In this paper, the effects of Cr₃C₂ addition amount on the particle size, morphology, and mechanical properties of ultrafine grained WC-6%Co-(0~1.0%)Cr₃C₂ cemented carbide were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and property detection. The results show that the average grain size of WC decreases rapidly at first and then slowly with the increase in the Cr₃C₂ addition amount. The addition of 0.25% Cr₃C₂ induces the anisotropic growth of WC grains, and the morphology of WC grains is a quasi-triangular prism. With the increase in the Cr₃C₂ addition amount, the morphology of WC grains becomes more regular and finally becomes a triangular prism. With the increase in the addition amount of Cr₃C₂, the hardness of ultrafine grained WC-6%Co-Cr₃C₂ cemented carbide first increases rapidly and then slowly, but the fracture toughness gradually decreases, and the bending strength first increases and then slowly decreases. When 0.6%Cr₃C₂ is added, the comprehensive performance of WC-6%Co cemented carbide is the best, and its Vickers hardness, bending strength, and fracture toughness are 18.42 GPa, 3 450 MPa, and 9.32 MPa·m^1/2, respectively.

WC-Co cemented carbide is widely used in the manufacturing industry, but how to select and design high-performance and low-cost binders is the current difficulty and hotspot in the field of replacing binders with cemented carbides. High entropy alloys (HEA) as binders can refine WC grains and improve the hardness, fracture toughness, corrosion resistance, and oxidation resistance of cemented carbide. This paper outlines the research progress of WC-HEA cemented carbide in terms of HEA binder composition design, WC-HEA preparation technology, microstructure, and comprehensive performance and describes the problems faced in this field such as poor sintering characteristics and susceptibility to phase transformation. It is intended to provide a reference for the exploration of the toughening mechanism of HEA as a binder phase and revealing the constitutive relationship between microstructure and mechanical properties of WC-HEA composites in subsequent research.

In view of the easy denitrification of the sintered body and the decomposition of N during the preparation of ultrafine-grained Ti(C,N)-based cermets by vacuum sintering, ultrafine-grained Ti(C,N)-based cermets are prepared by partial-pressure sintering with 130 Pa of nitrogen at 1 450 °C during the holding stage of the liquid phase, and the influence of the time of partial-pressure sintering under nitrogen on the microstructures and mechanical properties of cermets is investigated. The experimental results show that partial-pressure sintering under nitrogen can improve the uniformity of the internal structure of the sample. Under the influence of nitrogen, a Ni-rich layer will be formed in the outermost layer of the sample, and a TiN layer will be formed in the near-surface layer of the material. At the beginning of the partial pressure, the outermost layer of the sample is only the Ni-rich layer. With the increase in the partial pressure time, the black core phase in the near-surface layer of the organization dissolves under the influence of nitrogen, and the size of the black core phase decreases. The size of the annular phase increases until the black core phase gradually disappears, forming a Ti-rich (Ti,W)(C,N) solid solution, which is formed into the solid solution layer by merging the grown solid solution, As the partial pressure time increases, the titanium-rich solid solution reacts with N to form a TiN layer in the near-surface layer of the sample. The comprehensive mechanical properties of the sample are the best when the partial-pressure sintering time reaches 40 min, and its bending strength increases by 20% to 2 350 MPa. The Vickers hardness increases by 13.9% to 1 635 HV30, and the fracture toughness is not significantly improved.

The lattice constants, elastic constants, electronic structure, and charge distribution of Ti(C_0.5N_0.5) doped with metal W atoms were calculated and analyzed by using the first-principles method of density functional theory (DET). The results show that W atoms can exist in (Ti_1-xW_x)(C_0.5N_0.5) stably, but the addition of W atoms decreases the stability of the (Ti_1-xW_x)(C_0.5N_0.5) system, enhances the bonding energy among atoms, and distorts the lattice as Ti atoms and W atom shave different diameters. With the increase in W content, lattice distortion and lattice constant imbalance will be aggravated. The results of elastic constant calculation show that the appropriate addition of W atoms can improve the deformation resistance and hardness of (Ti_1-xW_x)(C_0.5N_0.5) and reduce the brittleness of the crystal. When x(W) = 12%, the deformation resistance and hardness of (Ti_1-xW_x)(C_0.5N_0.5) are the best. The theoretical hardness HV is increased by 6%. The calculation results of the electronic structure show that the state density increases at the Fermi level after doping W atoms, and the conductivity of (Ti_1-xW_x)(C_0.5N_0.5) is enhanced, which is much higher than that of Ti(C_0.5N_0.5). The charge difference density diagram shows that W atoms doping and replacing Ti atoms will form a polar covalent bond with C atoms, which can improve the inherent mechanical properties of (Ti_1-xW_x)(C_0.5N_0.5).

