Tungsten Carbide Composites Research Articles

Surface Heating Calculation of Composite Material Under the Influence of an Electron Beam on the Surface

Introduction. Modern plasma magnetic confinement systems use tungsten as a material in contact with plasma. Under the influence of high-density plasma irradiation, tungsten undergoes cracking, intense erosion, and macro-particle emission. High-temperature ceramics are considered a promising material for protective coating of plasma components, as they are resistant to thermal loads. One possible solution could be a boron carbide coating, which has a high melting temperature.Materials and Methods. The impact of an electron beam on samples of rolled tungsten and boron carbide and tungsten composite was studied in experiments on the BETA setup. The heat from the beam propagates into the samples, with the maximum temperature reached at the center and decreasing towards the edges. The modeling area represents a cross-section of the samples, optimal for a task with a cylindrical coordinate system. The numerical implementation is based on the correction scheme and the marching method.Results. A new model of heating the boron carbide and tungsten composite sample under the influence of surface heating by an electron beam is presented. The model is based on solving the heat conduction equation in an axially symmetric setup with constant values of specific heat capacity, density, and thermal conductivity of metals.Discussion and Conclusions. An analysis of the model of heating the composite material under the influence of surface heating by an electron beam at constant values of density, thermal conductivity, and specific heat capacity has been conducted. The modeling results are in demand for analyzing experimental results and planning experiments at the Beam of Electrons for Materials Test Applications (BETA) facility, created at the Budker Institute of Nuclear Physics SB RAS.

Insight into the microstructure and properties of Ni–WC composite through vacuum induction melting (VIM): The effects of thermal damage behaviour of cast WC controlled by VIM temperature

Ni–tungsten carbide (WC) composites were prepared using cast WC as hard particles. In this study, the thermal damage behaviour of cast WC particles and its effects on the microstructure and mechanical properties of Ni–WC composites were investigated. Results show that cast WC particles undergo edge dissolution and particle disintegration at 1600 °C and 1800 °C, respectively. The degree of thermal damage to cast WC particles increases from 30.55% to 48.84% when the melting temperature increases from 1600 °C to 1800 °C. In this process, the Ni-based melt gradually erodes the cast WC particles from the edge towards the centre. This leads to severe dissolution of the W2C phase, while the WC phase only dissolves partially. Notably, the degree of thermal damage to cast WC directly correlates with the W content in the melt. An increase in the W content enhances the volume fraction and nano-hardness of the M23(B, C)6 compound, improving the wear resistance of the composites.

Enhancing the mechanical properties and corrosion resistance of commercially pure titanium using tungsten carbide composites fabricated via additive manufacturing

Commercially pure Ti (CP Ti) exhibits an exceptional corrosion resistance, and it is thus critical in the aerospace, marine, and petrochemical fields. However, pure Ti also displays a modest strength and limited wear resistance. Therefore, several studies have explored the incorporation of reinforcing phases, such as ceramics and carbides, leading to the development of metal matrix composites. This study investigates the fabrication of CP Ti-WC composites using an additive manufacturing process and explores the effect of the WC content on the microstructure, mechanical properties, and corrosion resistance. Regarding the mechanical properties, the tensile strength and hardness progressively increase with increasing WC content owing to microstructural refinement and solid solution strengthening caused by W. The alloy containing 5 wt% WC displays the respective maximum strength and hardness of 1042 MPa and 362.2 HV. Furthermore, WC addition enhances the corrosion resistance of CP Ti in a 70 % H2SO4 solution. Compared to those of the other samples, the alloy with 5 wt% WC exhibits the lowest mass loss (0.00242 mg/cm2) and current density in the passivation region, which are attributed to the microstructural refinement aiding in the formation of a stable oxide layer. Thus, this research highlights the potential of CP Ti-WC composites, which exhibit improved mechanical performances and corrosion resistances for use in demanding applications, with insights into microstructural control and property enhancement.

