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Jun Tang - One of the best experts on this subject based on the ideXlab platform.

  • annealing induced shrinkage fill effect of tungsten Potassium Alloys with trace titanium doping
    International Journal of Refractory Metals & Hard Materials, 2020
    Co-Authors: Long-qing Chen, Xiaoliang Yang, Wenbin Qiu, Hao Deng, Yangyipeng Song, Jun Zhu, Jun Tang
    Abstract:

    Abstract The shrinkages presented in sintering process of tungsten Alloys are extremely detrimental to their practical applications in fusion reactors. Positively in this work, we effectively reduced the shrinkages via synergistically applying Ti-doping and annealing process on tungsten‑Potassium (WK) Alloys. This shrinkage-fill effect only works in the one with trace amount of titanium doping, such as 0.05 wt%Ti or 0.5 wt%Ti. Due to such effect, the compressive strength was improved by ~18%. Based on morphological and elementary analyses, we speculated that the Ti-rich particles along the grain boundaries of WK Alloys were activated and migrated into shrinkages during annealing. Further Ti doping (e.g. 1wt.%Ti) led to nanoscale grain refinement in WK Alloys, which almost doubled the compressive strength. In this case, an unconventional grain-refinement model was proposed. Furthermore, anomalous grain growth was observed in WK-3wt.%Ti, which was attributed to the formation of Ti-rich regions and the corresponding raise of energy in grain boundaries. The fabricating strategies in this work may benefit the design of refractory tungsten Alloys with less shrinkages and ultra-fine grains.

  • Annealing induced shrinkage-fill effect of tungsten‑Potassium Alloys with trace titanium doping
    International Journal of Refractory Metals and Hard Materials, 2020
    Co-Authors: Long-qing Chen, Xiaoliang Yang, Wenbin Qiu, Hao Deng, Yangyipeng Song, Jun Zhu, Jun Tang
    Abstract:

    Abstract The shrinkages presented in sintering process of tungsten Alloys are extremely detrimental to their practical applications in fusion reactors. Positively in this work, we effectively reduced the shrinkages via synergistically applying Ti-doping and annealing process on tungsten‑Potassium (WK) Alloys. This shrinkage-fill effect only works in the one with trace amount of titanium doping, such as 0.05 wt%Ti or 0.5 wt%Ti. Due to such effect, the compressive strength was improved by ~18%. Based on morphological and elementary analyses, we speculated that the Ti-rich particles along the grain boundaries of WK Alloys were activated and migrated into shrinkages during annealing. Further Ti doping (e.g. 1wt.%Ti) led to nanoscale grain refinement in WK Alloys, which almost doubled the compressive strength. In this case, an unconventional grain-refinement model was proposed. Furthermore, anomalous grain growth was observed in WK-3wt.%Ti, which was attributed to the formation of Ti-rich regions and the corresponding raise of energy in grain boundaries. The fabricating strategies in this work may benefit the design of refractory tungsten Alloys with less shrinkages and ultra-fine grains.

  • High thermal shock resistance realized by Ti/TiH2 doped tungsten-Potassium Alloys
    Journal of Alloys and Compounds, 2019
    Co-Authors: Long-qing Chen, Bo Huang, Xiaoliang Yang, Youyun Lian, Xiang Liu, Jun Tang
    Abstract:

    Abstract Tungsten-Potassium-titanium (W-K-Ti) Alloys were fabricated by spark-plasma-sintering (SPS) and traditional rotary swaging (RS) techniques. Doping conditions and sintering methods were compared on the relative density, microstructure, hardness, recrystallization temperature, and the thermal shock resistance properties. Transient heat loads under 0.37 GW m−2 were applied on the W-K-Ti samples at room temperature for different cycles and pulsed durations. It was found that moderate Ti-doping (0.05 and 0.075 wt%) in W-K Alloys can enhance the thermal shock resistance. Low-cycle thermal fatigue test suggested better thermal shock resistance in SPS-sintered W-K-Ti alloy (SPS-W-K-Ti) using TiH2 dopant. The main reason was that the decomposition of TiH2 significantly reduced the oxygen content of the ingots, which improved the ductility and thermal shock resistance of tungsten Alloys. Further fracture analyses indicated that Ti-doping through TiH2 formed intra- and inter- Ti-rich voids in TiH2-doped W-K alloy, while only intergranular Ti particles were found lying along grain boundaries in the Ti-doped one. The formation mechanism of the Ti-rich voids was investigated in detail. This work provides a potential route for obtaining plasma facing materials with high thermal shock resistance.