This paper takes the patent data in the field of cemented carbide in China and abroad as the research object, constructs the three-dimensional factor system of patent technology, economy, and law that affect the patent value, uses the multiple linear regression model to explore the influencing factors of the patent value in the field of cemented carbide, and excavates the differences of the factors that affect the patent value in the field of cemented carbide in China and abroad. The number of countries and the number of claims have a significant positive effect on the patent value in the cemented carbide field, while the number of patent families has a significant negative effect on the patent value in the cemented carbide field, and the significance is not affected by the region of the patent application. The factors that have a significant positive effect on the patent value in the field of cemented carbide in the influence factor system of China are the number of countries, the number of pages of literature, the number of claims, the number of IPC categories, and the number of independent claims according to the degree of influence, and the factors that have a significant negative effect are the number of patent family, the number of cited patents, and the number of patent applications. The factors that have a significant positive effect on the patent value in the field of cemented carbide in the influence factor system of other countries are the number of patent applications, the number of countries, the number of cited patents, the number of claims according to the degree of influence, and the factor that has a significant negative effect is the number of the patent family. By comparing the empirical results of the factors affecting the patent value in the field of cemented carbide in China and abroad, it is found that the number of cited patents and the number of patent applications have a significant negative impact on the patent value in the field of cemented carbide in China but have a positive impact on the patent value in the field of cemented carbide in other countries. Suggestions to enhance the patent value in the field of cemented carbide are as follows. The first is to promote collaborative innovation among industry, university, and research and the flow of technical knowledge in the cemented carbide field. The second is to apply the strategic layout of overseas cemented carbide patents to enhance the competitiveness of patented products. The third is to strengthen the quality management of patent documents and improve the judicial protection level of intellectual property rights for cemented carbides.

Binderless WC cemented carbide (binderless tungsten carbide, BTC) has excellent wear resistance, corrosion resistance, polishing performance, and oxidation resistance, which are unparalleled compared with traditional cemented carbide. It has a good application prospect in erosion-resistant and high wear-resistant tools, fine tools, oil and shale gas exploitation, and other fields. One of the key problems in the preparation of ultrafine/nanocrystalline BTC is to control the growth of WC grains. In this paper, the related research results of ultrafine/nanocrystalline BTC were reviewed from the aspects of preparation technology of ultrafine/nanocrystalline WC powder, material composition design of BTC, and molding process and sintering technology. The key role of raw material WC particle size, addition of second phase compounds, and advanced molding process and sintering technology in the densification process of BTC was emphasized. The performance differences of ultrafine/nanocrystalline BTC materials under different composition systems and different sintering processes were compared. It was pointed out that the main problems in the preparation process of ultrafine /nanocrystalline BTC were densification and strengthening and toughening, which could be solved by various advanced sintering technologies and developed second phase strengthening and toughening technologies, but they have not yet achieved industrial application. Finally, it was clarified that the development trend of ultrafine/nanocrystalline BTC was to obtain finer dense sintered bodies at low temperatures and low pressures.

Due to the extremely high hardness and stability of cemented carbide, its ultra-precision machining is still vital and costly in the manufacturing of glass lens molds. The application of mainstream ductile-regime machining and other technologies on cemented carbide is not satisfying. In this study, nano-indentation, Vickers indentation, single-point diamond turning, variable depth cutting, and other experimental methods were used to explore the removal mechanisms of cemented carbide WC-Co. Firstly, the effectiveness of applying traditional ductile-regime machining theory on cemented carbide was discussed according to the results of turning and following observations. Then, the micro-defects that may appear on the surface during machining and the control methods were analyzed. Finally, the critical turning parameters to reduce WC grain breaking were explored, and a single-point diamond turning process was conducted to verify the effectiveness of critical cutting parameters in controlling micro-defects on the surface during machining. 

Titanium dioxide (TiO₂) has been widely studied in the field of photocatalysis due to its excellent photocatalytic activity. However, the high recombination rate of photogenerated carriers and wide bandgap of TiO₂ limit its application. In this work, TiO₂/WO₃ heterostructured nanocomposite photocatalysts with oxygen vacancy defects were synthesized by introducing tungsten (W) into TiO₂. The introduction of oxygen vacancies reduced the band gap and broadened the light absorption range, while the heterojunction increased the photogenerated carriers and facilitated their separation. The experiment shows that TiO₂/WO₃ nanocomposite photocatalysts have enhanced photocatalytic activity, with up to 63.7 μmol of hydrogen produced from 100 mg of sample in 2 h. In addition, the TiO₂/WO₃ nanocomposite material shows excellent stability under simulated sunlight. This exploration provides new ideas for the design and preparation of TiO₂-based composite photocatalysts.

In response to the issues of low nucleation crystal seed, a small proportion of high-quality crystals, and numerous growth defects in the synthesis of type II a diamonds formed by a cubic press at high temperature and high pressure in China, this paper optimized the process parameter curves before and after the crystal synthesis. The results show that the optimal process plan is as follows. In the first 20 h of the growth stage, the diamond is slowly heated under low temperature and high pressure environment and taken insulation measures for a period of time. Then the constant power is heated to the set temperature, where the diamond grows for 3 days under high temperature and pressure. Within 2 h after the synthesis, the low-speed pressure relief with heating power in phases is adopted, which effectively controls the defects such as cracks and metal inclusions and improves the quality of synthetic crystals. The final number of seed nucleation is 25, and the proportion of excellent crystals is 92%.

Mo₂FeB₂-based cermets, synthesized from Mo, Fe, Cr, Ni, FeB, and C via a reaction boronizing sintering technique, are characterized by their exceptional hardness, strength, and toughness, coupled with comparatively economical production costs. This study delved into the fabrication of Fe-44.4%Mo-4.9%B-2.5%Cr-2.9%Ni-based cermets utilizing avacuum liquid phase sintering method and meticulously examined the morphological evolution, growth processes, and underlying mechanisms of the cermet’s hard phase at both solid and liquid phase sintering stages. The results reveal that below 600 °C, Fe amalgamates with lamellar FeB, initiating the formation of the Fe₂B phase and marking the onset of solid-phase sintering. As the temperature ascends to 900 °C, Mo commences nucleation at the Fe₂B interface, leading to the formation of Mo₂FeB₂ characterized by spiral growth patterns and the emergence of growth steps. Further temperature elevation to 1 000 °C propels the enlargement of Mo₂FeB₂ grains, surpassing critical radii and instigates the precipitation of diminutive Mo₂FeB₂ grains. At 1 050 °C, ongoing dissolution and precipitation processes result in the development of Mo₂FeB₂ grains with hexagonal cross-sections. Throughout this thermal trajectory, Mo₂FeB₂ grain growth traverses through four stages: nucleation, spiral growth, dissolution-precipitation, and the eventual establishment of hexagonal cross-sectional grains, culminating in the formation of hexagonal Mo₂FeB₂ grains derived from Mo, FeB, and Fe₂B phases. Beyond 1 050 °C, the cermets transition into the liquid phase sintering stage, characterized by columnar growth of the Mo₂FeB₂ hard phase. The growth activation energies determined for the long and short axes of the grains are 317 kJ/mol and 402 kJ/mol, respectively, suggesting a pronounced propensity for Mo₂FeB₂ grains to elongate along their long axis, ultimately yielding elongated grain structures.

