Tungsten Alloy Research Articles

Protection mechanism of B4C–TiB2–SiC composite ceramic under ultra-high velocity impact

As the penetration technology develops and the projectile velocity increases, it becomes imperative to investigate the protection mechanism of high-performance ceramic under hypervelocity impact. The impact process of tungsten alloy projectile penetrated into B4C–TiB2–SiC composite ceramic target using ballistic test and finite element simulation at an ultra-high velocity of 2154 m/s was researched in the present study. Additionally, the protection mechanisms were described in terms of the morphology of target damage, the behavior of projectile kinetic energy dissipation, and the temperature field cloud. The findings from the ballistic experiments highlighted that the formation of macro-damage areas (concentrated damage, cone crack, circumferential crack, and radial crack areas) and micro-fragmentation zones could consume a significant amount of impact energy. The mixed fracture mode and the typical inelastic deformation characteristics (dislocations and micro-twinning) contributed to the energy dissipation. Simulation results indicated that the surface dwell effect of the projectile exhibited the highest rate of energy consumption. Furthermore, the temperature field results indicated that the maximum temperature on composite ceramic surface could reach 2310 K, which was below the melting point of B4C ceramic (2723 K). However, this temperature could cause the melting of the majority of metal materials. Therefore, ceramic materials exhibited a significant advantage under conditions of ultra-high impact velocities.

Comparative Analysis of Metal Electrodeposition Rates towards Formation of High-Entropy WFeCoNiCu Alloy.

This study presents a calculation and comparison of Fe, Co, Ni and Cu deposition rates in the tungsten codeposition process based on the electrodeposition of numerous tungsten alloys. Eight different tungsten alloys containing from two to five metals were electrodeposited in constant conditions in order to compare the exact reduction rates. The calculated rates enabled control of the alloy composition precise enough to obtain a high-entropy WFeCoNiCu alloy with a well-balanced composition. The introduction of copper to form the quinternary alloy was found to catalyze the whole process, increasing the deposition rates of all the components of the high-entropy alloy.

Blistering and retention behavior of laser powder bed fused tungsten alloys under hydrogen plasma irradiation

In this study, pure tungsten (W) fabricated by powder metallurgy and laser powder bed fusion (LPBF) formed W-Ta and W-ZrC alloys were exposed to hydrogen plasma. Severe blistering was found in LPBFed W-Ta specimens due to a strong [111] crystallographic texture and the large number of particle-matrix interfaces in the LPBFed W-ZrC inhibits the blister growth. The retention of LPBFed W alloys is lower than that of pure W due to the presence of large columnar grains and cracks. The results highlight the capability of tailoring the microstructures of W alloys by the LPBF technique to achieve improved plasma-compatible performance.

Research on Coated Tool Life and Wear in Ta-2.5W Alloy Turning.

Due to its inherent high hardness, strength, and plasticity, tantalum-tungsten (Ta-W) alloy poses a considerable challenge in machining, resulting in pronounced tool wear, diminished tool lifespan, and suboptimal surface quality. This study undertook experiments utilizing uncoated carbide tools, TiAlN-coated carbide tools, and AlTiN-coated carbide tools for machining Ta-2.5W alloy. The investigation delved into the intricacies of surface temperature, tool longevity, and the distinctive wear characteristics under varying coating materials and cutting parameters. Concurrently, a comprehensive exploration of the wear mechanisms affecting the tools was conducted. Among the observed wear modes, flank wear emerged as the predominant issue for turning tools. Across all three tool types, adhesive wear and diffusion wear were identified as the principal wear mechanisms, with the TiAlN-coated tools displaying a reduced level of wear compared to their AlTiN-coated counterparts. The experimental findings conclusively revealed that TiAlN-coated carbide tools exhibited an extended tool lifespan in comparison to uncoated carbide tools and AlTiN-coated carbide tools, signifying superior cutting performance.

