The Experts below are selected from a list of 10869 Experts worldwide ranked by ideXlab platform
Yehua Jiang - One of the best experts on this subject based on the ideXlab platform.
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wettability and interaction mechanism for ni modified zta particles reinforced Iron matrix composites
2019Co-Authors: Yehua Jiang, Rong Zhou, Yixin HuaAbstract:Abstract The wetting behaviors of bare and Ni-modified zirconia toughened alumina (ZTA) with molten Iron matrix have been explored by sessile drop technique and gathered to compare their wettability. Experimental results show that the wetting angles of molten 65Mn steel and high chromium Cast Iron (HCCI) matrix on bare ZTA substrates are 104.1° and 102.3°, respectively, whereas it is decreased to 83.6° and 88.2° on Ni-modified ZTA substrates. The wetting angle of HCCI matrix on Ni plate is just 1.5° in 1 min. At high Casting temperature, element Ni originated from Ni coating can diffuse into molten Fe and keep constant basically. Small amount of element Ni can react with Al2O3 on ZTA/Fe interface to form Al2NiO4. A schematic illustration of the Cast-infiltration process is put forward, which indicates that Ni-modified ZTA can be wetted with molten Iron through Ni diffusion and reactive wetting. A ZTA/Al2NiO4/Fe interface layer is formed by mechanical bonding, interdiffusion and small amount of chemical reactions, to achieve composites with tight interfacial bonding strength. Besides, Ni-modified ZTA particles are prepared through electroless plating assisted with Ethaline additive and used as precursor to reinforce 65Mn steel matrix composite by nonpressure Casting infiltration method.
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change in primary cr fe 7c3 carbides induced by electric current pulse modification of hypereutectic high chromium Cast Iron melt
2018Co-Authors: Baoyu Geng, Rongfeng Zhou, Lu Li, Haiyang Lv, Yongkun Li, Yehua JiangAbstract:In this work, an electric current pulse (ECP) of 500A was applied on a hypereutectic high chromium Cast Iron (HHCCI) melt before it began to solidify, and the effect of ECP on primary carbides was investigated. The characteristics of the primary carbides were analyzed by X-ray diffraction (XRD), electron probe micro-analyzer (EPMA), transmission electron microscopy (TEM), micro hardness tester, and other techniques. The results showed that ECP not only refined the primary (Cr, Fe)7C3 carbides, but also decreased the average content of Cr in the primary carbides. At the same time, the average value of micro hardness of the primary carbides increased by about 84 Kgf/mm2, which contradicts existing knowledge that hardness increases with an increase in Cr content. XRD analysis showed that the crystal structure of the primary carbides did not change. The results of EPMA indicated that the Cr/Fe ratio gradually decreased from the center to the edges of the carbide particles. Further investigation revealed that the uneven distribution of elements caused by ECP led to an increase in defects (including twins, antiphase boundaries, and dislocations). This increase in defect density is the main reason for the increase in micro hardness instead of the expected decrease. The mechanism of the change in primary carbides was analyzed in detail in this paper, which has provided a new method for the refinement of primary carbides and for improving the properties of primary carbides.
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characterization of interfacial layer of zta ceramic particles reinforced Iron matrix composites
2018Co-Authors: Yudong Sui, Mojin Zhou, Yehua JiangAbstract:Abstract Experimental evidence is first provided for the reaction product in the interfacial layer of ZTA (zirconia toughened alumina) ceramic particles reinforced HCCI (high chromium Cast Iron). Phases formed in the interfacial layer during solidification were identified by TEM and HRTEM. It is confirmed that they were the amorphous Na4SiO4 phases. The diffusion of Al is faster than that of other elements in the interfacial layer. The hardness and modulus of interfacial layer were 1877.5 HV and 299.8 Gpa, respectively. The phase transformation (t-ZrO2→m-ZrO2 and θ-Al2O3→α-Al2O3) occurred during the composite preparation.
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modification of zta particles with ni coating by electroless deposition
2017Co-Authors: Y Jia, Yehua Jiang, Rong Zhou, Jing Feng, Yixin Hua, D WangAbstract:The modification of ZTA particles with Ni coating as reinforcement is systematically clarified to enhance the wearability of Ni-encapsulated ZTA (ZTA@Ni)-reinforced High-Chromium Cast Iron (HCCI) matrix composites. Continuous and uniform metallic Ni coatings are formed on ZTA surface by electroless deposition with ChCl-EG ionic liquid as additive. The coating thickness can be controlled by regulating deposition times and the ZTA@Ni particles with 24.35 μm are chosen as reinforced phase in HCCI matrix composites. Results show that Ni atoms can be permeated into matrix during the Casting process leading to the formation of diffusive nucleus to refine the particle size of carbides adjacent interface. A good combination between ZTA@Ni particles and HCCI matrix is observed in the composites. The dissolution and diffusion of metallic Ni can greatly reinforce the interfacial bonding strength to constitute a compact combination of the metallic phase and hard phase.