316L has excellent corrosion resistance and is currently the most widely used austenitic stainless steel. In this paper, 316L stainless steel was taken as the research object, and four cemented carbide inserts of EM (large rake angle), SM3(small chip angle), MM (small rake angle, and SF (large chip angle) with different groove structures were selected to be processed under the parameters of semi-finishing machining. The influence of different groove structures of stainless steel turning inserts on cutting performance was studied. The results show that the EM and MM inserts have the lowest cutting force. A smaller chip angle of the insert groove indicates a lower cutting force. Combined with the characteristics of the groove, it shows that the reasonable double rake angle design is conducive to reducing the cutting force, and the chip breaking ability of the inserts is mainly related to the size of the chip angle and the feed. In addition, when the chip angle is designed at 20°, good chip breaking performance can be obtained without causing a significant increase in the cutting force.

Cubic boron nitride (cBN) and carbon/nitride ceramic micro-powder were used as initial particles, and the extrusion experiment at room temperature and ultra-high pressure and sintering experiment at high temperature and high pressure were designed, respectively. Characterization was carried out using a laser particle size analyzer, SEM, and XRD. The study results show that the particle crushing and densification process of over 86.47% are completed within one minute under extrusion at ultra-high pressure. The particle crushing mechanism is manifested as brittle fractures and the formation of intragranular cracks. After crushing, it is easy to aggregate and has poor fluidity. The crushing rate of cBN particles is positively correlated with their grain size. Both cBN and ceramic micro-powder undergo two densification processes at ultra-high pressure, as well as high temperature and high pressure. The active surface and fine particles formed by particle crushing contribute to sintering densification. However, “internal injuries” such as cracks caused by particle crushing have a negative impact on the performance of the sintered body.

Ti(C,N)-based cermets have become an indispensable key material in the manufacturing industry because of their good hardness, wear resistance, and chemical stability. It is of great significance to further improve the strength and toughness of cermets to expand their application field and application scale. In this paper, the phase structure characteristics of Ti(C,N)-based cermets were summarized, and the application of high-entropy alloys/ceramics in the design and preparation of the binder phase and additive phase of Ti(C,N)-based cermets were reviewed. Finally, the main research direction of high-entropy alloys/ceramics was prospected: The microstructure evolution and mechanism of action on properties of Ti(C,N)-based cermets after adding binder phase of high-entropy alloys need to be further studied. At the same time, the mechanism of action of the additive phase of high-entropy ceramics in Ti(C,N)-based cermets is also an important research direction.

WC-Ni-based cemented carbides exhibit distinct advantages as magnetic material forming dies, key components in the mechanical seals of nuclear main pumps, and wear-resistant components under corrosive service conditions. Due to the intrinsic properties of the material system, the strength, hardness and toughness of WC-Ni-based cemented carbides are significantly lower compared to WC-Co-based cemented carbides with the same binder metal content and similar WC grain size. As a result, their high performance has been challenged. To lay the foundation for the efficient development of novel WC-Ni-based cemented carbides with enhanced performance, in this paper we review the progress on the control of the microstructure and physical and mechanical properties of WC-Ni-based cemented carbides, including WC-Ni ternary alloys, WC-Ni-based cemented carbides with additional alloying components, and plate-grained WC-Ni-based cemented carbides with Ti.

To enable real-time measurement of the cutting temperature in the cutting zone of single-crystal diamond tools and real-time monitoring of the surface quality of workpieces during ultra-precision machining with diamond tools, the semiconductor properties of boron-doped diamond were leveraged. The relationship between electrical resistance and temperature was established, revealing a measurement sensitivity of 6.2 Ω/°C. The developed boron-doped single point diamond tools were deployed on a diamond turning machine to measure the cutting temperatures during single point diamond turning (SPDT) of polymethyl methacrylate (PMMA) and carbon fiber reinforced polymer (CFRP) workpieces. The experiments validated that the boron-doped diamond tool cutting temperature measurement system could sensitively measure the cutting temperature throughout the precision machining process. Notably, during the cutting of CFRP workpieces, periodic variations in both cutting temperature and machined surface topography were observed. This finding holds significant value for guiding online monitoring of the ultra-precision machining state when employing single point diamond tools.

