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Microstructure and properties of WC reinforced Ni-based composite coatings with Y <sub/>2</sub> O <sub/>3</sub> addition on titanium alloy by laser cladding
摘要： In this study, WC reinforced Ni-based composite coatings with Y2O3 addition were deposited on Ti-6Al-4V titanium substrate by laser cladding. The phases, microstructure, microhardness and wear resistance of the composite coatings were studied by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, microhardness tester and wear tester. The results showed that good metallurgical bonding was achieved between the composite coatings and substrate. The phases mainly were γ -Ni, TiC, TiB2, Ni3B, M23C6 and WC. Most of the WC was dissolved in small pieces of WC during the laser cladding process. The microhardness of the composite coatings was about 3 times that of the titanium substrate and the wear resistance of the composite coatings had a significant increase.
关键词： titanium alloy,microstructure,Laser cladding,Y2O3,WC,Ni-based composite coatings
更新于2025-11-28 14:24:20
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Densification behavior, microstructure evolution, and tensile properties of selective laser melting additive manufactured TiB <sub/>2</sub> /AlSi10Mg composite
摘要： The fabrication of TiB2/AlSi10Mg composites by selective laser melting (SLM) additive manufacturing has been conducted. The influence of laser processing parameters on the densification behavior, microstructure evolution, and tensile properties of the SLM-processed composites is addressed. With the increase in laser volume energy density, the densification rate increased and reached 99% at a laser speed of 1000 mm/s. Meanwhile, the TiB2 particles underwent a partial melting behavior with the formation of an irregular pattern in the solidified part and complete melting with the smooth surface of the reinforcing particles as the laser volume energy increased. The cellular-dendritic microstructure and the width of the eutectic phase of the as-fabricated composites were significantly refined due to the high cooling rate and complete melting of the reinforcing particles as the nucleation sites using the laser energy density of 117 J/mm3. Therefore, the micro-hardness, ultimate tensile strength, yielding strength, and elongation of the as-fabricated TiB2/AlSi10Mg composites obtained in this process condition were 131.3 HV0.2, 375 MPa, 260 MPa, and 3.1%, respectively, which were significantly higher than those of the unreinforced AlSi10Mg alloy.
关键词： tensile properties,aluminum-based composite,selective laser melting,microstructure evolution
更新于2025-09-23 15:21:01
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Microstructure development, tribological property and underlying mechanism of laser additive manufactured submicro-TiB2 reinforced Al-based composites
摘要： Al-based composites reinforced with submicro-TiB2 particles were manufactured by selective laser melting (SLM) of powder mixture under different laser powers. The microstructure evolution and tribological property of SLM-processed AlSi10Mg/TiB2 composites were investigated. Al-based composites with high manufacturing quality and uniform dispersion of TiB2 particles throughout the matrix were obtained. The EBSD results showed that incorporation of TiB2 reinforcements imposed no appreciable influence on the crystallographic orientation and average grain size, while the grain size distribution was distinctly narrowed as a result of limitation on grain growth by addition of ceramic particles. The SLM-processed composites exhibited a continuous tendency of increasing microhardness and decreasing coefficient of friction (COF) along with wear rate with a laser power increasing from 350 to 450 W. The composites showed high microhardness of 126 HV0.2, exceeding over those of the Al-Si alloys and composites processing by conventional techniques. A low COF of 0.65 and wear rate of 5.2×10?4 mm3N-1m-1 were obtained for bulk-form composites at 450 W due to the combined effects of high manufacturing quality, microstructure homogeneity, and sound interfacial bonding.
关键词： Tribological property,Microstructure development,Selective laser melting (SLM),Al-based composite
更新于2025-09-16 10:30:52
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Hierarchically porous surface of PEEK/nMCS composite created by femtosecond laser and incorporation of resveratrol exhibiting antibacterial performances and osteogenic activity in vitro
摘要： To further improve the surface properties of polyetheretherketone (PEEK)/nanoporous magnesium calcium silicate (nMCS) composite (PMC), hierarchically porous surface of PMC (PMCF) were created by femtosecond laser, and resveratrol (RV) was incorporated into the porous surface of PMCF (RV@PMCF). Compared to PMC with flat surface, PMCF contained not only two types of micropores with different sizes (around 20 μm and 0.5μm) but also nanopores (around 4 nm), which exhibited remarkably increase in surface roughness and protein adsorption. In addition, PMCF displayed a slow-release of RV while PMC showed a burst-release of RV into cell cultured medium. Moreover, compared with PMC and PMCF, RV@PMCF with antibacterial performances inhibited the growth of E. coli and S. aureus thanks to the release of RV. In addition, compared with PMC, PMCF and RV@PMCF significantly promoted adhesion and proliferation of rat bone mesenchymal stem cells (BMSC). Furthermore, compared with PMCF, RV@PMCF obviously enhanced the proliferation and osteogenic differentiation as well as bone related genes expressions of BMSC. The results demonstrated that PMCF with hierarchically porous surface and incorporating of RV displayed antibacterial performances and osteogenic activity in vitro, Therefore, as a drug-loaded implant, RV@PMCF with good cytocompatibility would have a big potential for applications in orthopaedic fields.
关键词： femtosecond laser,osteogenic activity,antibacterial performances,polyetheretherketone based composite,hierarchically porous surface
更新于2025-09-16 10:30:52
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Hyperspectral Image Refined Plant Classification By Graph Based Composite Kernel
摘要： Recently, the popularity of using hyperspectral image to study and monitor plant characteristics and conditions has been increased. The use of hyperspectral image improves the breeding process and increases profits. In the case of hyper-spectral data with high spectral resolution characteristics suitable for intraclass classification, this paper focuses on the application of hyperspectral image analysis in distin-guishing among different plant species. Plant intraclass clas-sification is sophisticated due to its small spectral differ-ences. Hence, a refined hyperspectral image classification method for plant, referred as SI-GCK which uses Spectral Index (SI) to represent plant spectral, and take advantage of semi-supervised graph-based composite kernel (GCK) method to combine spectral information and spatial location of pixels for classification is presented in this paper. As a comparison, sequential floating forward selection (SFFS) is used to select spectral bands for SVM learning. Its accuracy of plant classification is nearly equal to result by means of SI, and the proposed method in this paper is better than afore-mentioned.
关键词： spectral index,plant classification,graph-based composite kernel,hyperspectral image
更新于2025-09-04 15:30:14