Pure Tungsten Research Articles

Hot Deformation Behavior and Simulation of Hot-Rolled Damage Process for Fine-Grained Pure Tungsten at Elevated Temperatures.

Fine-grained pure tungsten fabricated by a sol drying reduction low-temperature sintering method and hot isothermal compression tests were performed by using the Gleeble 3800 thermo mechanical simulator at deformation temperatures from 1273 K to 1473 K and strain rates from 0.001 s-1 to 1 s-1. In addition, the constitutive equation was established by least square method combined with the Zerilli-Armstrong model, and the hot deformation behavior was discussed. Moreover, based on constitutive equation, the influence of the rolling process and its parameters on temperature, strain, density and rolling force in the hot rolling process was investigated at elevated temperature by the finite element model (FEM). Furthermore, the form of rolling damage and its formation mechanism were analyzed. Results showed the grains of pure tungsten are dense, irregular polyhedral spherical and very fine, and the average grain size is about 5.22 μm. At a high strain rate, the flow stress increases rapidly with the increase in strain, while the stress-strain curve shows a flattening trend in the tested strain rate range with increasing temperature, and no flow stress peak exists, showing obvious dynamic recovery characteristics. Furthermore, the FEM simulation showed that compared with the rolling temperature, the reduction has a greater influence on the temperature, stress-strain field and its distribution. There are three kinds of damage in the hot rolling process: transverse cracks, longitudinal cracks and side cracks, which are attributed to the competition between additional stress caused by uneven deformation and material strength. Moreover, the control method of hot rolling defects had been preliminarily proposed. These results should be of relevance for the optimum design of the hot rolling process of pure tungsten.

Deposition of Iridium Coating on Pure Tungsten and High-Temperature Oxidation Behavior at 1300 K

Iridium (Ir) coating was electrodeposited on tungsten (W) substrate for resistance to high-temperature oxidation. The reduction of iridium was studied using an electrochemical cyclic voltammetry (CV) measurement technique. The structure characterization and performance testing were carried out by scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and a high-temperature oxidation test. The results showed that the reduction of tetravalent iridium ions to metallic iridium included three reduction steps. The deposited iridium coating had a fine polycrystalline + amorphous structure, no grain orientation phenomenon was observed after electrodeposition, and the microstructure was isotropic. The iridium-coated tungsten metal had excellent resistance to high temperatures at 1300 K, which was attributed to the better chemical stability of the oxide film generated on the surface of the iridium coating.

Effect of Chelating Agents on the Structural, Optical, and Dye-Degradation Properties of Tungsten Oxide Nanoparticles

A simple co-precipitation method was used to create pure tungsten oxide (WO3) nanoparticles using phthalic acid, citric acid, and oxalic acid as chelating agents. The influences of chelating agents on the structural, morphological, and optical properties were investigated. X-ray diffraction (XRD) patterns of WO3 nanoparticles showed the existence of combined phase of anorthic-monoclinic for all the samples, and the crystalline size was found to be reduced while using oxalic acid. The vibrational band observed in the region around (500–800 cm−1) in the FTIR spectra indicates the formation of WO3 nanoparticles. SEM images revealed the formation of WO3 agglomerates. The energy-dispersive X-ray (EDX) spectra of the WO3 nanoparticles confirmed the purity of synthesized nanoparticles. The enhanced light-absorption ability of oxalic-acid-assisted WO3 nanoparticles are inferred from the decreased band gap energy in UV–vis absorption spectra. The PL spectra showed emission in both the UV and visible regions. The optimized reaction parameters for obtaining high catalytic efficiency are identified by varying the concentrations of oxidant, catalyst, and dye during the catalytic reaction. The synthesized WO3 nanoparticles exhibited better catalytic degradation of CV than MB and RB dyes even with the lesser quantity of catalyst material.

Microstructure and Mechanical Properties of W-Al2O3 Alloy Plates Prepared by a Wet Chemical Method and Rolling Process.

The uneven distribution and large size of the second phase weakens the effect of dispersion strengthening in ODS-W alloys. In this article, the W-Al2O3 composite powders were fabricated using a wet chemical method, resulting in a finer powder and uniformly dispersed Al2O3 particles in the tungsten-based alloy. The particle size of the pure tungsten powder is 1.05 μm and the particle size of W-0.2 wt.%Al2O3 is 727 nm. Subsequently, the W-Al2O3 alloy plates were successfully obtained by induction sintering and rolling processes. Al2O3 effectively refined grain size from powder-making to sintering. The micro-hardness of the tungsten alloy plates reached 512 HV0.2, which is 43.7% higher than that of pure tungsten plates. The nano-hardness reached 14.2 GPa, which is 24.1% higher than that of the pure tungsten plate; the compressive strength reached 2224 MPa, which is 37.2% higher than that of the pure tungsten.

