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Phase equilibria of the Cr-Mo-Ru ternary system at 1100 °C and 1200 °C have been experimentally investigated using electron probe microanalyzer and x-ray diffraction. The σ-Cr2Ru forms a σ-(Mo5Ru3, Cr2Ru) continuous solid solution phase with the σ-Mo5Ru3 phase at 1200 °C, but not at 1100 °C. The BCC (Cr, Mo) continuous solid solution phase exists at both 1100 °C and 1200 °C. Based on the measured experimental results and the thermodynamic parameters of the three binary sub-systems, a set of self-consistent parameters of the Cr-Mo-Ru system was evaluated using the CALPHAD method. Several vertical sections, isothermal sections, and liquidus surface projection of the Cr-Mo-Ru ternary system were calculated in this study. The results of phase equilibrium experiments and thermodynamic calculations show that although the solid solubility of the σ phase in the Cr-Mo and Mo-Ru binary systems is relatively small, it is exceptionally large in the Cr-Mo-Ru ternary system. The current obtained thermodynamic parameters of the Cr-Mo-Ru ternary system can provide the essential information and support for the theoretical guidance on the design of the Ni-based multi-component superalloys. [ABSTRACT FROM AUTHOR]

The phase equilibria in the Co-W-Zr ternary system at 1200 and 1300 °C were experimentally investigated by electron probe microanalysis and x-ray diffraction. Totally eight three-phase and seven three-phase regions were confirmed in the 1200 and 1300 °C isothermal sections, respectively. There are two small Liquid regions at 1300 °C, but only one was found at 1200 °C. The Co11Zr2 phase was found at 1200 °C, and dissolved at 1300 °C. The solubility limit of Zr in the (αCo) is about 1.0 at.% at 1200 °C and 3.0 at.% at 1300 at.% and too much Zr addition in Co-based alloys may introduce the Co11Zr2, Co23Zr6 or Co2Zr_Laves phases. The addition of W in the (αCo) should be less than 14.9 at.% at 1200 °C and 15.8 at.% at 1300 °C to prevent the brittle Co7W6 phase. [ABSTRACT FROM AUTHOR]

In this study, the isothermal sections of the Co-Nb-Re ternary system at 1200, and 1300 °C have been experimentally determined combining the means of electron probe microanalysis (EPMA) and x-ray diffraction (XRD). The obtained experimental results showed that: (1) The Laves phase of λ3-Co2Nb (C36) was stable at 1300 °C. The temperature was beyond its stability limit in Co-Nb binary system. (2) The solubility of Re in the λ3 phase was so large that the nearest λ2-Co2Nb (C15) phase was essentially surrounded. (3) The solubility of Re in the μ-Co7Nb6 phase was 34.0 at.% at 1200 °C and 35.2 at.% at 1300 °C, respectively. (4) The liquid phase existed at 1300 °C dissolving about 4.0 at.% Re, but it was absent at 1200 °C. (5) The solid solution phase of (εCo, Re) extended from Re-rich to Co-rich side. [ABSTRACT FROM AUTHOR]

The phase equilibria of the Co-Ti-Ru ternary system at 1000, 1100, and 1200 °C were studied using the electron probe microanalyzer and x-ray diffraction. The results show that: (1) no ternary compound exists in the isothermal sections from 1000 to 1200 °C; (2) the phases of CoTi and TiRu form the continuous solid solution phase (Co,Ru)Ti; (3) the solubility of Ru in the Co3Ti phase is less than 5 at.% at isothermal sections 1000-1100 °C. These experimental results will provide useful information for the foundation for alloy design and the supplement for thermodynamic databases. [ABSTRACT FROM AUTHOR]

Two isothermal sections of the Ni-Cr-Ta ternary system at 1200 °C and 1300 °C have been determined by using electron probe microanalysis, energy dispersive spectroscopy and differential scanning calorimeter. A Laves phase (Ni, Cr)2Ta(HT)(C14 structure) with large solid solubility stabilized by the Ni addition was determined in both two isothermal sections. The composition range of this phase was about 25.8–66.0 at.% Cr, 2.5-44.3 at.% Ni, and 24.0-40.0 at.% Ta at 1200 °C, which increased with raising temperature. The melting point of the Ni-Cr alloys decreased with the addition of Ta. No ternary compound was found in both these two isothermal sections. The present work could be significant for practical application of nickel-based alloys and future thermodynamics assessment of the Ni-Cr-Ta ternary system. [ABSTRACT FROM AUTHOR]

In this study, the isothermal sections of the Co-Re-Ta ternary system at 1100, 1200, and 1300 °C have been experimentally investigated by means of electron probe microanalysis and X-ray diffraction. The results indicated the following: (1) The solid solubilities of the λ3, (εCo, Re), χ-Re7Ta3, and bcc-(Ta) phases were large and changed very little from 1100 to 1300 °C; (2) more interestingly, the λ2 phase, with a very limited solubility of Re, was surrounded by the λ3 phase; (3) the solubility of Re for the μ-Co6Ta7 phase increased slowly from 1100 to 1300 °C. These experimental results will be useful for Co-based high-temperature alloys, especially as a supplement for thermodynamic databases. [ABSTRACT FROM AUTHOR]

Two isothermal sections of the Ni-V-Ta ternary system at 1200 °C and 1000 °C have been experimentally established using X-ray diffraction, electron probe microanalysis, energy dispersive spectroscopy, and differential scanning calorimeter with equilibrated key alloys. The equilibrium composition of each phase is measured by electron probe microanalysis and energy dispersive spectroscopy. The results indicate that: (1) nine three-phase and eight three-phase regions were confirmed in the isothermal section at 1200 °C and 1000 °C, respectively; (2) the C14 phase with a large solubility of about 51.2 at. % Ni was observed at 1200 °C, while it forms a single-phase region at 1000 °C; (3) a small liquid region was confirmed at 1200 °C, but disappeared at 1000 °C. [ABSTRACT FROM AUTHOR]