三元扩散偶中的相区分布与四相平衡的关系

根据相区邻接规则和扩散偶中的相区分布的关系，运用三元扩散偶方法确定三元系中的四相转变从而导出三元系中相转变与扩散偶中相区分布的关系，利用Nb-Ti-Si三元系的试验，验证了包共析型转变前后等温截面与扩散中相区分布的关系。     

Mg-Zn-La系富Mg角固态相平衡的研究

利用SEM、XRD以及EPM对Mg-Zn-La系相图中富Mg角300℃的固态相平衡进行了研究.结果表明,在Mg-Zn-La系存在一个线性化合物(Mg,Zn)92La8(T相),而且在富Mg角存在一个由T相 α-Mg相组成的宽阔的两相区,以及α-Mg MgZn(La)相 T相的三相区.     

Partial phase diagram of Au-Ag-Dy ternary system

On the basis of Au-Ag, Au-Dy and Ag-Dy binary phase diagrams, the 700 ℃ isothermal section of Au-Ag-Dy ternary system（Dye≤35 %, mole fraction） was established by X-ray diffraction analysis, differential thermal analysis and optical microscopy. It is found that there is a long single-phase region, Au（Ag） or Ag（Au）, along the Au-Ag binary isomorphous system on the gold-silver-rich side of the 700 ℃ isothermal section and between the binary compound Au2Dy and Ag2 Dy there is the all proportional solid solution, （Au2 Dy） or （Ag2 Dy）. It is confirmed that the partial 700 ℃ isothermal section consists of six single-phase regions： solid solution Au（Ag） or Ag （Au）, （Au2 Dy） or （Ag2 Dy）, Au6 Dy, Au51 Dy14, Au3 Dy and Ag51 Dy14 ; nine binary-phase regions; （Au2 Dy） ＋ Au （Ag）, Au6Dy＋ Au（Ag）, Au（Ag） ＋Ag51 Dy14 , Ag51 Dy14 ＋ （Au2Dy）, Au3Dy＋（Au2Dy）, Au3Dy＋ Au51 Dy14, Au51 Dy14＋Au6Dy, Au51 Dy14＋Au（Ag） and Au（Ag） ＋Au3Dy; four ternary regions： Ag51 Dy14＋ （Au2Dy）＋ Au （Ag）, （Au2 Dy） ＋ Au（Ag） ＋ Au3 Dy, Au（Ag） ＋ Au3 Dy＋ Au51 Dy14 and Au51 Dy14＋ Au （Ag）＋ Au6 Dy. No new ternary compound is formed in the gold-silver-rich field（Dy≤35 %） of the Au-Ag-Dy ternary system.     

Experimental determination of phase equilibria in the Fe---Al---C system

The phase equilibria in the Fe---Al---C system have been determined between 800 °C and the liquidus surface. From cast alloys the liquidus surface was established. From electron microprobe analyses (EPMA) of quenched samples three isothermal sections at 800, 1000 and 1200 °C have been obtained. Additional high temperature X-ray diffraction experiments (HT-XRD) yielded three vertical sections and the temperatures of four invariant reactions. The influence of carbon on the transition temperature between the disordered (A2) and the ordered (B2) -solid solution was determined from HT-XRD experiments with single crystals. This transition is shifted remarkably to higher temperatures by the addition of carbon. Special emphasis was placed on establishing the homogeneity range of the K-phase and its dependence on temperature. This dependence is discussed in terms of order/disorder. In addition, the properties of the K-phase, lattice constant as function of chemical composition, microhardness and thermal expansion coefficient , have been determined.     

Determination of isothermal section of Ni—Pt—Ta ternary system at 1173K

The isothermal section of the Ni-Pt-Ta ternary system at 1173K was determined by means of the diffusion triple technology and the electron microprobe analysis.The phase relations in this system were studied.Linear compound(Ni,Pt)3Ta with small solubility forming between Ni3Ta and Pt3Ta was identified.Four binary compounds,i.e.Pt2Ta,Ni2Ta,NiTa and NiTa2,and four three-phase fields,i.e.Pt2Ta (Ta) NiTa2,Pt2Ta NiTa2 NiTa,Pt2Ta (Ni,PT)3Ta NiTa and (Ni,Pt)3Ta NiTa Ni2Ta,were also identified.     