Stress corrosion effects on ADC12 Al alloy tungsten inert gas welding joint in 3.5 wt% NaCl solution

The stress corrosion behavior of ADC12 Al alloy tungsten inert gas (TIG) welding joint (WJ) outside its elastic deformation range was studied using electrochemical testing methods combined with surface analysis techniques in 3.5 wt% NaCl solution at 30 °C. The results showed that, with the enlargement of imparted stress, the corrosion potential of the TIG WJ shifted positively, the corrosion current density increased, and the polarization resistance decreased, indicating that the corrosion rate of the TIG WJ increased with the enlargement of imparted stress. With the prolongation of immersion time, the corrosion rate of the TIG WJ increased and then subsequently decreased. In addition, the plasticity and ductility of the TIG WJ decreased with the enlargement of imparted stress. When the imparted stress was 2100 N and 4200 N, the corrosion products on its surface were mainly composed of Al2O3 and Al(OH)3. This study provided a theoretical basis for the selection of structural materials and welding methods in the automotive, marine and aerospace fields.

Structure of quenched Zr-W alloys

Quenched zirconium–tungsten alloys containing from 0.1 to 2.3 at.% tungsten were studied by X-ray diffraction analysis, transmission electron microscopy, and microhardness measurements. It is found that in the process of quenching, the martensitic β → α' transformation occurs in alloys with tungsten content up to 0.9 at.%, and the martensitic β → α″ transformation occurs in Zr–2.3 at.% W alloy. The formation of metastable ω-phase occurs in the Zr–2.3 at.% W alloy.

Effect of adding chrome-cobalt, titanium, and tungsten alloys to cold-cure acrylic resin oral stent for cancer patients with head and neck radiotherapy

Effect of adding chrome-cobalt, titanium, and tungsten alloys to cold-cure acrylic resin oral stent for cancer patients with head and neck radiotherapy

Cutting Performance and Tool Wear of AlCrN- and TiAlN-Coated Carbide Tools during Milling of Tantalum–Tungsten Alloy

Tantalum–tungsten alloys have been widely used in different industrial sectors—for example, in chemical, medical, aerospace, and military equipment. However, they are usually difficult to cut because of the large cutting force, rapid tool wear, and poor surface finish during machining. This paper presents the machining performance and cutting tool wear of AlCrN/TiAlN-coated carbide tools during the milling process of Ta-2.5W. The effects of cutting parameters on the cutting forces and surface roughness of AlCrN/TiAlN-coated carbide tools were obtained and analyzed. The results show that the wear resistance of AlCrN-coated tools is better than that of TiAlN-coated tools, and that the main wear mechanisms of both cutting tools are crater wear, adhesive wear, and diffusion wear. Compared to TiAlN-coated tools, AlCrN-coated tools reduced the cutting forces by 1% to 15% and decreased the surface roughness by 6% to 20%. A cutting speed within the range of 80–120 m/min can ensure a low cutting force while maintaining good surface roughness, which is more conducive to machining Ta-2.5W.

The behavior of 12⟨111⟩ screw dislocations in W–Mo alloys analyzed through atomistic simulations

Analyzing plastic flow in refractory alloys is relevant to many different commercial and technological applications. In this study, screw dislocation statics and dynamics were studied for various compositions of the body-centered cubic binary alloy tungsten–molybdenum (W–Mo). The core structure did not appear to change for different alloy compositions, consistent with the literature. The pure tungsten and pure molybdenum samples had the lowest plastic flow, while the highest dislocation velocities were observed for equiatomic, W0.5Mo0.5 alloys. In general, dislocation velocities were found to largely align with a well-established dislocation mobility phenomenological model supporting two discrete dislocation mobility regimes, defined by kink-pair nucleation and migration and phonon drag, respectively. Velocities were observed to increase with temperature and applied shear stress and with decreasing kink-pair formation energies. The 50 at. % W alloy was found to possess the lowest kink-pair formation energy, consistent with its higher dislocation velocity. Furthermore, molybdenum segregation to the dislocation line was found to be thermodynamically favorable specifically at low temperatures and was observed to significantly delay the onset of dislocation glide and then generally enhance dislocation velocities thereafter. This behavior was explained by examining the energy landscape of dislocation glide. Furthermore, a segregation/de-segregation phase transition was observed to occur around 2500 K beyond which no preferential segregation to the dislocation was found. Overall, our findings suggest strong dependencies of plastic flow in W–Mo alloys on composition and elemental segregation, in agreement with the available literature, and may provide useful information to guide the design of next generation structural materials.

