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Journal of mat.rials sci.nce & Technology 2002年第5期18卷 387-391页

作者： DaCHEN J.M.McNaney E.Saiz A.P.Tomsia R.O.Ritchie Dept. of mat. sci. Shanghai Jiaotong Univ. Shanghai 200030 China Dept. of mat. sci. and eng. Univ. of California Berkeley CA 94720 United States mat. sci. Div. Lawrence Berkeley Natl. Lab. Berkeley CA 94720 United States

Based on a series of newly developed bioactive glasses having suitable thermo-mechanical properties to allow application as fixation agents between bone and titanium alloy biomedical implants, the stress corrosion crack growth (SCCG) behavior of their interfaces with Ti6AI4V was investigated in simulated body fluid (SBF) with the objective of discerning the salient mechanisms of crack advance and to assess the reliability of the bonds. Results indicated that crack growth rates in Ti6AI4V/glass/Ti6AI4V sandwich specimens were nearly the same as or slightly lower than those in the bulk glasses at comparable stress intensities; indeed, cracks would prefer to propagate off the interface, suggesting that the Ti6AI4V/glass interface has relatively good crack-growth resistance. Mechanistically, interfacial crack growth appears to be controlled by the classic stress corrosion mechanisms for silicate glasses, with no discernible effect of bioactivity on the SCCG behavior being observed.

关键词： Stress corrosion Titanium alloy Bioactive glass Crack growth

Study on fracture characteristic of welded high-density polyethylene pipe

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China Welding 2002年第1期11卷 59-63页

作者：齐芳娟霍立兴张玉凤荆洪阳杨新岐 col.. of mat. sci. and eng. Tianjin Univ. Tianjin 300072 China

Crack opening displacement(COD) was applied to characterize the fracture initiation of the tough high density polyethylene. Normal single side notched three point bend specimens and silica rubber replica techniques were used to study the characteristic COD of high density polyethylene pipe and its butt fusion joints including the weld fusion zone and heat affected zone at different temperature from -78 ℃ to 20 ℃ . Testing results show that the characteristic COD appears to depend on the structural features that are determined by welding process and the testing temperature. As the temperature is lowered, the characteristic COD of all zones studied decreases. Because the welding process significantly changes some structural feature of the mat.rial, characteristic COD of the weld fusion zone is the smallest one among those of the three zones. The results can be used for the eng.neering design and failure analysis of HDPE pipe.

关键词： crack opening displacement high density polyethylene pipe butt fusion joint

Experimental Investigation and Numerical Simulation of the Grain Size Evolution during Isothermal Forging of a TC6 Alloy

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Journal of mat.rials sci.nce & Technology 2005年第2期21卷 155-160页

作者： Miaoquan LI, Shankun XUE, Aiming XIONG and Sheng.ui CHEN State Key Laboratory of Solidification Processing, School of mat.rials sci.nce and eng.neering, Northwestern Polytechnical University, Xi’an 710072, China Lab. of Solidification Proc. Sch. of Mat. Sci. and Eng. Northwestern Polytech. Univ. Xi'an 710072 China

Hot compression was conducted at a Thermecmaster-Z simulator, at deformat.on temperatures of 800-1040℃, with strain rates of 0.001-50 s-1 and height reduction of 50%. Grain size of the prior α phase was measured with a Leica LABOR-LUX12MFS/ST microscope to which QUANTIMET 500 software for image analysis for quantitative metallography was linked. According to the present experimental data, a constitutive relationship for a TC6 alloy and a model for grain size of the prior a phase were established based on the Arrhenius' equation and the Yada's equation, respectively. By finite element (FE) simulation, deformat.on distribution was determined for isothermal forging of a TC6 aerofoil blade at temperatures of 860-940℃ and hammer velocities of 9-3000.0 mm/min. Meanwhile, the grain size of the prior α phase is simulated during isothermal forging of the TC6 aerofoil blade, by combining FE outputs with the present grain size model. The present results illustrate the grain size and its distribution in the prior α phase during the isothermal forging of the TC6 aerofoil blade. The simulated results show that the height reduction, deformat.on temperature, and hammer velocity have significant effects on distribution of the equivalent strain and the grain size of the prior α phase.

