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Study on Cure Behavior of a Model Epoxy System by Means of ttt diagram

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材料工程 2006年第5期34卷 57-62页

作者： ZHANG Ming AN Xue-feng TANG Bang-ming YI Xiao-su National Key Laboratory of Advanced Composites BeijingInstitute of Aeronautical Materials Beijing 100095 China

Curing behavior of a model epoxies system (E-54/AG-80) with DDS as hardener was studied in this paper. Round disk compression mode DMA was executed to study the gel behaviors at different temperatures to determine the relationship between gel-time (t_ gel) and temperature. The cure kinetics was studied by dynamic DSC analysis. Parameters were obtained for establishing a phenomenological cure reaction model. The relationship between glass transition temperature (T_g) and cure degree (α) was also analyzed by both isothermal and dynamic DSC method based on DiBenedetto equation, which gave a mathematical description of T_g as a function of both time and temperature. Consequently, characteristic temperatures such as T_ g0, gelT_ g and T_ g∞ were determined. Finally, the Time-Temperature-Transition (ttt) diagram was designed based on the data and equations.

关键词： epoxy resin cure behavior ttt diagram

Crystallization Behavior in Fluoride-Free Mold Fluxes Containing TiO_2/ZrO_2

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Journal of Iron and Steel Research International 2011年第5期18卷 31-37页

作者： ZHANG Zuo-tai LI Jing LIU Peng College of Engineering Peking UniversityBeijing 100871China

The time-temperature-transformation （ttt） diagrams of fluoride-free mold fluxes containing TiO2/ZrO2 were constructed through the confocal scanning laser microscope （CSLM） technique. It was found that the crystallization temperature of F-free mold fluxes containing TiO2 or ZrO2 increases,while incubation time decreases with increasing basicity. The crystallization tendency increases with the zirconia addition in slag melt,as it may be thought that the addition solubility is limited in molten slag and the solid particles act as heterogeneous nucleation sites. Three types of crystal morphologies were observed,corresponding to different crystallization mechanisms. CaSiO3 and Ca3Si2O7 precipitate in the slag with low basicity,and Ca2SiO4 was formed with increasing basicity. The addition of TiO2 promotes the precipitation of CaTiO3. The logarithm of crystal growth rate increased with increasing isothermal temperature,suggesting that the crystal/melt interface reaction is the controlling step in the present experiment.

关键词： crystallization fluoride-free mold flux ttt diagram ZrO2 TiO2

C-Curves of Tool Steels for Annealing and Their Application

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Journal of Iron and Steel Research International 2003年第2期10卷 30-32页

作者： LIUZong-chang LIWen-xue SUNJiu-hong BaotouUniversityofIronandSteelTechnology Baoton014010China FushunSpecialSteelLtdCo Fushun113001China

ttt diagrams,CCT diagrams and critical points of steels H13,S7,S5 for annealing were measured and investigated by means of Formastor-Digital full-automatic phase transformation dilatometer in order to make their annealing technology reasonable and *** basis is provided for making a new annealing technology *** new technology improves the quality of annealed materials,saves energy and increases productivity.

关键词： annealing ttt diagram CCT diagram tool steel

Phase separation time/temperature dependence of thermoplastics-modified thermosetting systems

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Frontiers of Chemical Science and Engineering 2008年第3期2卷 276-285页

作者： Xiujuan ZHANG Xiaosu YI Yuanze XU The Key Laboratory of Molecular Engineering of Polymers Ministry of EducationDepartment of Macromolecular ScienceFudan UniversityShanghai 200433China Institute Aeronautic Materials Beijing 100095China

The cure-induced phase separation processes of various thermoplastics(TP)-modified thermosetting systems which show upper critical solution temperature(UCST)or lower critical solution temperature(LCST)were studied with emphasis on the temperature dependency of the phase separation time and its potential application in the cure time-temperature processing *** found that the phase separation time/temperature relationship follows the simple Arrhenius *** cure-induced phase separation activation energy E_(a)(ps)generated from the linear fitting of the Arrhenius equation is irrelevant to the detection means of phase separation *** also found that E_(a)(ps)is insensitive to TP content,TP molecular weight and curing rate,but it changes with the cure reaction kinetics and the chemical environment of the *** the established phase separation time-temperature dependence relation,we can easily establish the whole cure time-temperature transformation(ttt)diagram with morphology information which is a useful map for the TP/TS composites processing industry.

关键词： polymerization induced phase separation thermosetting thermoplastic time and temperature dependence Arrhenius equation ttt diagram

Acicular Ferrite Microstructure of A Low-carbon Mn-Mo-Nb Microalloyed Pipe Steel

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Acicular Ferrite Microstructure of A Low-carbon Mn-Mo-Nb Mic...

Transformation Behavior and Microstructure in a 40Cr2Ni2MoV Cast Steel

第二届先进钢铁结构材料国际会议

作者： XIAO Furen~(1,2), LIAO Bo~1, REN Deliang~1, SHAN Yiyin~2, YANG Ke~2 (1. Key Laboratory of Materials Science & Technology and College of Materials Science and Engineering, Yanshan University, Qinghuangdao 066004, RR. China 2. Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, RR. China)

＜正＞The transformations during cooling processes, the effects of hot deformation and the morphology of the final microstructure of a low carbon Mn-Mo-Nb microalloyed pipe steel designed for Acicular ferrite microstructure was investigated. The results show that there are three independent "C" curves of isothermal phase transformation, i.e., ttt diagram, of low-carbon microalloyed steel, namely, polygonal ferrites/pearlite "C" curve, the massive ferrite "C" curve and the Bainitic "C" curve, respectively. The hot deformation accelerates the Acicular ferrite transformation and refines the steel’s matrix. The microstructure of Acicular ferrite was discussed.

关键词： Pipeline Steel Acicular Ferrite CCT diagram ttt diagram

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Transformation Behavior and Microstructure in a 40Cr2Ni2MoV ...