Experimental investigation of phase equilibria and microstructure in the Co–Ti–V ternary system

The phase equilibria in the Co–Ti–V ternary system have been investigated by means of optical microscopy (OM), electron probe microanalyzer (EPMA), differential scanning calorimetry (DSC), field emission scanning electron microscope (SEM) and X-ray diffraction (XRD). The mechanical properties were measured by compressive tests. Four isothermal sections of the Co–Ti–V ternary system at 800 °C, 1000 °C, 1100 °C and 1200 °C were experimentally established. The results show that: (1) there is no ternary compound in this system; (2) the CoTi₂ phase and Co₃Ti phase stabilized by the V addition; (3) a large solubility of Ti in the σ-Co₂V₃ phase was observed at all isothermal sections of 800 °C, 1000 °C, 1100 °C and 1200 °C; (4) The alloy with the distribution of fine cuboidal Co₃Ti (L1₂) in (αCo) phase was observed. (5) The compressive strength of Co_77.29Ti_5.83V_16.88 (at.%) alloy at room temperature was measured to be about 1985 MPa. The newly determined phase equilibria in this system will provide useful information for the development of Co-based and Ti-based materials.     

Titanium-chromium-oxygen system

The Ti-Cr-O ternary system has been studied in detail near the titanium-rich corner within the limits of 10 wt pct O₂ and 20 wt pct Cr. Studies were extended, but not in detail, to the region beyond 25 wt pct O₂ (50 atomic pct) and 62 wt pct Cr (60 atomic pct). Four isothermal sections at 1400°, 1200°, 1000°, and 800°C are presented as well as two vertical sections at 1 and 2 wt pct O₂.     

Experimental investigation and thermodynamic calculation of the phase equilibria in the Co–Mo–W system

The isothermal sections in the Co–Mo–W ternary system at 600 °C, 800 °C, 1000 °C, 1100 °C, 1200 °C and 1300 °C have been determined using the Electron probe micro-analyzer (EPMA) and X-ray diffraction (XRD) techniques. A thermodynamic assessment of the Co–Mo–W ternary system was carried out by the CALPHAD (Calculation of Phase Diagrams) method. The Gibbs free energies of the liquid and solution phases were described by the subregular solution models, and those of intermetallic compounds were described by the sublattice model. A consistent set of thermodynamic parameters has been derived for describing the Gibbs free energies of each solution phase and intermetallic compound in the Co–Mo–W ternary system. The calculated phase diagrams and thermodynamic properties in the Co–Mo–W ternary system are in good agreement with experimental data.     

Ni-Ti-Ta三元体系的相平衡关系

采用X射线衍射和电子探针显微分析方法,获得Ni?Ti?Ta三元体系在1000和1200℃的全成分范围内等温截面相图.实验结果显示,Ni?Ti?Ta三元体系的1000和1200℃等温截面相图中均存在一个固溶度较小的三元化合物τ相,且通过相平衡可知,该相在1000℃的成分为(16.3～22.4)％Ta,(15.9～24.1...     

The Mn-Nd-Sn system (manganese-neodymium-tin)

The ternary system Mn-Nd-Sn has been investigated and phase relations have been determined in two isothermal sections at 800 and 545 °C. Furthermore, a critical assessment has been provided that also includes magnetic information and¹¹⁹Sn-M?ssbauer data on the ternary compounds.     

Experimental Investigation of Phase Equilibria in the Nb-Si-V Ternary System

In this study, three isothermal sections of the Nb-Si-V ternary system at 1100, 1200 and 1300 °C were experimentally established by means of back-scattered electron, electron probe microanalysis and x-ray diffraction. The isothermal sections at 1100, 1200 and 1300 °C have similar phase relationships, in which five three-phase regions have been determined. In all three isothermal sections, the (Nb,V)₂Si compound has been found for the first time, and the compounds NbSi₂ and VSi₂ form a complete solid solution phase (Nb,V)Si₂.     

