Induction of rhabdomyosarcoma by embedded military-grade tungsten/nickel/cobalt not by tungsten/nickel/iron in the B6C3F1 mouse.

Continued improvements in the ballistic properties of military munitions have led to metal formulations for which little are known about the long-term health effects. Previously we have shown that a military-grade tungsten alloy comprised of tungsten, nickel, and cobalt, when embedded into the leg muscle of F344 rats to simulate a fragment wound, induces highly aggressive metastatic rhabdomyosarcomas. An important follow-up when assessing a compound's carcinogenic potential is to test it in a second rodent species. In this study, we assessed the health effects of embedded fragments of 2 military-grade tungsten alloys, tungsten/nickel/cobalt and tungsten/nickel/iron, in the B6C3F1 mouse. Implantation of tungsten/nickel/cobalt pellets into the quadriceps muscle resulted in the formation of a rhabdomyosarcoma around the pellet. Conversely, implantation of tungsten/nickel/iron did not result in tumor formation. Unlike what was seen in the rat model, the tumors induced by the tungsten/nickel/cobalt did not exhibit aggressive growth patterns and did not metastasize.

Research Progress on Rolling Forming of Tungsten Alloy.

Tungsten is a metal with many unique characteristics, such as a high melting point, high hardness, high chemical stability, etc. It is widely used in high-end manufacturing, new energy, the defense industry, and other fields. However, tungsten also has room-temperature brittleness, recrystallization brittleness, and other shortcomings due to the adjustment of the composition and organizational structure, such as the addition of alloying elements, adjusting the phase ratio, the use of heat treatment and deformation strengthening, etc. Its performance can be improved to meet the requirements for use in different fields. At present, the main production method of tungsten alloy is powder metallurgy. The use of a rolling open billet rotary forging-stretching process can improve production efficiency and product quality, but in actual production, due to the combined effects of various factors, such as elastic deformation of rolling elements, plastic deformation of the rolled material, etc., the mechanical properties of tungsten plates and bars are often difficult to control effectively, seriously affecting rolling stability and production efficiency. For this reason, researchers have conducted extensive and deep research and optimization on the rolling process of tungsten alloys, including establishing mathematical models, performing numerical simulations, optimizing process parameters, etc., providing important references for the rolling and forming of tungsten alloys. Meanwhile, the material properties are greatly influenced by the microstructure, and the evolution of the microstructure can be well quantified by some advanced characterization techniques, such as SEM, TEM, EBSD, etc., so that certain properties of tungsten can be obtained by controlling the texture evolution. In conclusion, this paper comprehensively summarizes the research progress of tungsten alloy roll forming and provides an important reference for further improving the processing performance and production efficiency of tungsten alloy.

Determination of five-parameter grain boundary characteristics in nanocrystalline Ni-W by scanning precession electron diffraction tomography.

Determining the full five-parameter grain boundary characteristics from experiments is essential for understanding grain boundaries impact on material properties, improving related models, and designing advanced alloys. However, achieving this is generally challenging, in particular at nanoscale, due to their 3D nature. In our study, we successfully determined the grain boundary characteristics of an annealed nickel-tungsten alloy (NiW) nanocrystalline needle-shaped specimen (tip) containing twins using Scanning Precession Electron Diffraction (SPED) Tomography. The presence of annealing twins in this face-centered cubic (fcc) material gives rise to common reflections in the SPED diffraction patterns, which challenges the reconstruction of orientation-specific virtual dark field (VDF) images required for tomographic reconstruction of the 3D grain shapes. To address this, an automated post-processing step identifies and deselects these shared reflections prior to the reconstruction of the VDF images. Combined with appropriate intensity normalization and projection alignment procedures, this approach enables high-fidelity 3D reconstruction of the individual grains contained in the needle-shaped sample volume. To probe the accuracy of the resulting boundary characteristics, the twin boundary surface normal directions were extracted from the 3D voxelated grain boundary map using a 3D Hough transform. For the sub-set of coherent Σ3 boundaries, the expected {111} grain boundary plane normals were obtained with an angular error of <3° for boundary sizes down to 400 nm². This work advances our ability to precisely characterize and understand the complex grain boundaries that govern material properties.

Research Status of Manufacturing Technology of Tungsten Alloy Wire.

In light of the fact that tungsten wire is gradually replacing high-carbon steel wire as a diamond cutting line, it is particularly important to study tungsten alloy wire with better strength and performance. According to this paper, in addition to various technological factors (powder preparation, press forming, sintering, rolling, rotary forging, annealing, wire drawing, etc.), the main factors affecting the properties of the tungsten alloy wire are the composition of the tungsten alloy, the shape and size of the powder, etc. Combined with the research results in recent years, this paper summarizes the effects of changing the composition of tungsten materials and improving the processing technology on the microstructure and mechanical properties of tungsten and its alloys and points out the development direction and trend of tungsten and its alloy wires in the future.