Philippe Lagrange - One of the best experts on this subject based on the ideXlab platform.

  • Chemical, structural and electrical resistivity of two first stage arsenic-Potassium-graphite intercalation compounds
    Synthetic Metals, 2015
    Co-Authors: Jamal Assouik, Claire Hérold, Philippe Lagrange
    Abstract:

    The action on graphite of liquid arsenic-Potassium Alloys leads to the formation of a new series of graphite intercalation compounds. Two ternary phases of first stage have been observed and isolated. The alpha-type phase is obtained by action on graphite of composition Alloys close to that of defined K3As compound. On the other hand, the beta-phase is easily obtained by action on graphite of K-As Alloys whose chemical stoichiometry is equal or near to the 37 at.% As eutectic point composition. The Fourier transform analysis of the 001 reflexions family of these two phases showed that the intercalated metallic sheets between graphitic gaps in these phases are generally three-layered stacking according to K/As/K sequence along c-axis. An exam, by means classical X-ray diffraction and transmission electronic microscope (TEM) of the in-plane structure of these compounds revealed that the intercalated metallic sheets are perfectly crystallised and an equatorial stratum was defined for each of them. Electrical conductivity measurements have been carried out on these phases along both axis of graphite and showed that they are strongly anisotropic and exhibit a metallic character in parallel to graphitic plans.

Long-qing Chen - One of the best experts on this subject based on the ideXlab platform.

  • annealing induced shrinkage fill effect of tungsten Potassium Alloys with trace titanium doping
    International Journal of Refractory Metals & Hard Materials, 2020
    Co-Authors: Long-qing Chen, Xiaoliang Yang, Wenbin Qiu, Hao Deng, Yangyipeng Song, Jun Zhu, Jun Tang
    Abstract:

    Abstract The shrinkages presented in sintering process of tungsten Alloys are extremely detrimental to their practical applications in fusion reactors. Positively in this work, we effectively reduced the shrinkages via synergistically applying Ti-doping and annealing process on tungsten‑Potassium (WK) Alloys. This shrinkage-fill effect only works in the one with trace amount of titanium doping, such as 0.05 wt%Ti or 0.5 wt%Ti. Due to such effect, the compressive strength was improved by ~18%. Based on morphological and elementary analyses, we speculated that the Ti-rich particles along the grain boundaries of WK Alloys were activated and migrated into shrinkages during annealing. Further Ti doping (e.g. 1wt.%Ti) led to nanoscale grain refinement in WK Alloys, which almost doubled the compressive strength. In this case, an unconventional grain-refinement model was proposed. Furthermore, anomalous grain growth was observed in WK-3wt.%Ti, which was attributed to the formation of Ti-rich regions and the corresponding raise of energy in grain boundaries. The fabricating strategies in this work may benefit the design of refractory tungsten Alloys with less shrinkages and ultra-fine grains.

  • Annealing induced shrinkage-fill effect of tungsten‑Potassium Alloys with trace titanium doping
    International Journal of Refractory Metals and Hard Materials, 2020
    Co-Authors: Long-qing Chen, Xiaoliang Yang, Wenbin Qiu, Hao Deng, Yangyipeng Song, Jun Zhu, Jun Tang
    Abstract:

