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Highlights Establish processing-composition-microstructure-property relationships governing binderless tungsten carbide (BTC). Highlight the densification improving strategies and toughening methods for BTC. Provide key challenges as well as the outlook for superior peformance associated with BTC. WC-Co alloys have enjoyed great practical significance owing to their excellent properties during the past decades. Despite the advantages, however, recently there have been concerns about the challenges associated with the use of Co, i.e. price instability, toxicity and properties degeneration, which necessitates the fabrication of binderless tungsten carbide (BTC). On the other hand, BTC or BTC composites, none of them, to date has been commercialized and produced on an industrial scale, but only used to a limited extent for specialized applications, such as mechanical seals undergoing high burthen as well as high temperature electrical contacts. There are two challenges in developing BTC: fully densifying the sintered body together with achieving a high toughness. Thus, this review applies towards comprehensively summarize the current knowledge of sintering behavior, microstructure, and mechanical properties of BTC, highlighting the densification improving strategies as well as toughening methods, so as to provide reference for those who would like to enhance the performance of BTC with better reliability advancing them to further wide applications and prepare the material in a way that is environment friendly, harmless to human health and low in production cost. This paper shows that the fabrication of highly dense and high-performance BTC is economically and technically feasible. The properties of BTC can be tailored by judiciously selecting the chemical composition coupled with taking into careful account the effects of processing techniques and parameters.

Calibers 7.62 x39mm are one of the most common calibers used all over the world. As a result of developments of modern armors that become lighter, and with-stand more impact kinetic energies. Consequently, the development of ammunition becomes important to increase the combat ability of used weapons to face modern armors. In this paper, some modifications are already done in construction and design of existing bullets, in which the inner cores or parts of them are replaced by harder material, tungsten carbide, instead of lead or hard steel core. Some internal and external ballistic predictions are calculated to make sure the expected developments do not affect the weapons barrels compared with the original bullets and the check of the stability during the flight are also studied by using PRODAS package Resultant depths of penetrations are compared experimentally with that of original types, the experimental results show a noticeable increase in depth of penetration compared with that of original bullets.

HighlightsUltrafine tungsten carbide nanoparticles-decorated carbon nanosheets were successfully fabricated via a simple solvent-free strategy.The chemical composition of tungsten carbide/carbon composites can be easily manipulated by the weight ratio of dicyandiamide to ammonium metatungstate.The advantages in good performance and simple preparation provide a promising prospect for the application of these tungsten carbide/carbon composites.Carbides/carbon composites are emerging as a new kind of binary dielectric systems with good microwave absorption performance. Herein, we obtain a series of tungsten carbide/carbon composites through a simple solvent-free strategy, where the solid mixture of dicyandiamide (DCA) and ammonium metatungstate (AM) is employed as the precursor. Ultrafine cubic WC1−x nanoparticles (3–4 nm) are in situ generated and uniformly dispersed on carbon nanosheets. This configuration overcomes some disadvantages of conventional carbides/carbon composites and is greatly helpful for electromagnetic dissipation. It is found that the weight ratio of DCA to AM can regulate chemical composition of these composites, while less impact on the average size of WC1−x nanoparticles. With the increase in carbon nanosheets, the relative complex permittivity and dielectric loss ability are constantly enhanced through conductive loss and polarization relaxation. The different dielectric properties endow these composites with distinguishable attenuation ability and impedance matching. When DCA/AM weight ratio is 6.0, the optimized composite can produce good microwave absorption performance, whose strongest reflection loss intensity reaches up to − 55.6 dB at 17.5 GHz and qualified absorption bandwidth covers 3.6–18.0 GHz by manipulating the thickness from 1.0 to 5.0 mm. Such a performance is superior to many conventional carbides/carbon composites.

Tool wear is a key issue for the manufacturing performance of refill friction stir spot welding in high-volume manufacturing environments. As such, the aim of this study is to examine conditions in which tungsten carbide with a cobalt binder can succeed as a tool material in the spot welding of 2029 aluminum for a sustained lifetime. Critical factors are shown herein to include cleanliness and thermal management. The life of a WC-Co toolset is demonstrated to be approximately 2998 welds, which is of the same scale as conventional steel tooling. With a WC-Co shoulder and probe, the H13 clamp showed the only significant wear.

The welding of cemented carbide to tool steel is a challenging task, of scientific and industrial relevance, as it combines the high level of hardness of cemented carbide with the high level of fracture toughness of steel, while reducing the shaping cost and extending the application versatility, as its tribological, toughness, thermal and chemical properties can be optimally harmonised. The already existing joining technologies often impart either insufficient toughness or poor high-temperature strength to a joint to withstand the ever-increasing severe service condition demands. In this paper, a novel capacitor discharge welding (CDW) process is investigated for the case of a butt-joint between a tungsten carbide-cobalt (WC-Co) composite rod and an AISI M35 high-speed steel (HSS) rod. The latter was shaped with a conical-ended projection to promote a high current concentration and heat at the welding zone. CDW functions by combining a direct current (DC) electric current pulse and external uniaxial pressure after a preloading step, in which only uniaxial pressure is applied. The relatively high heating and cooling rates promote a thin layer of a characteristic ultrafine microstructure that combines high strength and toughness. Morphological analysis showed that the CDW process: (a) forms a sound and net shaped joint, (b) preserves the sub-micrometric grain structure of the original WC-Co composite base materials, via a transitional layer, (c) refines the microstructure of the original martensite of the HSS base material, and (d) results in an improved corrosion resistance across a 1-mm thick layer near the weld interface on the steel side. A nano-indentation test survey determined: (e) no hardness deterioration on the HSS side of the weld zone, although (f) a slight decrease in hardness was observed across the transitional layer on the composite side. Furthermore, (g) an indication of toughness of the joint was perceived as the size of the crack induced by processing the residual stress after sample preparation was unaltered.

