钛基二元纳米合金形成焓的尺寸效应

基于计算合金形成焓的改进Miedema模型和考虑纳米颗粒表面效应,研究了钛基二元纳米合金形成焓的尺寸和成分效应.计算结果表明钛基二元合金纳米颗粒的形成焓依赖颗粒尺寸,显示了明显的尺寸效应.纳米颗粒的形成焓随粒径的减小而增大,当粒径减小到某一临界尺寸时,纳米合金的形成焓由负值转变为正值,从而降低了纳米颗粒的热稳定性.当颗粒粒径小于10 nm时,纳米颗粒发生成分聚集,这种成分聚集发生的趋势取决于纳米合金的表面形成焓.     

Thermodynamic properties and mixing thermodynamic parameters of two-phase metallic melts

Based on the calculating model of metallic melts involving eutectic, the calculating equations of mixing thermodynamic parameters for two phase metallic melts have been formulated in the light of those equations of homogeneous solutions. Irrespective as to whether the activity deviation relative to Raoultian behavior is positive or negative, or the deviation is symmetrical or unsymmetrical, the evaluated results not only agree well with experimental values, but also strictly obey the mass action law. This testifies that these equations can authentically reflect the structural reality and mixing thermodynamic characteristics of two-phase metallic melts. The calculating equations of mixing thermodynamic parameters for the model of two phase metallic melts offer two practical criteria (activity and mixing thermodynamic parameters) and one theoretical criterion (the mass action law).     

Fe-Si-C合金熔体的活度解析计算

由三元碳饱和合金熔体的碳饱和数据以及其二元子系的精选活度数据作为边界条件，导出了计算三元合金熔体整个液态均相区内务组元活度的解析计算新方法．并用之于Fe－Si－C合金熔体在1873K温度下的活度计算和预测，取得与实验数据吻合较好的结果．     

计算合金热力学性质的Miedema理论

分析了Miedema理论,在二元合金热力学性质计算时,用Miedema理论结合几何模型的方法,能为生产实验提供理论依据。对于多元合金体系热力学性质的计算,由二元系溶体的热力学性质推算多元合金体系热力学性质的溶体模型,并介绍了由Toop模型和周模型外推得到的Miedema模型。但对于多元合金体系,其理论值与实验值并不如二元合金体系符合得那样好,为了能精确地计算三元以及多元合金体系的热力学性质,还需要对几何模型作进一步完善.     

Mg-Al,Sr-Al和Ba-Al熔体的作用浓度计算模型和热力学参数确定

根据相图、质量作用定律和金属熔体结构的共存理论制定了Mg-Al,Sr-Al和Ba-Al熔体的作用浓度计算模型并求得了相关的热力学参数,计算结果符合实际,证明所制定的模型和确定的热力学参数可以反映相应熔体的结构特点,但将相应文献的热力学参数代入同样熔体则未取得符合实际的结果,原因可能与文献中的热力学参数不符合液态下金属熔体内部化学反应的实际有关。     

High temperature scaling of Ni-15Cu-5Al alloy in 1 × 105 Pa pure oxygen

The oxidation of the ternary alloy Ni-15Cu-5Al in 1 × 105 Pa pure oxygen at 700 ℃ and 800 ℃ was studied. The results show that the behavior of the Ni-rich alloy is similar to that of the binary Ni-Al alloy with the same Al content in the form of an external NiO layer coupled to the internal oxidation of aluminium. The presence of 15%(mole fraction) Cu cannot modify substantially the values of relevant parameters affecting the transition from the internal to the external oxidation of aluminium. The presence of 5 % Al reduces the oxidation rate of the corresponding Ni-Cu alloy during the whole oxidation stages, though 5 % Al is still insufficient to form protective external alumina scales.     

A thermodynamic model of calculating mass action concentrations for structural units or ion couples in NaClO_4-H_2O and NaF-H_2O binary solutions and NaClO_4-NaF-H_2O ternary solution

A thermodynamic model of calculating mass action concentrations for structural units or ion couples in NaClO4-H2O and NaF-H2O binary solutions and NaClO4-NaF-H2O ternary strong electrolyte aqueous solutions was developed based on the ion and molecule coexistence theory (IMCT). A transformation coefficient was needed to compare the calculated mass action concentration and the reported activity, because they were usually obtained at different standard states and concentration units. The results show that tran...     

多元渣系脱磷热力学模型研究

本研究以共存理论为基础，建立了多元渣系脱磷热力学模型。并采用文献中的实验数据进行了验证．利用本模型可以用来计算磷的平衡分配比和渣中任一组元的活度，预测某一成分炉渣所具备的脱磷能力。为生产上选择合理的炉渣成分提供定性和定量的理论依据．     

论热风热力参数对干燥速率的影响与干燥技术分类

分析了热风热力参数，即热风温度和含湿量对球形物料干燥速率的影响，绘制了三线四区的热风含湿量—热风温度图。该图表明，按热风热力参数，干燥技术可分为低温、常温和高温高湿三大类。这些结论对干燥技术的分类、开发和应用具有普遍的理论与实践价值。     

High temperature scaling of Ni-15Cu-5Al alloy in 1×105 Pa pure oxygen

The oxidation of the ternary alloy Ni-15Cu-5Al in 1×10⁵ Pa pure oxygen at 700 °C and 800 °C was studied. The results show that the behavior of the Ni-rich alloy is similar to that of the binary Ni-Al alloy with the same Al content in the form of an external NiO layer coupled to the internal oxidation of aluminium. The presence of 15% (mole fraction) Cu cannot modify substantially the values of relevant parameters affecting the transition from the internal to the external oxidation of aluminium. The presence of 5% Al reduces the oxidation rate of the corresponding Ni-Cu alloy during the whole oxidation stages, though 5% Al is still insufficient to form protective external alumina scales. Foundation item: Project (50071058; 50271079) supported by the National Natural Science Foundation of China     

