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RESEARCh ON ThE WARM FORGING OF ALUMINUM ALLOYS: DEVELOPMENT OF A FORMULA TO DESCRIBE ThE SOFTENING BEhAVIOR OF A2011 IN FORGING PROCESS

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Acta Metallurgica Sinica(English Letters) 2003年第2期16卷 110-113页

作者： x.h.zhang K.Osakada x.Y.Ruan Division of Mechanical Science School of Engineering ScienceOsaka UniversityMachikaneyamaToyon-akaOsaka 560-8531JapanDivision of Mechanical ScienceSchool of Engineering ScienceOsaka UniversityMachikaneyamaToyon-akaOsaka 560-8531JapanNational Die and Mold CAD Engineering Research CenterShanghm Jiao Tong UniversityShanghai 200030China

To understand the forming behaviour of aluminum alloys, the upsetting test of aluminum alloys at evaluated temperature is conducted. Because in warm forging the flow stress decreases with increasing straining, which is so-called work softening, no appropriate material formulation is available. For the evaluation of flow stress of aluminum alloys in warm forging processes, in this paper, a formula is derived by analyzing the stress data measured at various temperatures. It is demonstrated that the formula fits the flow stress obtained from experiment.

关键词： aluminum alloy flow stress warm forging work softening

Mechanical properties of gas hydrate-bearing sediments during hydrate dissociation

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Acta Mechanica Sinica 2018年第2期34卷 266-274页

作者： x.h.zhang D.S.Luo x.B.Lu L.L.Liu C.L.Liu Institute of Mechanics Chinese Academy of SciencesBeijing 100190China College of Engineering University of Chinese Academy of SciencesBeijing 100049China Key Laboratory of Gas hydrate Ministry of Land and ResourcesQingdao 266071China Qingdao Institute of Marine Geology Qingdao 266071China

The changes in the mechanical properties of gas hydrate-bearing sediments(GhBS) induced by gas hydrate(Gh) dissociation are essential to the evaluation of Gh exploration and stratum instabilities. Previous studies present substantial mechanical data and constitutive models for GhBS at a given Gh saturation under the non-dissociated condition. In this paper, GhBS was formed by the gas saturated method, Gh was dissociated by depressurization until the Gh saturation reached different dissociation degrees. The stress–strain curves were measured using triaxial tests at a same pore gas pressure and different confining pressures. The results show that the shear strength decreases progressively by 30%–90% of the initial value with Gh dissociation, and the modulus decreases by 50% –75%. Simplified relationships for the modulus, cohesion, and internal friction angle with Gh dissociated saturation were presented.

关键词： Gas hydrate-bearing sediments Dissociation Mechanical properties Shear strength Triaxial test

Embedding laser-generated CdTe nanocrystals into ultrathin ZnIn_(2)S_(4) nanosheets with sulfur vacancies for boosted photocatalytic h_(2) evolution

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Journal of Materials Science & Technology 2023年第35期166卷 113-122页

作者： Z.G.Tai G.T.Sun x.h.zhang x.B.Yang T.Wang Z.Y.Fang Q.Ye L.C.Jia h.Q.Wang State Key Laboratory of Solidification Processing Center for Nano Energy MaterialsSchool of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Research&Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen 518063China School of Materials Science and Engineering Shaanxi Normal UniversityXi’an 710119China

To suppress the inner charge recombination and inject vast electrons,CdTe nanocrystals are embedded into ultrathin ZnIn_(2)S_(4) nanosheets to construct ZnIn_(2)S_(4)/CdTe heterostructures,where the nanocrystals are generated by a laser irradiation *** optimal ZnIn_(2)S_(4)/CdTe heterojunction exhibits an excellent catalytic activity of 24.3 mmol/h/g,which is relatively high among the ZnIn_(2)S_(4)-based photocatalysts with-out noble *** enhancement is ascribed to a win-win mechanism of nanoscale heterojunctions and sulfur *** strong electron coupling effect,which is verified by density functional the-ory(DFT)calculations,impels the photo-generated electrons transfer from CdTe to ZnIn_(2)S_(4),boosting the charge ***,the sulfur vacancies existing in ZnIn_(2)S_(4) can capture photoelectrons and act as active sites,facilitating the h_(2) generation *** addition,the ZnIn_(2)S_(4) base and the ZnIn_(2)S_(4)/CdTe heterojunction also possess an evident photothermal effect and renewable cycle phenomena,enhancing the photocatalytic *** research provides new insights into the regulation of charge transfer through embedding nanocrystals.

