Li,K|F,Cl互易系熔盐溶液的分子动力学计算机模拟研究

用分子动力学方法对Li,K?F,Cl系熔盐溶液进行了计算机模拟研究。计算了径向分布函数、偏克分子混合能等热力学性质以及Li~+,K~+,F~-和Cl~-的扩散系数。计算值与实验值大体符合。根据计算结果,讨论了熔盐溶液中离子和空孔分布的规律。     

氯化镁熔盐的分子动力学模拟

根据包括离子间极化作用势在内的离子间势对氯化镁熔盐做了分子动力学模拟．计算出的偏径向分布函数与中子衍射结果大致符合．计算结果表明，熔体中存在微观分布不均匀的缝隙，Ｍｇ２＋周围的Ｃｌ－离子数分布在２与６之间．熔盐含有和离子．     

COMPUTERIZED SIMULATION OF STRUCTURE OF CRYOLITE MELT

用Monte Carlo法对冰晶石熔体结构作计算机模拟研究。计算了1283K的3NaF·AlF_3熔体中离子分布的各种偏径向分布函数和若干局部结构的表征函数。结果表明:冰晶石熔化后,AIF_63-中部分F-离子远离Al~(3+)离子,和Na~+离子组成xNa~+·yF-离子集团。AlF_63-部分解体成为可用AlF_4-,AlF_52-代表的局部结构。部分Al~(3+)通过Al-F-Al(氟桥)连接,组成Al_2F_7-等离子集团。计算还表明:冰晶石熔体中自由体积的分布不均匀,xNa~+·yF-集团内部以及AlF_4-和xNa~+·yF-之间缝隙较大。     

铸钢在凝固区的流变行为SCIEI

用自行设计的流变性能测定仪测量了624钢(32MnNiMoCu)在凝固区内的应力、应变关系。建立了该钢的流变模型、本构方程并确定了流变特性参数。为开展铸钢的应力、应变和热裂纹的计算机数值模拟提供了理论基础及计算数据。     

COMPUTERIZED SIMULATION AND EXPERIMENTAL RESEARCH ON SOFT-SWITCHING ARC WELDING INVERTER POWER SOURCE

1.Arcweldinginverterhasbecomethefocusinthefieldofweldingpowerso~e,becauseofitssmallvolUIne,lightweight,goodconndingperfonnanceandaptnessforreal--timecontrollingofweldingprocess.HoWeVer,beingasophisticatedpowerelectIDnicdevice,theweldinginvertercanhaullybedevelopedusingconventionaltrial--and--failmethod.Besidesthelargehumanandmaterialresourcesandconsiderablebine,therearePchemsthatareinsolVable.ThisisespeciallytrUefortherecentlydevelopedsoftswitchingpowersources,inwhichseveralworkingmodesexi…     

COMPUTERIZED PREDICTION OF INTERACTION PARAMETERS AND PHASE DIAGRAMS OF CONTINUOUS SOLID SOLUTION OF BINARY ALLOY SYSTEMS

1.IntroductionAlthoughthecomputerizedpredictionofalloyphasediagramsbythermodynamicmethodhasmadegreatachievements,thelackofthermodynamicdataisoneoftheobstaclesforthecomputationofalloyphasediagrams.Manymethodsforcomputerizedalloyphasediagramshavebeenproposedinordertoovercometheobstacle.Forexample,thereareHume--Rotherytheory[']forsolidsolutiollofbinaryalloysystemandMiedema'stwoparameters.oded2](Ark*,A.;/sa)forthethermodynamicpropertyestimationofalloysystems.Che.[3--5]hajsappliedatomicparameter-…     

LiF-KCl熔盐溶液的径向分布函数SCIEI

本文利用X射线散射技术测定和Monte Carlo计算机模拟计算,获得了LiF-KCl熔体的径向分布函数。实验发现,在互易系LiF-KCl熔体中,小离子Li^+与F^-更易形成结合较为紧密的集团,而大离子K^+与Cl^-的结合相对较为松地,即出现“大大小小”效应。     

ADVANCED WAYS OF IMPROVING THEWELDED STRUCTURES

TheprogressintheleadingbranchesofthenowadaysindustryiscloselycormectedwiththesolutionofthoseProblems,whichareencounteredintheconstrUctionOfthereliableandlong--livedweldedstrUctures.TheseProblemsincludetheaPPlicationoftheadvancedstrUcturalmaterials,updatingthestandalsandnilesOfthestructUredesiring,OPtidrizationofthedesignofjointsandmembers,thesolutionoftheproblemsofthestructUleadaptabilitytofabrication,theselectionofoptimumtechnologiesOfwelding,thedesignofnecessapeoppmentforthestructu-refa…     

ON THE AB_3 TYPE ALLOY PHASES OF(Nd, Gd. Dy)-Ir SYSTEM

<正> 用计算机模式识别方法预测未知的合金中间相,是一种很有效的方法。用元素的价电子数Z、金属半径R、功函数φ等的函数张成多维空间,将已知金属间化合物绘入空间,用上述方法可以区分各种晶型的分布区域。据此可预报未知的合金中间相。我     

板料网格模型对薄板成形仿真计算结果的影响分析

本文以薄板冲压成形仿真中板料有限元网格模型为对象 ,研究了板料网格大小对仿真计算精度和计算效率的影响。以方形盒成形为例 ,分析了几种不同板料网格划分方案的仿真结果 ,并与 NUMISHEET 93的实验数据进行了对比 ,给出了进行薄板成形仿真时板料有限元网格模型的一般划分原则。并将结果应用于桑塔纳轿车车顶的成形仿真分析 ,实践证明本文所给出的这些建模原则是切实可行的。     