关键词： Titanium alloy Isothermal forging Grain size Model Finite element (FE) simulation

Effects of Process Technology on Structure and Properties of HMLS Fibers

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Journal of Donghua University(eng.ish Edition) 2001年第4期18卷 27-30页

作者：王学利王彪王华平张玉梅胡学超 col.. of mat. sci. and eng. Dong Hua Univ. Shanghai 200051 China

High modulus low shrinkage (HMLS) fibers have been prepared by using higher viscosity PET chips. The effects of the process conditions on their structure and properties have been studied by various testing techniques. The results show that the suitable spinning speed for preparing of HMLS fibers is 2 000 ～ 2 800 m/min. With the increase of the spinning speed, the density, crystallinity, and birefringence of the initial fibers increase obviously, but the shrinkage ratio decreases rapidly. The effects of process technology on properties of the HMLS fibers have also been discussed.

关键词： HMLS, PET fiber, structure, spinning process

Effect of Rare Earths-Treated Glass Fiber on Impact Wear-Resistance of Metal-Plastic Multilayer Composites

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Journal of Rare Earths 2002年第4期20卷 282-286页

作者：程先华薛玉君谢超英 Sch. of Mech. eng. Shanghai Jiaotong Univ. Shanghai 200030 China Sch. of mat. sci. and eng. Shanghai Jiaotong Univ. Shanghai 200030 China

The friction and wear properties under impact load and dry friction conditions of metal-plastic multilayer composites filled with glass fiber, treated with rare earth elements, were investigated. The worn surfaces were observed and analyzed by scanning electron microscopy (SEM). It shows that applying rare earth elements surface modifier to treat the glass fiber surface can enhance the interfacial adhesion between the glass fiber and polytetrafluoroethylene (PTFE), as well as promote the interface properties of the composites. This helps to form a uniformly distributed and high adhesive transfer film on the counterface and abate the friction between the composite and the counterface. As a result, the wear of composite is greatly reduced. The composite exhibits excellent friction properties and impact wear-resistance.

关键词： rare earths metal-plastic multilayer composites friction properties impact wear-resistance

Strain Softening and Hardening Behavior in AZ61 Magnesium Alloy

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Journal of mat.rials sci.nce & Technology 2004年第6期20卷 691-693页

作者： Haitao ZHOU, Liufa LIU, Qudong WANG, Da LU, Xiaoqin Zeng.and Wenjiang DINGNational eng.neering Research Center of Light Alloys Net Forming, School of mat.rials sci.nce and eng.neering, Shanghai Jiao Tong University, Shanghai 200030, China Ctr. of Light Alloys Net Forming Sch. of Mat. Sci. and Eng. Shanghai Jiaotong Univ. Shanghai 200030 China

The deformat.on behavior of AZ61 Mg alloy during hot deformat.on has been investigated in wide temperature and strain rate range by a Gleeble simulator. Specimens are deformed in compression in the temperature range of 523-673 K and at strain rates of 0.001-1 s-1. It is found that the flow curves exhibit a peak and then decrease towards steady-state of classical DRX, which decrease with rising temperature and decreasing strain rate. The deformat.on behavior of the specimens can be attributed to the occurrence of strain hardening and softening. As stress decreases, the strain hardening rate declines at a fast rate when temperature rises or strain rate decreases. The shapes of θ-σ curves indicate some important features such as subgrain format.on, the criticai stress, the peak stress and steady stress. The onset of DRX can be determined by the point of inflection on θ-σ or Inθ-σ curves.

