检索结果-南通市图书馆

Journal of University of Science and Technology Beijing 2002年第5期9卷 453-457页

作者： XizhongAn YuZhang 等 materialsscienceandengineeringschool UniversityofScience＆TechnologyBeijingBeijing100083China AppliedScienceSchool UniversityofScience＆TechnologyBeijingBeijing100083China

The growth of {100}-oriented CVD diamond film under two modifications ofJ-B-H model at low substrate temperatures was simulated by using a revised KMC method at atomicscale. The results were compared both in Cl-containing systems and in C-H system as follows: (1)Substrate temperature can produce an important effect both on film deposition rate and on surfaceroughness; (2) Aomic Cl takes an active role for the growth of diamond film at low temperatures; (3){100}-oriented diamond film cannot deposit under single carbon insertion mechanism, which disagreeswith the predictions before; (4) The explanation of the exact role of atomic Cl is not provided inthe simulation results.

关键词： CVD diamond film atomic Cl revised KMC (kinetic monte carlo) method atomic scale simulation

同方期刊数据库

Numerical analysis on solidification process and heat transfer of FGH95 superalloy droplets during PREP

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2003年第5期10卷 53-58页

作者： HuanmingChen BenfuHu YiwenZhang QuanmaoYu HuiyingLi materialsscienceandengineeringschool UniversityofScienceandTechnologyBeijingBeijing100083China PhysicsandElectricalInformationEngineeringSchool NingxiaUniversityYinchuan750021China CentralIronandSteelResearchInstitute Beijing100081China

In order to understand the relation between microstructure of superalloypowders and its solidification progress, the processing parameters are optimized during plasmarotating electrode processing (PREP). It was predicted from the results that the droplet velocities,droplet temperature, and fractional solidification with flight time about FGH95 superalloy droplethave been carried out based on Newtonian heat transfer formulation coupled with the classicalheterogeneous nucleation and the specific solidification process. It has been found that the dropletdynamic and thermal behavior is strongly affected by the distribution of droplet diameters, theproportion of cooling atmosphere, but is relatively unaffected by the droplet superheat.

关键词： plasma rotating electrode processing (PREP) heat transfer FGH95 superalloypowder numerical analysis

A new model for life prediction of GH4133 under TMF conditions

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2002年第4期9卷 287-291页

作者： JianguoWang HongyingWang ShipingXu LianqingWang YonglinKang StateKeyLaboratoryforAdvancedMetalsandMaterials UniversityofScienceandTeclmologvBeijing.Beijing100083China materialsscienceandengineeringschool UniversityofScienceandTechnologyBeijingBeijingBeijing100083China

Thermal mechanical cyclic strain tests were carried out under in-phase andout-of-phase conditions on a Nickel-base Superalloy GH4133 in the temperature range of 571-823 degC. Based on analyzing the present models of TMF (thermal mechanical fatigue) life prediction, a newmodel for predicting nickel-base superalloy TMF lifetime was proposed. TMF life of superalloy GH4133was calculated accurately based on the new model. Experimental TMF life has been compared with thecalculated results and all results fall in the scatter band of 1.5. The calculating results showthat the new model is not only simple, but also precise. This model will play great roles as lifeprediction of the metal materials and the engineering components subjected to non-isothermal serviceconditions.

关键词： thermal mechanical fatigue life production Nickel-base superalloy fatigue lifetime prediction model in-phase out-of-phase

Hardness variations during aging process of deformed W-Ni-Fe ternary alloys with high nickel-to-iron ratios

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2003年第4期10卷 78-80页

作者： RonghuaLi JihuaHuang ShengYin JunZhao SchoolofMechanical EleOronicandControlEngineeringNorthernJiaotongUniversityBeijing100044China materialsscienceandengineeringschool UniversityofScienceandTechnologyBeijingBeijing100083China

The aging precipitation behavior of beta phase in two kinds of alloys with7/3 and 9/1 ssickel4o-iron ratios during aging at 800 deg C after deformation was studied. Theresults show that there are two different kinds of aging hardness variation mechanisms (thesoftening mechanism and the hardening mechanism) deciding the hardness variations of the *** Ni/Fe is smaller than8/2, there is only the softening mechanism which results from the decreasing of dislocation densityand recovery or re-crystallization. And when NI/Fe is greater than 8/2 besides the softeningmechanism there is still the hardening mechanism that is induced by the precipitation of beta phase.

关键词： W-Ni-Fe ternary system aging precipitationss

A new simulation model and its application in CO_2 short-circuiting transfer welding

在线全文

学校读者我要写书评

暂无评论

China Welding 2002年第2期11卷 171-176页

作者：胡连海李桓李俊岳杨立军 materialsscienceandengineeringschool

A new simulation model of CO 2 short circuiting transfer welding may be employed to develop a new pattern of welding machine and to predict welding process parameters to obtain the optimum welding technology properties. In this paper, a new simulating model is developed according to the AWP (adapting welding physics process) waveform control method. Good agreement is shown between the predicted and experimentally determined results. The model will make an important promotion in the development of CO 2 arc welding technique.

