)Department of Plasticity Technology, Shanghai Jiao TOng University, Shanghai 200030 2)School of Material Science and Engineering, Northwestern Polytechnical University, xi’ an 710072, China)

In the present research, artificial artificial networks hare be applied to establish the constitutive rela- tionship model of Ti - 5Al - 2Sn - 2Zr - 4Mo - 4Cr (wt - % ) alloy. In the first stage of the re- search, an isothermal compressive experiment using Thermecmastor - Z hot simulator is studied to ac- quire the flow stress at different deformation temperature,equivalent strain and equivalent strain rate. Then,a feed - forward neural network is trained by using the experimental *** the training process is finished, the neural networks become a knowledge-based constitutive relationship system. Comparison of the predicted and experimental results results shows that the neural network model has good le- arning precision and good *** neural neural network methods are found to show much better agreement than existing methods with the experiment data, and have the advantage of being able to deal with noisy for or data with strong non - linear reationships. At last, this model can be aused to simulate the flow behavior of Ti - 5Al - 2Sn - 2Zr - 4Mo - 4Ca alloy.

关键词： titanium alloy consitutive relationship,hot fowl processes BP algo- rithm

THE LIMITATION OF MATANSITIC INVARIANT HABIT PLANE AND MARTENSITE MORPHOLOGy

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Acta Metallurgica Sinica(English Letters) 1996年第4期9卷 298-306页

作者： N.J. Gu, H.F. peng, x. y Song, F.x. yin and E.x. Wang(Department of Material Science and Engineering Hebei University of Technology, Tianjin 300132, China

The strain tensor and displacement vector associated with lattice deformation were introduced to discuss the effect of self-accommodation and plastic accommodation in martensitic transformation,and the models for {557}_f and {3,10,15}_f martensite fomation were proposed, along with the experimental verification. It is considered that the invariant habit plane may result from the self-accommodation between different martensitic variants causing the internal twin structure. However, as the strength of parent phase is low enough for the plastic accommodation to occur the dislocation substructure in martensite be produced, in which case the invariant habit plane is difficult to form so the{225}_f and {557}_f habit planes are difficult to explain by the phenomenological crystallographic theory. So,there are some limitations for the martensitic invariant habit *** the present work the authors also suggest that the martensite morphology depends on the competition between self-accommodation and plastic accommodation including factors not only of strength but also of structure of the parent phase However, when the density of crystal defects is high dislocations rather than twinned martensite will form in spite of the higher strength of the parent phase.

关键词： rystallography,martensitic transformation martensite morPhology

PERSPECTIVES IN MECHANICS OF HETEROGENEOUS SOLIDS

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Acta Mechanica Solida Sinica 2011年第1期24卷 1-26页

作者： C.Q. Chen J.Z. Cui H.L. Duan x.Q. Feng L.H. He G.K. Hu M.J. Huang y.Z. Huo B.H. Ji B. Liu x.H. peng H.J. Shi Q.P. Sun J.x. Wang y.S. Wang H.P. Zhao y.P. Zhao Q.S. Zheng W.N. Zou Department of Engineering Mechanics AML Tsinghua University Beijing 100084 China Academy of Mathematics and Systems Sciences Chinese Academy of Sciences Beijing 100190 China State Key Laboratory for Turbulence and Complex System and Department of Mechanics and Aerospace Engineering College of Engineering Peking University Beijing 100871 China CAS Key Laboratory of Mechanical Behavior and Design of Materials University of Science and Technology of China Hefei Anhui 230026 China School of Aerospace Engineering Beijing Institute of Technology Beijing 100081 China Institute for Advanced Study Nanchang University Nanchang 330031 China Depariment of Mechanics and Engineering Sciences Fudan University 220 Handa Road Shanghai 200433 China Department of Mechanical Engineering Hong Kong University of Science and Technology Hong KongChina Department of Mechanical Engineering Hong Kong University of Science and Technology Hong Kong China Institute of Engineering Mechanics Beijing Jiaotong University Beijing 100044 China State Key Laboratory of Nonlinear Mechanics Institute of Mechanics Chinese Academy of Sciences Beijing 100190 China

