Ductile-brittle transition temperature (DBTT) is a critical property of tungsten (W) materials for their application in a fusion reactor. The mechanism of ductile-brittle transition (DBT) has been the focus of debate in past decades. In this work, four-point bending test (4PBT) was performed to explore the controlling factors in different directions relative to the rolling direction. Opposite DBTT

Ultrafine WC-VC/Cr3C2 composite powders with uniform distribution of V/Cr were synthetized by a novel method composed of carbothermic reduction of the mixture of WO3 and V2O5/Cr2O3 at 1050 °C and the following carburization process at 1300 °C under hydrogen atmosphere. The effects of addition amount of VC or Cr3C2 on the phase constitution, particle size and micromorphology of WC-VC/Cr3C2 composite

Molybdenum (Mo) and its alloys are one of the refractory material groups of interest for additive manufacturing (AM), as they meet the requirements for some applications in aerospace and medical industries. The present research and development work aims to develop the proper parameter sets for pure Mo and its alloys, such as Mo-47.5Re wt% and characterize their microstructure and mechanical properties

Cavitation erosion is a common mode of wear in flow control and fluid handling systems. To mitigate this degradation mode, CoCr superalloys or facing coatings are commonly used for flow control or pump parts. Cemented carbides, however, generally present wear resistance superior to that of those materials due to the favourable combination of their mechanical properties. In this study, the cavitation

Mo-12Si-8.5B alloy with layered Mo2TiAlC2 (a new MAX phase) additions, in order to improve its fracture toughness, were prepared by hot pressing. The composition analysis combined with microstructure features revealed that after hot pressing sintering, the Mo2TiAlC2 does not decompose but still maintains the layered structure and exhibits a good interface bonding with the matrix. The grain size of

Alumina with different amounts of Cubic boron nitride (cBN) was synthesized by a high-pressure sintering method. By adjusting the sintering temperature to a relatively low level, the undesirable reverse transformation from cBN to hBN was avoided, and almost entirely dense composites were obtained. The sintering behaviors, phase compositions, microstructures, and mechanical properties of Al2O3-cBN composites

Ultrahard WB4-B and WB4-TaB2 based materials have been obtained by applying glass encapsulated HIPing to mixtures comprised of WB4 and free boron with and without metallic tantalum additions. Porosity removal is more efficient in the alloy containing metallic tantalum, achieving near full density at temperatures 300 °C lower than those reported so far for these materials. The WB4 phase is better stabilished

HfTa based alloys have recently been investigated as potential candidates for high-temperature structural applications. While most attentions have been given to the properties above ~1200 °C where the alloys are mainly single-phase BCC structures and have excellent oxidation performance due to formation of super-oxides, structural properties at lower temperatures are equally important for applications

Cemented carbide materials develop very large micro-stresses due to the coefficient of thermal expansion (CTE) mismatch between the metallic carbide phase and the binder phase. While micro-stresses developed in WC-Co cemented carbides have been investigated, there is very little to no information on the micro-stresses developed in NbC-Ni materials. In this study the thermal stresses developed in NbC-Ni

A TiO2-Nb2O5-SiO2-Al2O3/NbSi2/NbAl3 multilayer coating was prepared on Nb alloys through halide activated pack cementation (HAPC) and micro-arc oxidation (MAO). The multilayer coatings were composed of a TiO2-Nb2O5-SiO2-Al2O3 outer layer, a NbSi2 middle layer and an Al-rich inner layer. The isothermal oxidation resistance of TiO2-Nb2O5-SiO2-Al2O3/NbSi2/NbAl3 multilayer coated Nb alloy was investigated

This article is to devoted to investigate the effect of graphene oxide (GO) on the mechanical and tribological properties on WC-Co cemented carbide. Based on the microstructure and morphology of wear surface, it is found that the addition of GO has little effect on the densification process and the grain size of cemented carbide, thus hardly weakening the hardness, while the fracture toughness has

The paper presents the characteristics of Ti-Mo-xTiC composites manufactured under experimentally selected conditions using the upgraded field-assisted sintering technique (U-FAST). Mixtures of microstructural titanium powders and nc-Ti0.9Mo0.1C/C carbide powders protected from oxidation by a carbon shell were subjected to sintering. The powders with nc-Ti0.9Mo0.1C/C contents of 10 and 20 wt% were