Tribological Properties and Microstructures of Tungsten Carbide and Few-Layer Graphene-Reinforced Aluminum-Based Composites

Tribological Properties and Microstructures of Tungsten Carbide and Few-Layer Graphene-Reinforced Aluminum-Based Composites

An improvement in aluminium composites interface strength and microhardness through electroless cobalt coatings on tungsten carbide

Aluminium tungsten carbide (Al-WC) composites are extensively employed in defence and automotive industries, have been given an attempt to increase their interfacial strength. The improvement of interfacial strength is investigated by powder metallurgy process. It was calculated that the electroless cobalt coated WC reinforcement's ultimate breaking load had risen by 45% compared to uncoated reinforcement. The presence of cobalt in the aluminium matrix was confirmed by powder XRD and SEM examinations. Thus, the produced composites can be employed for heavy machinery as an alternative to monolithic alloys because of improved interfacial strength and micro hardness.

Experimental investigation on fabrication, characterization and properties of spark plasma sintered alumina-based tungsten carbide composites reinforced by carbon nanotubes

In this study, the alumina-based tungsten carbide (WC-Al2O3) composites reinforced by different weight percentages of carbon nanotubes were successfully prepared by the advanced spark plasma sintering technique. This study has the novelty that such composites with the given compositions were never sintered before using spark plasma sintering. The WC-Al2O3-CNTs composites were fabricated to design advanced tool materials with an optimum set of mechanical and thermal properties for high-temperature cutting applications. The experimental results revealed considerable growth in micro-hardness and fracture toughness in WC-Al2O3-CNTs composites as compared to WC-Al2O3 composites. The ideal set of mechanical properties was acquired by WC-Al2O3-CNTs-0.5 composite which also exhibited a minimum value of grain size. At higher concentrations of carbon nanotubes, the mechanical properties of composites tend to degrade due to the agglomeration of carbon nanotubes. The study presented better results in sintered composites than the composites fabricated through other sintering techniques. The improved strengthening and toughening results of WC-Al2O3-CNTs composites along with the fine microstructures were mainly acquired by inhibiting grain growth during sintering, improved dispersion of the constituents in the composites (electron probe microscopy analysis/wavelength dispersive spectroscopy mapping) and consolidation at shorter sintering periods in spark plasma sintering. A thermal study was also conducted to discuss the thermal stability of sintered composites at ambient as well as at higher temperatures to estimate the behavior of thermal conductivity and thermal diffusivity of composites at different temperatures.

Hydrothermal synthesis of ZnCr-LDH/Tungsten carbide composite: A disposable electrochemical strip for mesalazine analysis

The development of novel electrocatalyst materials with excellent characteristics is inevitably needed to satisfy the practical application of electrochemical sensors. In this study, the 2D ZnCr layered double hydroxide (LDH)/tungsten carbide (WC) composite was prepared by the hydrothermal method and investigated as the electrochemical electrode material for mesalazine (MSZ) detection. The ZnCr-LDH/WC modified electrode has superior electrocatalytic activity towards the MSZ detection compared to the reported modified and unmodified electrodes. The combination of ZnCr-LDH and WC constitutes a 2D/2D composite, which exhibits high electrical conductivity, a large specific surface area, and rapid electron transfer, thus guaranteeing efficient electrocatalytic performance. The ZnCr-LDH/WC modified electrode exhibits a wide working range (0.03–254 µM), low limit of detection (6.0 nM), high sensitivity (4.085 μA μM−1 cm−2), excellent selectivity, and good reproducibility towards the detection of MSZ. The fabricated electrochemical sensor has been successfully applied to determine the contents of MSZ in human-urine and river-water samples. The presented strategy will pave the way for developing 2D/2D composite for electrochemical applications.

In Situ Tungsten Carbide Formation in Nanostructured Copper Matrix Composite Using Mechanical Alloying and Sintering.

In this study, an in situ nanostructured copper tungsten carbide composite was synthesized by mechanical alloying (MA) and the powder metallurgy route. The microstructure and phase changes of the composite were characterized by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. Tungsten carbide phases (WC and W2C) were only present after MA and combination of sintering. Higher energy associated with a longer milling time was beneficial for the formation of WC. Formation of W2C and WC resulted from internal refinement due to heavy plastic deformation in the composite. The solubility of the phases in the as-milled and sintered composite was described by the changes of the lattice parameter of Cu. Chemical analysis of the surface of a composite of W 4f and C 1s revealed that the increased defects introduced by MA affect the atomic binding of the W-C interaction.