Effect of Hot Isostatic Pressing Process Parameters on Properties and Fracture Behavior of Tungsten Alloy Powders and Sintered Bars.

In order to investigate the effect of hot isostatic pressing (HIP) process parameters on the properties and fracture behavior of tungsten alloy, HIP experiments with different process parameters were carried out, and the relative density, Rockwell hardness, tensile properties, and tensile fracture behavior were analyzed. The results show that after HIP, the tungsten alloy samples obtained further densification, higher relative density and hardness, and lower dispersity. At 1300 °C and 140 MPa, the sintered bar achieved excellent mechanical properties: yield strength increased by 16.5%, tensile strength increased by 16.1%, and fracture strength increased by 85.3%. Comparing the two processes, the mechanical properties of tungsten alloy powders formed directly via HIP were not as good as those of the sintered bars. In addition, after HIP, the fracture mode of the tungsten alloy sintered bar samples was mainly ductile tear, and that of the tungsten alloy powder samples was mainly a full brittle fracture.

Experimental Study on Laser Ablation Texture-Assisted Grinding of Tungsten Alloy.

In order to machine the tungsten alloy with high efficiency, low damage and precision, laser ablation texture technology and precision grinding technology were combined to carry out grinding experiments of tungsten alloy and laser ablation texture-assisted grinding experiments. The advantages of laser ablation texture-assisted grinding tungsten alloy were investigated by comparing of the surface morphology, grinding force and surface roughness between ordinary grinding and laser ablative texture-assisted grinding. The results demonstrate that the surface morphology of ordinary grinding tungsten alloy was poor, the surface roughness was relatively high and the grinding force was relatively large. The surface morphology of the laser ablation texture-assisted grinding tungsten alloy processed by laser ablation texture was improved, the surface roughness decreased by 0.023 µm-0.204 µm, the normal force decreased by 49.91-59.46% and the tangent force decreased by 44.11-58.49%. Meantime, for the area ratio of texture A being the most, the grinding effect was related to the area ratio of texture, and the lowest grinding force and the best surface quality were observed on the tungsten alloy with the laser ablated texture A; the grinding forces and roughness of the other textures' workpiece was similar and close because of their similar area ratios. The results demonstrate that laser ablation texture-assisted grinding of tungsten alloy could improve machining quality and reduce grinding force, which would provide guidance for realizing the high efficiency and precision machining of tungsten alloy.

Microstructure Evolution and Deformation Mechanism of Tantalum-Tungsten Alloy Liner under Ultra-High Strain Rate by Explosive Detonation.

The microstructure evolution and plastic deformation mechanism of a Ta-2.5W liner under the ultra-high-strain-rate conditions generated by the explosive detonation were investigated in this study. For this purpose, a modular soft-recovery apparatus was designed to non-destructively recover the Ta-2.5W explosively formed projectile (EFP) in the ballistic endpoint. The electron backscattered diffraction (EBSD) method was employed to examine the microstructure of the Ta-2.5W liner before and after deformation. The microstructure of the recovered EFP exhibited significant grain refinement with preferred fiber texture. The theoretical computation results showed that the temperature of the EFP was in the range of 0.27-0.65 Tm. The deformation mechanism of the Ta-2.5W liner forming EFP driven by the detonation is the continuous dynamic recrystallization (CDRX) induced by high strain deformation, rather than the conventional dynamic recrystallization of nucleation and growth. The new grain structures evolve when the low-angle grain boundaries are transformed into the high-angle grain boundaries, and the specific grain refinement mechanism is the progressive rotation of subgrains near pre-existing grain boundaries.

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.

Multifunctional Electromagnetic Interference Shielding Ternary Alloy (Ni-W-P) Decorated Fabric with Wide-Operating-Range Joule Heating Performances.

