The wear performance of the plasma transferred arc (PTA) welding hard-facing materials manufactured reinforced by cast WC/W2C and coarse grain WC with different shapes are investigated. Coarse grain ...WC-Ni coating shows the best wear resistance in a high applied load condition, with spherical reinforced particles give higher wear performance than angular shape. WC, W2C, γ-Ni, M23C6, and M7C3 (M = Cr, Fe, W, and Ni) are detected in PTA coatings. The spherical cast and angular cast WC/W2C particles contain a higher volume of W2C, which is easier to be dissolved during the PTA welding process, resulting in lower retained reinforced particle volume and more precipitates concentration. In the PTA coating, the cast WC/W2C particles have a higher hardness, whereas the matrix has a relatively low hardness. The wear performance of PTA coating is more affected by the hardness rather than the coefficient of friction (COF). At a load of 5 N applied on the Si3N4 ball, the contact area between reinforced particles and counterparts, resulting in wear resistance is controlled by the hardness of the reinforced particles. When the load increases to 10 N, the hardness of the matrix controls wear performance. The precipitates formed between the carbides and matrix smooth the interface and strengthen the bonding, which prevents the cast WC/W2C from being pulled out from the matrix during the wear test.
•The microstructure of PTA coating reinforced by cast WC/W2C and WC is studied.•The reinforced particle decomposition is controlled by its geometry and W2C.•The hardness of coating or reinforced particles control the wear performance.•The wear performance of hard-facing materials has no direct relationship to COF.•Precipitates between WC/W2C and matrix retard the particles from pulling out.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Machining is the process of cutting or removing materials from a work item with a cutting tool to get the desired form. CNC is widely used because of its compact size which enables more number of ...productions in all type of automotive industries. Many intricate parts required by various industries are created using computer numerical control (CNC) machining. While mass production is useful in some cases, which require selective parts in most industries. Businesses require CNC for their manufacturing process, which enables them for précised jobs with help of this CNC machine software. CNC lathes can make precise cuts quickly with a variety of tools. Hence, the major objective of this work is to extend the life and quality of the cutting tool by improving its hardness and wear resistance by using DC Magnetron Sputtering to coat a 1 μm thin film layer of Tungsten carbide on High speed steel insert. This insert is to be characterized for chemical composition, micro structured, grain distribution and hardness of its surface etc.
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In this paper gradient based topology optimization (TO) is used to discover 3-D phononic structures that exhibit ultra-wide normalized all-angle all-mode band gaps. The challenging computational task ...of repeated 3-D phononic band-structure evaluations is accomplished by a combination of a fast mixed variational eigenvalue solver and distributed Graphic Processing Unit (GPU) parallel computations. The TO algorithm utilizes the material distribution-based approach and a gradient-based optimizer. The design sensitivity for the mixed variational eigenvalue problem is derived using the adjoint method and is implemented through highly efficient vectorization techniques. We present optimized results for two-material simple cubic (SC), body centered cubic (BCC), and face centered cubic (FCC) crystal structures and show that in each of these cases different initial designs converge to single inclusion network topologies within their corresponding primitive cells. The optimized results show that large phononic stop bands for bulk wave propagation can be achieved at lower than close packed spherical configurations leading to lighter unit cells. For tungsten carbide - epoxy crystals we identify all angle all mode normalized stop bands exceeding 100%, which is larger than what is possible with only spherical inclusions.
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Dynamic hardness of cemented tungsten carbides Hanner, Luke A.; Pittari, John J.; Swab, Jeffrey J.
International journal of refractory metals & hard materials,
September 2018, 2018-09-00, 20180901, 2018-09-01, Volume:
75, Issue:
C
Journal Article
Peer reviewed
Open access
Cemented tungsten carbides are composed of a hard tungsten carbide (WC) phase held together by a soft, ductile binder phase, typically cobalt (Co). This study examines the role of the binder ...composition and content on the Knoop hardness at quasi-static and dynamic strain rates. Seven different tungsten carbide materials were tested: four WC-Co systems containing 10%, 15%, 20% and 25% cobalt, two with a chromium‑nickel alloy binder phase, and one “binderless” tungsten carbide. Quasi-static Knoop hardness testing was performed at strain rates of 10−3 s−1 and at indentation loads between 300 and 30,000 g using a Wilson Tukon 2100 unit. Dynamic Knoop hardness testing was conducted at strain rates of 103 s−1 using a Dynamic Indentation Hardness Tester over a range of indentation loads. All of the materials exhibited a rate-dependent Knoop hardness, with the hardness increasing by up to 60% with increasing strain rate.
