Papers by Author: Chuang Dong

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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: Jian Bing Qiang, Liang Yuan, Qing Wang, Ying Min Wang, Chuang Dong, Wei Zhang, Akihisa Inoue
Abstract: With the aid of the atomic-cluster-plus-glue-atom model (ACPGA model) proposed by Dong et al [1] for bulk metallic glasses (BMGs), the formation and characteristic of Ni-Ta binary BMGs were investigated in this work. Binary glass-forming compositions containing 56.3–62.5 at.%-Ni were obtained by a composition formula [M-Ni6Ta6]Ni3 based on the ACPGA model. It was found that Ni-Ta BMGs with a diameter of 2 mm was obtained over a composition range of 59 ~ 62 at.%-Ni by copper mold casting method, which are in good agreement with our model prediction. Newly-developed Ni–Ta BMGs are a kind of extreme materials, which exhibit superior thermal stability (Tg = 993K) and a ultrahigh fracture strength of about 3.5 GPa.
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Authors: Qing Wang, Chun Lei Zhu, Yan Hui Li, Jiang Wu, Chuang Dong, Jian Bing Qiang, Wei Zhang, Akihisa Inoue
Abstract: The present paper investigates the bulk metallic glass formation in Co-based alloy systems with the guidance of the cluster line and minor-alloying principles. The selected basic ternary Co-B-Si alloy compositions are intersecting points of cluster lines, defined by linking special binary clusters to the third element. Then these basic ternary alloys are further minor-alloyed with Nb and quaternary bulk metallic glasses are obtained only by 4-5 at. % Nb minor-alloying of the basic composition Co68.6B25.7Si5.7 that is developed from dense-packed cluster Co8B3. The bulk metallic glasses are expressed approximately with a unified simple composition formula: (Co8B3)1(Si,Nb)1. In addition, a quantity of Fe substitution for Co further improves the glass-forming abilities.
1275
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: Qing Wang, Xiang Dong Zhang, Xiao Na Li, Chun Jun Ji, Chuang Dong
Abstract: [(Mo,Sn)(Ti,Zr)14]Nb1 serial alloy compositions were designed using a cluster-plus-glue-atom model to receive BCC β-Ti alloys with low Youngs modulus (E) in Ti-based multi-component systems, where the square brackets enclose the coordination polyhedron cluster CN14 of the BCC structure and Nb is the glue atom. These serial alloys were prepared into rods with a diameter of 6 mm by copper-mould suction casting method. XRD and tensile test results indicated that all these alloy series possessed a monolithic BCC structure except [SnTi14]Nb1 and [(Mo0.5Sn0.5)Ti14]Nb1 due to Sn deteriorating BCC structural stability. A combination of Mo0.5Sn0.5 at the cluster center, as well as low-E Nb and Zr in the glue and cluster shell respectively, can reach simultaneously low E and high BCC stability, incarnated in the [(Mo0.5Sn0.5)(Ti13Zr)]Nb1 alloy which has the lowest E of 48 GPa in the suction-cast state.
885
Authors: Qi Bin Liu, Long Jiang Zou, Min Zheng, Chuang Dong
Abstract: In the present paper, bioceramic coating with gradient compositional design was prepared on surface of Ti alloy by using wide-band laser cladding. Effect of rare earth Y2O3 content on gradient bioceramic composite coating was studied. The experimental results indicated that adding rare earth can refine grain. Different contents of rare earth affect formation of HA andβ-TCP in bioceramic coating. With increase of rare earth content, HA andβ-TCP were synthesized. When content of rare earth ranged from 0.4% to 0.6%, the active extent of rare earth in synthesizing HA andβ-TCP got best, which indicated that “monosodium glutamate” effect of rare earth played a dominant role. However, when rare earth content was up to 0.8%, the active extent of rare earth in synthesizing HA and β-TCP conversely went down, which demonstrated that rare earth gradually lost its catalysis in manufacturing HA andβ-TCP.
351
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.
1205
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.
1204
Authors: Li Dong, Peng Bo Zhang, Wei Qu, Ying Qin, Xian Xiu Mei, Ji Jun Zhao, Chuang Dong
Abstract: Thermal barrier coatings are used as thermal insulation and thermal protection for high-temperature components of aircraft engines. Service failure of the components is often caused by premature breaking of the coatings. The distributions of residual stress in a ZrO2/NiCoCrAlY thermal barrier coating during thermal cycling was here simulated using finite element method. Four kinds of models involving planar and curved interfaces between the bond and the ceramic top coat layers were established. The simulated results showed that the high residual stress which is about 100-300MPa is present at the interface between bond layer and ceramic layer. The residual stress in curved interface is larger than that in planar one, and concentrates mainly at the troughs. Structure for planar interface exhibits better than curved interface. The residual stress would increase obviously with the presence of thermally grown oxide layer.
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Authors: Qing Wang, Jian Bing Qiang, Ying Min Wang, Jun Hai Xia, Xin Fang Zhang, Chuang Dong
Abstract: The present paper covers in a comprehensive manner the formation of the Cu-based Cu-Zr-Al bulk metallic glasses (BMGs). Composition optimization for BMG formation is realized by using an “e/a-variant criterion”. This criterion is incorporated into the ternary phase diagram by a straight composition line, which is defined by linking a specific binary composition to the third element. There e/a-variant composition lines are constructed: (Cu9Zr4)1-xAl, (Cu61.8Zr38.2)1-xAlx and (Cu56Zr44)1-xAlx, where Cu9Zr4, Cu61.8Zr38.2 and Cu56Zr44 are specific cluster compositions in the Cu-rich Cu-Zr binary system. No Cu-based BMGs are obtained in the composition line (Cu9Zr4)1-xAlx using our suction casting techniques, while BMGs are obtained within an e/a span from 1.24 to 1.3 and from 1.28 to 1.36 respectively along the other two lines (Cu61.8Zr38.2)1-xAlx and (Cu56Zr44)1-xAlx. Thermal analysis results indicate that the BMGs on every composition line manifest increased thermal stability and glass forming ability (GFA) with increasing e/a ratios. The maximum appears in Cu58.1Zr35.9Al6 with the e/a value of 1.3, which belongs to the (Cu61.8Zr38.2)1-xAlx series. The characteristic thermal parameters of this BMG are Tg = 760K, Tg/Tm = 0.659 and Tg/Tl = 0.648, which are all superior to those reported for the known Cu55Zr40Al5 BMG.
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