共聚物系统的分子热力学模型

在非均核硬球链流体的基础上,通过引入方阱势能的贡献,导出了实际共聚物系统的发子热力学模型,并建立了相应的状态方程,建立的方程同计算机模拟结果比较,可发现方程能预测共聚物在不同条件下的压缩因子。     

金属熔体热力学模型的研究进展

根据不同研究方法的特点,综述了溶液模型法、几何模型法、相互作用系数法、解析计算法以及经验模型法等金属熔体热力学模型的研究进展,并对这些方法进行了简要的评述。     

Regularities of formation of ternary alloy phases between non-transition metals

Using a four-parameter model based on extended Miedema' s cellular model of alloy phases and pattern recognition methods, the regularities of formation of ternary intermetallic compounds between non-transition metals have been investigated. The criterion of formation can be expressed as some empirical functions of Φ (electronegativity), nws1/3( valence electron density in Wagn-er-Seitz cell), R (Pauling's metallic radius) and Z (number of valence electrons in atom).     

戊酮-2与脂肪醇系列溶液的超额焓模型

超额焓是现代科学研究和工程设计的重要基础数据,目前尚难以准确地预测.作者曾指出,溶液的性质取决于组成溶液的所有分子间的有机联系和相互制约,这种协同作用不是同种分子间或异种分子间个体相互作用的简单叠加,而是表现出一种整体的复杂的协同性行为.与纯液体相比,溶液的组成和性质之所以特殊,在于分子交互组成特殊的群聚体,在于分子间作用力特殊的协同作用.据此,构成超额焓的三系数模型.在此基础上,用Wiener指数定量表征模型关键参数,建立了戊酮-2与C3～C8脂肪醇组成的系列溶液超额焓的双参数模型,用实验数据进行了检验.结果表明,新模型计算值接近作者提出的三参数模型计算值,稍优于刘国杰提出的三参数模型计算值.     

改型In718镍基合金析出相的热力学模拟计算

采用Thermo-Calc热力学计算软件与相应的镍基高温合金数据库,计算了改型In718合金在960~1020℃固溶加二次时效后可能析出的平衡相,研究了不同固溶温度的变化对主要析出相的影响,分析了各相的析出规律,为进一步调整合金成分,改善合金力学性能提供了理论依据.     

链烷烃热力学性质的调和拓扑研究

基于Wiener指数(W)建立调和拓扑指数(H),该指数对乙烷至癸烷的149种烷烃呈现惟一性表征．将H、碳原子数(N)与85种链烷烃的标准生成焓(ΔfHm^θ)、标准熵(Sm^θ)、标准生成自由能(△fGm^θ)关联,线性相关系数依次为0．9966、0．9972、0．9892,非常接近或优于文献结果．表明H是具有良好的结构选择性和性质相关性的拓扑指数．     

利用织物粘弹性固体模型参数计算折皱回复角

基于纺织材料的粘弹性理论，利用标准固体单元和滑块并联组成的模型，在织物摩擦约束力偶与其弯曲曲率成正比的假设下，对织物的弯曲和折皱回复性能进行了分析，并利用纯弯曲实验得到的数据计算出织物的模型参数，进而计算出了织物在不同时刻的折皱回复角．所得理论值与实测值符合较好。     

Design of an age hardening Mg-Li alloy and its aging behavior

An effort was made to design an age hardening Mg-Li alloy based on the phase diagrams calculated by means of“THERMO-CALC”-a thermodynamic software. Experiments were carried out to verify the calculated results by melting the alloy and examining its structure and aging behavior. The results show that the alloy possesses a structure constituent as expected, besides,the alloy has apparent aging behavior and over aging happens even at lower temperature. Metastable (Mg, Li, A1, Zn) phase has been identified when the hardness reaches the aging peak. With the increase of the aging time, (Mg, Li, Al, Zn) phase transforms to stable α phase and over aging happens.     

钢液中镁合金复合脱氧热力学分析

镁具有净化钢液、细化钢中非金属夹杂物的作用．针对钢液镁处理技术的发展需求,本文采用一阶和二阶相互作用系数,基于吉布斯自由能最小原理计算得到了Mg-Al-O、Mg-Si-O、Mg-Ti-O、Mg-Zr-O的热力学优势区域图,并探讨合金元素含量与脱氧平衡产物间的关系．通过热力学计算,揭示了钢液镁处理在不同脱氧制度下钢中脱氧产物的变化规律,可为镁处理在生产实践中的应用奠定理论基础．     

金属Al电子结构与热力学性质的第一性原理计算

针对金属Al的电子结构与热力学性质,采用基于密度泛函理论的第一性原理以及CASTEP软件进行了理论计算,得到了金属Al的平衡晶格常数、相关弹性系数、电子能带、态密度、声子谱、声子态密度以及相关热力学参数,并对计算结果进行了理论分析.结果表明,金属Al具有明显的导电特性与良好的塑性.金属Al具有3条声学支波色散曲线与一个声子态密度峰.随着温度的增加,熵、焓均增加,而自由能减少.热容量随着温度的增加而迅速增加,当温度达到500 K后,热容量几乎不变,所得结论与物理规律相符合.