Papers by Author: Rui Long

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Authors: Yan Li, Shi Zhong Wei, Jian Ping Gao, Wan Hong Zhang, Rui Long
Abstract: Microstructure in anchoring site of TiC cermets/steel explosive cladding plate was analyzed by transmission electron microscope (TEM), scanning electron microscope (SEM) and energy-dispersive spectrometer (EDS). An intermittent micro-crystal layer, with thickness of about 10μm, was observed in anchoring area. The inner crystal size was in range of some nanometer to hundreds of nanometer. The phases of the layer are mainly austenite, ferrite, and some titanium carbide. A flow layer was observed in the area near the steel side. The diffusion of Ti is the most apparent and the diffusion length is about 15μm. The observation of the microstructure in anchoring area revealed the nature of explosive compound in metallurgical anchoring.
Authors: Yan Li, Shi Zhong Wei, Liu Jie Xu, Chun Wei Xu, Rui Long
Abstract: The high-speed steel (HSS) reinforced by in-situ VC /35CrMo compound roll was produced by electromagnetic semicontinuous casting. The element distribution and the structure morphology of the interface were analysed, and the mechanical properties were tested. The results indicate that the thickness of diffusion layer is around 50μm. The microstructure of the diffusion layer is pearlite, and next to the diffusion layer, the microstructures are ferrite and pearlite at the alloyed steel side. There are in-situ VC particles in martensitic matrix. At the high-speed steel side. The microhardness of HSS and 35CrMo is about 700HV and 250HV, respectively, and that of diffusion layer is near 350HV, which is between that of HSS and 35CrMo. The impact toughness is 100 Jcm-2. On the basis of the experiment, the interface of compound roll prepared by electromagnetic semicontinuous casting obtains good microscopic structure and mechanical properties, which are the results of the metallurgically bonded interface.
Authors: Liu Jie Xu, Hui Min Chen, Shi Zhong Wei, Rui Long
Abstract: The morphology and distribution of in-situ VC ceramics in cast high speed steel with about 5-10wt.% vanadium and 1.7-3.2wt.% carbon were studied. The results show that the elementary morphology of in-situ VC ceramics has six kinds: spherical, lumpy, flower shaped, strip, short rod shaped, and vermicular. The in-situ VC in high-speed steel has three kinds of distributions: grain boundary, chrysanthemum-like and homogeneous distributions, depending on the chemical composition of high-speed steel. The in-situ VC ceramics grows up along grain boundaries if the high-speed steel is hypoeutectic, leading to grain boundary distribution of VC ceramics. On the contrary, it distributes homogeneously when the high-speed steel is hypereutectic. Whereas, the in-situ VC ceramics takes on chrysanthemum distribution if the high speed steel is just eutectic. Modification can improve the morphology of primary VC ceramics, but has not obvious effect on the morphology of eutectic VC.
Authors: Shi Zhong Wei, Yan Li, Jian Ping Gao, Ying Ping Ji, Rui Long
Abstract: WC steel bond hard alloy powders were compacted by explosive compaction on the surface of carbon steel, then the composite layer was prepared by liquid-phase sintering in vacuum. The phases and microstructures of the interface of composite layer were observed by SEM, EDS, TEM. Result showed that the thickness of the interface was about 30μm, and the elements of W, Cr, C were detected in the interface. The structures of the interface were pearlites which were composed of the layered tablets of M23C6 and ferrite. The layered tablets were perpendicular to the interface. The structures were the pearlites and ferrites in the side of the carbon steel near the interface but globular carbides, whose phase is W3Fe3C, and pearlites in side of steel bond hard alloy. During sintering at 1623K, all elements of metal-powder and C, V, which were decomposed by hard-phase, interdiffused in the interface. The multiple carbides were found in the interface and steel bond hard alloy. As a result, the powders formed into compact alloy by itself, and at the same time there was a good metallurgical bonding between the carbon steel and the hard alloy.
Authors: Yan Li, Shi Zhong Wei, Rui Long
Abstract: The morphology and phase structure of Al/Cu explosive compounded interface were observed by scanning electron microscope, high-resolution transmission electron microscope and X-ray energy spectrometer. The results reveal that the interface of Al/Cu appears wave-like structure, with an average wavelength of 1.0mm and crest height of 0.3mm. Every wave has its front-nest. The wavelike interfaces are composed of microcrystal compound layer, non-crystal and nanocrystal. Several kinds of compounds such as Al9Cul2, Al4Cu9, Al2Cu, η-AlCu, β-AlCu3 and unidentified phase structure were found in Al/Cu interface. There are some bent lattice fringes around the front-nest. The research of microstructure in anchoring area revealed the nature of explosive cladding in metallurgical anchoring.
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