Compressive properties and deformation behaviors of sintered W-m-ZrO2 alloy under different temperature

The compressive properties of sintered tungsten alloys with different m-ZrO2 weight percentage (0, 0.5, 1.0%) were tested at room temperature and high temperature, and the hot deformation behaviors of the three metals were investigated under different temperature (1300–1600 °C) and strain rate (0.005–1 s−1). The room temperature strengthening model of zirconia particle reinforced tungsten alloy was established, and the hot deformation activation energy and constitutive equation of the three metals were calculated. Characterized by field emission scanning electron microscopy (FE-SEM) and the electron back scattering diffraction (EBSD) technique, the results show that zirconia doping can significantly refine the tungsten grain size, improve sintering densities, and uniformly disperse in the boundaries and inside of tungsten grain. The room temperature compression results show that the ultimate compressive strength and strain-to-failure of W-1.0 m-ZrO2 increase by 51.94% and 96.69%, respectively compared with pure tungsten. The main contribution to the room temperature strength of tungsten alloys is the fine grain strengthening caused by zirconia doping, about 60% for W-1.0 m-ZrO2，while the strengthening of the secondary phase particles accounts only for about 5%. High-temperature compression results show that zirconia doping increases the dislocation density of the alloy and significantly improve the ultimate compressive strength under high-temperature compression, but the influence of zirconia content on the strength will be weakened at high temperature. The doping of zirconia reduces the hot deformation activation of tungsten alloys and improves the hot processing behavior of tungsten alloy.

Effect of Fe11+ ion combined with helium and deuterium plasmas irradiation on the transient thermal shock behaviors of pure and potassium-doped tungsten

The large-scale warm-rolled pure tungsten (PW) and hot-rolled potassium-doped tungsten (W-K) plates were prepared by powder metallurgy technology to meet the demands of International Thermonuclear Experimental Reactor (ITER) in engineering application. In order to evaluate the performance of plasma-facing materials (PFM) in a more realistic service environment as much as possible, the influence of combined irradiation effects of high-energy iron (Fe) ion, deuterium (D) and helium (He) plasmas on the transient thermal shock behavior in the PW and W-K was investigated. The results indicate that the PW can generate more vacancy- and dislocation-type defects than that of W-K after irradiation. The cracking thresholds for un-irradiated PW and W-K are >0.66 and 0.44–0.55 GW/m2, respectively. However, the cracking threshold for both samples decreased to 0.22–0.33 GW/m2 after combined irradiation, indicating that the combined irradiation can significantly reduce the thermal shock resistance of PW and W-K. In addition, according to the statistical results of the crack density and width on the surface of irradiated samples, irradiated W-K owns better thermal shock resistance than irradiated PW under the same thermal shock condition. These results were also verified by the determination of residual stresses. Besides, the relationship between the evolution of irradiation-induced defects and K bubbles is also discussed in detail. These studies can provide an important reference for the identification of future PFM and numerical simulation under combined irradiation plus high thermal load.

Performance of a spaghetti calorimeter prototype with tungsten absorber and garnet crystal fibres

A spaghetti calorimeter (SPACAL) prototype with scintillating crystal fibres was assembled and tested with electron beams of energy from 1 to 5 GeV. The prototype comprised radiation-hard Cerium-doped Gd3Al2Ga3O12 (GAGG:Ce) and Y3Al5O12 (YAG:Ce) embedded in a pure tungsten absorber. The energy resolution was studied as a function of the incidence angle of the beam and found to be of the order of 10%/E⊕1%, in line with the LHCb Shashlik technology. The time resolution was measured with metal channel dynode photomultipliers placed in contact with the fibres or coupled via a light guide, additionally testing an optical tape to glue the components. Time resolution of a few tens of picosecond was achieved for all the energies reaching down to (18.5 ± 0.2) ps at 5 GeV.

