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Soon Hyung Hong - One of the best experts on this subject based on the ideXlab platform.
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spark plasma sintering behavior of nanocrystalline wc 10co Cemented Carbide powders
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2003Co-Authors: Soon Hyung HongAbstract:Abstract Microstructure and mechanical properties of WC–10Co Cemented Carbides fabricated by spark plasma sintering (SPS) process were investigated. Nanocrystalline precursor powders were prepared by spray drying process from solution containing ammonia meta-tungstate and cobalt nitrate, and followed by reduction and carbonization into nanocrystalline WC/Co composite powders by a mechano-chemical process. The WC particles of about 100 nm in diameter were mixed homogeneously with Co binder. The nanocrystalline WC–10Co powders were consolidated by SPS process at temperature ranged 900–1100 °C and under a pressure of 50 or 100 MPa, respectively. Optimum consolidation conditions, such as temperature and pressure, were determined by analysing the dimensional changes of powder compact during SPS process. Hardness and fracture toughness of consolidated WC–10Co Cemented Carbide were measured by using a Vicker's indentation test. The solute content within the Co binder phase of WC–10Co Cemented Carbide was evaluated by measuring the saturated magnetic moment. It is found that the hardness of Cemented Carbide was dependent on the density and grain size of WC. The fracture toughness of Cemented Carbides increased with increasing the saturated magnetic moment, while decreased rapidly when the liquid Co phase was formed during sintering.
Sheng Wang - One of the best experts on this subject based on the ideXlab platform.
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oxidation of ultrafine Cemented Carbide prepared from nanocrystalline wc 10co composite powder
Ceramics International, 2008Co-Authors: Hua Yang, Gangqin Shao, Xinglong Duan, Sheng WangAbstract:Abstract The oxidation behavior and associated properties, phases and microstructure of ultrafine WC–10Co-Cemented Carbide using WC–10Co nanocomposite powder prepared by spray pyrolysis-continuous reduction and carbonization technology, were investigated in the 450–700 °C temperature range at 50 °C intervals. The results showed that the working temperature of the cutting edge should be lower than 550 °C in air without coolant in order to assure the lifespan and working efficiency of ultrafine WC–10Co-Cemented Carbide materials as cutting tools.
Juntang Yuan - One of the best experts on this subject based on the ideXlab platform.
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effect of co content on microstructure and mechanical properties of ultrafine grained wc co Cemented Carbide sintered by spark plasma sintering
Ceramics International, 2018Co-Authors: Zhenhua Wang, Juntang YuanAbstract:Abstract The WC-Co Cemented Carbides with 4 wt%~14 wt% Co content were fabricated by spark plasma sintering. The effect of Co content on microstructure and mechanical properties of WC-Co Cemented Carbide were analyzed. The results showed that the grain size of Cemented Carbide with different Co content was in 220–380 nm. As the Co content increased, the density, fracture toughness and flexural strength of Cemented Carbide increased, but the hardness gradually decreased. The hardness decreased by approximately 1.6 GPa with per 2 wt% increase of the Co content when the Co content was below 10 wt%. The optimal comprehensive mechanical properties was optimal when Co content was 8 wt%. The hardness, fracture toughness, and flexural strength were 19.87 GPa, 12.27 MPa m1/2 and 1834 MPa, respectively. The Cemented Carbide fabricated in this paper are more excellent compared to the commercial Cemented Carbides.
Sture Hogmark - One of the best experts on this subject based on the ideXlab platform.
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rock penetration into Cemented Carbide drill buttons during rock drilling
Wear, 2008Co-Authors: Ulrik Beste, Staffan Jacobson, Sture HogmarkAbstract:In percussive and rotary percussive rock drilling, the rock is crushed into small fragments by the repeated hard impact of the drill bit, and subsequently removed by flushing water or air. To avoid excessive wear, the steel drill bit is equipped with a set of Cemented Carbide buttons that protrude from the bit to take the actual impact. The severe contact against the rock results in some wear of the button, but also in formation of surface layers of rock material and penetration and impregnation of rock material into the Cemented Carbide structure. This situation, with serious implications for the wear and fracture of the buttons, have previously not been reported. The present findings represent a significantly new understanding of the wear of the rock button material. The deterioration mechanisms are described in detail, using examples from a range of real drilling applications in different rock types. During operation, material in the surface layer of the drill button shifts from that of the original Cemented Carbide into an uncontrolled composite. This composite is formed by the WC Carbide hard phase and a binder consisting of a mixture of cobalt and rock. This new material should be expected to exhibit properties significantly different from the original Cemented Carbide.
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Resistance of a binderless Cemented Carbide to abrasion and particle erosion
Tribology Letters, 1998Co-Authors: Håkan Engqvist, N. Axén, Sture HogmarkAbstract:A binderless Cemented Carbide has been evaluated in abrasion and erosion tests. The binderless Carbide was compared with: SiC, Al2O3 and two conventional Cemented Carbides with 6% Co and different WC grain sizes (1 and 7 μm). In the abrasion tests, the materials were ground with silica, silicon Carbide and diamond particles in the size range of 5–15 μm. The erosion tests were performed with 80, 200 and 600 μm silicon Carbide erodents. The angle of impingement was 45° and the erodent velocity 70 m/s. In all tests, the conventional Cemented Carbides showed the highest, the binderless Cemented Carbide an intermediate and the ceramics the lowest wear resistance. Scanning electron and atomic force microscopy of the abraded surfaces revealed that the binderless Cemented Carbide was worn by a preferential removal of TiC grains. In erosion, the wear mechanism was largely plastic for the Cemented Carbides, whereas the ceramics were worn by micro-fracture. The SEM analysis also showed an impact scaling effect for the Cemented Carbides in erosion.
Hua Yang - One of the best experts on this subject based on the ideXlab platform.
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oxidation of ultrafine Cemented Carbide prepared from nanocrystalline wc 10co composite powder
Ceramics International, 2008Co-Authors: Hua Yang, Gangqin Shao, Xinglong Duan, Sheng WangAbstract:Abstract The oxidation behavior and associated properties, phases and microstructure of ultrafine WC–10Co-Cemented Carbide using WC–10Co nanocomposite powder prepared by spray pyrolysis-continuous reduction and carbonization technology, were investigated in the 450–700 °C temperature range at 50 °C intervals. The results showed that the working temperature of the cutting edge should be lower than 550 °C in air without coolant in order to assure the lifespan and working efficiency of ultrafine WC–10Co-Cemented Carbide materials as cutting tools.