Nanocrystalline cemented carbide is expected to become an ideal material for high-performance alloy tools due to its high strength, hardness, toughness, and wear resistance. In this work, nanocrystalline cemented carbides prepared at different sintering temperatures through different cooling methods were investigated with Cr3C2 and VC as grain growth inhibitors. The effects of sintering temperature

Scandium‑tungsten (ScW) cathodes have garnered a lot of research attention due to their high emission current density. Herein, the cathode working environment is simulated by heating in a vacuum chamber, and scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) are used to study the surface morphology and chemical oxidation states in the temperature range of 25 °C to 1300 °C

Laser powder bed fusion (L-PBF) offers significant potentialities for the design of complex part geometries. Due to the specific combination of properties, tungsten heavy alloys are used for special applications such as X-ray and γ-radiation shielding, balancing weights, collimators and molds. For optimum performance, complex geometries can be required in those applications. L-PBF of tungsten heavy

Ultra-high temperature Nb alloys are prospective for practical applications as aircraft materials. Sufficient efforts must be made to improve their manufacturing technologies and properties. The Nb-Ti-Al alloys with TiC addition were fabricated by laser solid forming (LSF) in this work. LSFed Nb-Ti-Al-TiC alloys which were composed of Nbss and (Nb,Ti)C had excellent formability and metallurgical quality

Binder jetting 3D printing (BJ3DP) is an emerging technology that can enable the production of tungsten heavy alloy (WHA) parts of great geometric complexity. Despite its promise, the industrial use of BJ3DP is today hindered by two shortcomings: (i) Printed parts have low strength in the as-cured state, and (ii) the mechanical properties of the sintered parts are poor when sintered using standard

In this study, a small-dimensional layered composites of WC-Co-Ni and stainless steel (SS 304) were obtained by self-made mold, in which the cermet was used in powder form and the steel as solid with a diameter of 1 mm. The effects of holding time (60–120 min) on the microstructure, bonding interface, element diffusion, microhardness and wear of WC-Co-Ni/stainless steel composite were examined under

Fluidic oscillator made of tungsten carbide, the core component of the fluidic hammer, has a significantly reduced service life under the erosion wear of drilling fluids with solid particles. Polycrystalline diamond composite (PDC) has the potential to solve this issue due to its extremely high hardness and wear resistance benefits. However, few studies on the slurry erosion wear of PDC have been reported

This study determined the possibility of reducing sintering temperature by designing a new tungsten heavy alloy (WHA). For this purpose, 90 W-(10-X)Ni-XSb alloys with different Sb (X = 2.4, 3.2, and 4) were sintered at 1100, 1200, 1300, and 1400 °C for 60 min. SEM equipped with energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD)analysis was used to evaluate the microstructure and

The effect of VC addition on microstructure, mechanical properties and high-temperature oxidation behavior of the TiC steel-bonded carbides, fabricated by two-step sintering, were examined by SEM, EDS, and XRD. The results show that an appropriate amount of VC enables the TiC steel-bonded carbide to further refine the hard phase particles while maintaining high density. When the VC addition amount

The use of fracture mechanics for rationalizing the fracture behavior of cemented carbides is valid, as far as sharp cracks, free of residual stresses and subjected to a well-defined stress state are used for assessing fracture toughness. However, machining a very sharp notch on the surface of hardmetals for fracture toughness testing has been a critical issue during many years. Within this context

A dense and uniform W-15Cu composite material was successfully prepared by adding different amounts of silver as the active agent followed by direct sintering and infiltration. The effects of silver additive content on the microstructure and properties of W-15Cu composites under the prefabricated tungsten skeleton re-osmosis copper process and direct sintering infiltration were studied by scanning

Rotary-percussive drilling through steel reinforced concrete not only subjects cemented tungsten carbide drill bits to intensive abrasive wear but additionally induces significant microstructural changes in the near-surface regions. These include micro-, meso- and macroscopic cracking; comminution of the WC; delamination of WC-binder interfaces; binder depletion and pore formation; partial WC dissolution

Molybdenum alloys are important structural components for a variety of high temperature applications in the aerospace and nuclear industries. Spark plasma sintering has been successful in producing highly dense refractory metals with desirable microstructural characteristics, where the final microstructure and sintering mechanisms depend heavily on the starting powder size and morphology. To understand