Phase transformation and hydrogen reduction behavior of nanoscale W-Y2O3 powders synthesized by nano in-situ composite method

Powder plays an important role in the performance of tungsten composites. In this work, the nano-scaled W-Y2O3 powder was successfully synthesized by two-stage process of nano in-situ composite method: the calcination in air and hydrogen reduction. The phase transformation and microstructure evolution of powder were investigated and observed by the XRD, SEM, EDS and TEM technologies. Besides, the reaction and refining mechanisms for hydrogen reduction have initially proposed as well. Results showed that the phase transformation processes went through two stages of dehydration and deamination and finally forms complete tungsten oxide during the calcination stage. While, in the reduction stage, WO3 phase was mainly reduced to different WOX (1/3 ≤ x < 3) intermediate phase, especially the formation of W3O phase. The morphology of reduction of W-Y2O3 powder evolves from hollow spheres to slices, fragments and nano-irregular polygon as the reduction temperature increases. Simultaneously, the average particle size of W-Y2O3 powder decreases significantly with the increase of reduction temperature, while the reduction temperature is 800 °C, the change trend is opposite, but it's still much lower than pure tungsten. The addition of Y2O3 significantly affected the phase transition and microstructure evolution behavior of composite powders. The reduction was started from the surface region of powder, and then in the form of cracks or porous structures extend into the interior of the powder until all the nano-particles were formed, which was able to be explained by “shrinkage fissure - particle rupture” and “nucleation - evaporation - sedimentation” model. Moreover, the core-shell structure and Y2WO6 phase formed by addition of Y2O3 can hamper the chemical vapor transport (CVT) and the formation of WO2(OH)2 phase, thus significantly refining the reduced W-Y2O3 powder(115 nm).

Influence of Parameters and Performance Evaluation of 3D-Printed Tungsten Mixed Filament Shields.

Currently, protective clothing used in clinical field is the most representative example of efforts to reduce radiation exposure to radiation workers. However, lead is classified as a substance harmful to the human body that can cause lead poisoning. Therefore, research on the development of lead-free radiation shielding bodies is being conducted. In this study, the shielding body was manufactured by changing the size, layer, and height of the nozzle, using a 90.7% pure tungsten filament, a 3D printer material, and we compared its performance with existing protection tools. Our findings revealed that the shielding rate of the mixed tungsten filament was higher than that of the existing protective tools, confirming its potency to replace lead as the most protective material in clinical field.

In-situ solid solution of Mo or Cr in WB2: Densification, microstructure, and properties

Pure tungsten diboride (WB2) ceramic prepared by the boro/carbothermal reduction combined with spark plasma sintering (SPS) of WB2 can reach a relative density >90%. However, the final sintered density still needs further improvement to meet the application requirement. In this study, the WB2 ceramics doped with Mo or Cr (W0.95Mo0.05B2 and W0.95Cr0.05B2) were prepared and the effects of Mo or Cr doping on powder characters, sintering behavior, microstructure, mechanical and physical properties of WB2 were systematically investigated. The results showed that the average particle size of the WB2 powders was increased significantly after adding either dopant, and the relative density of WB2 ceramics was improved from ∼93% to ∼95% and 96% with Cr and Mo addition, respectively. However, the Vickers hardness of WB2 with either dopant was reduced. On the other hand, the W0.95Mo0.05B2 solid solution exhibited slight improvement on both of the thermal and electrical conductivity as compared with WB2. But, both of the thermal and electrical conductivity of W0.95Cr0.05B2 solid solution decreased significantly to about 50% of the values obtained for WB2. The decrease in thermal and electrical conductivity of W0.95Cr0.05B2 solid solution was mainly attributed to the formation of high concentration of atomic defects, i.e. dislocations.

Enhanced sintering of tungsten

W and W-La2O3 powders with a range of particle sizes were processed by furnace sintering, direct resistance sintering, and spark plasma sintering to determine the effects of current and pressure on densification and grain size. The results from these experiments are combined with experimental data from literature and compared to a model for densification based on master sintering curve concepts to assess the effectiveness of finer particle sizes, the application of current, and the combined application of current and pressure for achieving sintered densities above 96% of theoretical for pure tungsten and for tungsten containing small amounts of oxides and/or carbides. Experimental results for grain size are also compared to the model predictions for pressureless sintering. The same model is used to assess the effectiveness of transition metal additions, the application of pressure, and the application of electromagnetic radiation on enhancing the sintering of tungsten and refining its grain size.

