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Chongxin Tian - One of the best experts on this subject based on the ideXlab platform.

  • surface nanocrystallization of cu cr alloy by a high power density continuous laser beam
    Materials Letters, 2019
    Co-Authors: Litian Zhang, Chongxin Tian
    Abstract:

    Abstract A nanostructured surface layer of ∼300 μm thickness was fabricated on Cu-30Cr (wt%) hypereutectic alloy by a continuous laser beam with high power density (1.08 × 107 W/cm2). The average grain size of Cr-rich particles was refined to ∼40 nm, and the Solid Solubility Limit of Cr in Cu was extended to 1.96 at. %. Experimental results show that the dispersion of nano-sized Cr-rich spheroids in Cu-rich matrix was attributed to the Brownian motion of Cr-rich spheroids, and the high cooling rate (5.75 × 106 K/s) during liquid phase separation which inhibits the collisions between Cr-rich spheroids.

Litian Zhang - One of the best experts on this subject based on the ideXlab platform.

  • surface nanocrystallization of cu cr alloy by a high power density continuous laser beam
    Materials Letters, 2019
    Co-Authors: Litian Zhang, Chongxin Tian
    Abstract:

    Abstract A nanostructured surface layer of ∼300 μm thickness was fabricated on Cu-30Cr (wt%) hypereutectic alloy by a continuous laser beam with high power density (1.08 × 107 W/cm2). The average grain size of Cr-rich particles was refined to ∼40 nm, and the Solid Solubility Limit of Cr in Cu was extended to 1.96 at. %. Experimental results show that the dispersion of nano-sized Cr-rich spheroids in Cu-rich matrix was attributed to the Brownian motion of Cr-rich spheroids, and the high cooling rate (5.75 × 106 K/s) during liquid phase separation which inhibits the collisions between Cr-rich spheroids.

Minghung Tsai - One of the best experts on this subject based on the ideXlab platform.

  • quantitative prediction of Solid Solubility Limit in single phase high entropy alloys
    Applied Physics Letters, 2021
    Co-Authors: Ting Chang, Minghung Tsai
    Abstract:

    A thermodynamic model that can predict the Solid Solubility Limit (SSL) in single phase HEAs is proposed. The accuracies of our model and other representative existing models were verified experimentally using a model single phase FCC alloy and 11 alloying elements. The results show that existing models substantially overestimate the SSLs in HEAs, leading to large prediction errors. In contrast, our model has considerably higher accuracy. The mean absolute prediction error for our model is only 2.9 at. %—less than 1/8 that of the best existing model. These results demonstrate that quantitative prediction is achievable through the present model.

Pedro Durán - One of the best experts on this subject based on the ideXlab platform.

  • sintering microstructural development and electrical properties of gadolinia doped ceria electrolyte with bismuth oxide as a sintering aid
    Journal of The European Ceramic Society, 2006
    Co-Authors: J Tartaj, C Moure, Pedro Durán
    Abstract:

    Abstract A considerable reduction (≥250 °C) in the sintering temperature, enhancement of the sintering density, and a slight improvement of the electrical properties, can be achieved by using bismuth oxide in the range of 0.2 to 2 wt.%, as a sintering aid for gadolinia-doped ceria (GDC) ceramic electrolytes. Dilatometric experiment (CHR) and SEM observations indicate that a liquid phase-assisting sintering mechanism contributes to the improvement in sintering density for bismuth oxide concentrations exceeding 0.5 wt.%. The addition of small amount of Bi 2 O 3 ≤0.5 wt.% also results in the achievement of highly dense ceramic bodies (≥99% of theoretical density) after sintering at 1200 °C for 4 h, which indicates that the addition of Bi 2 O 3 to gadolinia-doped ceria promoted the sintering process by a cooperating volume diffusion-liquid phase-assisting mechanism. Based on the lattice constant data, the Solid Solubility Limit of Bi 2 O 3 in gadolinia-ceria is, probably, lower than 1.0 wt.%. Grain size also increased with increasing Bi 2 O 3 content up to 0.5 wt.% and then it decreased with further addition of Bi 2 O 3 . The addition of the smaller amounts of bismuth oxide, i.e., ≤1.0 wt.% Bi 2 O 3 slightly enhanced the total ionic electrical conductivity of the gadolinia-doped ceria electrolyte. The sintering temperature strongly influenced the electrical conductivity of the doped-GDC ceramics. The best sample was that containing 1.0 wt.% Bi 2 O 3 sintered at 1400 °C for 2 h which had an ionic electrical conductivity of 4 S m −1 at 700 °C, and an activation energy of 0.58 eV for the oxide-ion conduction process in air.

