Chromium carbide is a high melting point material with good wear resistance, corrosion resistance, and oxidation resistance under high temperature environments. Chromium nitride is a ceramic material with high hardness, high melting point, and excellent chemical stability. They have excellent chemical stability and wear resistance and have been widely used as a coating of materials. To obtain high-quality chromium carbide and chromium nitride powders, stable physical properties and micro-topography control are required. In addition, the control of iron, silicon, calcium, and other trace impurities is necessary. A method for rapid determination of aluminum, silicon, calcium, and iron in chromium carbide and chromium nitride by inductively coupled plasma emission spectrometry was established. Microwave digestion of samples was conducted by using hydrofluoric acid and nitric acid. High-purity chromium matrixes were matched, and the standard working curve method was used to determine aluminum, silicon, calcium, and iron in chromium carbide and chromium nitride. The intensity of each element showed a good linear relationship with concentration, and the corresponding correlation coefficients were all greater than 0.999. The detection limits of the method were less than 0.0005%, and the lower limits of quantification of the method were less than 0.0015%. The tested relative standard deviation of each element ranged from 0.30% to 6.94%, and the spiked recoveries ranged from 96.0% to 105.0%. The method was simple and sensitive, and it could meet the production quality control requirements of cemented carbide or thermal spray powders.

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.

In this paper, the precursor of the cobalt-ammonia complex was prepared by adding catalysts, organic polymerization dispersants, and initiators with cobalt sulfate heptahydrate as raw material and ammonia water as a complexing agent. It was then transferred into a high-pressure stirred reactor, heated, and stirred. After reaching the set temperature, hydrogen at a certain pressure was introduced for the reaction. The reaction product was centrifuged with deionized water and methanol, and the ultrafine cobalt powder was obtained after vacuum drying. The effects of reaction temperature, cobalt-ammonia complex ratio, and hydrogen pressure on the actual yield of ultrafine cobalt powder, as well as those of initiator, catalyst, and dispersant dosages on the Fisher particle size of ultrafine cobalt powder were studied. The results show that ultrafine spherical cobalt powder with Fisher particle size of less than 0.6 μm, uniform particle size distribution, and actual yield of greater than 99.5% can be synthesized by controlling the amount of initiator, catalyst, and dispersant when the reaction temperature is 140 °C; the hydrogen pressure is 2.5 MPa, and n (Co)∶n (NH3) is 1∶2.3.

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.

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.

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.

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.

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.

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, 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.

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 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.

Coarse-grained cemented carbide demonstrates exceptional thermal conductivity and resistance to thermal fatigue, rendering it highly promising for applications in mining tools and hard surface materials. As the main intermediate product of tungsten, ammonium paratungstate (APT) with high-alkaline metal content facilitates the production of coarse particles of tungsten carbide powder for the preparation of coarse-grained cemented carbide. This investigation employed an ammonium tungstate solution as a raw material to explore the initial sodium content in the solution, as well as the types and quantities of additives, crystallization rate, and the influence of APT washing times on sodium content in APT crystals. The results indicate that the type of additives has no effect on the sodium content in APT crystals, but the amount of sodium hydroxide, crystallization rate, and APT washing times have a greater impact. By controlling the adding amount of sodium hydroxide at a sodium-tungsten mass ratio of 4‰ and achieving a crystallization rate of 90%, high-sodium APT products with a sodium content exceeding 0.029% can be produced after four rinses with pure water. Furthermore, other impurity elements meet zero-grade requirements of national standards.

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.

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.

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 research on the synthesis mechanism of artificial diamonds meets the inherent requirements of developing new quality productive forces and can efficiently guide the preparation of high-quality diamond crystal materials, especially in predicting and exploring synthesis boundary conditions, controlling nucleation and growth processes, and regulating and modifying properties. In order to have a deeper understanding of the diamond synthesis process, this article provided a detailed explanation of relevant synthesis mechanisms of high-temperature and high-pressure method, detonation method, and vapor deposition method used in diamond synthesis. Due to the limitations of current technological conditions, direct real-time observation of the synthesis process is not possible, and there is currently no unified understanding of the synthesis mechanism of artificial diamonds. The above theoretical research mainly relies on the analysis of experimental processes and products before and after synthesis. The authors believed that with the help of molecular dynamics and other methods for simulation, the use of in-situ measurement equipment such as in-situ X-ray for real-time monitoring, and consideration of other characterizations during the synthesis process, it is expected to further reveal the essence of artificial diamond synthesis in the future.

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.

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 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.