Simultaneous analysis of long-pulse laser irradiated plasma-facing materials (PFMs) microstructure and hardness by in-situ laser Opto-ultrasonic dual detection (LOUD)

Laser-induced transient heat load events such as edge localized mode (ELM) could induce recrystallization, grain growth, surface degradation, and hardness changes. In this regard, we used the long-pulse laser beams with power densities ranging from 0.165 to 1.909 GW m−2 to simulate transient heat load events for pure tungsten and tungsten heavy alloy (WHA) materials. The investigated samples showed that pure tungsten exhibited a higher recrystallization threshold, steady grain growth, and less surface hardness deterioration than WHA. However, the real-time simultaneous analysis of structural and mechanical properties such as matrix elements, grain size, surface degradation, and hardness changes is challenging in this domain. Therefore, in this study, we utilized a novel laser Opto-ultrasonic dual detection (LOUD) multimodal technique that integrates the benefits of laser-induced breakdown spectroscopy (LIBS) and laser ultrasonic testing (LUT) for simultaneous and in-situ detection of elemental information, grain size and hardness. The preliminary results showed that the variation in hardness is well correlated with the LIBS calibration curve formed by the ionic to atomic line intensity ratio and plasma electron temperature (Te). Despite the different matrix compositions of both samples, the observed increase in the value of Te with hardness justifies the Saha-Eggert relation. The coefficient of determination (R2 ≥ 0.970) value in the calibration curve and Te for hardness evaluation showed the goodness of the fitted model. Furthermore, the correlation of grain size with ultrasonic acoustic attenuation (α) was analyzed by the pulse-echo technique of the ultrasonic waveform for investigated samples. The results showed that grain size is also directly associated with acoustic attenuation with R2 > 0.989. The findings showed that the regression coefficient has a good approximation, which demonstrates the preciseness and potential ability of the LOUD technique for in-situ grain size and hardness analysis.

(Digital Presentation) Electrochemical Reduction of Oxygen-Containing Tungsten Compounds on a Liquid Gallium Cathode in an Eutectic Melt of Calcium and Sodium Chlorides

This paper presents the results of studies of electrochemical reduction of oxygen-containing tungsten compounds (WO3, CaWO4) in a molten eutectic mixture of calcium and sodium chlorides. In contrast to the known methods of direct electrochemical reduction of refractory metal oxides, it is proposed to reduce the initial oxygen-containing tungsten compounds in powder form on a liquid gallium cathode without resorting to pre-pressing and sintering operations.In the temperature range 600-1000 °C, at which the electrochemical reduction of these compounds takes place, gallium does not evaporate, does not interact with the components of the melt, or with the initial compounds of tungsten or pure tungsten. The liquid gallium cathode not only provides reliable contact with highly dispersed initial tungsten powder compounds and their uniform polarization but also protects the reduced metal from contamination by products of electrolysis and electrolyte. In addition, gallium, due to its lower specific weight than tungsten oxide, protects WO3 from unwanted interactions with calcium chloride, which causes the formation of volatile tungsten oxochlorides and the loss of the initial tungsten trioxide. Due to the large difference in crystallization temperatures of the molten electrolyte (over 500 °C) and the gallium cathode (~ 30 °C), as well as the difference in specific weights of the electrochemical cell components, fine tungsten powder isolated during electrolysis is easily separated from melt and gallium.During the reduction of tungsten trioxide at the beginning of electrolysis on the surface of the gallium cathode, sodium and calcium cations, which are part of the electrolyte mixture, are discharged. In the range of reduction temperatures (700-800 °C) the discharge potentials of sodium and calcium cations are almost the same. As the gallium cathode is saturated with isolated metals (sodium and calcium), tungsten trioxide is reducedWO3 + 3nM → W + 3MnO, where М = Na, Ca,and n = 2 when sodium is involved in the reduction and n = 1 when the reducing agent is calcium. The formed metal oxides (MnO) react with tungsten trioxide, forming a mixture of tungstates of the appropriate metalsWO3 + MnO → MnWO4 Both oxides and tungstates of calcium and sodium have a lower specific weight than gallium, so as they accumulate, they float to the interface: cathode/melt, where at the appropriate values of the electrode potential, also participate in electrode processesMnWO4 + 6е− → W + MnO + 3О2− MnO + 2е− → nM + О2−.Reduced tungsten settles to the bottom of the gallium cathode container, and calcium and sodium contribute to the reduction of tungstates.The results of voltammetric studies of oxidized and unoxidized monocrystalline tungsten, tungsten cathode, on the surface of which is applied a film of WO3, gallium cathode with tungsten starting compounds (WO3, CaWO4) in a molten eutectic mixture of sodium and calcium chlorides indicate in favor of the fact that this process takes place in stages in several stages. This is also supported by the results of electrolysis under potentiostatic conditions at different potentials of the cathode relative to the unpolarized tungsten electrode. The mixture of tungsten and calcium tungstate is the reduction product at potentials lower than the reduction potentials of sodium and calcium tungstates. For example, with a reduction potential of −1.3 V, the reduction products of both tungsten trioxide and calcium tungstate contain no more than 2.0% of tungsten, the rest is calcium tungstate. Reduction at a potential of −2.0 V provides a product with a tungsten content of not less than 20.0%. Finally, the reduction at a potential equal to or greater than −2.4 V at the cathode produces tungsten without the content of extraneous phases. The degree of extraction of tungsten from tungsten trioxide is not less than 65.0%, from calcium tungstate is about 72.8%.The morphology of reduced tungsten was studied by scanning electron microscopy. The resulting tungsten powder has the form of dendritic crystals with a size of several tens of micrometers.