Anti-corrosion study of tungsten alloy coating on tube column under high CO2 partial pressure

In order to address the low-cost corrosion prevention of wellbore tubing in high-temperature and high-pressure gas injection development environments, tungsten alloy-coated tubing specimens were selected for corrosion experiments. Microscopic characterization techniques such as SEM/EDS were used to analyze the corrosion product composition, phase structure, and three-dimensional morphology of the specimens. Uniform corrosion rates and localized pitting corrosion rates of the specimens were tested separately. Based on the uniform corrosion rate, residual strength verification and service life prediction of the tubing after corrosion were conducted. The study revealed that in a simulated gas injection development corrosion environment at a high temperature of 190 °C, as the CO2 partial pressure increased, both the uniform corrosion rate and pitting corrosion rate of the tungsten alloy-coated specimens gradually increased. When the CO2 content reached 100%, the uniform corrosion rate was 0.4300 mm/a, and the pitting corrosion rate was 0.4684 mm/a. The main substances causing material corrosion were O, Cl, and S in the environment. Furthermore, with the increasing CO2 partial pressure, the damage to the tungsten alloy coating on the specimen's surface deepened. By verifying the residual strength of the tubing after corrosion, it was found that at a temperature of 190 °C and a CO2 content of 38%, the tensile safety factor of the production tubing exceeded the critical value in the 10th year, and the casing's tensile safety factor exceeded the critical value in the 36th year. This research can provide reference insights for the selection of tungsten alloy coatings for corrosion prevention in gas injection wellbore tubing.

Near-ultraviolet photodetector using cerium hexaboride alloy

This article investigates a new type of heterostructure photodetector (PD) made of cerium hexaboride (CeB6) and tungsten (W) alloy deposited on top of a nitrogen-doped silicon carbide substrate. Density function theory (DFT) suggests that the alloy with 67% CeB6 and 33% W provides an optimal photo response for the PD. The optimum alloy thickness is computed numerically using particle swamp optimization (PSO) in lumerical Finite difference time domain (FDTD) software, and the alloy is fabricated using direct current (DC) and radio frequency (RF) sputtering. The performance of the PD is experimentally characterized, and our findings show a maximum photocurrent of 71.86 nA and a maximum responsivity of 94.1 µAW−1 at the near ultraviolet (UV) wavelength of 405 nm.

Feasibility of kinetic orbital bombardment

Abstract In this paper, the possible impact effects of orbital bombardment systems and their feasibility are studied. These effects are the projectile penetration into concrete and steel targets and seismic effects. The equations of motion for the re-entry of a projectile and the penetration were solved numerically. The projectile penetration is modelled using the Alekseevskii–Tate model. By varying the altitude (h), projectile length (L), manoeuvre velocity (ΔV) and the target properties, the flight time (t), earthquake magnitude (M) and penetration depth (P) are calculated. The calculations show that the impact of a tungsten alloy rod with a length of 8 m and a 0.4 m diameter results in an earthquake with a seismic magnitude of only 2.5 on the Richter scale. For concrete, the optimal result is obtained for a projectile with a length of 0.56 m. It penetrates 1.79 m with a minimal ΔV trajectory. These results show that a kinetic orbital bombardment system is not feasible without major technological developments, the impact angle being a bottleneck of the concept. Moreover, one has to accept very high costs. Without any means to change the attitude of the projectile, using ICBMs or bombers shows a better penetration performance than re-entry. Highlights Weapons in orbit may provide a strategic advantage. However, they are restricted by international space laws. Impact angle of the projectile is a bottleneck for kinetic orbital bombardment. Larger impact angles can be achieved, but at the expense of a larger mass-to-orbit. A hypersonic drag device may be used to optimise the impact angle and thus improve the system. Alternative projectile delivery methods (Bomber, Intercontinental Ballistic Missile (ICBM)) show better performance for both steel and concrete targets. Essentially, only penetration phenomena matter because the seismic effects are not significant. Therefore, orbital bombardment systems don’t even resemble weapons of mass destruction (WMD). Given their limited effect, destroying a particular target requires a guidance and flight control system, which, given the high velocities, may not be feasible.