Co-Cu-Zn三元系相平衡的实验研究

本实验通过采用电子探针显微分析和X-ray衍射分析方法实验研究了Co-Cu-Zn三元体系在800°C和1000°C时的相平衡。在这两个等温截面中均未发现三元化合物。在800°C等温截面,Co在β-CuZn相中的固溶度为32.36%,Cu在β1-CoZn相中的固溶度为5.28%。除此之外,γ-Co5Zn21和γ-Cu5Zn8具有相同的晶体结构,因此,它们之间形成了一个贯穿连续固溶体相。1000°C的等温截面中,β-CuZn相、β1-CoZn相、γ-Co5Zn21相、γ-Cu5Zn8相都消失了。随着温度从800°C上升到1000°C,液相区域增大。     

Ni-Al-Sn三元系相平衡的实验研究

采用电子探针显微分析和X-ray衍射分析方法实验研究了Ni-Al-Sn三元体系在800°C和1000°C时的相平衡。结果表明：(1) Ni-Al-Sn三元体系在800°C和1000°C时均未发现三元化合物;(2) Ni-Al侧包含NiAl、Ni3Al、Al3Ni和Al3Ni2四个化合物,其中800°C时,Sn在NiAl和Ni3Al中的固溶度在分别为3.1和14.7 at.%,在1000°C时分别为3.0和8.0 at.%。而Sn在Al3Ni和Al3Ni2相中几乎没有固溶度;(3) Ni-Sn侧包含Ni3Sn(r)、Ni3Sn(h)和Ni3Sn2(h)三个化合物相。800°C时,Ni3Sn(r)相的固溶度为4.2 at.%,1000°C时,Ni3Sn(r)相转变为Ni3Sn(h)相,拥有5.5 at.% 的固溶度。另外,800°C时,Al在Ni3Sn2(h)相中的固溶度为8.4 at.%,1000°C时为12.1 at.%;(4) Ni-Al-Sn三元体系Al-Sn侧为相互贯通的液相区域,实验测得的Ni在Al-Sn侧的溶解度约为1 at.%。     

New investigation of phase equilibria in the system Al-Cu-Si

The phase equilibria and invariant reactions in the system Al-Cu-Si were investigated by a combination of optical microscopy, powder X-ray diffraction (XRD), differential thermal analysis (DTA) and electron probe micro analysis (EPMA). Isothermal phase equilibria were investigated within two isothermal sections. The isothermal section at 500 °C covers the whole ternary composition range and largely confirms the findings of previous phase diagram investigations. The isothermal section at 700 °C describes phase equilibria only in the complex Cu-rich part of the phase diagram. A new ternary compound τ was found in the region between (Al,Cu)-γ₁ and (Cu,Si)-γ and its solubility range was determined. The solubility of Al in κ-CuSi was found to be extremely high at 700 °C. In contrast, no ternary solubility in the β-phase of Cu-Al was found, although this phase is supposed to form a complete solid solution according to previous phase diagram assessments. Two isopleths, at 10 and 40 at.% Si, were investigated by means of DTA and a partial ternary reaction scheme (Scheil diagram) was constructed, based on the current work and the latest findings in the binary systems Al-Cu and Cu-Si. The current study shows that the high temperature equilibria in the Cu-rich corner are still poorly understood and additional studies in this area would be favorable.     

Cu-Ni-Sn三元系相平衡的热力学计算

基于Cu-Ni-Sn三元系的相平衡和热力学的实验信息,采用亚正规溶体模型描述液相和fcc相的Gibbs自由能,为了预测该体系中bcc相的A2-B2有序-无序转变,bcc相的Gibbs自由能采用双亚点阵模型进行描述.利用CALPHAD(相图计算)方法评估了Cu-Ni-Sn三元系各相的热力学参数,计算的富Cu侧相图和热力学性质与实验数据比较一致.并对该三元系中bcc相的A2-B2有序-无序转变及fcc相的溶解度间隙进行了计算.这些计算结果对利用析出强化以及Spinodal分解开发高强度和高导电性的新型Cu基合金的组织设计具有一定的指导意义.     

Solid-phase equilibria in the Ti-rich part of the Ti---Al system

The solid-state-phase equilibria in the Ti-rich portion of the Ti---Al system (0–50%Al) have been investigated at temperatures between 800°C and 1415°C by electron probe microanalysis (EPMA) and by transmission electron microscopy (TEM) on diffusion couples as well as on annealed alloys. The TEM observations on the diffusion couples show that the phase field ₂, (ordered hexagonal DO₁₉) extends up to the β (bcc A2) phase field, leading to two peritectoid transformations, β + → ₂ at T = 1210 ± 10°C and β + ₂→ at T = 1160 ± 10°C (: hexagonal A3). The diffusion-couple experiments yield the tie lines of the observed phase equilibria. The present results confirm the existence of a eutectoid transition → ₂ + λ (λ: ordered fcc Ll₀) at about T = 1120 ± 10°C. An updated phase diagram based on these data is presented.     

773K isothermal section of Gd—Ni—Ti ternary system

The 773K isothermal section of the Gd-Ni-Ti system was investigated b X-ray diffractometry,optical microanalysis and electron probe microanalysis techniques.The results show that it consists of 13 single-phase regions,23 two-phase regions and 11 three-phase regions.The maximum solid solubility of Ti in Ni,Gd2Ni17,GdNi5 and Gd2Ni7 are 6.0%,3.0%,3.0%,and 2.5(mole fraction).respectively.     