The W-0.25 wt%Al2O3 alloy was fabricated by a powder metallurgy processing route, including hydrogen reduction, induction sintering and hot swaging. Al2O3 particles are absorbed on the surface of W particles with size ranging from 50 to 1000 nm. The microstructure of sintered alloy presents equiaxed grains with an average size of 8.6 μm and TEM result shows that a semi-coherent relationship exists

Chemical short-range order (CSRO) plays an important role in the mechanical properties of high-entropy alloys (HEAs). However, the research on the effect of CSRO on the mechanical properties of HEAs only focuses on the single-phase systems, which limits the control of mechanical properties for more HEAs by adjusting CSRO. In this work, the different effects of CSRO on the strength and ductility of

For further clarify the correlation mechanism between the high temperature oxidation and tribological properties of cemented carbide, two groups of test samples of YT15 cemented carbide were prepared and heated to 500 °C ~ 900 °C, then cooled to room temperature in air and cutting fluid medium respectively. The surface morphology, oxidation characteristics, hardness, wettability, and tribological property

In this work, ultrafine-grained Wf/WCu composites have been developed in this work using skeleton pre-sintering at respective 1050 °C, 1150 °C, 1250 °C and 1350 °C followed by infiltration under a reductive hydrogen atmosphere. The resulted microstructure including sinterability, grain orientation distribution and phase constituents, the resulted mechanical properties including microhardness and compressive

The ambient pressure is increasing with depth of ocean, however there are few studies about the effect of the pressure on the tribocorrosion behavior. Thus, the influence of hydrostatic pressure on the tribocorrosion behavior of the HVOF WC-10Co-4Cr coating sliding against Si3N4 was studied. Hydrostatic pressures were 0, 20, 40, 60, and 80 MPa, respectively. Experimental results indicate that the hydrostatic

The ultrasonic irradiation is successfully introduced into Nb-Si-Mo melt. The coarse silicide has been refined significantly. Ultrasonic irradiation can increase the solid solubility of Si in Nbss phase. The vibration attenuates during propagation in transition region, leading to the silicide with specific shape in linear arrangement. The wavelength and introducing efficiency of the standing wave are

B4C-SiC composites can be used in many areas due to their superior properties. However, in order to be used as a body armor material in areas requiring high performance, their fracture toughness needs a degree of improvement. In this study, 0–20 wt% TiB2 was added to B4C-SiC samples that were consolidated at 1950 °C by spark plasma sintering method. The contribution of TiB2 to the microstructure, elastic

In high-speed metal machining, cutting tools in the form of cemented carbide inserts coated with thin wear-resistant coatings are commonly used. These coatings are often made of metal carbonitrides with cubic rock salt crystal structure and different growth textures. However, the influence of the crystallographic texture of the coatings on their wear by plastic deformation due to the chip flow during

To solve critical issues of premature failure for copper tungsten (CuW) based electrical contacts during arc erosion at the moment of arc breakdown, we proposed a new strategy of using metal doped reduced graphene oxides (rGOs) and in-situ formed tungsten carbides to inhibit movements of cathode spots during the arc ablation process. CuW composites were reinforced with Cu modified rGO nanopowders (i

Four NbSi based ultrahigh temperature alloys with compositions of Nb-16Si-20Ti-1ZrC-xZrB2 (x = 0, 0.5, 1, 3) (at.%) were prepared by vacuum non-consumable arc melting. The microstructure evolution, fracture toughness, and fracture behavior of four alloys were investigated. Results showed that four alloys consisted of Nbss, γ-(Nb,X)5Si3, and (Nb,X)3Si phases. The low content of ZrB2 facilitates the

Defects such as abnormal grain growth and cracking are easy to occur in the process of loose tooling forging of large-size molybdenum rods prepared by powder metallurgy. In this work, the forging process of molybdenum rods was simulated, which were heated to 1350 °C, and one end of them was subjected to loose tooling forging with deformation of 20%, 30% and 40%, and then they were subjected to secondary

In present study, the feasibility of wire-based additive manufacturing of commercially pure tungsten using electron beam technique could be demonstrated. Three different representative volumetric AM structures were built and subsequently characterized. The parts show a sound visual appearance with the absence of macroscopic cracks or severe distortion. The fabricated parts exhibit high density and

