In situ oxide dispersion strengthened tungsten alloys with high compressive strength and high strain-to-failure

Huang, Li-Chun; Jiang, Lin; Topping, Troy D.; Dai, Chen; Wang, Xin; Carpenter, Ryan; Haines, Chris; Schoenung, Julie M.

doi:10.1016/j.actamat.2016.09.034

Cited by 105 publications

(25 citation statements)

References 27 publications

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“…Possessing high melting point (3693 K), high thermal conductivity, and strong mechanical properties, tungsten has been widely used in military and electrical industries [1]. In the international thermonuclear experimental reactor (ITER), tungsten is considered as the most promising candidate for plasma-facing materials owing to its high resistance to irradiation and low erosion yield [2].…”

Section: Introductionmentioning

confidence: 99%

Cracking Behavior in Additively Manufactured Pure Tungsten

Wang

et al. 2018

Acta Metall. Sin. (Engl. Lett.)

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In this study, near fully dense (96.5%) pure tungsten bulks were additively manufactured and the cracking behavior was investigated. A crack network with a spacing of * 100 lm was observed in the fabricated bulks. It was observed that the laser scanning strategy, which could tailor the microstructure, affected the crack distribution pattern in fabricated tungsten. The calculated surface temperature difference (7300 K) was much higher than the cracking criterion (800 K) of tungsten, indicating that cracking is almost inevitable in laser additive manufacturing of tungsten. It could be concluded that crack network formed because the cracks emerged in every laser molten track and then interconnected in the layer-by-layer building process.

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Section: Introductionmentioning

confidence: 99%

Cracking Behavior in Additively Manufactured Pure Tungsten

Wang

et al. 2018

Acta Metall. Sin. (Engl. Lett.)

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“…From the temperature evolution curve, the relation between the heat-transfer coefficient (h) versus time (t) can be fitted with Equation (1). The equivalent temperature, T τ , of the substrate just after laser scanning, can then be determined from the fitted result, and the mean laser absorption can then be represented as:…”

Section: Effect Of Powder Spheroidization On Densificationmentioning

confidence: 99%

“…Tungsten is widely used in the electronic and aerospace industries, and in military applications because of its high melting point (3420 • C), thermal conductivity (174 W m −1 K −1 at 25 • C), hardness, and strength [1,2]. It is also recognized as the most promising plasma-facing material for use in future nuclear fusion reactors on account of its excellent radiation-shielding properties against heat and plasma flux [3,4].…”

Section: Introductionmentioning

confidence: 99%

Dense Pure Tungsten Fabricated by Selective Laser Melting

Wang

Zhou

et al. 2017

Applied Sciences

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Additive manufacturing using tungsten, a brittle material, is difficult because of its high melting point, thermal conductivity, and oxidation tendency. In this study, pure tungsten parts with densities of up to 18.53 g/cm 3 (i.e., 96.0% of the theoretical density) were fabricated by selective laser melting. In order to minimize balling effects, the raw polyhedral tungsten powders underwent a spheroidization process before laser consolidation. Compared with polyhedral powders, the spherical powders showed increased laser absorptivity and packing density, which helped in the formation of a continuous molten track and promoted densification.

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“…Upon sintering, the oxygen impurities tend to form tungsten oxide particles, which are found primarily at the grain boundaries and their junctions. While they may act as grain-growth inhibitors through grain-boundary pinning (similarly to other dispersion particles introduced intentionally) [12], they may also reduce the material's ductility [33] and/or undermine high-temperature stability due to a lower melting point (~1700 • C [42]) [13]. Oxygen impurities also affect the sintering efficiency, as indicated in Refs.…”

Section: Discussionmentioning

confidence: 99%

“…[12,13]. It may have formed as a result of incomplete reduction of the more naturally occurring WO 3 [30][31][32] or through segregation of oxygen dissolved in the W matrix or adsorbed on the W powder grains [12,33]. Contrary to oxygen impurities, present in the form of tungsten oxide, no tungsten carbide was detected in any of the XRD patterns.…”

Section: Chemical (In)homogeneitymentioning

confidence: 99%

On the Structural and Chemical Homogeneity of Spark Plasma Sintered Tungsten

Matějíček

Vilémová

Veverka

et al. 2019

Metals

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Tungsten-based materials are the prime candidate plasma-facing materials for future fusion reactors, such as DEMO. Spark plasma sintering is a prospective fabrication technology with several advantageous features. The concurrent application of electric current, temperature and pressure enhances the sintering process, allowing for lower temperatures and shorter sintering times than traditional powder metallurgy processes. This in turn helps to avoid excessive grain growth and phase segregation in W-alloys. This study is focused on several factors that may influence the homogeneity of the sintered compacts-namely the diffusion of carbon from the graphite die, purity of the powder and sintering conditions. The following characteristics of spark plasma-sintered tungsten compacts were studied: composition (especially carbon and oxygen content), porosity, mechanical properties (hardness and fracture strength), and thermal diffusivity. The effects of the abovementioned processing factors were quantified, and local variations of selected properties were assessed. plasma sintering (SPS, also called Field Assisted Sintering Technology, FAST) is a progressive technique to consolidate various materials, metals as well as ceramics, glass etc. Relatively low temperatures, high heating rates and short processing times-compared to traditional sintering techniques-are generally favorable for the retention of fine grains. In SPS, the sintered material in the form of powder is introduced into a die and, subsequently, high-intensity (pulsed or steady) electric currents up to several thousand A and uniaxial pressure up to hundreds MPa are applied. The die and the powder are heated by Joule heating. Graphite foil is usually inserted between the powder and the die in order to eliminate undesirable bonding of sintered material to the die. Depending on the parameters and the sintered material, temperature can reach up to~2400 • C and with suitable parameters, fully dense samples can be obtained [5][6][7]. Sintering parameters have a considerable effect on the resulting microstructure, homogeneity and other properties of the samples. Basic variables characterizing the sintering process are: (i) sintering temperature, (ii) applied pressure, and (iii) duration of the holding time at the sintering temperature. The results are also sensitive to the heating rate, manner of pressure application, die dimensions, sintering atmosphere etc.

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In situ oxide dispersion strengthened tungsten alloys with high compressive strength and high strain-to-failure

Cited by 105 publications

References 27 publications

Cracking Behavior in Additively Manufactured Pure Tungsten

Cracking Behavior in Additively Manufactured Pure Tungsten

Dense Pure Tungsten Fabricated by Selective Laser Melting

On the Structural and Chemical Homogeneity of Spark Plasma Sintered Tungsten

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