关键词： CO 2 arc welding simulation model short circuiting transfer welding parameters prediction

Cellular automata modelling of austenite grain coarsening during reheating——I. Normal grain coarsening

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2004年第6期11卷 517-523页

作者： WanhuaYU E.J.Palmiere S.P.Banks JingtaoHan materialsscienceandengineeringschool UniversityofScienceandTechnologyBeijingBeijing100083China DepartmentofEngineeringMaterials UniversityofSheffieldSheffieldS13JDUK DepartmentofAutomaticControlandSystemsEngineering UniversityofSheffieldSheffieldS13JDUK

A two-dimensional cellular automaton (CA) model has been developed for thedescription of the normal grain coarsening process. The probabilistic CA method incorporatingMoore's definition of the neighbourhood is used to simulate the normal grain coarsening process witha new transition rule. The model simulates the grain coarsening process in as much detail that ispossible, from the point of initial nucleation to subsequent coarsening with computational *** unique result is that the grain coarsening speed can be controlled by the specific method, thisresult is vital to model the grain coarsening quantitatively. In order to make this model valid,experimental work has been done to provide solid evidence for this model. Comparison of themodelling result and the experimental result has been carried out.

关键词： computer simulation grain growth microstructure reheating

Influence of copper on quality of hot strips by EAF-CSP process

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2004年第1期11卷 57-61页

作者： YuanliWang DeluLiu WeiranShao JieFu YonglinKang DeguangZhou ZhongbingWang materialsscienceandengineeringschool UniversityofScienceandTechnologyBeijingBeijing100083China MetallurgicalEngineeringSchool UniversityofScienceandTechnologyBeijingBeijing100083China GuanzhouZhujiangIronandSteelCo.Ltd. Guangzhou510620China

Electron microscopy and X-ray Energy Dispersive Spectroscopy (XEDS) study oninfluence of Cu on low carbon hot strips produced by CSP (Compact Strip Production) process has beencarried out. The results indicated that copper segregation and enrichment at interfacial layerbetween oxidized surface and steel matrix is the key factor, which results in microcracks and edgeflaws on the strips. The primary considerations to prevent detrimental effects from Cu includecontrolling copper content in proper level, higher soaking temperature and non-oxidizable atmosphereduring soaking. Copper sulfide precipitates with nanometers in size were observed, they may bebeneficial to the properties of CSP products, and influence of Cu on quality of CSP hot strips isdiscussed.

关键词： Cu segregation surface flaws CSP hot strips copper sulfide nano-scaledprecipitates

Perpendicular magnetic anisotropy of Co_(85)Cr_(50)/Pt multilayers

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2004年第4期11卷 319-323页

作者： PolHwang BaoheLi TaoYang ZhonghaiZhatt FengwuZhut DepartmentofPhysics KimI1SungUniversityPyongyangDPRK materialsscienceandengineeringschool UniversityofScienceandTechnologyBeijingBeijing100083China DepartmentofPhysicsandMathematics BeijingTechnologyandBusinessUniversityBeijing100037China

The CoCr/Pt bilayers and (CoCr/Pt)_(20) multilayers with Pt underlayer wereprepared by DC magnetron sputtering. The effects of prepared condition on perpendicular magneticanisotropy were investigated. The results show that the thickness of Pt under-layer has a greateffect on the microstructure and perpendicular magnetic anisotropy of CoCr/Pt bilayers and(CoCr/Pt)_(20) multilayers. When the thickness of Pt underlayer increases, Pt(lll) and CoCr(002)peaks of both CoCr/Pt bilayers and (CoCr/Pt)_(20) multilayers increase and the bilayer periodicityof the multilayers is improved. The effective magnetic anisotropy of (CoCr/Pt)_(20) multilayers withPt underlayer was much larger than that of CoCr/Pt bilayers. The (CoCr/Pt)_(20) multilayers has astronger perpendicular magnetic anisotropy than that of CoCr/Pt bilayers. This is ascribed to theinterface magnetic anisotropy of the multilayers.

关键词： multilayers perpendicular magnetic anisotropy effective magnetic anisotropyconstant interface magnetic anisotropy

Forging process modeling of cone-shaped posts

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2004年第3期11卷 256-259页

作者： XuefengLiu LingyunWang LiZhang materialsscienceandengineeringschool UniversityofScienceandTechnologyBeijingBeijing100083China CollegeofMaterialsScienceandEngineering ChongqingUniversityChongqing400044China Library UniversityofScienceandTechnologyBeijingBeijing100083China

Using the rigid visco-plastic Finite Element Method (FEM), the process offorging for long cone-shaped posts made of aluminum alloys was modeled and the correspondingdistributions of the field variables were obtained based on considering aberrance of grids, dynamicboundary conditions, non-stable process, coupled thermo-mechanical behavior and other specialproblems. The difficulties in equipment selection and die analysis caused by the long cone shape ofpost, as well as by pressure calculation were solved.

关键词： coupled thermo-mechanical analysis constitutive relationship rigidvisco-plastic FEM cone-shaped post

Microstructure evolution and precipitation behavior of low carbon steel hot strips produced by CSP

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2004年第4期11卷 364-367页

作者： YonglinKang KeluWang HaoYu JieFu DeluLiu ZhongbingWang XuewenChen materialsscienceandengineeringschool UniversityofScienceandTechnologyBeijingBeijing100083China MetallurgicalandEcologicalEngineeringSchool UniversityofScienceandTechnologyBellingBelling1000153China GuangzhouZhujiangSteelCo.Ltd. Guangzhou510620China

The microstructures of low carbon steel before, during and after rollingdeformation of each stand were observed using optical microscope. The result showed that themicrostructures were very fine after six passes rolling deformation. The effect of the first standreduction on microstructure refinement was very distinct. During the rolling process, with theincrease of the accumulated strain, the microstructures would further refine, and the density ofdislocation would increase at the same time. In continuous casting thin slabs and each finishingstand, lots of observed precipitates were mainly A1_2O_3 and MnS along the grain boundaries or ingrains, which played an important role in the mechanical properties of the hot strips of low carbonsteel produced by CSP (compact strip production) technology.

关键词： CSP microstructure refinement precipitation mechanical property