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碳纳米管对环氧树脂基纳米复合材料的力学和电学性能影响(英文)

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新型炭材料 2014年第6期29卷 419-425页

作者： F.Vahedi h.r.shahverdi M.M.Shokrieh M.Esmkhani Materials Science and Engineering Department Faculty of EngineeringTarbiat Modares UniversityJalal Ale Ahmad Highway 14115-111TehranIran Composites research Laboratory Center of Excellence in Experimental Solid Mechanics and DynamicsMechanical Engineering DepartmentIran University of Science and Technology 16846-13114TehranIran

以碳纳米管(MWCNT)为添加剂,制备出碳纳米管/环氧树脂复合材料,并探讨MWCNT质量分数对其力学和电学性能的影响。结果表明,当MWCNT含量分别为0.1%和0.25%时,该复合材料的拉伸强度和弯曲模量达到最大值。随着M WCNT含量的增加,拉伸模量增... 详细信息

以碳纳米管(MWCNT)为添加剂,制备出碳纳米管/环氧树脂复合材料,并探讨MWCNT质量分数对其力学和电学性能的影响。结果表明,当MWCNT含量分别为0.1%和0.25%时,该复合材料的拉伸强度和弯曲模量达到最大值。随着M WCNT含量的增加,拉伸模量增加和应变损坏率降低,这表明复合材料由塑性变形到脆性变形演变。当M WCNT含量为0.05%时样品弯曲强度最高;当M WCNT含量为0.5%时,样品出现电渗流阈值。M WCNT在环氧树脂基体中的良好分散对提高复合材料力学性能起重要作用。分散不均的MWCNT易团聚,会引起早期失效和电学性能降低。

关键词：多壁碳纳米管力学和电学性能纳米复合材料拉伸性能硬度弯曲性能

Effects of Nb Alloying on Nano-Crystallization Kinetics of Fe_(55-x)Cr_(18)Mo_7B_(16)C_4Nb_x(x=0, 3) Bulk Amorphous Alloys

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Journal of Materials Science & Technology 2011年第8期27卷 735-740页

作者： S. Ahmadi h.r. shahverdi S.S. Saremi Faculty of Engineering Department of Materials Science Tarbiat Modares University

Crystallization kinetics of Fe55-xCrzsMo7B10C4Nbx（x= 0, 3） bulk amorphous alloys were analyzed using X-ray diffraction and differential scanning; calorimetric （DSC） tests. In practice, crystallization and growth mechanism were evaluated using DSC tests at four different heating rates （10, 20, 30, and 40 K/rain） and kinetic models. Two-step crystallization behavior was observed when Fe55Cr18MOTB16C4 and Fe52Cr18MoTB16C4Nb3 bulk amorphous alloys were annealed, where Fe36Cr12M010 phase was crystallized in the first step of crystallization. results show that Fe36Cr12Mo10 and Fe3C phases were crystallized in the structures of the alloys after further annealing： process. Activation energy for the crystallization of Fe36Cr12Mozo phase was measured to be 543 kJ/mol in Fe52Cr18MoTB16C4Nb3 alloy and 375 kJ/mol for Fe55Cr18Mo7B16C4 alloy according to Kissinger-Starink model. Moreover, a two-dimensiona nucleation rate was found in Fe52Cr18Mo7B16C4Nb3 diffusion controlled growth mechanism with decreasing alloy whereas a three-dimensional diffusion controlled growth mechanism with decreasing nucleation rate was found in crystallization of Fe36Crz2Mo10 phase during annealing of Fe55Cr18MoTB16C4 alloy. TEM （transmission electron microscopy） observations reveal that crystalline Fe36Cr12M010 phase nucleated in the structures of the alloys in an average size of 10 nm with completely mottled morphology.

关键词： Avrami exponent Crystallization Kinetic models Growth mechanisms Bulk amorphous alloys

Nanocrystallization of α-Fe Crystals in Fe_(52)Cr_(18)Mo_7B_(16)C_4Nb_3 Bulk Amorphous Alloy

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Journal of Materials Science & Technology 2011年第6期27卷 497-502页

作者： S. Ahmadi h.r. shahverdi S.S. Saremi Faculty of Engineering Department of Materials Science Tarbiat Modares University

Crystallization kinetics of Fe52Cr18Mo7B16C4Nb3 alloy was evaluated by X-ray diffraction（XrD）,differential scanning calorimetric（DSC） tests and transmission electron microscopy（TEM） observations in this research *** effect,crystallization and growth mechanism were investigated by using DSC tests at four different heating rates（10,20,30,40 K/min）.results showed that a two-step crystallization process occurred in the alloy in which α-Fe and Fe3B phases were crystallized,respectively in the structure after heat *** energy for the first step of crystallization,i.e.α-Fe was measured to be 421 and 442 kJ/mol according to Kissinger-Starink and Ozawa models,***,Avrami exponent calculated from DSC curves was 1.6 and a two-dimensional diffusion controlled growth mechanism with decreasing nucleation rate was observed in the ***,it was known from the TEM observations that crystalline α-Fe phase nucleated in the structure of the alloy in an average size of 10 nm and completely mottled morphology.

关键词： Bulk metallic glasses (BMGs) Structural amorphous steels (SASs) Avrami exponent Crystallization and kinetic models