•Seven cemented carbide materials were evaluated for indentation hardness under quasi-static and dynamic testing conditions.•Dynamic hardness was measured at strain rates of ~ 103 s−1 with an apparatus based on Kolsky pressure bar principles.•All of the tungsten carbide materials exhibited a rate-dependent Knoop hardness value.•The change in Knoop hardness from quasi-static to dynamic was observed to grow with an increasing amount of binder phase.
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A tungsten carbide ceramic containing 5 vol% silicon carbide was hot pressed to full density at 1820 °C. A small amount of transient liquid phase based on W-C-Si-O facilitated oxide ...removal in the reducing environment and favoured the development of a bimodal microstructure containing sub-micrometric grains with square or rod-like morphologies. These microstructural features led to outstanding mechanical properties from room to elevated temperatures. For the first time, WC-materials were characterized up to 1500 °C exhibiting flexural strength over 1 GPa in the whole temperature range and fracture toughness from 7 to 15 MPa⋅√m.
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Composite coating of metallic-ceramics tungsten carbide (WC) in nickel matrix has been achieved by direct current (DC) electrodeposition using watt's bath solution on stainless steel substrate. The ...deposition parameters such as current density, bath temperature, and stirring rate were maintained at constant levels for all the coating configurations. The surface morphologies, microstructure, and chemical composition of the composite coating were studied using scanning electron microscope (SEM), X-ray diffraction (XRD), and energy dispersive analyzer x-ray system (EDX), respectively. The surface morphology and microstructure analysis showed that the composite coatings form cauliflower-like grain colonies, grain size was calculated from Scherrer equation it was less than 60 nm for all composite coating. Micro hardness of composite coating was increased by increasing WC load in solution and decreasing grain size. The electrochemical corrosion behavior of composite coating was evaluated by potentiodynamic polarization measurements and electrochemical impedance spectroscopy (EIS) in aerated 0.5 mol/l H2SO4 at room temperature, showing passivation behavior of all composite coating, good protection of Ni-8g/l WC on stainless steel substrate.
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•Ni-WC and Ni-Co-WC were deposited by simple and economic electrodeposition method.•Addition of metallic ceramics tungsten carbide enhances surface morphology.•Hardness of coating increase by addition WC and increase dramatically by adding Co.•Ni-WC creates corrosion passivation behavior.•The coating layer is stable after corrosion tests.
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This research aimed to develop lead-free polymer composites based on poly-methyl methacrylate (PMMA) and embedded with tungsten carbide (WC) micro and nanoparticles for use in radiation protection ...applications. PMMA was filled with 20 %, 40 %, and 60 % by weight of WC micro- and nanoparticles. The shielding features of the proposed polymer mixtures were evaluated at different radioactive sources of different energies using the HPGe detector. The results revealed that the investigated composites containing micro and nano-structured WC particles showed superior radiation shielding at 81 keV due to the K-edge of the W element occurring at 69.5 keV. The findings also demonstrated that composites loaded with WC nanoparticles were more effective in shielding gamma radiation than those loaded with WC microparticles, even at the same filler wt.%. Furthermore, the sample containing 60 % by weight of nano-WC, coded as P-60nWC, had superior shielding performance than other polymer-based composites reported in the literature. Thus, the proposed nano-WC/PMMA composites can be effectively employed in radiation facilities as alternative environmentally and lead-free radiation shielding materials to protect people and the environment from the harmful risks of gamma radiation.
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The impact of the addition of tungsten carbide (1 to 7 wt%) on the microstructure and wear characteristics of the nickel–tungsten carbide composite layer fabricated by the plasma transferred arc ...(PTA) process was studied. With the addition of nanoparticles, the degree of segregation becomes lower while heterogeneous nucleation increases and refining of the microstructure enhances. Wear rate and coefficient of friction for all samples with increasing the load from 1 to 5 N decrease and wear mechanism changes from abrasive to adhesive. The higher wear resistance for samples with 3%wt is due to a decrease in the porosity of the composite coatings, strong interfacial bonding, and promotion in the deposition efficiency at the same time.
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