Experimental Investigation of Phase Equilibria in the Fe-Si-Ti Ternary System

The phase equilibria of the Fe-Si-Ti ternary system were investigated by electron probe microanalyzer (EPMA), back scattered electron (BSE) and X-ray diffraction (XRD) on the equilibrated alloys. Twenty-four alloys of the Fe-Si-Ti ternary system were prepared. In this study, three isothermal sections of the Fe-Si-Ti ternary system at 1000, 1100 and 1200 °C were respectively determined and seven ternary compounds were confirmed. The ηFe₅Si₃ phase is discovered at 1100 and disappeared at 1200 °C. The obtained experimental results show that there is large solubilities of Si in the TiFe₂ phase. The newly determined phase equilibria of the Fe-Si-Ti system will provide useful information for the development of silicon steels.     

Determination of the Fe-Cr-Mo Phase Diagram at Intermediate Temperatures using Dual-Anneal Diffusion Multiples

A recently developed dual-anneal diffusion-multiple approach is employed to the determination of the Fe-Cr-Mo phase diagram at intermediate temperatures. Diffusion multiples of Fe-Cr-Ni-Co-Mo were first annealed at 1200 °C for 500 h to create wide ranges of solid solution compositions. Subsequent annealing of the diffusion multiples at individual intermediate temperatures induced various precipitate phases. Electron probe microanalysis (EPMA) across the interface between large precipitates and the matrix phase provided local equilibrium information for the establishment of equilibrium tie-lines which are utilized to construct the Fe-rich part of the Fe-Cr-Mo isothermal sections at 900 and 800 °C. The Mo-rich part of the isothermal sections at intermediate temperatures was not obtained due to the sluggish kinetics of precipitation and growth, resulting in too small precipitates for reliable EPMA composition evaluation. A complete 1200 °C isothermal section of the Fe-Cr-Mo system is also established from EPMA data on a water quenched diffusion multiple that was annealed at 1200 °C for 500 h only without a second anneal.     

Experimental Investigation and Thermodynamic Calculation of the Phase Equilibria in the Cr-Hf-Ti Ternary System

The phase equilibria of the Cr-Hf-Ti ternary system has been firstly investigated by electron probe micro-analyzer, x-ray diffraction and differential scanning calorimetry on equilibrated alloys. Three isothermal sections of the Cr-Hf-Ti ternary system at 1100, 1200 and 1300 °C were determined. Meanwhile, this ternary system was also thermodynamically optimized using the calculation of phase diagrams method. The calculated result replies that the existing temperature range of the C15 (Cr₂Hf) increased due to addition of the third element Ti.     

Phase Equilibria in the Al-Co-Ni Alloy System

The phase equilibria in the Ni-Co rich region (<50 at.%Al) of the Al-Co-Ni system were studied experimentally for two isothermal sections at 1100 and 800 °C. Metallography, energy dispersive spectroscopy, hardness and x-ray diffraction were used for characterization and determination of γ, γ′ and β phases within the ternary system. Phase boundaries in the isothermal sections and a partial liquidus projection are modified compared to previously published work. Comparison is made to the isothermal sections computed using Thermo-Calc and the TCNI8 database. No definitive experimental evidence corroborating the predicted existence of a Nishizawa horn was obtained.     

Experimental Investigation of Phase Equilibria in the Fe-Nb-Ta System

The phase equilibria in the Fe-Nb-Ta ternary system at 1200, 1100 and 1000 °C were experimentally investigated. The microstructure of each sample was observed using scanning electron microscopy, and phase compositions were measured by energy dispersive spectrometry. The constituent phases of typical samples were analyzed with x-ray diffraction. The experimental results indicated that the continuous solid solution phases, Fe₂(Nb,Ta) and Fe₇(Nb,Ta)₆, were formed between Fe₂Nb and Fe₂Ta and Fe₇Nb₆ and Fe₇Ta₆, respectively, and no ternary compounds were found in this system in these isothermal sections. Based on the experimental phase equilibria data obtained in the present work, three isothermal sections at 1200, 1100 and 1000 °C were constructed.     