关键词： AZ61 Mg alloy Recrystallization Strain hardening and softening

Preparation of Glass Ceramic Based on Granulated Slag and Gullet

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Journal of Wuhan University of Technology(mat.rials sci.nce) 2001年第4期16卷 31-35页

作者：韩建军 Key Lab. for Silicate mat. sci./eng. Ministry of Education Wuhan University of Technology Wuhan 430070 China

The glass-ceramic was prepared on the basis of mat.rials of granulated slag containing high-calcium oxide and cullet. The content of granulated slag ranges from 50% - 60% wt in the glass compositions. The samples were analyzed by DTA , SEM and XRD. The results show that the main crystal phase of the glass- ceramic is β-CaSiO3 , Which is in scattering fiber or col.mn form. The applying properties have also been measured.

关键词： glass- ceramic cullet utilization of industrial waste

THE INFLUENCE OF Mo DIFFUSION ON THE THERMAL BEHAVIOR OF TBCs ON Ni_3Al BASED ALLOY IC-6

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Acta Metallurgica Sinica(eng.ish Letters) 2002年第1期15卷 45-48页

作者： D.B. Zhang S.K. Gong H.B. Xu Y.F. Han Dept. of mat. sci. and eng. Beijing Univ. of Aero. and Astron. Beijing 100083 China

Conventional two-layered structure thermal barrier coatings (TBCs) were prepared onto γ'-Ni3Al based alloy IC-6 by electron beam physical vapor deposition (EB-PVD). Isothermal oxidation and thermal cycling tests were carried out to investigate the effect of Mo content at the interface between bond coat and ceramic top coat caused by diffusion. It has been found that the alloy coated with TBCs presented the lowest oxidation weight gain value for the reason that the ceramic top coat in TBC system can effectively stop Mo oxides evaporating. The life time of TBCs has close relation with Mo content at the interface between the bond coat and top coat. Spaliation of ceramic top coat occurred during thermal cyclic testing when Mo atoms accumulated at the interface up to certain amount to decline the combination between the bond coat and top coat.

关键词： EB-PVD thermal barrier coatings (TBCs) thermal cyclic diffusion

Glass forming ability of Zr-and Fe-based alloys at quenching from melts

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Journal of Harbin Institute of Technology(New Series) 2002年第2期9卷 196-200页

作者：孙剑飞高玉来沈军王刚邢大伟周彼德 Sch. of mat. sci. and eng. Harbin Inst. of Technol. Harbin 150001 China

The master alloy ingots (MAI) with the nominal composition Zr 52.5 Ti 5Cu 17.9 Ni 14.6 Al 10 and Fe 61 Co 7Zr 10 Mo 5W 2B 15 (at%) were prepared by arc melting in Ti gettered Ar atmosphere. The Zr based buttons of 6 mm and 9 mm in diameter were fully amorphous, but those of 13 mm in diameter experienced crystallization. The glass forming ability (GFA) of Fe based alloys was relatively lower, and the buttons obtained were fully crystallized. The microhardness of the Zr based buttons was about 500(Hv), and the Fe based rod obtained by injection technique exhibited a high Vickers hardness of 1329. In addition, an amorphous crystalline transition layers were observed in both the buttons and the rods.

关键词： bulk amorphous alloy metallic glass glass forming ability supercooled liquid region overheating

Phase Development and Crystallization Kinetics of NiTi Prepared by Mechanical Alloying

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Journal of mat.rials sci.nce & Technology 2003年第6期19卷 560-562页

作者： Xunyong JIANG, Xueping GAO and Deying SONGInstitute of New Energy mat.rial Chemistry, Nankai University, Tianjin 300071, ChinaDepartment of mat.rials sci.nce and eng.neering, Tianjin Institute of Technology, Tianjin 300191, China Inst. of New Energy mat. Chem. Nankai Univ. Tianjin 300071 China Dept. of mat. sci. and eng. Tianjin Inst. of Technol. Tianjin 300191 China

NiTi alloy is produced by mechanical alloying(MA). It becomes amorphous after milling for enough time, such as 100 h in this paper. DSC measurement shows that the crystallization temperature is 676 K for the amorphous powder. Activation energy of crystallization is 199.98 kJ/mol for MA powder, which is lower than that of amorphous prepared by magnetron sputtering. Avrami parameter of crystallization is 1.07.

关键词： NiTi Mechanical alloying Amorphous Crystallization