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Formation,thermal stability and mechanical properties of Ti_(42.5)Zr_(7.5)Cu_(40)Ni_5Sn_5 bulk metallic glass

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Science China(Physics,Mechanics & Astronomy) 2008年第4期51卷 372-378页

作者： HUANG YongJiang,SHEN Jun & SUN JianFei School of Materials Science and Engineering,harbin institute of technology,harbin 150001,China School of Materials Science and Engineering Harbin Institute of Technology Harbin China

Ti42.5Zr7.5Cu40Ni5Sn5 bulk metallic glass with a critical diameter of 4 mm was fabri-cated by the conventional copper mould casting method. The supercooled liquid region ΔTx,reduced glass transition temperature Trg,γ parameter,and δparameter of the alloy were measured to be 63.9 K,0.561,0.393,and 1.400,respectively,im-plying that the alloy has an excellent glass-forming ability. The bulk metallic glass exhibits high compressive fracture strength of 2162 MPa with distinct plastic strain of 0.9%. The fracture surface consists mainly of vein-like patterns,typical of bulk glassy alloys.

关键词： amorphous alloy mechanical properties thermal stability glass-forming ability

Effects of Cure Pressure Induced Voids on the Mechanical Strength of Carbon/Epoxy Laminates

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Journal of Materials Science & technology 2005年第1期21卷 87-91页

作者： Ling LIU, Boming ZHANG, Zhanjun WU and Dianfu WANGCenter for Composite Materials, harbin institute of technology, harbin 150001, ChinaProf., Ctr. for Composite Mat. Harbin Inst. of Technol. Harbin 150001 China

This work aims at designing a set of curing pressure routes to produce laminates with various void contents. The effects of various consolidation pressures resulting in different void contents on mechanical strength of carbon/epoxy laminates have been examined. Characterization of the voids, in terms of void volume fraction, void distribution, size, and shape, was performed by standard test, ultrasonic inspection and metallographic analysis. The interlaminar shear strength was measured by the short-beam method. An empirical model was used to predict the strength vs porosity. The predicted strengths conform well with the experimental data and voids were found to be uniformly distributed throughout the laminate.

关键词： Carbon/epoxy laminates Autoclave curing Void Mechanical strength

A Novel Stable Clustering Design Method for Hierarchical Satellite Network

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Chinese Journal of Aeronautics 2010年第1期23卷 91-102页

作者： Zhou Mu,Guo Qing,Wang Zhenyong Communication Research Center,School of Electronics and Information Engineering,harbin institute of technology,harbin 150001,China Communication Research Center School of Electronics and Information Engineering Harbin Institute of Technology Harbin 150001 China

This article proposes a novel stable clustering design method for hierarchical satellite network in order to increase its stability,reduce the overhead of storage and exert effective control of the delay performances based on a 5-dimensional vector model. According to the function of stability measureinent and owing to the limitation of minimal average routing table length, the hierarchical satellite network is grouped into separate stable connected clusters to improve destruction resistance and reconstruction ability in the future integrated network. In each cluster, redundant communication links with little contribution to network stability and slight influences on delay variation are deleted to satisfy the requirements for stability and connectivity by means of optimal link resources, and, also, the idea of logical weight is introduced to select the optimal satellites used to communicate with neighboring cluster satellites. Finally, the feasibility and effectiveness of the proposed method are verified by comparing it with the simulated performances of other two typical hierarchical satellite networks, double layer satellite constellation（DLSC） and satellite over satellite（SOS）.

关键词： satellite network hierarchical structure stability analysis clustering algorithms vector measurements

A fast local routing repair scheme for wireless mobile ad hoc network

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Science China(Information Sciences) 2011年第1期54卷 111-122页

作者： QIN DanYang,SHA XueJun & XU YuBin Electronics and Information Engineering School,harbin institute of technology,harbin 150001,China Electronics and Information Engineering School Harbin Institute of Technology

Mobile ad hoc network(MANET)is a centerless packet radio network which does not use fixed *** has recently received tremendous attention due to its capabilities of self-configuration and ***,attenuation and interference caused by node mobility and wireless channel sharing weaken the stability of communication links.A mathematical exploring model for the next hop has been established based on the optimal exploring *** negative impact of wireless routes discontinuity has been alleviated by a novel fast local routing repair scheme(FLRRS)proposed in this paper,wherein the route requirement zone has been restricted into a pie slice region on intermediate nodes according to the solution of exploring *** scheme is an effective approach in reducing the average end-to-end delay during routing *** also allows continuous packet forwarding for fault ***-2 based simulation results showed remarkable successful packet delivery rate and end-to-end delay improvements of source-initiated routing protocol with the fast local repair scheme,especially in the case of high dynamic environments with heavy traffc loads.