The in-situ carbothermal reduction method was used to fabricate Ti(C,N)-based cermets, and the effects of Nb₂O₅ on microstructures and mechanical properties of Ti(C,N)-based cermets were studied. The results indicate that when the content of Nb₂O₅ increases from 0% to 2.80%, the hard phase grains of the cermets are significantly refined, and the number of “white core/gray rim” grains increases. Moreover, room-temperature transverse rupture strength (TRS), hardness, critical thermal shock temperature difference, and high-temperature TRS increase, while the fracture toughness decreases. As Nb₂O₅ content rises, there are holes in the microstructure of the cermets, and room-temperature TRS, hardness, critical thermal shock temperature difference, high-temperature TRS, and fracture toughness gradually decrease. The cermets with Nb₂O₅ content of 2.80% exhibit the best comprehensive mechanical properties, with a room-temperature TRS of 2 439 MPa, a hardness of 90.6 HRA, a fracture toughness of 12.8 MPa·m^1/2, a critical thermal shock temperature difference of 360 ℃, and a high-temperature TRS of 1 519 MPa, respectively.

Ti(C_0.5,N_0.5) - 20%WC-8%TaC-5%Mo₂C-22%FeCoCrNi (A) and Ti(C_0.5,N_0.5)-20%WC-8%TaC-5%Mo₂C-22%CoCrNi (B) cermets were prepared by using (Fe)CoCrNi high and medium entropy alloy atomized powders, respectively. Ti(C_0.5,N_0.5)-20%WC-8%TaC-5%Mo₂C-12%Co-12%Ni (C) with the same binder metal volume ratio was used as the reference alloy. The electrochemical experiment results show that despite the presence of decarburization phase (η phase) and poor microstructure homogeneity, compared with the cermet C without microstructure defects, in H₂SO₄ (pH=1), Na₂SO₄ (pH=7), and NaOH (pH=13) solutions, the values of average self-corrosion current density (J_corr) for cermets A and B are decreased by 33% and 88%, and the values of average charge transfer resistance (R_ct) are increased by 97% and 219%, respectively. The defects of microstructures do not affect the improvement of corrosion resistance. In the H₂SO₄ solution, J_corr for cermet B is decreased by 89%, and R_ct is increased by 750%. The corrosion resistance of cermets in extremely corrosive media can be significantly improved by using CoCrNi medium entropy alloy as the binder metal. The formation mechanism of heterogeneous structure accompanied by the formation of η phase in cermets A and B is discussed from the perspective of intrinsic properties of high and medium entropy alloys and the wettability of the alloy system.

The effects of different Mo additions on the WC grain size, hardness, friction and wear, and corrosion resistance of WC-Ni-Mo cemented carbide were investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and property detection. The results indicate that the average grain size of WC remains basically unchanged within the studied composition range (w(Mo) = 1.5%~2.0%) as the Mo addition changes. The hardness of WC-Ni-Mo cemented carbide slightly decreases with the increase in Mo addition, while the friction and wear resistance is improved. The corrosion resistance of WC-Ni-Mo cemented carbide with 2% Mo addition is higher than that of WC-Ni-Mo cemented carbide with 1.5% Mo addition in acid solution, and its electrochemical stability is more favorable. In general, the comprehensive performance of WC-8%Ni-2%Mo alloy is preferable to that of WC-8.5%Ni-1.5%Mo cemented carbide.

In this paper, a variety of coated PcBN inserts were used to turn test on nodular cast iron QT500-7, and the processing life, wear patterns and mechanism and coating protection mechanisms of uncoated and different coated PcBN inserts were studied. The test results show that the machining life of the coated PcBN insert is improved under the same cutting conditions. The coated PcBN insert with CVD α-Al₂O₃ has the longest processing life, followed by the PcBN insert coated with PVD TiAlSiN, and then the PcBN insert coated with PVD TiAlN with the shortest processing life. The wear patterns of the PcBN insert mainly include front insert wear, back insert wear, micro-edge breakage and damage. The wear mechanisms include not only mechanical wear but also adhesive wear, diffusion wear, and oxidation wear. These wear mechanisms occur simultaneously and affect each other. As a chemical and thermal barrier, the coating can form an “isolation layer” between the PcBN insert and the workpiece, reducing mechanical wear, diffusion wear, and bonding wear between the insert and the workpiece, and effectively preventing oxidative wear, thereby avoiding premature micro-breakage or breakage of the insert and improving its processing life.

The study investigated the effect of Cr3C2 and VC doping on the magnetic properties of WC-6%Co cemented carbide with varying carbon contents. Meanwhile, by employing ultrafine-grained tungsten carbide with a particle size of 0.4 μm and submicron tungsten carbide with a particle size of 0.7 μm, the trend of changes in the coercive force and relative magnetic saturation of the cemented carbide under different particle sizes was observed, along with the characteristics of the corresponding microelement distribution. The results show that in the WC-6%Co cemented carbide system, when it is in the two-phase region, the relative magnetic saturation strength of the cemented carbide under different grain sizes increases with the increase in carbon content, showing a positive correlation. When only Cr3C2 is added, a portion of Cr may precipitate in the form of Cr-rich composite carbides (M7C3), dispersing and inhibiting grain growth. Meanwhile, an increase in carbon content enhances the precipitation of M7C3, further intensifying its grain refinement effect. Consequently, a positive correlation is observed between the coercive force and carbon content. When the mass fraction of Cr3C2 is 1%, and that of VC is 0.3%, the interfacial segregation of VC plays a dominant role in inhibiting grain growth, thereby weakening the influence of M7C3. Simultaneously, an elevated carbon content leads to a reduction in the liquidus, facilitating grain growth. Due to the competing effects of various mechanisms, the introduction of composite inhibitors consisting of Cr3C2 and VC results in a negative correlation between the coercive force of fine-grained cemented carbide and carbon content.