不同拉拔工艺对管材尺寸精度的影响

高精度管材是一种表面质量（特别是内表面质量）要求很高,内径尺寸允许偏差很小的管材,多用于精密设备。简要概述了目前管材生产现状以及高精度管材的发展前景,分析了不同拉拔工艺对管材尺寸精度的影响．介绍了计算机仿真技术在拉拔工艺研究中的应用及现有模拟结果。     

二元连续固溶体合金交互作用参数与相图的计算机预报

利用人工神经网络方法讨论了原子参数与二元合金相的交互作用参数的关系,并通过热力学原理与人工神经网络方法的结合计算了二元连续固定溶体合金相图,所计算的相图与实测相图符合得很好。     

Cu—Ni合金组元的偏原子体积与平均原子体积的关系

本文建立了固溶体组元的偏摩尔性质与平均摩尔性质的一般关系式手ＣＣ理论中的偏摩尔性质函数;导出了组元的偏摩尔性质与平均摩尔性质的差值方程和差值约束方程,以及Ｇｉｂｂｓ－Ｄｕｈｅｍ一般式;证明由ＣＣ理论中固溶体平均摩尔性质各组合函数求得的偏摩尔性质是相等的,但在一般情况下,偏摩尔性质不等于组元的平均摩尔性质。以Ｃｕ－Ｎｉ合金和组元的平均原子体积以及组元的偏原子体积的计算为例,证明了这些论述。     

熔盐—液体金属相互溶解度的规律性

应用原子参数（阴阳离子半径，价电子数，表征金属元素价电子云密度的ｎ＾１／３ｗｓ参数）－人工神经网络方法研究了熔盐－液体金属系的互溶度，会溶温度及偏晶点成分的规律，研究结果表明，金属元素的ｎ＾１／３ｗｓ愈大，熔协在液体金属中溶解度便小，训练后神经网络可以预报熔盐液体金属系的会溶温度和偏晶点成分，预报值和实测值相当符合。     

碘对N18锆合金应力腐蚀开裂的影响

研究了再结晶退火N18锆合金在碘气氛中的应力腐蚀开裂（SCC）行为,着重研究了350℃时碘分压对该合金SCC的影响.结果表明,随着碘分压增加,N18合金对碘致应力腐蚀开裂 的敏感性增加,开裂的临界应力强度因子KISCC降低,裂纹萌生所需的应力降低,裂纹萌生所需的时间也缩短;SCC裂纹的快速扩展也受碘分压的强烈影响,碘分压越高, 裂纹扩展过渡到快速的穿晶准解理方式时对应的应力强度因子越低;碘分压不仅影响腐蚀产物层的形成,也影响裂纹扩展方式.碘分压的影响规律可用碘的扩散机制及Zr-I-O体系的化 学平衡来解释.     

IMEC—金属间化合物检索和预报的专家系统

采用化学键参数-模式识别方法总结的金属间化合物的形成、晶型和化学配比规律,建立了能检索、预报二元金属间化合物的专家系统——IMEC。可用人机对话形式提供任何二元合金系的金属间化合物的存在、晶型和化学配比的信息。     

MOLECULAR DYNAMIC SIMULATIONS OF MOLTEN NaF

The structure and transport properties in molten NaF have been studied using the method ofmolecular dynamics simulation. The calculations are based on two models of interionic potentials,which are Fumi-Tosi potential (FT) and the Fumi-Tosi potential without Van derWaals attractive item (FT). The radial distribution function (RDF) and the Na~+ andF~- self-diffusion coefficients have been calculated. The calculated results are in good agreementwith the experimental ones. The calculation shows that the two models give nearly identicalradial distribution function and self-diffusion coefficient, but the results of FTpotentialare a little better than those of FT potential.     

INVESTIGATION OF THE EFFECT OF TEMPERATURES ON TENSILE LOAD DROPS OF TITANIUM ALLOY

1.IntroductionLowtemperaturesmaysignificantlyaffectthemechanica1propertiesofmaterials-Basedonthelowtemperaturestrellgth-toughnesscharacteristics,cry0genicstructuralmaterial8weredividedint0threeclassesbyMorrisll].Thefirstclassincludesmaterialsthatundergoaductile-brittletransitionatlowtemperatures,thesecondclassthatremainsductileatalltemperaturesandthethirdthemetastablealloyswhoseductilityandtoughnessarelargelydeterminedbylowtemperaturephaJsetransf0rmations.Severalillterestingmechanicalphenomen…     

IMEC——AN EXPERT SYSTEM FOR RETRIEVAL AND PREDICTION OF BINARY INTERMETALLIC COMPOUNDS

An expert system,IMEC,for the retrieval and prediction of binary intermetallic compoundshas been built.The rules found by chenlieal bond parameter-pattern recognition method havebeen used for computerized prediction.Data base of known mtermetallic compounds andchemical bond parameters of metallic elements and the knowledge proeessing system are included in the expert system.By man-machine interfacing,the formation,stoichiometry andcrystal type o fall binary intermetallic compounds can be predicted or retrieved.     

NUMERICAL SIMULATION OF CASTING＇S MOLD FILLING PROCESS

Numerical simulation of casting＇s mold filling process is the main and the most important aspect of the foundry CAE technology. But it is time-consuming; it may take dozens of hours or several days. While with the development of computer hardware, numerical simulation of casting＇ s mold filling process has made rapid progress. The simulation results, therefore, have become more and more practical. This study tries to find some clues of the computational time of mold filling process. Firstly, this paper introduces mathematic model and the basic route of numerical simulation of casting＇s mold filling process. Then the computational time of mold filling process has been carefully studied, and some new and useful results have been gained from the study of the computational time. Finally, this paper has given some real applications of numerical simulation of casting＇s mold filling process.