关键词： Photocatalysis hydrogen evolution Laser irradiation heterostructure Sulfur vacancies

A study on centrifugal casting of high speed steel roll

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China Foundry 2004年第S1期1卷 49-53页

作者： h.G.Fu x.h.zhang Department of Mechanical engineering Tsinghua UniversityBeijing 100084P.R.China Roll Made LTD.of Taiyuan Iron and Steel(Group)Company Taiyuan 030003ShanxiP.R.China

high speed steel (hSS) rolls can replace traditional rolls such as alloyed cast iron rolls and powder metallurgical (PM) hard alloy rolls. The main reasons for the replacement are that the wear resistance of low-cost alloyed cast iron rolls is poor and the cost of high-quality PM hard alloy rolls is very high. By means of centrifugal casting, hSS rolls having excellent wear resistance have been manufactured. The hardness of the hSS roll is 6.5~67 hRC, the range of variation is smaller than 2 hRC and its impact toughness is 15 J/cm^2. The wear rate of hSS rolls used in the pre-finishing stands of high-speed hot wire-rod rolling mill reaches 2.5×10^(-4)mm per ton steel. Furthermore, the manufacturing cost of hSS rolls is significantly lower than that of PM hard alloy rolls; it is only 30 percent of that of PM hard alloy rolls.

关键词： high speed steel centrifugal casting roll segregation crackle

STUDY IN FO RMATION OF SUB GRAINS AND MICROCRACKS IN WEIDED METAIS UNDER FATIGUE LOAD

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Acta Metallurgica Sinica(English Letters) 1999年第4期12卷 713-718页

作者： S.Z.Dong ,J.B.Li, x.h.zhang and J.zhang Shenyang University ,Shenyang 110044 ,China

With TEM( Transmission Electron Microscope) ,ithasobserved and analyzedthatforming processof Sub grainsand position offormingfatigue microcracksarein Welded metalsofthe16 Mnsteelundertensile tensilestress. Theresultsindicatedthattheforming processof Sub grainsfrom dislocationtanglecellstotheSub grains. Thepositionofformingfatigue micro crackisattheoxidativeinterfaceand granular noncrgstallines and Sub boundaries. Thece mentiteineutectoidsafterfracture may beproduced microcracks.

关键词： fatigueload welded metals forming sub grains crackinitiation

STUDY ON hIGh TEMPERATURE PERFORMANCES OF MCrAlx COATINGS DEPOSITED BY MULTI-ARC ION PLATING

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Acta Metallurgica Sinica(English Letters) 1999年第5期12卷 1019-1024页

作者： J. zhang, J.B. Li, Q.heng and x.h.zhang Shenyang University,Shenyang 110044,China L.Q.Qi LiMing Aeroengine Manufacfruing Corperation, Shenyang 110043,China

NCoCrAlSiYhf and CoNiCrAlTaY coatings which belong to protective Al 2O 3 scale forming type were deposited by multi arc ion plating technique . The effect of deposition process parameters on qualities of the coatings was discussed. The high temperature oxidation performances isothermal oxidation with 950℃ / 500h and 1100℃ / 100h were studied. And also, the hot corrosion performances at 700℃ and 800℃, with molten mixed salt composed of 75%wt Na 2SO 4 and 25%wt NaCl were investigated. Then the high temperature protection decaying mechanisms were proposed.

关键词： multi arc ion plating superalloy coating isothermal oxidation hotcorrosion

Effects of anions on the photocatalytic h2 production performance of hydrothermally synthesized Ni-doped Cd0.1Zn0.9S

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Effects of anions on the photocatalytic H2 production perfor...

Solar photocatalytic hydrogen production in a CPC based solar reactor:fundamentals,reactor design and preliminary results

第九届全国氢能学术会议

作者： x.h.zhang,D.W.Jing and L.J.Guo xi’an Jiaotong University,China

Development of visible light driven photocatalysts has been urged from the viewpoint of using the solar energy more effectively to resolve the global energy and environmental ***,there are just a few of photocatalysts that can work efficiently under visible light irradiation until *** authors have recently reported that Ni doped

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Solar photocatalytic hydrogen production in a CPC based sola...

Photocatalytic hydrogen production over metal-doped CdxZn1-xS under visible light

第九届全国氢能学术会议

作者： D.W.Jing,h.Liu,x.h.zhang,L.J.Guo xi ''an Jiaotong University,China

＜正＞In despite of so many types of solar reactors designed for solar detoxification purposes,it is surprising that no similar attempt has been made for photocatalytic hydrogen production, which in our option,is one of the most promising approaches for solar to chemical energy *** both the similarity and dissimilarity for these two processes and by

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Photocatalytic hydrogen production over metal-doped CdxZn1-x...