A single factor method was used to conduct milling experiments on 7075 aluminum alloy, and the effects of rotational speed and feed rate on chip morphology, surface roughness, machined surface morphology, and residual stress were analyzed. The results show that as the rotational speed and feed rate increase, the degree of chip curling increases, resulting in regular curling and breaking of chips. When the feed rate f=0.05 mm/r, the chips exhibit two states, and irregular chips can easily cause instability in the cutting process, leading to poor surface quality. Higher rotational speed indicates smaller surface roughness. As the feed rate increases, the surface roughness first decreases and then increases, the reason for the initial decrease is that when the feed rate f=0.05 mm/r, the cutting process is unstable, resulting in a larger surface roughness value than when f=0.1 mm/r. High rotational speed is beneficial for forming more regular machined surface patterns, with fewer adhesives and clearer and more regular surface contours. A larger feed rate ensures a wider and deeper blade pattern and rougher surface contour. Under the squeezing effect, the residual stress on the surface of the aluminum alloy during cutting presents a compressive stress state, and as the rotational speed gets higher, the residual compressive stress on the machined surface becomes smaller. As the feed rate increases, the cutting force and the residual compressive stress are larger.

The profile accuracy detection and surface precision dressing of diamond abrasive discs are key issues in the field of diamond tool manufacturing. In order to achieve high-precision measurement of the profile error of the abrasive disc, an on-machine measurement method based on laser triangulation was proposed. The sub-micron accuracy of the surface error of the abrasive disc was effectively detected. The experimental results show that this method can be conveniently used to evaluate the dressing accuracy under different dressing parameters. The precision dressing technology of bronze-sintered diamond abrasive discs was studied by using the single-point diamond dressing method in the experiment. The effects of the dressing depth, spindle speed, spindle reciprocation frequency, and dressing pressure on the surface dressing accuracy of the abrasive disc were investigated, based on which the dressing parameters were optimized. The optimized parameters are: dressing depth 1 μm, spindle speed 3 000 r/min, reciprocating frequency 0.15 Hz and contact pressure 14.7 N. Abrasive discs with different dressing accuracies were used to grind wedge-shaped diamond micro-tools, respectively. The experimental results indicate that the proposed accuracy detection and surface precision dressing methods of abrasive discs are of significant application value improving the manufacturing accuracy of diamond tools.

Chemical vapor deposition (CVD) multilayer composite coating can effectively improve the life of the cutting tool, and the cutting temperature is one of the important factors affecting the coating performance. In this paper, the back face wear of tools with different coating structures for cutting 45 steel was compared by experiment, and the cutting temperature was obtained by finite element simulation. According to the finite element simulation and experimental results, the cutting temperature was considered to analyze the life of tools with different CVD multilayer composite coating (TiCAl2O3-TiN) for cutting 45 steel. The results show that when cutting 45 steel, the outermost tool without TiN coating has the shortest life. The coating structure has little effect on the maximum temperature of the tool tip, and the difference between tools with different coating structures is only less than 10 °C. The outermost tool coated with TiN coating can reduce the high-temperature area of the rake face. In order to improve tool life, when the cutting temperature is below 850 ° C, the innermost TiC coating thickness should be reduced appropriately, and the outermost TiN coating thickness should be increased. After the cutting temperature exceeds 850 °C, TiN coating thickness should be appropriately reduced, and Al2O3 coating thickness should be increased.

This paper studied the influence and mechanism of different iron-based catalysts on IIa type cultivated diamonds under high temperatures and pressures. The results show that the optimal crystallinity of the FeAl-C catalyst is 72.2%, and the weekly yield is 25.61 ct (1 ct = 0.2 g). The average weight of a single diamond is 1.19 ct. FeCo-C catalyst has a weekly yield of 44.37 ct, and the average weight of a single diamond is 2.11 ct, but the optimal crystallinity is 36.8%, and there are many defects. Scanning electron microscope (SEM), energy disperse spectroscopy (EDS), and electron back scattering diffraction (EBSD) are used to reveal the effects of FeAl and FeCo catalysts on the growth of cultivated diamonds due to structural differences. The results show that the average mass fraction of Al and Fe in the FeAl catalyst is 4.86% and 95.14%, respectively. The average mass fraction of Co and Fe in the FeCo catalyst is 37.33% and 62.67%, respectively. The difference in solid solubility between metals leads to the difference in phase distribution and grain orientation. The grains of the FeAl catalyst are coarse, large, and uniform, with the same orientation, and the formed single-phase structure and single texture reduce the catalytic activity when the catalyst selectivity is enhanced, resulting in uniform transfer and precipitation of carbon on the crystal seed surface, which promotes the formation of high-quality crystals and leads to a low yield of the FeAl system. The grains of the FeCo catalyst are small but heterogeneous, containing multiple solid solution phases and multiple textures, which increase the catalytic activity of the catalyst and speed up crystal growth and yield. As the selectivity decreases, the process of carbon transfer and precipitation on the crystal seed surface is more complicated, and the morphology is unstable, which makes it easy to produce more crystal defects.

Three types of ultrafine cemented carbide rods with different cobalt phase uniformity and a cobalt mass fraction of 6% were made into PCB milling cutters. The physical and mechanical properties, microstructure, and milling cutter performance of the three types of ultrafine cemented carbide rods and PCB milling cutter samples were compared. The cobalt phase distribution uniformity of the cemented carbide rods was quantitatively analyzed using ICALIBUR cobalt phase analysis software, and the influence of cobalt phase distribution uniformity on the performance of PCB milling cutters was studied. The results indicate that the uniformity of cobalt phase distribution is not reflected in the physical and mechanical properties and can only be detected through direct cobalt phase distribution detection methods. The detection of cobalt phase analysis software shows that the mass fraction of the cobalt phase is in the range of 5%~7%. Sample A is 50%; sample B is 66%, and sample C is 80%. After the PCB milling cutter is made, the life of sample A and sample B with poor cobalt phase uniformity is more than 20% lower than that of sample C with better cobalt phase uniformity. Poor cobalt phase distribution uniformity can cause uneven hardness in the local area of the cutting edge of milling cutters made of cemented carbide rods, resulting in uneven wear and chipping during use, leading to reduced service life.

