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.

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 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.

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.

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.

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. 

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 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.

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.

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.

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%.

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.

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.

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.

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.

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.

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.

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.

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.

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 powder properties, pressing properties, microstructure and properties of WC-8%Co-0.4%VC ultrafine cemented carbide mixture prepared by three groups of slurries with different solid contents were studied. The results show that with the decrease in the solid content of the mixture, the content of fine powder in the mixture increases, and the degree of particle breakage increases. The loose density of the mixture gradually decreases from 3.4 g/cm³ to 2.5 g/cm³ , and the fluidity gradually deteriorates from 32 s to 39 s; the pressing pressure of the mixture PS21 increases from 2 250 N to 4 050 N, and the green compact strength decreases from 5.52 MPa to 2.88 MPa. The decrease in the solid content of the mixture leads to the gradual decrease in the average size and maximum size of vanadium-containing particles in the mixture, from 1.085 µm to 0.523 µm and from 1.627 µm to 0.876 µm, respectively. With the decrease in the solid content of the mixture, the uniformity of the cobalt phase in the alloy gradually decreases. When the solid content is as low as 57%, a cobalt pool of more than 1 µm will be formed, which will reduce the bending strength of the alloy. When the solid content is 64%, the alloy has a uniform distribution of WC grains and cobalt phase at the same time, and the bending strength is the highest, reaching 2 780 MPa. Therefore, adjusting the solid content of the mixture reasonably can effectively control the comprehensive mechanical properties of the alloy.

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.

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.

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.

Ultrafine-grained cemented carbide is the main material for manufacturing micro drills used on printed circuit boards (PCBs). Cobalt content in cemented carbides is an important parameter that affects their mechanical properties. Three types of ultrafine-grained carbide micro drills with different cobalt contents and an average grain size of 0.3 µm were prepared. They had the same structural design, with a diameter of 0.3 mm and a flute length of 5.0 mm. The performance of the three types of micro drills in drilling a high Tg (Glass Transition Temperature) PCB under six sets of drilling parameters was tested and evaluated from the aspects of wear, hole position accuracy, and hole wall quality. The results show that lower cobalt content indicates smaller micro drill wear and higher hole position accuracy. The cobalt content has no significant impact on hole wall quality. Appropriately increasing the feed speed will help reduce micro drill wear and improve drilling quality. Excessive feed speed will lead to chipping of cutting edges and serious deterioration of hole wall quality. In general, the 0.3 mm diameter carbide micro drill with a cobalt content of 6% and an average grain size of 0.3 µm has the best drilling performance.

Ti(C,N)-based cermet was prepared by high temperature and low pressure sintering in Ar + N2 atmosphere with submicron Ti(C,N), different kinds of ultrafine carbides, ultrafine Co powder, and Ni powder as raw materials. The phase composition and microstructure of Ti(C, N) - based cermet were studied by X-ray diffraction (XRD) and scanning electron microscope (SEM). The Vickers hardness and fracture toughness of the specimens were calculated by the Vickers hardness tester. The results show that the sintering temperature is slightly higher than the traditional temperature due to the increase in the types of carbide components. When the sintering temperature is 1 470 °C, the microstructure distribution of the cermet is uniform, and there is no obvious grain growth. The phase only have (Ti,M)(C,N) (M = W, Mo, Nb, and Ta) solid solution phase and Co + Ni bonding phase. At this time, the hardness and fracture toughness of the specimens match the best (1 730HV10 and 8.02 MPa ∙ m1/2 ). Through the optimization of the sintering process, the cooperative regulation of microstructure and mechanical properties is realized.

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.

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.

Carbon fiber reinforced resin matrix composite (CFRP) has excellent physical and chemical properties, which can replace traditional materials in many fields. The existing forming process is relatively mature, and the development prospects are broad. However, CFRP is a typical difficult-to-process material due to its non-uniformity and anisotropy, so optimizing its processing technology has become a key point in China and abroad. Based on current research progress, this article first provided a brief overview of the composition of CFRP from the perspectives of the carbon fiber reinforcement phase and resin matrix. Then, it summarized the traditional and non-traditional processing methods of CFRP, so as to seek efficient processing techniques. Finally, this article provided prospects for the modification of resin matrix, the improvement of diamond coating performance, and the study of cutting mechanism, which can serve as a reference for researchers in related fields.