Experimental Investigation of Phase Equilibria in the Cu-Fe-Zr Ternary System

The phase equilibria in the Cu-Fe-Zr ternary system was experimentally investigated by optical microscopy, electron probe micro-analyzer and x-ray diffraction on the equilibriated alloys. Three isothermal sections of the Cu-Fe-Zr ternary system at 1000, 1100 and 1200 °C were experimentally determined, and no ternary compound was found in this system. The further result in the present work shows that the Fe₂₃Zr₆ phase in the Cu-Fe-Zr ternary system is an equilibrium phase rather than oxygen-stabilized phase.     

Constitution of the ternary system Al-Ru-Ti (Aluminum-Ruthenium-Titanium)

Phase relations in the ternary system Al-Ru-Ti were studied on arc-melted alloys and specimens annealed at 1100 °C, 950 °C, and 800 °C employing optical and electron microscopy, x-ray diffraction, and electron probe microanalysis. The results, in combination with an assessment of all literature data available, were used to construct liquidus and solidus surfaces, a series of isothermal sections, and a Schulz-Scheil diagram monitoring solidification (crystallization) in thermodynamic equilibrium. The crystal structure of the ternary G-phase was determined by x-ray single crystal diffraction to be a filled variant of the Th₆Mn₂₃-type (space group Fm3m). Furthermore, a new ternary compound with AuCu₃-type structure was detected.     

Constitution of the ternary system Al-Ru-Ti (Aluminum-Ruthenium-Titanium)

Phase relations in the ternary system Al-Ru-Ti were studied on arc-melted alloys and specimens annealed at 1100 °C, 950 °C, and 800 °C employing optical and electron microscopy, x-ray diffraction, and electron probe microanalysis. The results, in combination with an assessment of all literature data available, were used to construct liquidus and solidus surfaces, a series of isothermal sections, and a Schulz-Scheil diagram monitoring solidification (crystallization) in thermodynamic equilibrium. The crystal structure of the ternary G-phase was determined by x-ray single crystal diffraction to be a filled variant of the Th₆Mn₂₃-type (space group Fm3m). Furthermore, a new ternary compound with AuCu₃-type structure was detected.     

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.     

Phase equilibria of Zn-Al-Ti ternary system at 450 and 600 °C

The phase relationships in the Zn-Al-Ti system at 450 and 600 °C were experimentally determined using equilibrated alloys method. The specimens were investigated by means of scanning electron microscopy coupled with energy dispersive spectroscopy and X-ray diffractometry. Eleven and eight three-phase regions are confirmed in the 450 and 600 °C isothermal sections, respectively. The Ti₂Al₅ which only exists at high temperature (990-1199.4 °C) in Ti-Al binary system is confirmed in two isothermal sections due to the dissolution of zinc. The T phase is confirmed as a ternary compound rather than an extension phase of TiZn₃ at 450 °C. The T₂ phase is a new ternary phase stable at 450 and 600 °C in Zn-Al-Ti ternary system.     

Phase Equilibria and Ternary Intermetallic Compound with L1<Subscript>2</Subscript> Structure in Co-W-Ga System

Phase equilibria and stabilities of intermetallic phases appearing in the Co-rich portion of the Co-W-Ga ternary alloys were investigated and isothermal section diagrams at 1200, 1100, 1000, and 900 °C were determined. A fine cuboidal phase with an L1₂ structure was observed at 900 and 800 °C, where the composition of the new ternary compound obtained by aging at 900 °C for the Co-7.4W-12.0Ga alloy was Co-11.2W-11.4Ga (at.%). It was confirmed that this compound is metastable at 900 °C but is more stable at 800 °C. These results mean that the thermodynamic stability of the metastable Co₃W L1₂ phase, especially in the low temperature region, increases by the addition of Ga.     

Isothermal Sections in the (Fe,Ni)-Rich Part of the Fe-Ni-Al Phase Diagram

The ternary Fe-Ni-Al phase diagram below 50 at.% Al was investigated by a combination of powder x-ray diffraction (XRD) and electron probe microanalysis (EPMA). Ternary phase equilibria and accurate phase compositions of the respective equilibrium phases were determined within the partial isothermal sections at 900, 1000, 1100 and 1200 °C.