Microstructure and compressive deformation behavior of W-Ni3Al-Co model alloys by two-step sintering

The regulation of microstructure can improve the mechanical properties of tungsten alloys. To regulate the microstructure, the W-Ni3Al-Co alloys with different Ni3Al/Co ratios were prepared using a two-step sintering method, and the microstructure and compressive deformation behavior were investigated. The results showed that the particle sizes of the W-rich phase in the network structure were refined with the increase of the Ni3Al/Co ratio, and a large fraction of twin boundaries were detected in the adhesive phase. The compressive deformation behavior of a W-7Ni3Al-3Co alloy with excellent compressive properties was investigated by the EBSD technique. The results demonstrated that twins in the FCC binder phase hindered the stress concentration in the binder phase and at the interface of the W/binder phases through twin-dislocation interactions. The W network structure underwent the uniform global deformation that restricted grain boundary sliding during deformation and prevented crack extension and consolidation. Twins in the binder phase and the W network structure were both important factors in improving the compressive properties of W-Ni3Al-Co alloys.

X-ray Fluorescence Analysis of the Elemental Composition of Tungsten, Nickel and Copper

The purpose of this work was to conduct an X-ray fluorescence analysis of the elemental composition of tungsten, nickel and copper metal waste using an Olympus Delta portable spectrometer.Methods. To determine the chemical composition of raw materials, samples of metal waste in the form of copper rods, tungsten rods of various diameters and scraps of nickel plates intended for recycling were examined. To determine the elemental composition of metal waste, the method of X-ray fluorescence analysis (XFA) was chosen. The X-ray fluorescence method is based on the ratio of the intensity of X-ray fluorescence to the concentration of elements in the sample. Samples irradiated with powerful X-ray tube radiation, in response, emit characteristic fluorescent radiation of atoms proportional to their concentration in the sample. This method allows us to qualitatively assess the elemental composition of complex samples without violating their physico-chemical properties with minimal time costs. The Olympus Delta spectrometer was used as an express analyzer of metals and alloys, with the help of which experimental data on the composition of metal waste of tungsten, nickel and copper were obtained.Results. Based on the conducted studies aimed at X-ray fluorescence analysis of the elemental composition of tungsten, nickel and copper metal waste using the Olympus Delta portable spectrometer, it was found that the samples of the studied metal waste correspond to the following grades of alloys: tungsten rod made of tungsten grade VA; nickel plate made of nickel grade PNK-0T1; copper rod made of copper grade M3r.Conclusion. The results obtained will allow further research on their processing by the method of electroerosive dispersion and reuse in the production of heavy tungsten alloys. Renovation of metal waste, including tungsten, nickel and copper metal waste, will contribute to resource conservation, import substitution and ensuring the technological sovereignty of the Russian Federation.

Application of concrete damage evolution equation considering confining pressure and strain rate effects in projectile penetration

Repeated loading and unloading tests were carried out on concrete under different confining pressures and strain rates to characterize the damage using the decrease in elastic modulus, and a damage evolution equation considering the effects of confining pressure and strain rate was established. At the same time, the yield criterion and equation of state of the Holmquist–Johnson–Cook (HJC) model were modified by combining the experimental data of high confining pressure. The modified model was validated by performing single-element numerical simulations for different stress states. Then, experiments were carried out on the penetration of tungsten alloy projectiles into concrete slabs, with penetration velocities ranging from 172 m/s to 302 m/s. The depth of penetration and crater area were obtained. Numerical simulations were subsequently carried out using the proposed model. The results showed that this model can describe the behaviour of concrete under dynamic loading. Finally, the damage evolution mechanism of concrete during the penetration process is analysed in conjunction with the proposed damage evolution equation.

The synergetic effect of TaC particles and Re alloy on microstructure and mechanical properties in tungsten alloy

TaC enhancement particles and Re alloy were used to improve the strength and ductility of the tungsten alloy. The synergetic effect of TaC addition and Re alloying on relative density, microstructure, and mechanical properties of tungsten alloy were investigated. The results indicated that a W-based composite with 2.5 wt% TaC addition and 25 wt% Re alloying exhibited yield stress of 1.23 GPa, the ultimate compressive stress of 2.86 GPa, bending strength of 1.30 GPa and strain capacity of 42 %, which was increased by 114 %, 140 %, 226 %, and 133 % than those of pure W. Further analysis revealed that the grain boundary purification, grain refinement, and kinematic strain gradient contribution because of the addition of TaC, lattice distortion, and the generation of dislocations because of the addition of Re alloying are the main strengthening mechanisms in W–TaC-Re composite.