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numerical simulation of mold filling process for high chromium Cast Iron matrix composite reinforced by zta ceramic particles
2015Co-Authors: Xiaoyu Chong, Yehua Jiang, Jing FengAbstract:Abstract The mold filling process of high chromium Cast Iron matrix composites reinforced by zirconia toughened alumina (ZTA) ceramic particles (referred as HCCI/ZTAP composites hereinafter) by infiltration Casting were simulated using finite element analysis software in this paper. Volume of fluid (VOF) method and porous medium model were used to describe the flow phenomenon during infiltration process. Multiphase flow and heat transfer equations were solved by finite element method. The comparison between the experimental observations and simulation results indicates that the formulated model and method could provide a solution with acceptable accuracy, thus a promising tool to optimize the processing parameters. After trial calculations, the optimal parameters and pouring system were determined eventually. A complete Casting without any defects was prepared at the pouring temperature of 1843 K and pouring velocity of 0.2 m/s by top filling in an enclosed gating system.
Bowen Xiong - One of the best experts on this subject based on the ideXlab platform.
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effect of volume ratio of liquid to solid on the interfacial microstructure and mechanical properties of high chromium Cast Iron and medium carbon steel bimetal
2011Co-Authors: Bowen Xiong, Baiping LuAbstract:Abstract The high chromium Cast Iron and medium carbon steel bimetal was fabricated by liquid–solid Casting technology. The effect of volume ratios of liquid to solid (6:1, 10:1 and 12:1) on the interfacial microstructure and mechanical properties of bimetal was investigated. The interfacial microstructure was analyzed using scanning electron microscope (SEM) and transmission electron microscope (TEM). The shear strength and microhardness in as-Cast condition were studied at room temperature. The results show that the volume ratios of liquid to solid affect significantly the interfacial microstructure. When liquid–solid volume ratio was 6:1, the unbonded region was detected in interface region because the imported heat energy cannot support effectively the diffusion of element, whereas, when liquid–solid volume ratios reach 10:1 and 12:1, a sound interfacial microstructure was achieved by the diffusion of C, Cr, Mo, Cu and Mn, and metallurgical bonding without unbonded region, void and hole, etc. was detected. With the increase of liquid–solid volume ratio, the elemental diffusion activity improves, resulting in the increase of width of interface transition region. At the same distance from interface, with the increase of liquid–solid volume ratio, the microhardness is degraded in HCCI, but increased in MCS. The shear strength is also improved with the increase of liquid–solid volume ratio.
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effect of volume ratio of liquid to solid on the interfacial microstructure and mechanical properties of high chromium Cast Iron and medium carbon steel bimetal
2011Co-Authors: Bowen Xiong, Changchun CaiAbstract:Abstract The high chromium Cast Iron and medium carbon steel bimetal was fabricated by liquid–solid Casting technology. The effect of volume ratios of liquid to solid (6:1, 10:1 and 12:1) on the interfacial microstructure and mechanical properties of bimetal was investigated. The interfacial microstructure was analyzed using scanning electron microscope (SEM) and transmission electron microscope (TEM). The shear strength and microhardness in as-Cast condition were studied at room temperature. The results show that the volume ratios of liquid to solid affect significantly the interfacial microstructure. When liquid–solid volume ratio was 6:1, the unbonded region was detected in interface region because the imported heat energy cannot support effectively the diffusion of element, whereas, when liquid–solid volume ratios reach 10:1 and 12:1, a sound interfacial microstructure was achieved by the diffusion of C, Cr, Mo, Cu and Mn, and metallurgical bonding without unbonded region, void and hole, etc. was detected. With the increase of liquid–solid volume ratio, the elemental diffusion activity improves, resulting in the increase of width of interface transition region. At the same distance from interface, with the increase of liquid–solid volume ratio, the microhardness is degraded in HCCI, but increased in MCS. The shear strength is also improved with the increase of liquid–solid volume ratio.
Baoluo Shen - One of the best experts on this subject based on the ideXlab platform.
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effects of high temperature and cryogenic treatment on the microstructure and abrasion resistance of a high chromium Cast Iron
2009Co-Authors: Jun Wang, Haohuai Liu, Hongshan Yang, Ji Xiong, Hongyuan Fan, Baoluo ShenAbstract:Abstract Effects of deep cryogenic treatment on the microstructure, hardening and abrasion resistance behaviors of 16Cr1Mo1Cu Cast Iron subjected to destabilization treatment were investigated. The results show that the cryogenic treatment can effectively reduce the retained austenite after destabilization heat treatment, but cannot make retained austenite transform completely. Cryogenic treatment can markedly improve bulk hardness and abrasion resistance of the high chromium Cast Iron. In the course of destabilization treatment and then cryogenic treatment, the amount of precipitated secondary carbide, M23C6, was more than that in air cooling. The additional fine secondary carbide precipitated during the cryogenics treat after destabilization heat treatment comparing with air cooling, is the main reason for the increase of the bulk hardness and wear resistance.