    Abstract The shrinkages presented in sintering process of tungsten Alloys are extremely detrimental to their practical applications in fusion reactors. Positively in this work, we effectively reduced the shrinkages via synergistically applying Ti-doping and annealing process on tungsten‑Potassium (WK) Alloys. This shrinkage-fill effect only works in the one with trace amount of titanium doping, such as 0.05 wt%Ti or 0.5 wt%Ti. Due to such effect, the compressive strength was improved by ~18%. Based on morphological and elementary analyses, we speculated that the Ti-rich particles along the grain boundaries of WK Alloys were activated and migrated into shrinkages during annealing. Further Ti doping (e.g. 1wt.%Ti) led to nanoscale grain refinement in WK Alloys, which almost doubled the compressive strength. In this case, an unconventional grain-refinement model was proposed. Furthermore, anomalous grain growth was observed in WK-3wt.%Ti, which was attributed to the formation of Ti-rich regions and the corresponding raise of energy in grain boundaries. The fabricating strategies in this work may benefit the design of refractory tungsten Alloys with less shrinkages and ultra-fine grains.

  • High thermal shock resistance realized by Ti/TiH2 doped tungsten-Potassium Alloys
    Journal of Alloys and Compounds, 2019
    Co-Authors: Long-qing Chen, Bo Huang, Xiaoliang Yang, Youyun Lian, Xiang Liu, Jun Tang
    Abstract:

    Abstract Tungsten-Potassium-titanium (W-K-Ti) Alloys were fabricated by spark-plasma-sintering (SPS) and traditional rotary swaging (RS) techniques. Doping conditions and sintering methods were compared on the relative density, microstructure, hardness, recrystallization temperature, and the thermal shock resistance properties. Transient heat loads under 0.37 GW m−2 were applied on the W-K-Ti samples at room temperature for different cycles and pulsed durations. It was found that moderate Ti-doping (0.05 and 0.075 wt%) in W-K Alloys can enhance the thermal shock resistance. Low-cycle thermal fatigue test suggested better thermal shock resistance in SPS-sintered W-K-Ti alloy (SPS-W-K-Ti) using TiH2 dopant. The main reason was that the decomposition of TiH2 significantly reduced the oxygen content of the ingots, which improved the ductility and thermal shock resistance of tungsten Alloys. Further fracture analyses indicated that Ti-doping through TiH2 formed intra- and inter- Ti-rich voids in TiH2-doped W-K alloy, while only intergranular Ti particles were found lying along grain boundaries in the Ti-doped one. The formation mechanism of the Ti-rich voids was investigated in detail. This work provides a potential route for obtaining plasma facing materials with high thermal shock resistance.

Jamal Assouik - One of the best experts on this subject based on the ideXlab platform.

  • Chemical, structural and electrical resistivity of two first stage arsenic-Potassium-graphite intercalation compounds
    Synthetic Metals, 2015
    Co-Authors: Jamal Assouik, Claire Hérold, Philippe Lagrange
    Abstract:

    The action on graphite of liquid arsenic-Potassium Alloys leads to the formation of a new series of graphite intercalation compounds. Two ternary phases of first stage have been observed and isolated. The alpha-type phase is obtained by action on graphite of composition Alloys close to that of defined K3As compound. On the other hand, the beta-phase is easily obtained by action on graphite of K-As Alloys whose chemical stoichiometry is equal or near to the 37 at.% As eutectic point composition. The Fourier transform analysis of the 001 reflexions family of these two phases showed that the intercalated metallic sheets between graphitic gaps in these phases are generally three-layered stacking according to K/As/K sequence along c-axis. An exam, by means classical X-ray diffraction and transmission electronic microscope (TEM) of the in-plane structure of these compounds revealed that the intercalated metallic sheets are perfectly crystallised and an equatorial stratum was defined for each of them. Electrical conductivity measurements have been carried out on these phases along both axis of graphite and showed that they are strongly anisotropic and exhibit a metallic character in parallel to graphitic plans.

Xiaoliang Yang - One of the best experts on this subject based on the ideXlab platform.