Spark Plasma Sintering of Electric Discharge Machinable 1.5Yb-1.5Sm-TZP-WC Composites

Electrically conductive zirconia tungsten carbide composites are attractive materials for manufacturing precision components by electrical discharge machining due to their high strength, toughness and electrical conductivity. In this study, nanocomposite ceramics with a ytterbia samaria co-stabilized zirconia 1.5Yb-1.5Sm-TZP matrix and 24–32 vol.% tungsten carbide dispersion were manufactured by spark plasma sintering (SPS) at 1400 °C for 15 min at 60 MPa pressure. The materials exhibited high strengths of 1300–1600 MPa, a moderate fracture resistance of 6 MPa√m and an ultrafine microstructure with grain sizes in the 150 nm range. Scanning electron microscopy and RAMAN spectroscopy revealed the in situ formation of carbon during the SPS process and carbon formation scales with tungsten carbide content, and this apparently impedes bending strength.

A review of fabrication and properties of spark plasma sintered tungsten carbide based advanced composites

The high-performance tool materials have been inevitably used for most of the cutting tool applications where high reliability and difficult to cut materials are of major demand. The cemented carbides and its composites offer an excellent combination of the properties where it can be used for tool materials due to its high wear resistance, high hardness at elevated temperatures, and considerable fracture toughness. However to obtain optimum values of mechanical properties and uniformly distributed ultrafine grains, a number of new fabrication techniques, alteration in the content of cemented carbide composition, and variation in the parameters of fabrication process have been employed. This review paper will come in handy for researchers and scientists working on advanced cemented carbides and spark plasma sintering as it overviews the recent work done on tungsten carbide composites using the novel spark plasma sintering technique considering different process parameters in order to achieve ultrafine microstructures of sintered specimens, enhanced mechanical properties of composites in addition to energy as well as time saving considerations. The thorough review of various research papers revealed that the parameters of the sintering (sintering temperature, applied pressure, surrounding environment), additives in sintering (both content and composition), reinforcement of cemented carbide with other materials, nano-filler/whisker addition, partial or complete removal of metallic phase from the cemented carbide affect the properties of sintered specimens and their calculated as well as optimum setting can provide an excellent combination of properties desired in cutting tool operations.

Investigation on the Microstructure and Mechanical Properties of Aluminum 7075 Reinforced With Different Weight Percentage of Tungsten Carbide and Cobalt Metal Matrix Hybrid Composites

In this paper an effort has made to develop and characterize Al7075 alloy reinforced with Tungsten carbide (WC) & Cobalt (Co). For uniform grain size and homogeneity of the reinforcements with matrix, Cermets (WC-Co) of grain size 50 microns were prepared with the help of ball milling operation. An experiment was conducted to evaluate the microstructure; mechanical properties like hardness test & tensile test as per the standards for different weight percentages of Cermets like 3, 6 and 9wt. %. Micrographs were studied to know the micro structure of the composite material and the result showed the, randomly dispersed reinforcement particles & fine interdendritic precipitates were seen. A comparative study was conducted for the microstructure and mechanical properties by using Cermets with varied weight percentages reinforced with Al7075 matrix. Mechanical properties results reveal that there is a considerable improvement in tensile strength and hardness as the percentage of Cermet increased from 3 to 9wt. %.

Advanced superhard composite materials with extremely improved mechanical strength by interfacial segregation of dilute dopants

Control of heterointerfaces in advanced composite materials is of scientific and industrial importance, because their interfacial structures and properties often determine overall performance and reliability of the materials. Here distinct improvement of mechanical properties of alumina-matrix tungsten-carbide composites, which is expected for cutting-tool application for aerospace industries, is achieved via interfacial atomic segregation. It is found that only a small amount of Zr addition is unexpectedly effective to significantly increase their mechanical properties, and especially their bending strength reaches values far beyond those of conventional superhard composite materials. Atomic-resolution STEM observations show that doped Zr atoms are preferentially located only at interfaces between Al2O3 and WC grains, forming atomic segregation layers. DFT calculations indicate favorable thermodynamic stability of the interfacial Zr segregation due to structural transition at the interface. Moreover, theoretical works of separation demonstrate remarkable increase in interfacial strength through the interfacial structural transition, which strongly supports reinforcement of the interfaces by single-layer Zr segregation.

