Papers by Author: Sheng Zhi Hao

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Authors: Thierry Grosdidier, J.X. Zou, Jiang Wu, X.D. Zhang, K.M. Zhang, Ai Min Wu, Sheng Zhi Hao, Chuang Dong
Abstract: High current pulsed electron beam (HCPEB) is a fairly new technique for surface modifications, including hardening, alloying and formation of metastable phases. The present contribution gives some new insights on the microstructure modifications encountered at the top surface of HCPEB treated metals. In particular, the potential of the technique for structure modifications associated with the use of the pulsed electron beam under “heating” and “melting” conditions are highlighted.
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Authors: Thierry Grosdidier, Xiang Dong Zhang, Jiang Wu, Nathalie Allain-Bonasso, Ke Min Zhang, Jian Xin Zou, Ying Qin, Xiao Na Li, Sheng Zhi Hao, Chuang Dong
Abstract: High current pulsed electron beam (HCPEB) is a fairly new technique for improving surface properties such as corrosion and wear resistances. One of the negative effects induced by HCPEB is the potential formation of craters on the surface of the HCPEB treated materials. These changes can impair the corrosion-resistance by promoting pitting. The mechanisms of nucleation and growth are detailed and the effect of the number of pulses on crater formation is discussed.
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Authors: Sheng Zhi Hao, Dong Yun He, Min Cai Li, Yang Xu, Chuang Dong
Abstract: High current pulsed electron beam (HCPEB) has been developed as a useful tool for surface treatment of materials. In the present work, the fundamental principle of HCPEB source was described along with the device configuration and working parameters. Through the different kinds of HCPEB surface treatment experiments conducted, the enhanced surface properties induced by HPCEB treatment were illustrated and explained with their microstructure characterization results.
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Authors: Bo Gao, Yi Hao, Gan Feng Tu, Shi Wei Li, Sheng Zhi Hao, Chuang Dong
Abstract: High current pulsed electron beam (HCPEB), a novel high-power energetic beam technology, has been developed as a useful tool for surface modification of materials. In the present work, the effect of HCPEB treatment on microstructure and wear resistance of Al-15Si and ZK60-1Y Mg alloys was investigated. The results show that a supersaturated solid solution of (Al) and (Mg) is formed on top surface of melted layer induced by rapid heating and cooling during HCPEB process. In addition, the melted layer of approximately 5~11μm thickness is obtained on the ZK60-1Y Mg alloy surface. Wear resistance of Al-15Si and ZK60-1Y Mg alloys are significantly improved after HCPEB treatment. It is demonstrated that HCPEB technology has a good application future in enhancing surface properties of Al-Si and Mg alloys.
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Authors: Thierry Grosdidier, Y. Samih, Nathalie Allain-Bonasso, Bernard Bolle, Z.X. Zou, Y. Quin, Sheng Zhi Hao, Chuang Dong
Abstract: The low energy high current pulse electron beam (LEHCPEB) irradiation induces ultra fast dynamic temperature fields in the surface of the material to which is associated dynamic stress fields that causes intense deformation at the material surface and sub-surface. Improved surface properties (hardness, corrosion resistance) can be obtained using the LEHCPEB treatment. Under the “Melting” mode, the top surface (few µm) which is melted and rapidly solidified (107 K/s), can solidify has nano-domains formed from the highly under-cooled melt. The thermal stress wave that propagates in the sub-surface imposes strain hardening and grain size refinement. This induces a sub-surface hardening that can extent over about 100 µm. The use of the “Heating” mode is less conventional. This mode can promote grain size refinement, hardening as well as texture modification without modification of the sample geometry.
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Authors: Y. Hao, Bo Gao, Gan Feng Tu, Z. Wang, Sheng Zhi Hao
Abstract: The paper reports an analysis of the effect of high current pulsed electron beam(HCPEB) on microstructure transformations and wear resistance of hypereutectic Al-Si alloys. HCPEB treatment with 2.5 J /cm2 energy density leads to the formation of “halo” centered on primary Si, composition homogeneity, the formation of supersaturated solid solution of Al and grain refinement of top melted surface layer. The wear resistance of 15 pulse-treated Al-17.5Si and Al-20Si alloys is drastically improved by a factor of 6.5 and 2, respectively. The increase of hardness in modified surface layer has a positive effect on wear of hypereutectic Al-Si alloys.
693
Authors: Yang Xu, Sheng Zhi Hao, Xiang Dong Zhang, Min Cai Li, Chuang Dong
Abstract: The surface irradiation of 6063 aluminum alloy by high current pulsed electron was conducted with the aim of replacing the complicated pre-treatment in the processes of electroless plating. To explore the microstructure changes, optical metallography, SEM (scanning electron microscope), XRD (X-ray diffraction) analyses were carried out, and the sliding tests were used for the detection of wear resistance. It was concluded that the HCPEB irradiation could replace the pre-treatment of aluminum substrate as required in conventional electroless plating with a decreased surface roughness of Ni-P alloy plating layer. The plates exhibited an amorphous microstructure as demonstrated by XRD analysis. The plates, produced with the routine of HCPEB irradiation, activation and electroless plating possess, also exhibited good quality, even better than that of conventional electroless plating technique.
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Authors: Thierry Grosdidier, Jian Xin Zou, K.M. Zhang, Sheng Zhi Hao, Chuang Dong
Abstract: Low energy high current pulsed electron beam (LEHCPEB) is a fairly new technique for surface modifications, including hardening, alloying and formation of metastable phases as well as improvement in wear and corrosion properties. The present contribution gives some new insights on the microstructure modifications encountered at the top surface of HCPEB treated metals. In particular, the potential of the technique for structure modifications associated with the use of the pulsed electron beam under “heating” and “melting” conditions are highlighted.
1091
Authors: Hui Hui Wang, Sheng Zhi Hao
Abstract: High current pulsed electron beam (HCPEB) treatment was conducted on 40CrNiMo7 steel. The surface microstructure was characterized by metalloscopy and X-ray diffraction methods. The microhardness and wear resistance of modified surface were measured. After the HCPEB treatment, the surface crater structure was observed due to the inhomogeneity of initial material. A modified layer of depth ~ 7 μm was formed with a hybrid microstructure composed mainly of martensite and a small quantity of austenite. The surface microhardness of HCPEB modified sample was increased drastically to more than 1000 HK. The wear resistance increased by about 36% as compared to the initial state.
276
Authors: Y. Samih, Bernard Bolle, N. Alain-Bonasso, Sheng Zhi Hao, Chuang Dong, Thierry Grosdidier
Abstract: The present paper presents the first results of an ongoing research dedicated to the analysis of microstructure in steels surfaces treated by Low Energy High Current Pulsed Electron Beam (LEHCPEB). Various steels - 316L (a stainless steel), D2 (a cold-worked die steel) and 4Cr13 (a martensitic steel) - have been treated by LEHCPEB in order to improve the understanding of the surface microstructure modifications induced by this treatment. The microstructures in the modified surface were characterized by microscopy and diffraction techniques.
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