Using the traditional preparation method of TiC+TiN powder mixture or simply the Ti(C, N) solid-solution powder to prepare cermet cannot properly avoid the direct contact between TiC, TiN or Ti(C, N) phase and (CoNi) binder phase with undesirable wettability, which is disadvantageous to the strength and toughness of cermet. Here, we introduced a new routine using the (Ti, W)(C, N) solid-solution powder

The features of the synthesis of a composite coating based on η-carbide (Fe,W)6C and tungsten applied to an iron substrate have been studied. Coatings are produced by high-speed selective laser sintering of WFe powders mechanically alloyed in a liquid hydrocarbon. The phase composition of the coating starts its formation from the nucleation and growth of (Fe,W)6C carbide inclusions of up to 400 nm

Two-phase fully dense high entropy carbide (HEC) cermets were successfully prepared following the conventional cemented carbide/cermet processing route. Cold isostatically pressed equimolar TiC, VC, NbC, TaC and WC powder mixtures with 12 vol% Ni binder were pressureless sintered in the solid state and liquid phase sintering regimes respectively. A homogeneous rock-salt (space group Fm3¯m) HEC phase

In the four temperature ranges of 1300–1600 °C, the diffusion bonding of oxide dispersion enhanced tungsten (ODS-W) and molybdenum hafnium carbon (MHC) alloy prepared by mechanical alloying method was successfully prepared by spark plasma sintering (SPS). In this work, the interface microstructure, mechanical properties and thermal shock resistance of ODS-W/MHC are studied. At above 1500 °C, the W

Although cemented carbides have been increasingly investigated for additive manufacture, cemented carbides with low melting point metal binders have rarely been explored. In this study, a cemented carbide with AlSi10Mg alloy binder was fabricated by selective laser melting (SLM). The processing parameters were optimized through response surface methodology (RSM). The microstructure and mechanical properties

The hardness–toughness trade-off relationship is an essential challenge when creating high-performance WC–Co hardmetals. In this work, by combining plasma milling and low-pressure sintering, a dual-scale plate-like WC–8Co hardmetal is fabricated. The hardmetal simultaneously exhibits ultra-high strength (1701 kgf/mm2) and fracture toughness (21.77 MPa*m1/2), with bimodal grain size distributions of

The recent advances in rock, coal, gas and oil drilling under continuously increasing loads and increased cutting speeds motivate the interest in and development of coarse and supercoarse sintered carbides. Complex drilling conditions are best simulated during in-service tests but their objectiveness and reliability are often problematic. Therefore, performance testing of real cutting tools in controlled

In this study, the WC-CoCr coating and Al2O3-TiO2 coating were deposited by high-velocity oxygen-fuel (HVOF) spraying and atmospheric plasma spraying (APS), respectively. Both coatings were immersed in 3.5 wt% NaCl solution with 20 ppm Na2S to investigate their long-term corrosion resistances in the simulated seawater environment. The corrosion behaviors of both coatings for different times were investigated

Direct melt infiltration does not produce sintered closed holes and considerably reduces the time required for preparation compared with pre-sintered WC skeleton followed by melt infiltration of Co. However, it may lead to alloy collapsing and deformation. In this study, WC and Co green parts were prepared via binder jet 3D printing. The two parts were stacked layer by layer then subjected to melt

Aiming to explore a sustainable process for tungsten extraction from wolframite concentrate, the digestion behavior and mechanism of wolframite in HCl solution at atmospheric pressure were firstly investigated in this work. The results showed that the digestion efficiency of wolframite reached 99.3% at the optimum condition: particle size of D(95) = 20 μm, stirring intensity of 250 r/min, reaction

This paper concerns the influence of increasing the milling time, which is performed by a high-energetic rotary-vibratory mill and WC-Co balls, on boron carbide sintering. The commercial boron carbide powder was characterised regarding the morphological, grain size and phase composition after 0–16 h of milling. The prepared green bodies were sintered using dilatometry to determine the WC contamination

The article developed new fatigue models based on unloading energy for molybdenum alloys. According to the relationship between unloading energy, strain amplitude and number of cycles in fatigue experiment of molybdenum alloys，a low cycle fatigue model is established, which has a simpler structure and certain universality, and a unified fatigue model based on unloading elastic strain energy density