Nb—Ti—Si三元系1473K等温截面的测定

运用扩散偶技术结合电子探针微区成分分析方法对Nb-Ti-Si三元扩散偶进行相分析，测得Nb-Ti-Si三元系1473K下所生成的7个扩散层，分别是TiSi2,TiSi,Ti5Si3,Nb5Si2和M3Si，此扩散偶中未发现三元化合物，并根据扩散偶中的相区分布和相图中相区分布的关系，得出Nb-Ti-Si三元系1473K下的等温截面。     

Experimental Investigation of the Mo–Ti–Zr Ternary Phase Diagrams

In this work, the phase diagrams of the Mo–Ti–Zr ternary system were determined by means of X-ray diffraction, optical microscopy, and electron probe microanalysis. Two isothermal sections of the Mo–Ti–Zr ternary system at 900 and 1100 °C were experimentally established. There are three two-phase regions and one three-phase region at both isothermal sections. The existence of the three-phase region (β₁?+?Laves?+?β₂) at 900 and 1100 °C indicates that the β phase (bcc solid solution) separates into two phases, i.e. Mo, Ti rich solid solution β₁ and Ti, Zr rich solid solution β₂. No ternary compounds were detected. The maximum solubilities of Ti in the Laves phase were found to be 19.3 at.% at 900 °C and 18.3 at.% at 1100 °C, respectively. The liquidus projection and reaction scheme of the Mo–Ti–Zr system were also presented based on the present experimental work and literature information.     

Thermodynamic and experimental study of Ti---Ag---Cu alloys

Phase equilibria in the ternary Ti---Ag---Cu system have been studied thermodynamically and experimentally at various temperatures. The thermodynamic analysis was performed by combining the most recent data on the binary Ag---Cu, Ti---Ag and Ti---Cu systems and experimental information obtained by the diffusion couple technique. The eutectic and three non-eutectic binary Ag---Cu alloys were melted and annealed in evacuated Ti ampoules at temperatures of 900, 950 and 1000 °C for various times and subsequently quenched in water. Both the calculations and the experimental results confirm that in the ternary system there is a miscibility gap, which divides the liquid phase into solutions of low and high Ti content. Furthermore, no ternary compounds were found. Several isothermal sections and the activity of titanium as a function of the copper-to-silver ratio and temperature are presented.     

Al-Si-Fe三元系热力学计算与评估

利用Calphad技术和应用Pandat相图计算软件,重新评估了Al-Si-Fe体系液相投影图,550、727、800℃等温截面,以及不同成分合金在1 477℃时的液相混合焓。结果表明,计算所得相图及液相混合焓与实验数据相符,该工作建立的热力学模型及参数可作为外推建立Al-Zn-Si-Fe等高元体系数据库的基础,并对相关体系的材料设计工作具有重要的指导意义。     

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

1　ＩＮＴＲＯＤＵＣＴＩＯＮＢｅｃａｕｓｅｏｆｔｈｅｉｒｈｉｇｈｓｔｒｅｎｇｔｈ ,ｇｏｏｄｐｌａｓｔｉｃｉｔｙａｎｄｃｏｒｒｏｓｉｏｎｒｅｓｉｓｔａｎｃｅ ,ｅｓｐｅｃｉａｌｌｙｌｏｗｄｅｎｓｉｔｙａｎｄｅｘｃｅｌｌｅｎｔｆｒａｃｔｕｒｅｔｏｕｇｈｎｅｓｓ ,     

Phase equilibria in the Fe–Rh–Ti system II. CVM calculations

Cluster Variation Method (CVM) calculations of phase equilibria in the bcc Fe–Rh–Ti system were performed in the irregular tetrahedron (IT) approximation including tetrahedron interactions. The energy parameters were obtained from a fit to recent experimental data on phase equilibria at 1000 °C and 800 °C. At these temperatures the ordering between first nearest neighbours dominates leading to large single-phase fields with B2 ordering. At lower temperatures the calculations predict additional ordering between second nearest neighbours of type D0₃. In the Fe–Ti system the second neighbour interactions are of segregation type leading to miscibility gaps between the disordered A2 and the ordered B2 phases extending from the binary Fe–Ti system into the ternary system. Calculated isothermal sections are presented at several temperatures. The complex ordering in the ternary system leads to strong variations of chemical potentials with composition. This is shown by calculated iso-chemical potential contours.     