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.

In view of the easy denitrification of the sintered body and the decomposition of N during the preparation of fine-grained Ti(C, N) - based cermets by vacuum sintering, cermets were prepared by nitrogen partial pressure sintering during the liquid heating, insulation, and cooling phases of Ti(C,N)- based cermets. The influence of the nitrogen filling process on the microstructures and mechanical properties of cermets was investigated. The results show that the sintered body is basically dense when nitrogen atmosphere sintering is carried out during the liquid insulation phase, combined with the liquid cooling phase. There is an obvious gradient structure from the surface to the core. The surface is a gray (Ti,Me)(C, N) solid solution layer rich in W and Mo with a coreless ring structure. Compared with those in vacuum sintering, the bending strength and fracture toughness of cermets sintered in the nitrigen atmosphere do not change much, but its hardness increases by about 10%. The increase in hardness mainly comes from the fact that nitrogen partial pressure sintering inhibits the decomposition and escape of nitrogen in the sintered body, thereby increasing the nitrogen content of the sintered body. In addition, nitrogen atmosphere sintering promotes grain refinement in the core, and the hardness of the sintered body increases due to the fine grain strengthening mechanism.

GH4169D has been widely used in the manufacturing of aero engine blades, and the surface integrity after milling significantly affects the working performance of the blades. The milling experiment of GH4169D high-temperature alloy was carried out to study the influence of different process parameters on the surface integrity after milling. The results show that with the increase in milling speed, the surface roughness of GH4169D high-temperature alloy during milling along width cutting direction first increases and then decreases. The roughness along the width cutting direction increases with the increase in cutting width. Milling speed and cutting depth have a greater impact on microhardness. A large milling speed indicates a weak hardening phenomenon; a larger cutting depth indicates an obvious hardening phenomenon. The residual stress on the surface of GH4169D after milling is tensile stress, and a larger cutting speed indicates a larger residual tensile stress. The same relationship is shared between the residual tensile stress and the feed per tooth. When the milling speed becomes larger, the depth of the surface residual stress gradually becomes larger, and the peak of the residual compressive stress becomes smaller. As the milling width becomes larger, the depth of the maximum residual compressive stress does not change significantly, but the peak changes significantly. ap is within 0.16-0.24 mm, and the surface residual stress changes significantly. The depth of the maximum residual compressive stress increases, and the peak value decreases. The plastically deformed layer becomes thinner with increasing milling speed and thicker with increasing cutting depth.

A surface defect detection algorithm for hard alloy roller collars was proposed to reliably and accurately detect small and similar surface defects of different categories on hard alloy roller collars. This algorithm was based on the collected surface image of roller collars, and color space processing was performed on the hard alloy roller collar image to generate a variance saliency map of the color space distribution of the hard alloy roller collar image. The saliency map was input into a multi-scale attention mechanism network model, and edge contour defects were extracted from the saliency map through the pyramid segmentation attention module in the model encoder section. They were combined with internal region defects output by global average pooling, and then surface defect detection results were output through upsampling processing. The test results show that the algorithm has good application effects, generating a saliency map that can present the overall contour structure of the roller collar and the location of defects on the roller collar, providing a reliable basis for subsequent surface defect detection of roller collars. It accurately detects small and similar surface defects of different categories, with an average positioning error of less than 0.018 mm and high detection accuracy.

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.

This study focused on the influence of blade shape on the bending fracture failure of micro-drills with large aspect ratios through a combination of finite element simulation and experimental validation. Firstly, based on the transverse rupture strength theory, the strength parameters of the cemented carbide material were determined. Subsequently, finite element simulation was performed to compare the bending fracture characteristics of micro-drills with large aspect ratios in the blade shapes (double-blade single slot and single-blade single slot) with the same chip space for two conventional parameter settings, and validation experiments were designed. The influence of blade shape on the bending fracture of micro-drills with large aspect ratios was analyzed in terms of bending and breaking force, fracture mode, and drilling breakage rate. Simulation and bending fracture resistance experiments show that the double-blade single slot exhibits higher bending fracture resistance than the single-blade single slot, and the bending resistance is optimal when the slot end is downward. The micro-drills with large aspect ratios in two blade shapes show multiple fragmentations in the bending fracture process, and their fracture failure is mainly related to the stress expansion of internal micro-fractures. In addition, in the drilling experiment, the double-blade single-slot micro-drills do not break after drilling 3 000 holes, while the single-blade single-slot micro-drills break in all cases, which further proves that the double-blade single-slot design has an obvious advantage in reducing breakage rate and expanding life expectancy.