In order to investigate the effect of alkaline cleaning agents on cobalt loss on the surface of WC-10%Co cemented carbide insert, APMT1135PDER-M1 and WC-TiC-TaC-6%Co cemented carbide insert, WNMG080412-DX, cleaning machine cleaning and cleaning agent soaking tests were conducted. The results indicate that alkaline cleaning agents are prone to causing cobalt loss on the surface of cemented carbide inserts; WC-TiC-TaC-Co cemented carbide insert, WNMG080412-DX, is more prone to cobalt loss than WC-Co cemented carbide insert, APMT1135PDER-M1 after three consecutive cleaning or soaking cycles (especially in alkaline cleaning agents such as sodium hydroxide + potassium hydroxide + amino trimethylphosphonic acid, as well as potassium hydroxide + amide + 2-butoxyethanol). The surface cobalt content is much lower than the set cobalt content of the substrate; the surface cobalt content of the inserts that have already been cleaned and lost cobalt after wet sandblasting approaches the set value of the substrate. It is suggested that the WC-TiC-TaC-Co cemented carbide insert should be cleaned at most once before coating in actual production. If backwashing is required due to surface cleanliness or other reasons, wet sandblasting treatment should be carried out first before cleaning.

The cutting force of the indexable insert drill affects the radial force balance and chip shape of the tool, lowering the dimensional accuracy and surface quality of the workpiece. It is particularly important to study the insert cutting force for stable applications of the indexable insert drill. In this paper, the insert groove of the indexable insert drill was optimized based on cutting force analysis. Firstly, the insert groove parameters were selected, and the orthogonal test scheme was designed. The key parameters affecting the insert cutting force were determined through simulation results. Secondly, the parameters were ranked based on their influence, and the optimal groove parameter combination was obtained. Finally, it was verified by a drilling test. The radial cutting force of the insert of the indexable insert drill was reduced by 18.1% by optimizing the insert groove parameters. The difference between finite element simulation and drilling experiment was only 6.61%. The results show that the orthogonal test method based on finite element simulation is suitable for the insert groove optimization of the insert groove and can effectively reduce the cutting force.

In this paper, the problems of uneven arc radius and size in polishing and passivating the cutting edge of the cemented carbide blade by commonly used roller brush passivation equipment were analyzed. Based on the working principle of roller brush passivation equipment, this paper analyzed the reasons for the inconsistent arc radius and size in passivating the cutting edge of cemented carbide blades from two aspects of brush motion and brush wear. Through the mathematical modeling of the equipment movement mode, it is found that when the product enters the brush and leaves the brush, the number of product rotations is not an integer, which will result in a longer processing time for a certain corner or a certain cutting edge of the product. At the same time, the uncertainty of brush wear will cause a difference in the actual processing time, which causes the inconsistency of the arc radius and size of the cutting edge. This is the inevitable defect of the equipment design.

99% alumina ceramics doped with Cr₂O₃-Y₂O₃-MgO were prepared by pressureless sintering at temperatures of 1 480 °C, 1 500 °C, 1 530 °C, and 1 550 °C. The effects of varying doping amounts of Cr₂O₃ on the densification, microstructure, microwave dielectric properties, and insulation properties of the 99% alumina ceramics were studied. The results show that appropriate amounts of Cr₂O₃, Y₂O₃, and MgO can promote sintering, reduce intergranular voids, improve density, and enhance overall performance. Under the conditions of w(Cr₂O₃) = 0.4%, w(Y₂O₃) = 0.24%, w(MgO) = 0.16%, and sintering temperature of 1 530 °C, the ceramics exhibit a density of 3.919 cm³, a dielectric constant (ε_r) of 9.985, a dielectric loss (tanδ) of 0.000 5, and a breakdown voltage of 25.3 kV. The doping of Cr₂O₃ improves the microwave dielectric and insulation properties of the 99% alumina ceramics, showing promising potential in electronic packaging materials.

The WC-13%Co cemented carbide was treated by liquid phase rapid cooling (1350 °C and above) and solid phase quenching rapid cooling technology (1100 °C and below) at high temperatures. The effects of two treatment methods on the microstructure and physical & mechanical properties of the cemented carbide were studied. The results show that compared with the sintered state, the microstructure of the cemented carbide after rapid cooling treatment has no obvious change, while the grain size after liquid phase rapid cooling treatment and solid phase rapid cooling treatment increases by 28.13% and 18.75%, respectively. In terms of physical & mechanical properties, the rapid cooling treatment has a certain change compared with the sintered state. Compared with the solid phase rapid cooling treatment, the physical & mechanical properties of the liquid phase rapid cooling treatment change significantly. Compared with the sintered state, the cobalt magnetic and coercive magnetic forces decrease by 4.5% and 1.0 kA/m, respectively. The vickers hardness, crack length and solid solubility of W in the cobalt phase increase by 0.98 GPa, 33.3 μm and 6%, respectively. The main reason for the significant change is that the solid solubility of W in the binder phase Co increases significantly after the liquid phase rapid cooling treatment, which has a significant strengthening effect on the cemented carbide.