  • The Solid Solubility Limit of TiO2 in 3Y-TZP studied by Raman spectroscopy
    Materials Letters, 1999
    Co-Authors: F. Capel, Miguel A. Bañares, Carlos Moure, Pedro Durán
    Abstract:

    Raman spectra of tetragonal zirconia Solid solutions have been studied for the ZrO2–Y2O3–TiO2 system. A linear relationship between the frequency of the Raman lines associated to the Zr–OI and ZrOII stretching modes, as a function of the TiO2 content seems to exist. The constancy in the frequency of the two Raman modes beyond a determined TiO2 concentration was taken to establish the Solid Solubility Limit of TiO2 into tetragonal zirconia (3Y-TZP) which, on the other hand, was in close agreement with that obtained by precision lattice parameter measurements. The influence of the TiO2 addition on the Zr–OI and Zr–OII bond lengths in 3Y-TZP is also reported.

M E Yakinci - One of the best experts on this subject based on the ideXlab platform.

  • synthesis and characterization of er substituted bi 2223 h tc glass ceramic superconductors
    Journal of Alloys and Compounds, 2004
    Co-Authors: M A Aksan, M E Yakinci
    Abstract:

    Abstract The Bi 2 Sr 2 Ca 2 Cu 3− x Er x O 10+ δ ( x = 0.5 and 1.0) H- T c system was prepared by glass–ceramic technique to investigate the microstructural formation, thermal and transport properties. We have found that Er +3 ions have a Solid Solubility Limit in the Bi-2223 system and this Limit was passed at x = 1.0. Below this Limit glass samples were prepared and converted to the glass–ceramic form easily, but after the Solid Solubility Limit glass formation was diminished and crystallized samples were formed after melt quenching. The substitution had considerable effect on the electrical properties comparing with the unsubstituted Bi-2223 material. The T c values of the x = 0.5 and 1.0 sample were found to be 71 ± 0.1 K. The thermoelectric power data were analyzed in view of “two band model with linear T -term” and “Xin’s two band model”. Thermoelectric power was obtained to be positive for the both samples, indicating that the hole type conductivity is dominant in the materials prepared. The magnitude of thermal conductivity, κ , was also influenced by the Er concentration. When the Er concentration was increased the magnitude of κ was suppressed. It strongly indicates that the impurities play a significant role in Limiting the heat transport due to a strong increase of the electron–phonon-impurity scattering rate.

  • synthesis and characterization of glass ceramic bi2 xgaxsr2ca2cu3o10 y superconductors
    Superconductor Science and Technology, 2000
    Co-Authors: M A Aksan, M E Yakinci, Y Balci
    Abstract:

    We have melt quenched a series of Ga substituted Bi2-xGaxSr2Ca2Cu3O10+y samples with the compositions with x = 0.2, 0.4, 0.6, 0.8 and 1.0. Microstructure, thermal properties including crystallization activation energy, magnetic and superconducting properties were investigated. We have found that Ga3+ ions have a Solid Solubility Limit in the BSCCO system and this Limit was passed at x = 0.6. Below this Limit HTc BSCCO n = 3 phase was obtained, but after the Solid Solubility Limit samples yield multiphase superconducting properties. Extended heat treatment at 840?C displayed no suppression of the Solid Solubility Limit. The crystallization kinetic studies were investigated using non-isothermal kinetic models of Kissinger and Augis-Bennet. Higher crystallization activation energies, Ea, were obtained compared to unsubstituted BSCCO materials, glassification improved and glass handling time increased. The substitution had a slight effect on Jc, the flux pinning in the material was improved and better Jc values were obtained below the Solid Solubility Limit.