The Micro- and Nano-mechanics Working Group of the Chinese Society of Theoretical and Applied Mechanics organized a forum to discuss the perspectives, trends, and directions in mechanics of heterogeneous materials in January 2010. The international journal, Acta Mechanica Solida Sinica, is de- voted to all fields of solid mechanics and relevant disciplines in science, technology, and engineering, with a balanced coverage on analytical, experimental, numerical and applied investigations. On the occasion of the 30TM anniversary of Acta Mechanica Solida Sinica, its editor-in-chief, Professor Q.S. Zheng invited some of the forum participants to review the state-of-the-art of mechanics of heterogeneous solids, with a particular emphasis on the recent research development results of Chinese scientists. Their reviews are organized into five research areas as reported in different sections of this paper. ~I firstly brings in fo- cus on micro- and nano-mechanics, with regards to several selective topics, including multiscale coupled models and computational methods, nanocrystal superlattices, surface effects, micromechanical damage mechanics, and microstructural evolution of metals and shape memory alloys. ~II shows discussions on multifield coupled mechanical phenomena, e.g., multi-fields actuations of liquid crystal polymer networks, mechanical behavior of materials under radiations, and micromechanics of heterogeneous materials. In ~III, we mainly address the multiscale mechanics of biological nanocomposites, biological adhesive surface mechanics, wetting and dewetting phenomena on microstructured solid surfaces. The phononic crystals and manipulation of elastic waves were elaborated in ~IV. Finally, we conclude with a series of perspectives on solid mechanics. This review will set a primary goal of future science research and engineering application on solid mechanics with the effort of social and economic development.

关键词： heterogeneous materials smart materials biological materials multiscale mechanics micro- and nano-mechanics damage and fracture constitutive relation elastic wave surface effects

Utilizing Multilayer Design of Organic-Inorganic Hybrids to Enhance Wearable Strain Sensor in Humid Environment

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Chinese Journal of Polymer Science 2023年第7期41卷 1037-1050页

作者： Chen-Chen Lu Wei-Chen Gao peng Li Wei Wu Robert K.y.Li Hui Zhao Guangxi Key Laboratory of Clean Pulp&Papermaking and Pollution Control School of Light Industry and Food EngineeringGuangxi UniversityNanning530004China Guangxi Key Laboratory of Calcium Carbonate Resources Comprehensive Utilization College of Materials and Chemical EngineeringHezhou UniversityHezhou542899China Department of Materials Science and Engineering City University of Hong KongTat Chee AvenueKowloonHong Kong999077China

Flexible strain wearable sensors have attracted considerable attention due to their advantages of low cost, lightweight, high sensitivity and good flexibility. However, the strain sensors are easy to be damaged in an extreme humidity environment or by the wearer’s sweat in the process of use, resulting in detection disorder or even a short circuit. Furthermore, preparation of sensors with stable properties under extreme environments is one of the most important research directions. To fill this gap, a flexible sensor was prepared by using polyurethane and carbon nanotubes, then modified by polydopamine and 1H,1H,2H,2H-perfluorodecane-mercaptan. A typical tunnel model was used to explain the working mechanism of the sensor, the sensitivity of the sensor is also explained and evaluated by the tunneling theory. The results show that the sensor has good sensitivity (the sensor has a stable sensing signal output under a strain range from 2% to 300%) and stability over 8500 cycles. At the same time, the sensor has good superhydrophobicity, the water contact angle reaches 152°, and it is still stable in a humid environment. Moreover, this sensor shows excellent performance in monitoring human joint motion (such as finger, elbow, wrist and knee) and physiological signals (such as speaking and drinking). This work provides an effective design method for the sensor which can be applied in a high humidity environment.

关键词： Wearable strain sensor Polyurethane Carbon nanotubes Superhydrophobicity