  • annealing induced shrinkage fill effect of tungsten Potassium Alloys with trace titanium doping
    International Journal of Refractory Metals & Hard Materials, 2020
    Co-Authors: Long-qing Chen, Xiaoliang Yang, Wenbin Qiu, Hao Deng, Yangyipeng Song, Jun Zhu, Jun Tang
    Abstract:

    Abstract The shrinkages presented in sintering process of tungsten Alloys are extremely detrimental to their practical applications in fusion reactors. Positively in this work, we effectively reduced the shrinkages via synergistically applying Ti-doping and annealing process on tungsten‑Potassium (WK) Alloys. This shrinkage-fill effect only works in the one with trace amount of titanium doping, such as 0.05 wt%Ti or 0.5 wt%Ti. Due to such effect, the compressive strength was improved by ~18%. Based on morphological and elementary analyses, we speculated that the Ti-rich particles along the grain boundaries of WK Alloys were activated and migrated into shrinkages during annealing. Further Ti doping (e.g. 1wt.%Ti) led to nanoscale grain refinement in WK Alloys, which almost doubled the compressive strength. In this case, an unconventional grain-refinement model was proposed. Furthermore, anomalous grain growth was observed in WK-3wt.%Ti, which was attributed to the formation of Ti-rich regions and the corresponding raise of energy in grain boundaries. The fabricating strategies in this work may benefit the design of refractory tungsten Alloys with less shrinkages and ultra-fine grains.

  • Annealing induced shrinkage-fill effect of tungsten‑Potassium Alloys with trace titanium doping
    International Journal of Refractory Metals and Hard Materials, 2020
    Co-Authors: Long-qing Chen, Xiaoliang Yang, Wenbin Qiu, Hao Deng, Yangyipeng Song, Jun Zhu, Jun Tang
    Abstract:

    Abstract The shrinkages presented in sintering process of tungsten Alloys are extremely detrimental to their practical applications in fusion reactors. Positively in this work, we effectively reduced the shrinkages via synergistically applying Ti-doping and annealing process on tungsten‑Potassium (WK) Alloys. This shrinkage-fill effect only works in the one with trace amount of titanium doping, such as 0.05 wt%Ti or 0.5 wt%Ti. Due to such effect, the compressive strength was improved by ~18%. Based on morphological and elementary analyses, we speculated that the Ti-rich particles along the grain boundaries of WK Alloys were activated and migrated into shrinkages during annealing. Further Ti doping (e.g. 1wt.%Ti) led to nanoscale grain refinement in WK Alloys, which almost doubled the compressive strength. In this case, an unconventional grain-refinement model was proposed. Furthermore, anomalous grain growth was observed in WK-3wt.%Ti, which was attributed to the formation of Ti-rich regions and the corresponding raise of energy in grain boundaries. The fabricating strategies in this work may benefit the design of refractory tungsten Alloys with less shrinkages and ultra-fine grains.

  • High thermal shock resistance realized by Ti/TiH2 doped tungsten-Potassium Alloys
    Journal of Alloys and Compounds, 2019
    Co-Authors: Long-qing Chen, Bo Huang, Xiaoliang Yang, Youyun Lian, Xiang Liu, Jun Tang
    Abstract:

    Abstract Tungsten-Potassium-titanium (W-K-Ti) Alloys were fabricated by spark-plasma-sintering (SPS) and traditional rotary swaging (RS) techniques. Doping conditions and sintering methods were compared on the relative density, microstructure, hardness, recrystallization temperature, and the thermal shock resistance properties. Transient heat loads under 0.37 GW m−2 were applied on the W-K-Ti samples at room temperature for different cycles and pulsed durations. It was found that moderate Ti-doping (0.05 and 0.075 wt%) in W-K Alloys can enhance the thermal shock resistance. Low-cycle thermal fatigue test suggested better thermal shock resistance in SPS-sintered W-K-Ti alloy (SPS-W-K-Ti) using TiH2 dopant. The main reason was that the decomposition of TiH2 significantly reduced the oxygen content of the ingots, which improved the ductility and thermal shock resistance of tungsten Alloys. Further fracture analyses indicated that Ti-doping through TiH2 formed intra- and inter- Ti-rich voids in TiH2-doped W-K alloy, while only intergranular Ti particles were found lying along grain boundaries in the Ti-doped one. The formation mechanism of the Ti-rich voids was investigated in detail. This work provides a potential route for obtaining plasma facing materials with high thermal shock resistance.