Competitive roles of dislocations on blister formation in polycrystalline pure tungsten

Dislocation in tungsten is a significant contributing factor to blister formation in terms of both the nucleation and growth of bubbles under high-flux deuterium (D) ion irradiation. Unfortunately, the focus of previous publications was limited to only extreme cases which was either dislocation-rich or recrystallized. Therefore, this study aims to further improve the understanding of the microstructure dependence of blister formation in pure tungsten based on a more detailed comparison. The modification of the surface structure after D exposure has been investigated using various tungsten specimens with individual dislocation densities introduced by different annealing processes. The experimental results demonstrated that the number density of blisters and D retention increased with decreasing dislocation density, but decreased again when the tungsten material was fully recrystallized. Such an unexpected appearance of blisters was understood based on the competitive roles of intrinsic dislocations in blister formation by three aspects: trapping site, diffusion channel, and trigger of local plastic deformation necessary for blister growth. It was finally concluded that the dislocation mainly acted as a diffusion channel under the present exposure conditions wherein the irradiation temperature was quite high and the exposed materials possessed the recovered dislocation structure, thereby resulting in the acceleration of blister formation with decreasing dislocation density due to the lowered out-diffusion rate of D. However, in recrystallized tungsten, blister formation was restrained by the poor plasticity as well as the complete lack of trap sites.

A review on additive manufacturing of refractory tungsten and tungsten alloys

We review the progress of additive manufacturing effort on refractory metal tungsten and tungsten alloys. These materials are excellent candidates for a variety of high temperature applications but extremely challenging to fabricate via additive manufacturing due to a series of existing issues during the manufacturing. We outline these issues and discuss the current understanding and progress to tackle them. Laser powder-bed-fusion, laser directed-energy-deposition, and electron beam powder-bed-fusion are three common techniques that have been applied to additively manufacture pure tungsten. This overview discusses current observations and understanding on the issues associated with each of these techniques. We identify future research opportunities in additive manufacturing of refractory metals.

Characterization and determination of the gamma radiation attenuation coefficient in the W20Cu3Ni metallic alloy to be applied in the transport of radioactive substances

The final responsibility of civil society protection regarding the nuclear sector in every country is a local/national governmental duty. The way this task is wielded changes little from country to country. The principal concern is to reduce the exposure of people to sources that eventually emit radiation. The shield used for this purpose is called biological shielding. The W20Cu3Ni metallic alloy was obtained using W powder as a matrix and the infiltrating elements Cu and Ni and subjected to sintering processes at different temperatures. All samples were analyzed by X-ray diffractometry, scanning electron microscopy (SEM). The main objective of this work is to determine the gamma radiation attenuation coefficients of the W20Cu3Ni metallic alloy subjected to different sintering temperatures. The determination of the alloy attenuation coefficient was performed using an experiment set up with a source of cobalt (Co-60), which emits characteristic energy peaks of 1.173 MeV and 1.332 MeV. The gamma rays are focused to reach the detector and the resulting photons are counted for 1800 s in three situations. Initially, the gamma rays are directed to the detector in a free path. The second experiment consists of using pure tungsten to shield the radiation, i.e., all gamma rays have to pass through it before entering the detector. Finally, the metallic alloy replaces tungsten, and the same measurements are done. Despite the amount of copper and nickel present in the final sample, the results obtained for this new metallic alloy are very satisfactory. The measurements of the gamma attenuation coefficient in the W20Cu3Ni metallic alloy at different temperatures, showed significant results, ie, a difference between 7.08% and 14.63% lower than the attenuation coefficient of pure tungsten used as a reference. Therefore, this new W20Cu3Ni metal alloy has excellent potential for application in shielding systems and in the transport of substances with high nuclear activity used in the production of radioisotopes and radiopharmaceuticals.

