Influence of size of nanoparticles and plasma pressure compaction on microstructural development and hardness of bulk tungsten samples

Srivatsan, T. S.; Manigandan, K.; Petraroli, M.; Trejo, Rosa M; Sudarshan, T. S.

doi:10.1016/j.apt.2012.05.008

Cited by 18 publications

(6 citation statements)

References 35 publications

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“…The average hardness value of LGW is 5.44 GPa, which is smaller than that of SGW (6.52 GPa). Present results are consistent with the result of Li and coworkers, who reported the nano-hardness values decreased from 9.11 GPa to 7.16 GPa when the grain size of W increased from 6.66 μm to 8.65 μm [41]. According to the Hall-Petch relationship, the yield strength decreases with the increase of grain size.…”

Section: Nano-indentation Resultssupporting

confidence: 93%

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Surface modification and helium release of tungsten irradiated by 40 keV helium ions

Xia,

Jiang,

Shi

et al. 2023

Phys. Scr.

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The effects of grain boundaries and surface roughness on tungsten irradiated by 40 keV He ions with a flux of 1.6 × 1017 He+/(m2s) to a fluence of 6.6 × 1021 He/m2 at room temperature were investigated. It was found that rough surfaces can suppress the surface blistering on tungsten. This may be due to the grooves appeared on rough tungsten limiting crack growth, resulting in the release of helium. However, the influence of grain boundaries on denseness of blistering was not obvious except the difference in blistering cap. The number of blister with detached cap on large grain tungsten samples (LGW, with the grain size of ~50 µm) is more than that on small grain tungsten samples (SGW, with the grain size of ~5 µm). In addition, the effect of grain boundaries on helium retention in tungsten cannot be ignored. The total He release from SGW was 2.56 × 1021 He/m2, which was smaller than the value (4.10 × 1021 He/m2) of LGW.

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Section: Nano-indentation Resultssupporting

confidence: 93%

“…According to the Hall-Petch relationship, the yield strength decreases with the increase of grain size. This relation is shown in the following formula [41,42]:…”

Section: Nano-indentation Resultsmentioning

confidence: 99%

Surface modification and helium release of tungsten irradiated by 40 keV helium ions

Xia,

Jiang,

Shi

et al. 2023

Phys. Scr.

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“…Previous efforts to synthesize ultrafine grain W articles using powder processing have generally found that pressure-assisted sintering and alloying are necessary for achieving high relative densities without grain growth. [6,[12][13][14][15][16][17][18][19] Hot isostatic pressing, for example, was used to consolidate 50 nm W particles to >95% relative density between 1093 and 1193 K (820 and 920 °C). [20] Because these temperatures are below the grain growth onset temperature of unalloyed tungsten (1273-1373 K (1000-1100 °C)), grain growth was suppressed, and the compacts retained grain sizes as small as 150 nm.…”

Section: Introductionmentioning

confidence: 99%

“…[21] Attempts to replicate these results using other pressure-assisted sintering techniques such as field assisted sintering (FAS) used lower stresses; whereas the hot isostatic pressing study used an isostatic pressure of 1 GPa, the maximum uniaxial stress reported in FAS studies is 266 MPa. [6,[16][17][18][19] Consequently, these FAS studies generally required higher soak temperatures (>1273 K (1000 °C)) or longer hold times to achieve similar relative densities. Despite FAS's fast ramp rates, the higher thermal excursion led to coarse (>1 μm) grains and commensurately degraded mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

Powder-Route Synthesis and Mechanical Testing of Ultrafine Grain Tungsten Alloys

Cordero

Huskins²,

Park

et al. 2014

Metall Mater Trans A

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We report a W-rich alloy (W-7Cr-9Fe, at%) produced by high energy ball milling, with alloying additions that both lower the densification temperature and retard grain growth. The alloy's consolidation behavior and the resultant compacts' microstructure and mechanical properties are explored. Under one condition, a 98% dense compact with a mean grain size of 130 nm was achieved, and exhibited a hardness of 13.5 GPa, a dynamic uniaxial yield strength of 4.14 GPa in Kolsky bar experiments, and signs of structural shear localization during deformation.

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“…This high--energy ball milling method produces high energy impacts on powders by collision between powder particles and grinding media leading to nanocomposite powders with good sinterability [7,8]. To activate sintering and reduce sintering temperature of tungsten from 2800 • C to 1400 • C, the addition of small amounts of the transition metals, such as Ni, Fe, Co or Pd is practiced [5,9,10].…”

Section: Introductionmentioning

confidence: 99%

Nanostructured W-Cu Electrical Contact Materials Processed by Hot Isostatic Pressing

Tsakiris¹,

Lungu²,

Enescu³

et al. 2014

Acta Phys. Pol. A

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Nanostructured W Cu Ni electrical contact materials to be used in low voltage vacuum switching contactors for nominal currents up to 630 A were developed successfully by hot isostatic pressing. W Cu Ni composite powder mixtures with copper content of 20 to 40 wt% and 1 wt% Ni were mechanically alloyed in Ar atmosphere by high--energy ball milling with a ratio of milling steel balls: powders mixtures of 8:1 and rotation speed of 400 rpm for 10 and 20 h. The e ect of mechanical alloying on the sintering response of composite compacts was investigated. Also, the sintered contacts were characterized from the point of view of physical, microstructural, mechanical, and functional properties. The nanostructured electrical contacts presented very good sinterability and homogeneous structures with a maximum compactity degree of about 89%. The best W Cu Ni compositions with relative density of about 80%, chopping currents lower than 5 A, copper content lower than 40% as W 20Cu 1Ni (10 h of mechanical alloying and 20 h of mechanical alloying) and W 30%Cu Ni (10 h of mechanical alloying) were selected to be used in vacuum contactors.

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Influence of size of nanoparticles and plasma pressure compaction on microstructural development and hardness of bulk tungsten samples

Cited by 18 publications

References 35 publications

Surface modification and helium release of tungsten irradiated by 40 keV helium ions

Surface modification and helium release of tungsten irradiated by 40 keV helium ions

Powder-Route Synthesis and Mechanical Testing of Ultrafine Grain Tungsten Alloys

Nanostructured W-Cu Electrical Contact Materials Processed by Hot Isostatic Pressing

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