Effect of different tungsten compound reinforcements on the electromagnetic radiation shielding properties of neopentyl glycol polyester

In this study, isophtalic neopentyl glycol polyester (NPG-PES) based composites with different loading ratios of pure tungsten metal (W), tungsten (VI) oxide (WO3), tungsten boron (WB) and tungsten carbide (WC) composites were prepared as alternative shielding materials for ionizing electromagnetic radiation (IEMR) shielding. Structural characterizations of the composites were done. Gamma spectrometric analysis of composites for 80–2000 keV energy range was performed and their usability as IEMR shielding was discussed. As a result, the produced composites showed a shielding performance of 60–100% of the lead (the most widely used IEMR shielding material) depending on the reinforcement material, reinforcement loading rate and experimental conditions. Thus, it was reported that produced composites could be an alternative to lead shieldings that have several disadvantages as toxic properties, difficulty of processing and inelasticity.

Statistical analysis of mechanical properties of Al-SiC-WC and Al-SiC-Al2O3 hybrid composites

Abstract Metal Matrix Composites play a vital role in many engineering applications due to its multiple mechanical characterizations. Aluminium being light weight material and reinforcements of Aluminium with high strength materials like Tungsten Carbide and Alumina enhances its mechanical properties. This investigation deals with analysis of mechanical properties of Aluminium-Silicon Carbide–Alumina composites and Aluminium-Silicon Carbide–Tungsten Carbide composites. Aluminium is reinforced with Silicon Carbide powder and Alumina powder. Stir casting process is used for fabricating the samples with three different process parameters namely stirring speed, stirring time and stirring temperature. 12 samples are fabricated with 3 samples for each material composition. The material composition for Al-SiC-Al2O3 composites with Aluminium are 3% of the SiC by weight and 3%, 4% of Aluminium oxide by weight and the proportions for Al-SiC-WC Composites are 3% of SiC by weight and 3%, 4%of Tungsten Carbide by weight. The mechanical properties for all the samples were investigated with tensile test, impact test and hardness test. Statistical Analysis using ANOVA were analyzed to find the significant variations in the properties of the material and found that Aluminium with 3% Silicon Carbide and 4% Tungsten Carbide by weight had least variations with high strength.

Friction and sliding wear studies on functionally graded Al LM25/WC composite

Functionally graded LM25/15 wt.% Tungsten carbide composite of dimension Øout 150 mm x Øin 110 mm x 100 mm and thickness 20 mm was studied to understand the influence of process parameters (applied load, sliding velocity, sliding distance) on the dry sliding wear rate and co-efficient of friction. A 5-level 3 parameter central composite design was developed using response surface methodology considering applied load (10-50N), sliding velocity (1-3 m/s) and sliding distance (500-2500 m) as input parameters. Dry sliding experiments were performed on pin-on-disk tribometer at ambient conditions. Significance tests, Analysis of Variance and confirmation experiments were done to check the accuracy of generated regression model. Generated surface plots revealed wear rate to be increasing as applied load and sliding distance increases and decrease as sliding velocity increases. Worn surface analysis performed revealed formation of deep grooves at high load, MML formation at high velocities and heavy delamination and particle pull-out at high sliding distances.

Fabrication of tungsten carbide–diamond composites using SiC-coated diamond

Tungsten carbide (WC) and SiC-coated diamond composites were prepared by spark plasma sintering at 1473–1873 K for 300 s under 130 MPa under vacuum. The diamond particle surface was coated with silicon carbide (SiC) via rotary chemical vapor deposition to improve the interfacial bonding of the WC–diamond composites. The relative density of the WC–20 vol% diamond (SiC) composite increased from 61% to 94% with increasing sintering temperature. Raman spectroscopic analysis showed that the diamond-to-graphite transition did not occur at any of the investigated sintering temperatures. The WC–20 vol% diamond composite sintered at 1773–1873 K exhibited high hardness (30.5 GPa) and fracture toughness (12.3 MPa m1/2). The high hardness resulted from the SiC coating functioning as an interlayer to improve the bonding between the diamond and WC body. The improvement in fracture toughness was attributed to the presence of diamond, which effectively blocks crack propagation and promotes crack deflection.