WC-Ni-based cemented carbides can be applied in extreme working conditions such as magnetic material forming dies and key component of the mechanical seal of nuclear main pump. Nonetheless, the high performance and quality stability control of WC-Ni-based cemented carbides has been challenging due to the intrinsic nature of the material system. The carbon window in the two-phase region, the solid-liquid transition temperature, the wetting behavior during liquid-phase sintering, and the solid-solution characteristics of alloy components in the binder phase are key parameters for the composition and preparation process design of the hard composite material. Taking the WC-Co-based cemented carbides with the most complete preparation process as the reference, we summarize the intrinsic properties and research progress of WC-Ni-based cemented carbides in the above four aspects, aiming to lay the foundation for the efficient development of new high-performance WC-Ni-based cemented carbides.

In the past two decades, many researchers have extensively studied the cermet with high entropy alloys as binder phase, and they have obtained many beneficial results. This article first introduced the preparation methods of high entropy alloys used as binder phases for cermet and the sintering preparation techniques of cermet with high entropy alloys as binder phases. Finally, it evaluated the effects of various process parameters including sintering temperature, sintering time, carbon content, binder phase composition, and binder phase content on the microstructure, mechanical properties, oxidation resistance, and corrosion resistance of cermet with high entropy alloys as binder phases, so as to provide a reference for the research on cermet with high entropy alloys as binder phases.

In the production of cemented carbides, hafnium is often used as an additive to improve the mechanical properties of cemented carbides. Therefore, accurate determination of the hafnium content in cemented carbides is of great significance. The existing chemical volumetric method for determining hafnium in cemented carbides has the disadvantages of high risk, complex operation, and low analysis efficiency. This article explored the determination method of hafnium in cemented carbides from the aspects of sample pre-treatment, selection of analytical lines, and exploration of matrix effects. It established a method for determining the hafnium content in WC-Co cemented carbides by using inductively coupled plasma atomic emission spectrometry, which was safe, efficient, and simple to operate, at a low cost. Under the selected conditions, a mixed solution with sulfuric acid: ammonium sulfate (1: 1) was combined with citric acid and hydrogen peroxide to serve as the pretreatment solvent, and the hafnium spectral line 264.141 nm was selected as the analytical spectral line. The standard solution was prepared using the matrix matching method. The linearity of the method calibration curve was greater than 0.999 9, and the linear range was 0.0-2.0 μg/mL. The detection limit was 0.008 4 μg/g, and the recovery rate was 99.17%-103.63%. The RSD was less than 0.758%. This method provided a reliable method for detecting the hafnium content in WC-Co cemented carbides.

This article selected 06 type WC powder as the research object and processed it by using jet milling technology. The influence of the jet milling technology on the microstructure morphology, particle size, particle size distribution, and related characteristics of the powder was studied. The differences in the properties of WC powder processed with the jet milling technology and the ball milling technology were compared. The research results indicate that the rotational speed of the grading wheel has a significant impact on the particle size and uniformity of the WC powder produced during the jet milling process. The higher rotational speed of the grading wheel indicates a smaller particle size and more concentrated particle size distribution of WC powders. When the rotational speed of the grading wheel is ≥ 3 900 r/ min, particles with a size of ≥2 μm are completely eliminated. However, the excessively high rotational speed of the grading wheel will reduce equipment production efficiency. When the rotational speed of the grading wheel reaches 4 200 r/min, the equipment production efficiency drops to 53.8 kg / h, while the oxygen and impurity content of the powder is increased. Compared with that produced by ball milling, the WC powder produced by jet milling has a more concentrated particle size distribution and fewer impurity content, and the microstructure of the alloy produced is more uniform. The powder obtained by jet milling is conducive to the preparation of high-quality ultrafine grain cemented carbide products.

In this paper, WC-32%(Co-Ni)-1.3%Cr cemented carbide was studied, and three cemented carbide samples with different cobalt / nickel ratios were prepared by powder metallurgy. Through performance testing, microstructure analysis, and electrochemical polarization curve testing, the influence of cobalt and nickel content changes on the microstructure, mechanical properties, and corrosion resistance of WC-32%(Co-Ni)- 1.3%Cr cemented carbide with high bonding agent was studied. The results show that with the decrease in cobalt content and the increase in nickel content, the cobalt magnetism, coercivity, and hardness of the cemented carbide decrease linearly. The grain size and density of the cemented carbide remain almost unchanged, and the transverse rupture strength of the cemented carbide changes very little at around 2 400 MPa. The corrosion trend of WC-32%(Co-Ni)-1.3%Cr cemented carbide with a high bonding agent varies with the change in cobalt / nickel ratio in neutral and acidic solutions. As the cobalt content decreases, and the nickel content increases, the self-corrosion potential of the cemented carbide increases, and the corrosion current density decreases in H2SO4 solution with pH = 1. The corrosion resistance of the cemented carbide with a cobalt/nickel ratio of 1:3 is much higher than that of the cemented carbide with a cobalt/nickel ratio of 1:1 or 3:1. High-nickel cemented carbide can significantly improve the corrosion resistance of the cemented carbide in acidic solutions. With the decrease in cobalt content and the increase in nickel content, the self-corrosion potential of the cemented carbide in NaCl solution with pH = 7 increases, and the corrosion current density decreases. There is no significant difference in corrosion resistance between cemented carbides with a cobalt/nickel ratio of 1:1 and 1:3, but it is much higher than the corrosion resistance of cemented carbides with a cobalt/nickel ratio of 3:1.

