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.

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.

The temperature field in the pressure sintering furnace is simulated by ANSYS FLUENT, and the temperature distribution in the high temperature section (furnace temperature is 1450 °C is analyzed. It is found that the temperature distribution in the furnace is uneven, the batch temperature difference reaches 16 °C, and the temperature difference of products at the furnace door is the largest. It is considered that the shape and distribution of the heating element have the greatest influence on the uniformity of the temperature field. To optimize the temperature distribution in the furnace, three improvement schemes are put forward, such as increasing the size of the heating element at the furnace door and adding a heating ring or rod at the furnace door. The result shows that after changing the number, structure, and distribution of heating elements, the batch temperature difference of products in the furnace with three optimization schemes decreases by 4.6 °C, 3.2 °C, and 2.8 °C respectively. Specifically, increasing the size of the heating rod at the furnace door has the best optimization effect. It not only significantly reduces the temperature difference of the products at the furnace door, but also improves the temperature uniformity of products in the loading area, which provides a guarantee for improving the quality of sintered products.

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.

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.

Type A milling cutter with unequal pitch and damping edge belt structure, type B milling cutter with unequal pitch and double straight back angle, and type C milling cutter with equal pitch structure were selected as experimental tools. The 316L cutting performance of these milling cutters with different geometric structures was studied. The cutting force in the machining process was measured by a force meter. The effect of geometric structure on cutting performance was analyzed by spectrogram and machining surface roughness. The results show that when cutting 316L stainless steel, the cutting force of the type A milling cutter is reduced by about 16%, and the surface roughness is increased by about 25%.

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.

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.

High-silicon aluminum alloy has become the most promising metal-based electronic packaging material due to its excellent physical and chemical properties, such as low coefficient of thermal expansion, low density, and good thermal conductivity. However, conventional preparation methods for high-silicon aluminum alloys, such as powder metallurgy, result in low density, the formation of pores, coarse microstructure, and high cost during alloy preparation. This paper took Al-60Si ultra-high-silicon aluminum alloy as the research object and used the ProCast numerical simulation method to calculate the distribution of temperature field and flow field during the solidification process of Al-60Si alloy under different pouring temperatures, centrifugal speeds, and other process conditions. The optimal process parameters were determined to be a centrifugal speed of 800 r/min, a pouring temperature of 1 200 °C, and a pouring speed of 16.5 mm/s. In addition, high-performance fine-grained Al-60Si alloy cast rings were prepared. It is found that different sizes of primary silicon phases are distributed in the outer, middle, and inner layers of the cast rings, and most of the outer parts are block-like primary silicon phases. The middle and inner layers are thick lath-like primary silicon phases. By calculating the coefficient of thermal expansion, it is found that the overall coefficient of thermal expansion of Al-60Si after centrifugation is small, and the outer layer of the cast ring has the smallest coefficient of thermal expansion and better performance.

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.

Cemented carbide has the advantages such as high hardness, strength, and toughness and is an important cutting tool material. Generally, the service life can be extended by coating on the surface of cemented carbides. Diamond coatings are the preferred choice for processing materials such as carbon fiber composites, graphite, and ceramics due to their extremely high hardness, wear resistance, high thermal conductivity, and low coefficient of thermal expansion. However, low toughness is the primary disadvantage that limits the application of diamond coatings on the cemented carbide. At the same time, high thermal stability is the key to stable service of diamond coating on cemented carbides under high speed and high temperature cutting conditions. Based on the structure and composition design of diamond coatings, this paper mainly focuses on the effects and mechanisms of multilayer and gradient diamond coating design on their toughness and related properties. The mechanisms and strategies for enhancing the thermal stability of diamond coatings are explored. Additionally, the preparation process of diamond coatings is summarized, and the experimental methods for precisely determining the fracture toughness and thermal stability of diamond coatings are summarized. It is intended to ascertain the design method of hard and tough diamond coatings with great thermal stability, so as to effectively improve the performance of cutting tools.

In recent decades, superhard blades have been widely used in automobile manufacturing, 3C electronics, and other fields that require long tool life and high production rhythm. It also puts higher requirements on the mass production of superhard blades. This paper explored the material properties, manufacturing process, and characteristics of superhard tools and introduced three processing methods for sharpening superhard blades. The paper discussed the mechanical grinding method. Based on the process of small and medium-sized batch manual sharpening, the sharpening process and algorithm required for automated unattended production were developed and integrated into automated machine tool products.

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.

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.

In this paper, the new CVD diamond composite coating tool milling experiment of the self-developed high density and high strength isotropic graphite material was carried out, and the cutting performance of the new CVD diamond composite coating tool and PCD tool were compared. The test results show that the flank wear has exceeded the standard 0.3 mm after the PCD tool milling processing 25 min., while the flank wear is only 0.25 mm after the new CVD diamond composite coating tool processing to 45 min., which shows that the new CVD diamond composite coating tool is of good wear and service life in high-speed milling graphite, and can adapt to the processing requirement of high performance isotropic graphite. It was also found that the graphite surface quality of the new CVD diamond composite coating tool was inferior to PCD tool in the initial milling stage, but the machining surface quality was better than PCD tool in the longer processing time.

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.

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.

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.

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%.

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. 

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.

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.

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.

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.

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.

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.

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.

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.

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.

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).