共查询到20条相似文献,搜索用时 15 毫秒
1.
贵金属二元合金相图研究的新进展和展望 总被引:5,自引:1,他引:4
对贵金属二元合金相图研究现状及其可靠性进行了全面的分析,把贵金属与周期表中各元素的相互作用分成连续固溶体、简单包晶型、简单共晶型、简单偏晶型、生成化合物的复杂体系和在固态和液态都不互溶的6种类型,并把它们放在元素周期表中进行研究后,定性总结了它们的若干规律;评价了二元相图坐标的热力学表示原理;评价了二元相图的半径验计算法和中间相的IUPAC(国际理论化学和应用化学联合会)和MSIT(国际材料科学组织)表示法,强调半经验的热力学计算法比较成熟,而按第一原理的理论计算法尚处在快速发展中;展望了贵金属二元合金相图的发展方向。 相似文献
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目前在二元相图中普遍存在两个被疏忽的问题:一是关于二元系中许多中间相在某一温度发生晶型转变时如何表示的问题,在已发表的二元相图资料中,大部分用水平实线或虚线来表示这种晶型转变,而二元相图中水平实线或虚线通常是用来表示三相平衡的等温反应,但中间相的晶型转变不是三相平衡的等温反应,所以,不能用实线或虚线来表示;二是对某些沸点较低的组元,在温度高于其沸点温度时,靠近这些组元的端际单相区应该是气相,而许多二元相图中仍然标为液相.本文作者认为应该重视由于疏忽而产生的这两类问题,并加以改正,以免让读者产生误解. 相似文献
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J. Guo 《金属学报(英文版)》1999,12(3):216-220
1.IntroductionAlthoughthecomputerizedpredictionofalloyphasediagramsbythermodynamicmethodhasmadegreatachievements,thelackofthermodynamicdataisoneoftheobstaclesforthecomputationofalloyphasediagrams.Manymethodsforcomputerizedalloyphasediagramshavebeenproposedinordertoovercometheobstacle.Forexample,thereareHume--Rotherytheory[']forsolidsolutiollofbinaryalloysystemandMiedema'stwoparameters.oded2](Ark*,A.;/sa)forthethermodynamicpropertyestimationofalloysystems.Che.[3--5]hajsappliedatomicparameter-… 相似文献
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利用Calphad方法重新评估了Mg-Si二元系的液相,并结合Mg-Zn和Zn-Si二元系热力学数据,外推得到Mg-Zn-Si三元系热力学参数;同时根据Mg2Si-MgZn2伪二元相图实验数据评估了Mg-Zn-Si系的液相三元相交互作用参数,计算相图与实验数据较一致。利用Scheil凝固模型模拟了Mg-2.33Zn-0.9Si(at%)合金的凝固过程,预测了镁合金在铸造冷却过程中的相演变信息,模拟计算结果与实验结果吻合较好 相似文献
5.
二元连续固溶体合金交互作用参数与相图的计算机预报 总被引:2,自引:0,他引:2
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。 相似文献
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K. W. Richter H. Ipser Institut für anorganische Chemie Universit?t Wien W?hringerstrasse A- Vienna Austria 《金属学报(英文版)》2002,15(2):143-148
1. IntroductionAmong the III-V compound semiconductors, GaSb and InSb, belong to the narrowbandgap materials which gained increasing interest during the last yearsIl,2l due to theirhigh potentiality for many electronic and optoelectronic aPplications. The… 相似文献
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纳米金属微粒二元相图的尺寸效应和形状效应 总被引:1,自引:0,他引:1
通过考虑相图计算公式中基本参数——熔化温度和熔化焓的尺寸效应与形状效应,研究了完全互溶的二元纳米金属微粒系统理想溶液的相图.研究结果表明,纳米微粒的相图也依赖于微粒的尺寸和形状因子.对Cr-Mo纳米微粒系统相图的计算结果表明,纳米微粒相图的固相线和液相线要比相应块体材料的固相线和液相线低,但与已报道的结果不同的是,固、液相线变化的幅度基本相同.这与本文目前不仅考虑了纳米微粒熔化温度的影响,还考虑了纳米微粒熔化焓的影响有关. 相似文献
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The diagram of Ag-Cu-Ge system was constructed from the investigation of 13 internal sec-tions by DTA heating as well as cooling curves in an atomsphere of dry N_2 . The phase dia-gram is subdivided into two pseudo-ternary systems shown as Ag-Cu-Cu_3Ge andAg-Cu_3Ge-Ge. Both systems belong to simple eutectic type. The ternary eutectic points liein." E_1, Ag(22.0)-Cu(58.8)-Ge(19.2), 632℃ and E_2 , Ag(44.3)-Cu(29.5)-Ge(26.2), 533℃.The three side binary systems were redetermined. 相似文献
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Shuang-Lin Chen Jie-Yu Zhang Xiong-Gang Lu Kuo-Chih Chou Y. Austin Chang 《Journal of Phase Equilibria and Diffusion》2006,27(2):121-125
Graham scan, a computational geometric algorithm for finding a two-dimensional convex hull, is introduced to calculate binary
phase diagrams. This algorithm is modified and applied to find the convex hull of discrete points in the space of Gibbs energy
vs mol fraction. The modified Graham scan algorithm has a very low computational cost, which improves efficiency in binary
phase diagram calculation. 相似文献
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杠杆安律可以用来计算处于两相平衡的二元合金中每个相的质量分数,它也可以用来估算二元合金在接近平衡状态下,不同组织组成物的质量分数,从而使它具有实用价值。应用杠杆定律时,必须遵循相图的基本规律并使用标准术语。 相似文献
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利用CALPHAD方法,选择和建立合理的热力学模型,并结合相平衡及热力学性质的相关实验信息,对Mo-RE (RE: Ce, Pr, Nd, Sm, Eu, Tb, Ho, Er, Tm, Yb, Lu)各二元系相图进行了热力学优化与计算。其中,液相和端际固溶体相的Gibbs自由能采用亚正规溶体模型描述,气相的Gibbs自由能采用理想气体模型描述。计算结果与实验数据取得了良好的一致性,最终得到了一组自洽的合理描述Mo-RE二元系各相自由能的热力学参数,建立了Mo-RE (RE: Ce, Pr, Nd, Sm, Eu, Tb, Ho, Er, Tm, Yb, Lu)二元合金相图的热力学数据库。该热力学数据库可以提供相平衡及热力学性质等多种信息,为外推计算三元以及更多组元体系的相平衡提供理论基础,并为相关体系的合金设计及制备提供重要的理论指导。 相似文献