Flexible electromagnetic interference (EMI) shielding textiles with wide-operating-range Joule heating performances are urgently indispensable in the application of artificial intelligence, communication industry, and wearable electronics. Herein, a simple and cost-effective approach is proposed to construct multifunctional textiles by electroless depositing a nickel-tungsten-phosphorus (Ni-W-P) ternary alloy on a polyamide (PA) fabric. The resultant fabric with a thickness of ∼117 µm exhibits a favorable EMI shielding effectiveness (SE) of 43.6 dB within 2-12.5 GHz. Particularly, finite difference time domain (FDTD) simulation was introduced to investigate the effects of the PA fabric mesh number and Ni-W ratio on the EMI SE value, which was validated by experimental results. In addition, the conductive fabric demonstrates excellent heating efficiency (up to 140 °C under 2 V within 60 s), a wide operating range (from 40 to 140 °C), and simultaneously, satisfactory reproducibility by undergoing dozens of heating and cooling cycles. Notably, EMI SE of the multifunctional fabric remains unchanged even after a series of durability measurements including 180 °C heating, ultrasonication treatment, and repetitive peeling tests, respectively. Therefore, the prepared Ni-W-P coated PA fabric with prominent chemical stability and mechanical robustness endows enormous potential in multi-scene applications.

Coupled Electrodeposition of Fe-Co-W Alloys: Thin Films and Nanowires.

The electrodeposition of Fe-Co-W alloys was examined using a rotating cylinder Hull (RCH) cell and conditions were determined to create nanowires. The metal ion reduction mechanism was a combination of induced and anomalous codeposition, with water reduction as a gas evolving side reaction, rending deposition into recesses a challenge. In thin film deposition, under kinetic control, the addition of Fe ions into the electrolyte, greatly reduced the Co partial current density, and thus it's content in the deposit. The change of Co partial current density was attributed to an anomalous codeposition behavior, but it had a minimal effect in changing the W wt% in the deposit, despite the expected inducing characteristic of Fe when codeposited with tungsten. Deposition conditions were determined to electrodeposit Fe-Co-W nanowires having similar concentration as the thin films. Nanowires were electrodeposited into polycarbonate membranes under pulsed current at room temperature.

The Role of the Component Metals in the Toxicity of Military-Grade Tungsten Alloy.

Tungsten-based composites have been recommended as a suitable replacement for depleted uranium. Unfortunately, one of these mixtures composed of tungsten (W), nickel (Ni) and cobalt (Co) induced rhabdomyosarcomas when implanted into the leg muscle of laboratory rats and mice to simulate a shrapnel wound. The question arose as to whether the neoplastic effect of the mixture could be solely attributed to one or more of the metal components. To investigate this possibility, pellets with one or two of the component metals replaced with an identical amount of the biologically-inert metal tantalum (Ta) were manufactured and implanted into the quadriceps of B6C3F1 mice. The mice were followed for two years to assess potential adverse health effects. Implantation with WTa, CoTa or WNiTa resulted in decreased survival, but not to the level reported for WNiCo. Sarcomas in the implanted muscle were found in 20% of the CoTa-implanted mice and 5% of the WTa- and WCoTa-implanted rats and mice, far below the 80% reported for WNiCo-implanted mice. The data obtained from this study suggested that no single metal is solely responsible for the neoplastic effects of WNiCo and that a synergistic effect of the three metals in tumor development was likely.

1H NMR spectroscopic analysis detects metabolic disturbances in rat urine on acute exposure to heavy metal tungsten alloy based metals salt.

Heavy metal tungsten alloys (HMTAs) have been found to be safer alternatives for making military munitions. Recently, some studies demonstrating the toxic potential of HMTAs have raised concern over the safety issues, and further propose that HMTAs exposure may lead to physiological disturbances as well. To look for the systemic effect of acute toxicity of HMTA based metals salt, (1)H nuclear magnetic resonance ((1)H NMR) spectroscopic profiling of rat urine was carried out. Male Sprague Dawley rats were administered (intraperitoneal) low and high dose of mixture of HMTA based metals salt and NMR spectroscopy was carried out in urine samples collected at 8, 24, 72 and 120 h post dosing (p.d.). Serum biochemical parameters and liver histopathology were also conducted. The (1)H NMR spectra were analysed using multivariate analysis techniques to show the time- and dose-dependent biochemical variations in post HMTA based metals salt exposure. Urine metabolomic analysis showed changes associated with energy metabolism, amino acids, N-methyl nicotinamide, membrane and gut flora metabolites. Multivariate analysis showed maximum variation with best classification of control and treated groups at 24h p.d. At the end of the study, for the low dose group most of the changes at metabolite level reverted to control except for the energy metabolites; whereas, in the high dose group some of the changes still persisted. The observations were well correlated with histopathological and serum biochemical parameters. Further, metabolic pathway analysis clarified that amongst all the metabolic pathways analysed, tricarboxylic acid cycle was most affected at all the time points indicating a switchover in energy metabolism from aerobic to anaerobic. These results suggest that exposure of rats to acute doses of HMTA based metals salt disrupts physiological metabolism with moderate injury to the liver, which might indirectly result from heavy metals induced oxidative stress.