关键词： FLRRS optimal exploration parabolic partial differential equation fault resilience MANET

Microstructure and Mechanical Properties of Si_3N_4 Composites Containing SiC Platelet

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Journal of Materials Science & technology 1998年第2期14卷 151-155页

作者： Tao WEI Yu ZHOU Tingquan LEI and Yujin WANG (School of Materials Science and Engineering, harbin institute of technology, harbin 150001, China) School of Materials Science and Engineering Harbin Institute of Technology Harbin 150001 China

Hoppressed Si3N4/SiC platelet composites had been investigated with respect to their microstructure and mechanical properties. The results indicate that Vickers hardness, elastic modulus and fracture toughness of the composites were increased by the addition of SiC platelet until the content up to 20 vol pct. A slight decrease in flexural Strength was measured at room temperature with increasing SiC platelet content. The high temperature flexural strength tests at 1150, 1250, and 1350℃ were conducted. It was found that the flexural strength at elevated temperature was degraded with the rising temperature, and the downward trend of flexural strength for the composite containing 10 vol. pct SiC platelet was less. The results indicate that SiC platelet had a positive influence on the high temperature strength. Effects of SiC platelet reinforcement were presented

关键词： SiC Microstructure and Mechanical Properties of Si3N4 Composites Containing SiC Platelet MPa

Hot compressive deformation behaviors and micro-mechanisms of TA15 alloy

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Rare Metals 2007年第S1期26卷 162-167页

作者： LIU Yong,ZHU Jingchuan,WANG Yang,and ZHAN Jiajun School of Materials Science and technology,harbin institute of technology,harbin 150001,China harbin Inst Technol Sch Mat Sci & Technol Harbin 150001 Peoples R China

The hot deformation behaviors of TA15 alloy,as well as the microstructure obtained after compressive deformation,were *** results show that TA15 alloy exhibits a peak stress when deformed at temperature lower than 900 ℃,implying recrystallization ***,steady flow stress-stain behavior is observed without peak stress when deformation is employed at temperature higher than 900 ℃,showing recovery ***-deformation band appears at deformation temperature of 750 ℃,and equiaxed grains are found at 800 ℃,implying the occurrence of *** deformed at 925 ℃,the specimen shows the recovery characteristics with dislocation networks and sub-grain boundaries.

关键词： TA15 alloy hot compressive deformation micro-mechanisms

Study on Laser Welding of Al Composite

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Journal of Materials Science & technology 2001年第1期17卷 173-174页

作者： Jitai NIU Zhonghong LAI MuZhen WANG Liming LIU and Lin WU National Key Laboratory of Advanced Welding Production technology, harbin institute of technology, harbin 150001, China harbin Inst. of Technol. Harbin 150001 China

The effects of laser welding parameter on strength of welded joints were studied. The mechanism for loss of joint strength was analyzed. It was pointed out that an important factor affecting joint strength is the reaction between matrix and reinforced phase. On the basis of this, the concept of critical St activity a[si]min was proposed. Using appropriate welding parameters and Si activity, high quality laser welded joints in an aluminum matrix composite SiCw/6061Al can be Successfully obtained.

关键词： joint strength welded joints aluminum matrix composite welding parameters strength of

High Temperature Tensile Properties of 30 vol. pct ZrCp/W Composite

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Journal of Materials Science & technology 2003年第2期19卷 167-170页

作者： Yujin WANG, Yu ZHOU, Guiming SONG and Tingquan LEI School of Materials Science and Engineering, harbin institute of technology, harbin 150001, China Sch. of Mat. Sci. and Eng. Harbin Inst. of Technol. Harbin 150001 China

In order to improve the high temperature strength of tungsten, 30 vol. pct ZrC particles were added to the tungsten matrix to form a 30ZrCp/W composite. The tensile properties from 20C to 1880C of the composite were examined. It was shown that with increasing testing temperature, the nonlinearity of the stress strain curve of 30ZrCp/W composite becames obvious over 1200C and the Young's modulus decreases and the elongation increases. The ultimate tensile strength increases at first and then decreases with increasing testing temperature. The maximum strength of 431 MPa was obtained at 1000C. The strengthening mechanism at high temperatures is the load transfer to ZrC particles and dislocation strengthening of the tungsten matrix with an effect of grain boundary strengthening.

关键词： ZrCp/W composite Tensile strength High temperature Strengthening mechanism Load transfer Dislocation strengthening

Two-way Shape Memory Effect in a Ti-Ni-Nb Shape Memory Alloy with Wide Hysteresis

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Journal of Materials Science & technology 2001年第1期17卷 13-14页

作者： Liming WANG Xianglong MENG Wei CAI and Liancheng ZHAO School of Materials Science and Engineering, harbin institute of technology, harbin 150001, China Sch. of Mater. Sci. Harbin Inst. of Technol. Harbin 150001 China

A two-way shape memory effect (TWSM E) in the Ti46.3Ni44.7Nb9 alloy has been systematically investigated by means of bending test and transmission electron microscopy (TEM ) observations. Based on the analysis of the ... 详细信息

关键词： Ti Ni Two-way Shape Memory Effect in a Ti-Ni-Nb Shape Memory Alloy with Wide Hysteresis Wide