Cemented carbides are indispensable in modern industry due to their various superior properties, but the contradiction between their hardness and toughness limits further performance improvement. Multi-scale material calculation methods integrate multi-scale theoretical models with key experiments, which ensure the efficient development of new materials and provide scientific support for the strengthening and toughening of cemented carbides. This article introduced theoretical methods such as first-principles calculations, thermodynamic and kinetic calculations, phase field simulations, and finite element simulations and demonstrated effective measures for the synergistic enhancement of strength and toughness in cemented carbides, including binder phase strengthening and toughening (nano-scale phase precipitation), hard phase strengthening and toughening (spinodal decomposition), and microstructure optimization (surface gradient structures and whisker toughening). It also discussed the efficient enhancement of cemented carbide performance through a combination of theoretical design and key experimental validation. Multi-scale material calculation methods can provide a theoretical basis and practical guidance for designing and preparing high-strength and high-toughness cemented carbide materials. In the future, it is necessary to further study the intrinsic mechanisms of material microstructure evolution and its structure-property relationships on this basis, so as to promote innovation and progress in the development of cemented carbide materials.

In order to improve the service life of cemented carbide under complex stress conditions, this paper added a few-layer graphene (FLG) (with 1-3 layers) to WC-Co cemented carbide to improve its wear resistance. According to the characterization results, compared with the graphene-free sample, the addition of 0.05% FLG (mass fraction) increases the density and hardness of the sample by 3.6 percentage points and 101HV30, respectively, and it reduces the friction coefficient and wear depth of the sample by about 0.16 and 90%, respectively. The analysis shows that the reason why FLG can enhance the wear resistance of the sample is that it not only can improve the density and hardness of the sample at the same time but also has lubrication and protection effects. In addition, it can supplement carbon in the sintering process. When the mass fraction of FLG exceeds 0.05%, although the friction coefficient of the sample continues to decrease, the density, hardness, and wear resistance all show a downward trend, mainly because too much graphene will lead to agglomeration, and the performance of the graphene after agglomeration will be reduced, making it difficult to achieve an ideal strengthening effect.

Selective laser melting (SLM) technology is currently one of the primary processes for additive manufacturing of WC-Co cemented carbides. However, due to the significant differences in physical properties between the metallic and ceramic phases, obtaining crack-free and pore-free cemented carbide components with high performance through SLM printing remains a significant challenge. This work first investigated the influence of laser power, scanning speed, and hatch spacing on the porosity of the fabricated specimens by using WC-Ti powder, which has a relatively small difference in melting points. On this basis, a function relationship between laser process parameters and the density of the printed parts was established. It was found that the scanning speed had the most significant impact on the density of the fabricated specimens. Moreover, by further synergistically optimizing the laser spot size and powder particle size, the porosity of SLM-printed WC-Co cemented carbides was reduced to 1.5%, and cracks were eliminated. Molecular dynamics simulations were employed to reveal the mechanism by which the optimized matching of laser spot size and powder particle size inhibited the formation of cracks, pores, and other defects in the printed cemented carbides. Based on optimized WCCo composite powder, SLM technology, and subsequent heat treatment conditions, a nearly fully dense cemented carbide cutting insert with a bimodal grain microstructure was fabricated. The insert exhibited a Vickers hardness of (1 300 ± 20) HV30, a bending strength of (1 020 ± 130) MPa, and a compressive strength of (3 520 ± 240) MPa. The overall mechanical properties of this material are comparable to those of sintered cemented carbides with similar compositions and grain sizes, demonstrating promising application prospects.

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.

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.