To investigate the effect of W doping on the microstructure and properties of CrAlN coatings, coatings of Cr0.36Al0.64N, Cr0.34Al0.64W0.02N, and Cr0.32Al0.63W0.05N were prepared by using the cathodic arc evaporation method. The composition, microstructure, thermal stability, mechanical properties, and oxidation resistance of the coatings were studied by using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffractometer (XRD), simultaneous thermal analyzer, and nanoindenter. All three coatings exhibited a face-centered cubic structure. The hardness increases with the W content, rising from (28.61±0.82) GPa of Cr0.36Al0.64N to (30.87±0.80) GPa of Cr0.34Al0.64W0.02N and (32.37 ± 1.44) GPa of Cr0.32Al0.63W0.05N. W doping reduced the“droplet”defects generated during the cathodic arc evaporation process, with defects decreasing as W content increases. The addition of W suppressed the thermal decomposition of CrAlN coating and enhanced its thermal stability. However, W doping reduced the oxidation resistance of the CrAlN coating. After 15 hours of isothermal oxidation at 1 100 ° C, The oxide layer thicknesses of the Cr0.36Al0.64N, Cr0.34Al0.64W0.02N, and Cr0.32Al0.63W0.05N coatings were approximately 260.6 nm, 359.8 nm, and 445.9 nm, respectively.

Nuclear fusion energy is considered to be one of the ideal energy sources in the future due to its high energy density, cleanness, and safety. In order to improve the performance of tungsten as the first wall and divertor material of nuclear fusion reactor, tungsten alloy (KW) strengthened by potassium (K) bubble diffusion via K doping is one of the methods to improve the high temperature stability of tungsten. In this paper, the microstructure and recrystallization behavior of K-doped tungsten with different K contents were studied. High-density KW was prepared by powder metallurgy, and sintering and rolling were carried out. The results show that the addition of K significantly increases the recrystallization temperature of tungsten, among which the alloy with higher K content (81 μg / g) shows the highest recrystallization temperature (1 500 ℃ ). Scanning electron microscope (SEM) analysis shows that K bubbles are mainly distributed at the grain boundaries, effectively pinning the grain boundaries, hindering the migration of grain boundaries, and improving the high temperature thermal stability of the material, which provides an optimization reference direction for the application of tungsten-based alloys in nuclear fusion reactors.

This paper addresses the problems of the short service life of traditional carbide-coated tools for carbon fiber composite (CFRP) drilling, defects such as burrs on the processed workpiece, and large fluctuations in hole machining roughness. The machining performance of diamond-coated tools with different coating structures and different edge structures was prepared and compared. The results show that when diamond-coated tools are used for drilling CFRP materials, the composite structure of microcrystalline diamond (MCD)/nano-crystalline diamond (NCD) has better abrasion resistance and longer service life than a single MCD-coated structure; the cutting edge structure can be optimized by decreasing the inverted cone of the drill bit and the angle of the tip and increasing the front angle of the slot, the front angle and width of the back of of the chip pocket at drill tip. The average roughness of the machined hole diameter of the diamond-coated tools with optimized cutting edge structures is significantly reduced, and the roughness extreme difference is reduced from 4.105 μm to 0.848 μm.

High temperature and high pressure method, an effective method for synthesizing gems, has the advantages of ultra-high isostatic pressure and short synthesis time in the preparation of composite materials. In this paper, WC-3%Co cemented carbide was prepared at high temperature and high pressure, and the phase composition and mechanical properties of the cemented carbide samples were characterized by using tools including a universal testing machine, an X-ray diffractometer (XRD), and a microhardness tester. The effects of sintering temperature on the phase and physical and mechanical properties of WC-3%Co cemented carbide were investigated. The results show that sintering at high temperature and high pressure can ensure that the prepared cemented carbide samples are pure WC and Co phases; the relative density of the samples increases with the increase of temperature and can reach 99.3% at 1 450 °C; the hardness, bending strength and fracture toughness of the samples increase firstly and then decrease with the increase in sintering temperature. WC-Co cemented carbide samples prepared at 1 400 °C have excellent mechanical properties, of which bending strength reaches 2 230 MPa, hardness reaches 22.78 GPa and fracture toughness reaches 11.9 MPa·m^1/2.

Adding grain inhibitors to fine tungsten oxide or tungsten powder to produce tungsten carbide powder containing inhibitors is a method for preparing ultrafine cemented carbides. It is generally believed that inhibitors in WC powder are either solidly soluble in the WC phase or exist as independent phases. However, due to the small amount added, it is difficult to determine its phase or solid solution content through examining methods. This article attempts to establish quantitative indicators through benchmark evaluation to determine the degree of solid solution of grain inhibitors in powders, and evaluates the fine and ultrafine WC powders prepared by adding different amounts of Cr and Cr, V mixed grain inhibitors. The test result indicates that difficulty in determining the solid solution amount is due to the neglect of the carbon deficient phase and corresponding solid solution product phase during production. The evaluation method uses W₂C, (W,Cr,V)₂C and WC as benchmark objects to determine the solid solution amount. The diffraction peak position and full width at half maximum are used as benchmark indicators to weaken the influence of other factors that interfere with lattice constant changes, such as uncertainty of crystal type caused by fewer spectral peaks, and changes in crystallization degree caused by process parameters or inhibitor addition. Within the range of 1% inhibitor addition, the peak positions of (W,Cr,V)₂C and WC in the powder increase with the addition of Cr inhibitor, and the peak area of (W,Cr,V)₂C also shows a gradually increasing trend. Sample powders are prepared as cemented carbide and measured for WC grain size, and some results show that the trend is consistent with quantitative indicators.