Deformation and failure by weaving dislocation networks in body-centered-cubic tungsten

Dislocation is the primary carrier for accommodating plastic deformation in metals. It is generally envisaged that metals with low initial dislocation density have high strain-to-failure and good formability, and vice versa. However, contrary to most metals, body-centered-cubic pure tungsten becomes brittle after reducing its dislocation density by recrystallization, while its formability increases after heavy deformation. To elucidate the mechanism of this counterintuitive mechanical behavior, by combining ex-situ indentation tests and dislocation reconstruction techniques, we find that tungsten’s deformation and failure processes are accompanied by the formation of a specific dislocation pattern. Dislocation networks are governed by a mechanism similar to the weaving process of the spider’s orb web. After heavy deformation, subgrains are generated due to the weaving process. The recurring weaving of dislocations reduces the mean free path for crack propagation, which is considered as the main reason for the increased formability of tungsten after deformation.

Publisher Correction: Effect of ambient pressure change on pure tungsten laser spot welding

Publisher Correction: Effect of ambient pressure change on pure tungsten laser spot welding

Confinement and absorption layer free nanosecond laser shock peening of tungsten and its alloy.

Traditionally, nanosecond laser shock peening (ns-LSP) of metals requires an additional application of an absorption layer (black paint) and more importantly a confinement layer (typically water or transparent material) on the workpiece for introduction of compressive stresses. In this paper, we demonstrate for the first time, to the best of our knowledge, introduction of compressive stresses in pure tungsten and its alloy TAM7525 (75% tungsten and 25% copper) without any absorption and confinement layer for ns-LSP. Peak compressive stresses of -349 MPa and -357 MPa were measured in pure tungsten and TAM7525, respectively, when a 0.25-cm2 area was irradiated by a Yb:YAG laser (1030 nm) operating at ∼5 J, ∼2 ns with circular polarization. These peak compressive stresses (without confinement layer) compare well to those with tungsten ns-LSP done with water as confinement layer at twice the energy at 10-ns pulse duration. Furthermore, compared to femtosecond laser shock peening (fs-LSP) of aluminum at atmospheric pressure, the depth of compressive stresses recorded in tungsten and its alloy (∼7 times denser than aluminum) is nearly four times more in the case of confinement layer free nanosecond laser shock peening (CLF-ns-LSP).

Three-dimensional porous tungsten via DLP 3D printing from transparent ink

Tungsten, an essential refractory metal material, has the characteristics of high melting and boiling points, high hardness, low expansion coefficient, and low vapor pressure. An indirect strategy to print three-dimensional (3D) refractory metal materials via digital light processing (DLP) followed by a post-treatment process was proposed. To analyze this strategy, a transparent ink with tungsten salts was developed, printed into a 3D precursor via DLP, and subsequently transited into 3D porous tungsten. The ultraviolet rheological properties and stability of the ink, transition process from the precursor to a 3D article, and the properties of the obtained 3D porous tungsten were investigated. This ink was preferable for DLP 3D printing, possessing consistency, stability and favorable absorbance at the wavelength of 385 nm. With increasing temperature, the weight of the tungsten salt in the 3D precursor decreased by 8.97% and was transited to tungsten oxide below 460 °C, reduced to pure nano-sized tungsten at approximately 700 °C, and finally sintered into porous articles. The organics initially contributed to polymerization during printing as well as reduction as a carbon reducer after pyrolysis. The pore size distribution of porous tungsten is nonlinear or multimodal, depending on the final sintering temperature. At 1200 °C, two distinct peaks are observed in the pore distribution curves of the products. At 1400 °C, the small pore as a whole decreases from approximately 100–1000 nm. Correspondingly, the relative density of the samples increased with temperature.