Pore Formation Mechanism in W–C Hard Coatings Using Directed Energy Deposition on Tungsten Alloy

Pore Formation Mechanism in W–C Hard Coatings Using Directed Energy Deposition on Tungsten Alloy

Investigation of Effect of W-Zn-Co Alloy on Microstructure And Hardness of The Epoxy Composites

This research investigates the production of epoxy resin composites reinforced by the synthesized heavy tungsten alloys (W-7Zn-3Co-Y2O3). Y2O3 is used for dispersion of the compound during the ball milling process. Laminating resin component A and hardened component B were used to produce polymer epoxy matrix. The tungsten heavy alloys reinforced epoxy composites were examined in terms of Vickers hardness, density measurement and microstructural characterization . The results indicate that the 16 hour-milled reinforced epoxy composites have the highest hardness value.

Nuclear Meltdown Relocation and Core Catcher Analysis

Nuclear meltdown with the potential human and environmental harm is one of the major accident hazard (MAH) faced by nuclear power plants. Limiting (or entirely avoiding) criticality events are the main design strategies for reactors of generations 3½ and 4 (Gen3½ and Gen4). These include ensuring negative void and negative temperature coefficients (for both moderator and fuel) regardless of operational conditions, which provide a self-regulating mechanism that helps preventing accidents occurrence (i.e., to address safety and reliability aspects of Gen4’s goals). However, in severe accident scenarios (e.g. during loss-of-coolant, LOCA, events) where failure to extract heat from the reactor may lead to core degradation, strategies to mitigate reactor meltdown and relocation are critical in the design of safety protocols. This work aims to numerically investigate core relocation as an integrated multi-fluid and heat dynamics problem in which flow of melted materials (UO2, Zircaloy and graphite) are modelled through interface capturing/tracking methods. Two interface tracking/capturing methods were compared, the level-set volume of fluid method (VOF) in Ansys Fluent, and the compressive advection method (CAM) in Fluidity/ICFERST. Both methods are in good agreement for the core relocation simulation. An in-vessel core catcher (IVCC) of tungsten alloy was also proposed to demonstrate core degradation control strategy through cooling of the melted multi-materials. The IVCC was simulated with a multifluid model in Ansys Fluent, in a specified applied heat flux model. The thickness of the IVCC is 0.20 m and the heat flux used is 600 kW m-2. The tungsten material used was able to withstand both thermal and mechanical loads on the lower plenum by extracting decay heat from the corium.

Self‐Supported Catalytic Electrode of CoW/Co‐Foam Achieves Efficient Ammonia Synthesis at Ampere‐Level Current Density

AbstractConversion of air and water into valuable chemicals of ammonia (NH3) by plasma activation and electrochemical reduction is a promising approach to achieve zero carbon‐emission synthesis of NH3. However, designing highly efficient electrochemical catalysts is one of the key challenges in accomplishing this strategy. Herein, a self‐supported cobalt–tungsten alloy supported on cobalt foam (CoW/CF) is developed via a simple and efficient method at room temperature. Surprisingly, the catalyst exhibits ultra‐high NH3 partial current density (1559 mA cm−2), superior NH3 yield rate (164.3 mg h−1 cm−2), and high Faradaic efficiency (98.1%) under the condition of 0.2 M nitrate/nitrite, outperforming most of the reported values of electrosynthesis of NH3 to the knowledge. The introduction of W makes the Co atom surface electron deficient, which can enhance the adsorption of NOx− and mitigate the excessive bonding of hydroxyl radicals (OH*) generated during nitrite (NO2*) hydrogenation, thereby reducing the energy barrier of the potential‐determining step. More interestingly, a scale‐up reaction system is established, achieving an NH3 yield rate of 4.771 g h−1 and successfully converting the NH3 in solution into solid NH4Cl. The aforementioned progress significantly enhances the facilitation of NH3 electrosynthesis industrialization.