The promising potential of photodynamic therapy (PDT) has fueled the development of minimally invasive therapeutic approaches for cancer therapy. However, overcoming limitations in PDT efficacy in the hypoxic tumor environment and light penetration depth remains a challenge. We report the engineering of tungsten carbide nanoparticles (W 2 C NPs) for 1,064 nm laser-activated dual-type PDT and combined theranostics. The synthesized W 2 C NPs allow the robust generation of dual-type reactive oxygen species, including hydroxyl radicals (type I) and singlet oxygen (type II), using only single 1,064 nm laser activation, enabling effective PDT even in the hypoxic tumor environment. The W 2 C NPs also possess high photothermal performance under 1,064 nm laser irradiation, thus enabling synergistically enhanced cancer therapeutic efficacy of PDT and photothermal therapy. Additionally, the photoacoustic and X-ray computed tomography bioimaging properties of W 2 C NPs facilitate the integration of tumor diagnosis and therapy. The developed W 2 C based theranostic nanoagents increase the generation of reactive oxygen species in hypoxic tumors, improve the light penetration depth, and facilitate combined photothermal therapy and photoacoustic/computed tomography dual-mode bioimaging. These attributes could spur the exploration of transition metal carbides for advanced biomedical applications.

Tungsten carbide (WC) is one of the most robust mold materials in precision glass molding owing to its excellent hardness at high temperatures. However, the fabrication of a microlens array (MLA) shape on a WC mold is challenging. Electrical discharge machining (EDM) is highly effective in fabricating conductive materials regardless of their hardness. However, due to electrode wear, the machining accuracy and consistency of the MLA are gradually reduced in the EDM process. In this study, a micro copper ball–assembled array electrode (BAAE) was proposed and developed to achieve high efficiency, accuracy, and consistency in MLA mold manufacturing. The copper balls aligned in an array on the position template were used as the electrode to fabricate MLA in EDM. The general calculation method for the maximum service cycles of copper balls was developed to achieve maximum utilization of the copper balls. The in situ rotation of the copper ball updated the processing area, significantly improving the consistency of the lenslet morphology. The effects of two polarity processing were investigated, and the positive processing was chosen. The efficiency of BAAE was significantly improved through the implementation of array alignment and path planning. The effectiveness and efficiency of the ball rotation were confirmed by comparing the lenslet morphology with the ball end–formed electrode. The EDM using BAAE is proven to be capable of improving the efficiency, accuracy, and consistency of MLA mold manufacturing.

This paper presents the results of an estimation of the structural and roughness parameters of the outer surface layers of a barrel drill made of cobalt matrix sintered tungsten carbide samples (WC-Co) made by sintering and subjected to finishing by grinding. In order to evaluate the geometric and functional structure of the surface, profilometric measurements were carried out at different scan lengths. The geometric structure of the studied surfaces was characterized by the roughness parameters Ra, Rq, and Rz, while the functional structure was determined by the reduced profile heights Rpk, Rk, Rvk and the material ratios Mr1 and Mr2 determined by the Abbott-Firestone curves. Multiscale analysis of the dependence of the roughness and functional parameters on the measurement lengths was carried out using the root mean square (RMS) method, from which monofractal structures of the surface profile variations were found. Consistency of the fractal dimensions estimated for the drill bit might be due to its finer finishing.

Recently, the need for enhanced cutting tools to fabricate next-generation multilayer ceramic capacitors (MLCCs) and batteries has been identified. This is because existing cutting tools cause problems such as defects, burrs, and breaking of MLCCs when the MLCCs are cut using the existing cutting tools. Furthermore, the productivity of MLCCs should be improved. To overcome these problems, enhanced cutting tools should have sharper blade angles and thinner widths. Currently, a cutting tool with a thickness of tens of micrometers is used in the industry. Also, cutting tools made of cemented tungsten carbide are difficult to machine. Therefore, fine ablation technology is required for their application. Machining technology using femtosecond lasers has been studied to realize fine ablation. However, studies on the subject are limited. Therefore, we studied fine ablation using the beam-shaping technology. In this study, a femtosecond laser with a wavelength of 1030 nm, a maximum repetition rate of 200 kHz, and a maximum pulse energy of 1 mJ was used. Additionally, a slit-optic system was used to transform the laser beam with Gaussian energy distribution into the laser beam with a quasi-flat top energy distribution. We demonstrated a machining depth resolution of 25 nm for cemented tungsten carbides using a femtosecond laser with a fluence of 0.32 J/cm 2 .

The paper is dedicated to the life prolongation of the tools designed for deep-hole drilling. Among available methods, an ion implantation process was used to improve the durability of tungsten carbide (WC)-Co guide pads. Nitrogen fluencies of 3 × 1017 cm−2, 4 × 1017 cm−2 and 5 × 1017 cm−2 were applied, and scanning electron microscope (SEM) observations, energy dispersive spectroscopy (EDS) analyses, X-ray photoelectron spectroscopy (XPS) and Secondary Ion Mass Spectrometry (SIMS) measurements were performed for both nonimplanted and implanted tools. The durability tests of nonimplanted and the modified tools were performed in industrial conditions. The durability of implanted guide pads was above 2.5 times greater than nonimplanted ones in the best case, presumably due to the presence of a carbon-rich layer and extremely hard tungsten nitrides. The achieved effect may be attributed to the dissociation of tungsten carbide phase and to the lubrication effect. The latter was due to the presence of pure carbon layer with a thickness of a few dozen nanometers. Notably, this layer was formed at a temperature of 200 °C, much smaller than in previously reported research, which makes the findings even more valuable from economic and environmental perspectives.