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effects of cryogenic treatment on microstructure and abrasion resistance of crmnb high chromium Cast Iron subjected to sub critical treatment
2008Co-Authors: Haohuai Liu, Jun Wang, Hongshan Yang, Baoluo ShenAbstract:Effects of cryogenic treatment on the microstructure, and abrasion resistance of CrMnB High-Chromium Cast Iron subjected to sub-critical treatment were investigated by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and wear test. The results show that cryogenic treatment makes the alloy present a more refined and homogeneous matrix. In the course of sub-critical treatment followed by cryogenic treatment, the amount of precipitated secondary carbide was more than that in air cooling. Cryogenic treatment can further reduce the austenite content but cannot make retained austenite transform to martensite completely. After cryogenic treatment, the hardness and abrasion resistance of CrMnB High-Chromium Cast Iron can be improved obviously due to the precipitation of carbides, the martensite transformation, and a refined microstructure resulting from cryogenics treatment.
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the precipitation and transformation of secondary carbides in a high chromium Cast Iron
2006Co-Authors: Jun Wang, Hongshan Yang, Baoluo Shen, Cong Li, Sijiu HuangAbstract:Abstract The precipitation and transformation of secondary carbides in a newly developed 16Cr–1Mo–1Cu Cast Iron subjected to a destabilization heat treatment was investigated. The results showed that the initial fine secondary carbide precipitation from the austenite matrix consist of (Fe,Cr) 23 C 6 . Two kinds of (Fe,Cr) 23 C 6 carbides initially precipitated: one is cubic with a cube–cube orientation relationship with the austenite matrix, and the other is grainy with no orientation relationship with the matrix. The latter carbide may be precipitated in the cooling process after a destabilization treatment. With prolonged holding time, the fine (Fe,Cr) 23 C 6 carbides have transformed into M 7 C 3 rods with an orientation of [100] (Fe,Cr)23C6 [100] (Fe,Cr)7C3 and (01¯5) (Fe,Cr)23C6 (010) (Fe,Cr)7C3 between the M 23 C 6 and M 7 C 3 carbides.
Changchun Cai - One of the best experts on this subject based on the ideXlab platform.
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effect of volume ratio of liquid to solid on the interfacial microstructure and mechanical properties of high chromium Cast Iron and medium carbon steel bimetal
2011Co-Authors: Bowen Xiong, Changchun CaiAbstract:Abstract The high chromium Cast Iron and medium carbon steel bimetal was fabricated by liquid–solid Casting technology. The effect of volume ratios of liquid to solid (6:1, 10:1 and 12:1) on the interfacial microstructure and mechanical properties of bimetal was investigated. The interfacial microstructure was analyzed using scanning electron microscope (SEM) and transmission electron microscope (TEM). The shear strength and microhardness in as-Cast condition were studied at room temperature. The results show that the volume ratios of liquid to solid affect significantly the interfacial microstructure. When liquid–solid volume ratio was 6:1, the unbonded region was detected in interface region because the imported heat energy cannot support effectively the diffusion of element, whereas, when liquid–solid volume ratios reach 10:1 and 12:1, a sound interfacial microstructure was achieved by the diffusion of C, Cr, Mo, Cu and Mn, and metallurgical bonding without unbonded region, void and hole, etc. was detected. With the increase of liquid–solid volume ratio, the elemental diffusion activity improves, resulting in the increase of width of interface transition region. At the same distance from interface, with the increase of liquid–solid volume ratio, the microhardness is degraded in HCCI, but increased in MCS. The shear strength is also improved with the increase of liquid–solid volume ratio.
Baiping Lu - One of the best experts on this subject based on the ideXlab platform.
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effect of volume ratio of liquid to solid on the interfacial microstructure and mechanical properties of high chromium Cast Iron and medium carbon steel bimetal
2011Co-Authors: Bowen Xiong, Baiping LuAbstract:Abstract The high chromium Cast Iron and medium carbon steel bimetal was fabricated by liquid–solid Casting technology. The effect of volume ratios of liquid to solid (6:1, 10:1 and 12:1) on the interfacial microstructure and mechanical properties of bimetal was investigated. The interfacial microstructure was analyzed using scanning electron microscope (SEM) and transmission electron microscope (TEM). The shear strength and microhardness in as-Cast condition were studied at room temperature. The results show that the volume ratios of liquid to solid affect significantly the interfacial microstructure. When liquid–solid volume ratio was 6:1, the unbonded region was detected in interface region because the imported heat energy cannot support effectively the diffusion of element, whereas, when liquid–solid volume ratios reach 10:1 and 12:1, a sound interfacial microstructure was achieved by the diffusion of C, Cr, Mo, Cu and Mn, and metallurgical bonding without unbonded region, void and hole, etc. was detected. With the increase of liquid–solid volume ratio, the elemental diffusion activity improves, resulting in the increase of width of interface transition region. At the same distance from interface, with the increase of liquid–solid volume ratio, the microhardness is degraded in HCCI, but increased in MCS. The shear strength is also improved with the increase of liquid–solid volume ratio.