Characterization of the residual stresses introduced by a new joining method in diamond and tungsten carbide composites

In this work, a co-sintering method was used to attach diamond to cemented carbide composites. The joining method consists of sintering a green part (ring) of cemented carbide (CC) around a thermally stable diamond composite (TSDC) part (plug) to radially contain it. During the sintering step, the green body shrinks to a controlled level and therefore forms interference fit between the two parts (mismatch between the inner diameter (ID) of the CC ring and the outer diameter (OD) of the TSDC cylinder). The residual stresses induced by this process as well as the bond strength between the CC and the TSDC parts were quantitatively evaluated. It is shown that the interface pressure between the two parts, and the level of residual stresses, increased with increase in the designed interference fit, as well as with the increase of the ID/OD ratios of the CC ring.For the chosen material combination (cemented carbide ring comprised 90 vol% WC and 10 vol% Co with medium coarse WC grains; diamond composite plug comprised 84 vol% diamond and 16 vol% SiC), the values of the hoop stresses at the interface in the CC ring measured by neutron diffraction was determined to be between 150 MPa and 550 MPa, depending on the ID/OD ratio. It was also found that for a given ID/OD ratio, the increase of the designed interference fit had little effect on that attained due to the plastic deformation of the cemented carbide material at the interface during the sintering (dynamic) process. A mechanical bond around 60 MPa was nevertheless achieved.

Fracture energy based approach for cemented carbides grain debonding

Cemented carbide materials exhibit high hardness and fracture toughness. As a consequence they possess an excellent wear resistance that make them a material of choice for the manufacturing of cutting, drilling and forming tools. Cemented carbide materials are made of tungsten carbide (WC) grains embedded in a ductile metal phase, generally made of cobalt. The wear mechanism of the tungsten carbide and cobalt composites (WCCo) operates in several successive steps: removal of the cobalt binder in the surface vicinity, plastic deformation and/or fracture of WC grains, debonding of WC grains and finally galling of workpiece material in the cavities freed of the WC grains. The present study focuses on the debonding step of the WCCo wear mechanism.A micromechanical finite element is developed to study de sensitivity of a WC grain to be torn off the surface of a WCCo composite structure. The model considers a single WC grain embedded in a homogeneous elementary volume of WCCo material. The geometry of the WC grain is a rectangle which perimeter, width and length are based on statistical analyses of actual WCCo die surfaces used in cold forming. Cohesive elements are used to model the junction between the grain and the elementary volume. The grain is torn off the surface when the fracture energy calculated within the cohesive element is totally consumed. The loadings applied on the grain are based on actual cold heading forming sequences. Various grain size, shape, orientation and friction conditions are tested. Results show that grain orientation, friction and WCCo material toughness play a great role in WC grain removal. Equiaxed grains with small perimeter are less sensitive to debonding.

Effect of Tungsten Carbide Reinforcement on the Aluminum 6061 Alloy

Abstract Aluminum matrix composites are often preferred in automotive, aerospace, and ship building owing to their enhanced properties over conventional engineering aluminum alloys. In this article, the results of the investigations on the mechanical properties and sliding wear behavior of aluminum–tungsten carbide (WC) composites are presented and discussed. Metal matrix composites of Al6061 containing different percentages of WC were prepared by powder metallurgy techniques. All testing was conducted according to ASTM standards. The dry sliding wear tests were conducted at a constant velocity and load varying from 10 to 40 N. The composite density was found to increase with greater filler contents and is further in agreement with the values of theoretical density. The Brinell hardness and ultimate tensile strength of the composites increased with a greater ceramic phase and decreased filler size, with a decrease of percentage elongation. The dry sliding wear of the composites with WC reinforcement displayed the greater resistance to wear.

Effects of HfC Particles on Crack Initiation and Propagation Behavior of WC/Co Composites

Tungsten carbide composites were prepared by cold-pressing and hot-pressing sintering; fracture toughness and bending strength of the specimens were tested. The microstructures of HfC/WC/Co composites were observed with the SEM. The mathematical models were established to investigate the relationship between stress intensity factors of crack straight-through, crack deflection, and crack bifurcation with crack length, based on the crack propagation energy release rate. The simulation software ABAQUS was used to verify the four crack propagation methods of crack straight-through, crack deflection, crack bifurcation and crack pinning. The simulation results show that adding appropriate amount of HfC can effectively improve the fracture toughness and bending strength of the composites. The homogeneous distribution of HfC and Co in the matrix has a significant effect on the improvement of the strength and toughness of the composites, and the improvement mechanism is to disperse or transfer the stress at the crack tip to HfC by crack deflection, crack bifurcation, crack pinning, transcrystalline fracture, etc. As a result, the stress concentration at the crack tip in the matrix is reduced, and the toughness of the composites is improved.