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用改进的半导体材料生长中的液相外延设备测定了GaAs在Bi中溶解度。根据测定结果,获得了富Bi侧的Bi-GaAs二元平衡图。同时发现,在所研究的温度范围内相同的溶解时间内的溶解量与饱和溶解量之比与温度的关系也各不相同。这一现象似可认为是某些金属间溶解过程中的普遍特性。 相似文献
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The Sn−Ti−Zn ternary phase diagram has been constructed using the CALPHAD technique. The Ti−Zn binary system phase boundaries
were determined using differential scanning calorimetry and the solid-liquid diffusion couples method. In addition, the formation
energy of some stoichiometric compounds was obtained using first-principle band energy calculations. For the ternary system,
some alloys were prepared by equilibration at 600 or 700 °C, and the compositions of the precipitates were analyzed using
electron probe microanalysis. Thermodynamic assessment of the Ti−Zn and Sn−Ti−Zn systems was performed based on the experimental
information and by adopting reported values of the thermodynamic properties of the Sn−Zn and Sn−Ti binary systems. Microstructural
observation showed that Sn3Ti5Zn12 exists in the ternary system. Seven types of invariant reaction on the Sn-rich liquidus surface of the ternary system are
predicted by the phase diagram calculations. The ternary eutectic point falls at 0,0009 mass% Ti and 8.69 mass% Zn, at T=192.40°C, which is slightly lower than the calculated eutectic point of Sn−Zn binary alloy (T=192.41°C). Based on these results, a nonequilibrium solidification process using the Scheil model was simulated.
This paper was presented at the International Symposium on User Aspects of Phase Diagrams, Materials Solutions Conference
and Exposition, Columbus, Ohio, 18–20 October, 2004. 相似文献
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合金元素对Au的强化效应与应用 总被引:7,自引:4,他引:3
本文讨论了二元Au合金系中富Au端相图特征,合金元素在Au合金中分布及强化与脆化倾向性,分析了合金元素对Au的固溶强化参数和没淀强化参数,轻金属(尤其是Be)具有最高固溶强化参数,Ti具有最高沉淀强化参数;稀土金属兼具高的固溶强化参数和沉淀强化参数,是强化Au与Au合金的重要合金元素,讨论了某些实用Au合金的强化机制。 相似文献
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FENG Shuifu ZHO U Jicheng Shanghai Institute of Metallurgy Academia Sinica Shanghai China ZHOU Jicheng Shanghai Institute of Metallurgy Academia Sinica Shanghai China 《金属学报(英文版)》1990,3(11):312-315
A modified liquid phase epitaxy apparatus for semiconductor materials was used to measurethe solubility of GaAs in Bi.Two phase diagrams rich in Bi under H_2 and N_2 atmosphereswere obtained according to the results of measurement.A new phenomenon,in which theparameter Q value(quantity of GaAs dissolved in Bi in fixed time/saturation quantitu,ofGaAs in Bi)was different from each other at various temperatures and there existed a maxi-mum Q value at definite temperature,was observed.This phenomenon may be regarded as acommon feature of a simple binary metallic system which has the phase diagram similar tothat of Bi-GaAs.The difference observed from the dependence of Q values on temperature inboth H_2 and N_2 atmospheres was discussed. 相似文献
20.
Hideki Hosoda Shuichi Miyazaki Yoshinao Mishima 《Journal of Phase Equilibria and Diffusion》2001,22(4):394-399
In order to express multicomponent phase relationships, a new type of phase diagram, named a “pillar phase diagram,” is proposed.
The pillar phase diagram is a sort of quaternary and Brewertype phase diagram. A pillar phase diagram at a temperature is
easily constructed by (1) composing three sides of Brewer-type ternary-phase diagrams along the periodic table and (2) piling
triangles of general ternary phase diagrams along the periodic table. Using the pillar phase diagrams, systematic understandings
of phase constitution and stability along the periodic table can be performed for (1) binary intermetallics containing ternary
and quaternary additional elements and (2) ternary intermetallics containing quaternary elements. Thus, the diagrams are convenient
in terms of alloy design of multiphase intermetallic alloys. In this paper, the concept and the construction method of the
pillar phase diagrams are described, and some examples are shown for systems related with L12 Ni3Al, B2 NiAl, L21 Ni2AlTi, B2 NiTi, B2 FeTi, L10 TiAl, and L12 Al3Ti alloys. 相似文献