Fe-Ti二元体系的热力学重新优化(英文)

为提高Fe-Ti二元系外推到三元或多元体系的能力,应用CALPHAD方法重新优化了该二元系。与前人的优化工作相比,重点放在对两个二元金属间化合物Fe2Ti和FeTi的热力学描述上。因目前普遍采用双亚点阵模型来描述C14_Laves相,所以采用双亚点阵模型来描述Fe2Ti相。通过检验包含Fe-Ti二元系的三元体系Fe-Ti边界上Fe2Ti相的均匀化范围进一步证实了Fe2Ti相的相边界。FeTi相具有BCC_B2晶体结构,因而将其处理成为BCC_A2相的有序相,并且用统一的Gibbs 能函数来描述有序和无序相。另外一个特别关注的方面就是重现这两个化合物的实测热容。计算结果与有关相图和热力学性质实验结果的广泛对比显示两者符合得很好,从而证明了所得热力学描述的有效性。     

Phase equilibria in the Fe–Rh–Ti system I. Experimental results

Two isothermal sections of the ternary system Fe–Rh–Ti were determined experimentally at 1000 °C and 800 °C using annealed alloys and diffusion couples. No ternary compound was found in this system. The B2 ordered phase is stable in all three binary subsystems of the Fe–Rh–Ti system and forms a range continuous solid solution at both temperatures. At 800 °C the B2-phase exhibits a tetragonal structure at certain ranges of composition. The same structure was observed in the binary Ti–Rh system. Within the B2 phase domain pseudo-interfaces were observed when the diffusion path crosses equiatomic compositions. A large miscibility gap between A2 and B2 was observed in the Fe-rich part of the Fe–Rh–Ti system.     

Experimental Investigation and Thermodynamic Calculation of Phase Equilibria in the Mg-Pb-Sn Ternary System

The phase equilibria of the Mg-Pb-Sn ternary system were investigated using a combined method of electron probe microanalyzer and x-ray diffraction. Three isothermal sections of the Mg-Pb-Sn ternary system at 200, 300 and 400 °C were experimentally established. The phase equilibria of Mg-Pb-Sn ternary system were thermodynamically assessed by using CALPHAD (Calculation of Phase Diagrams) method on the basis of the presently determined experimental data. A consistent set of thermodynamic parameters has been derived for describing the Gibbs free energies of each solution phase and intermetallic compound in the Mg-Pb-Sn ternary system. The calculated phase diagrams and thermodynamic properties in the Mg-Pb-Sn ternary system are in good agreement with experimental data.     

Experimental Investigation and Thermodynamic Calculation of the Co-Cr-Mo System

The isothermal section of the Co-Cr-Mo system at 1200 K has been investigated experimentally using scanning electron microscopy coupled with energy dispersive x-ray spectroscopy and x-ray diffraction. Six three-phase regions exist in the 1200 K isothermal section. The experimental results indicated that the maximum solubility of Cr in Co-Mo binary compounds Co₃Mo and μ at 1200 K is 5.2 and 23.6 at.%, respectively, and that of Mo in Co-Cr binary compound σ is 39.6 at.%. Based on the literature data of the thermodynamic assessment of Co-Mo, Co-Cr, Cr-Mo binary systems and experimental results of the ternary system, the thermodynamic calculation for Co-Cr-Mo system was carried out by means of CALPHAD technique. The computational results and the experimental data are self-consistent reasonably.     

Assessment of the Fe–Ni–Al system

For the present assessment, the available experimental data from the literature on the Fe–Ni–Al system was reviewed, to provide reliable information for application- and alloy development-oriented purposes and for a future thermodynamic modelling of the system. The data consists of phase relationships and phase boundaries in the ternary system, as well as thermochemical and diffusion (both experimental and ab initio) results. The present status of the modelling of the system, following the Calphad formalism as well as other approaches, is also described.     

Experimental Investigation and Thermodynamic Calculation of the B-Co-Zn Ternary System

The 450 °C isothermal section of the B-Co-Zn ternary system has been determined using scanning electron microscopy, electron probe microanalysis and x-ray diffraction. Seven three-phase regions exist in the 450 °C isothermal section, and no ternary compound is found. The experimental results indicate that the maximum solubility of B in β₁, γ, γ₁ and γ₂ is 0.31, 2.54, 0.52 and 2.51 at.%, respectively. The solubility of Zn in Co₂B and CoB is not greater than 0.6 at.%. On the basis of the literature data of the thermodynamic assessment of Co-B, Co-Zn binary systems and B-Zn system obtained in the present work, the phase diagram calculation for B-Co-Zn ternary system was carried out by means of CALPHAD method. The calculated results and the experimental data are in good agreement.     

Assessment of phase diagram and thermodynamic properties of the Al-Ga-Sb system

The experimental thermodynamic and phase diagram data of the Al-Ga-Sb ternary system have been critically assessed. With the assessed thermodynamic parameters, the pseudobinary AlSbGaSb phase diagram, the isothermal ternary sections, and the thermodynamic properties were calculated and compared with the related experimental data.