Practical applications of phase diagrams in continuous galvanizing

Zn-Fe based high-order phase diagrams have found a wide range of applications in continuous galvanizing. With the development of computer software DEAL (DetermineEffectiveALuminum), the Zn-rich corner of the Zn-Fe-Al phase diagram is being used daily for scientific interpretation of bath assays. Computer software PAL (PredictAluminumLevel), also developed by Teck Cominco Metals Ltd., assesses transient equilibria between the steel substrate and the liquid galvanizing alloy for the estimation of Fe dissolution and Al consumption in galvanizing. Aluminum deportment in galvanizing baths has been scientifically described based on the fact that bath assays corresponding to different locations and depths of a galvanizing bath formed one tie-line in the liquid-Fe₂Al₅ two-phase field of the Zn-Fe-Al phase diagram. Zn-Fe based high-order phase diagrams also afford a better understanding of the mechanisms for a number of industrial phenomena. These practical applications of the Zn-Fe based phase diagrams are detailed in the article. This article is based on a presentation made at the Galvanizers Association Ninety-Seventh Meeting held in Lexington, KY, from Oct 17 to 19, 2005.     

Phase equilibria in Co−Al−Re ternary system at 1100 and 1300 °C

Isothermal sections of the Co?Al?Re ternary system at 1100 and 1300 °C were determined experimentally by electron probe microanalysis and X-ray diffraction. The results show that there are seven three-phase regions in the 1100 °C isothermal section and five three-phase regions in the 1300 °C isothermal section. The solid solubilities of αCo, εRe and CoAl increase a little with temperature increasing from 1100 to 1300 °C. The solubility of Co in compounds AlRe₂, Al₁₁Re₄ and Al₄Re is negligible, <1.5 at.%. And no ternary compounds are found.     

Determination of phase equilibria in the Ni-Ta-Zr system at 1223 K

The phase equilibrium relations of the ternary Ni-Ta-Zr system at 1223 K were investigated by means of diffusion triple and electron probe microanalysis (EPMA) techniques. Two ternary compounds were found and a series of tie lines and tie triangles have been determined. The maximum solubility of Ta in NiZr2 is about 13.5% (atom fraction). The corresponding tentative isothermal section at this temperature was constructed based on current experimental information.     

Thermodynamic evaluation of the phase equilibria and glass-forming ability of the Ti−Be system

The glass-forming ability of Ti−Be alloys is of great interest. Experimental and theoretical evaluations of the glass-forming ability of this binary alloy show that the formation of a metastable TiBe phase with a CsCl-type B2 structure controls the glass-forming ability in this system. However, there is no information on the thermochemical properties of metastable TiBe for the quantitative evaluation of the glass-forming ability using Davies-Uhlmann kinetic formulations. We have carried out a thermodynamic analysis using experimental phase diagram data and the energy of formation of the stoichiometric compounds from ab initio calculations. Furthermore, the Gibbs energy of formation for the body-centered cubic (bcc) phase was evaluated over the entire composition range by applying the cluster expansion method (CEM) to the total energy of some bcc-based ordered structures obtained from ab initio calculations. For the bcc phase, the two-sublattice formalism, (Ti, Be)_0.5(Ti,Be)_0.5, was adopted to describe the A2/B2 transformation. A good agreement between the calculated values and experimental phase equilibria was obtained. Evaluation of the glass-forming ability was also attempted utilizing the thermodynamic quantities obtained from the phase diagram assessment. The calculated glass-forming ability agrees well with the experimental results. 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.     

550 AND 450℃ ISOTHERMAL SECTIONS OF Fe-Ni-C PHASE DIAGRAM

用电子探针波谱(WDS)及扫描透射电镜能谱法(EDS)测定了Fe—Ni—C相图的550、450℃等温截面。     

PARTIAL PHASE DIAGRAM OF Ag-Cu-Tb SYSTEM

The partial phase diagram of Ag—Cu—Tb system on the Ag—Cu—rich region at room tem- perature is investigated by X-ray diffraction and optical microscopy analyses.The sectionconsists of six singlephase regions,nine binary phase regions and four ternary phase regions,No ternary intermetallic compound is found.     

Fe—Ni—C相图的550,450℃等温截面

用电子探针波谱(WDS)及扫描透射电镜能谱法(EDS)测定了Fe—Ni—C相图的550、450℃等温截面。     

550 AND 450°C ISOTHERMAL SECTIONS OF Fe-Ni-C PHASE DIAGRAM

By using WDS method of EPMA and EDS tecbnique of STEM.550 and 450℃ isother-mal sections of Fe-Ni-C phase diagram were determined.     

Transformations and phase relations in Nb—Ti—Si ternary system at 1373—1473K

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