检索结果-南通市图书馆

Journal of University of Science and Technology Beijing 2006年第5期13卷 411-415页

作者： Guoan Chen Wangyue Yang Shouzhen Guo Zuqing Sun Materials Science and Engineering School University of Science and Technology Beijing Beijing 100083 China State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 China

The hot compression tests using Gleeble 1500 were performed by varying the true strain up to 1.6 （80% reduction） in Nbfree and Nb-microalloyed steels. The effect of Nb addition on the transformation kinetics during deformation of undercooled austenite was investigated. It was found that as compared with Nb-free steel, the transformation incubation period of Nb-bearing steel was prolonged and the transformation kinetics curves parallelly moved to higher strain because of the solute Nb drag effect. Studies on kinetics also showed that the deformation-enhanced ferrite transformation （DEFT） of the two steels were composed of three stages, which can be expressed by the J-M-A equations individually. However, the parameter n related to the mode of nucleation and growth is somewhat different in the first and second stages of the two steels, and the same in the third stage for both the steels corresponding to the nucleation Of retained austenite.

关键词： Nb-microalloyed steel deformation-enhanced ferrite transformation transformation kinetics J-M-A equations

MODELLING FOR PREDICTION OF CONTINUOUS COOLING transformation kinetics OF HOT-DEFORMED AUSTENITE STEEL

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 1998年第3期11卷 225-229页

作者： J.B.Qu Z.D.Wang X.H.Liu G.D.Wang Northeastern Univ Shenyang China

On the thermodynamics basis of regular solution sub-lattice model and soperelement model, kinetics basis of Cahn's transformation kinetics theory, and according to Scheil's additivity rule and eoperimental results obtained by thermal dilation method,a prediction model of transformations from hot-deformed austenite to ferrite, pearlite and bainite in low alloy steels, which could be applied to continuoas cooling process, is developed. The calculated transformed junctions of each phase based on laboratory controlled rolling and controlled cooling conditions in a low alloy steel are in reasonable agreement with the measured ones.

关键词： transformation kinetics thermodynamics continuous cooling,hot-deformed austenite

Calculation of AF transformation kinetics in HSLA steel weld

在线全文

学校读者我要写书评

暂无评论

China Welding 2004年第1期13卷 46-50页

作者：张国栋潘春旭黄安国李志远余圣甫市川和利 Department of Physics Wuhan University School of Materials Science and Engineering Huazhong University of Science and Technology Welding & Joining Research Center Nippon Steel Corporation

It is of great importance for obtaining the perfect welding properties to control the acicular ferrite (AF) transformation behavior reasonably in steel weld. AF continuous transformation kinetics in the HSLA steel weld was calculated and modeled based on the direct growth on the inclusions inert interface. The simulation results are coincident with the experimental value well.

关键词： acicular ferrite high strength low alloy steel weld transformation kinetics modeling

Calculation of AF transformation kinetics in HSLA steel weld

在线全文

学校读者我要写书评

暂无评论

Calculation of AF transformation kinetics in HSLA steel weld

Roles of pre-formed martensite in below-Ms bainite formation,microstructure,strain partitioning and impact absorption energies of low-carbon bainitic steel

湖北省暨武汉焊接学会成立二十五周年2005年焊接学术年...

作者：张国栋潘春旭黄安国李志远余圣甫市川和利 Department of Physics Department of Physics School of Materials Science and Engineering School of Materials Science and Engineering School of Materials Science and Engineering Welding ＆ Joining Research Center

＜正＞It is of great importance for obtaining At perfect welding properties to control the acicular ferriter （AF） transformation behavior reasonably in steel weld. AF （?） transformation kinetics in the HSIA steel weld was calculated and modeled based on the direct growth on the inclusions inert interface. The simulation results are coincident with the experimental value well.

关键词： acicular ferrite high strength low alloy steel weld transformation kinetics modeling

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2022年第1期96卷 69-84页

作者： Lihe Qian Zhi Li Tongliang Wang Dongdong Li Fucheng Zhang Jiangying Meng State Key Laboratory of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao 066004China National Engineering Research Center for Equipment and Technology of Cold Strip Rolling Yanshan UniversityQinhuangdao 066004China Library of Yanshan University Yanshan UniversityQinhuangdao 066004China

The roles of pre-formed martensite(PM)in below-Ms bainite formation,microstructure,crystallography,strain partitioning and mechanical properties of a low-carbon bainitic steel were investigated using electron-backscattered diffraction,transmission electron microscopy,micro digital image correlation technique and mechanical tests.It is demonstrated that the pre-formation of martensite eliminates the incubation time for bainite transformation at various austempering temperatures below Ms,indicative of its acceleration effect at the early stage of transformation.This effect is mainly attributed to the surfaces or tips of the PM acting as the nuclei of subsequently-formed bainite,with initial bainite tending to form around the PM.However,the finishing time for below-Ms bainite transformation,especially at even lower temperatures,is retarded,owing to the dividing effect of PM on parent austenite grains,the decreasing effect of lowered isothermal temperature on the diffusion rate of carbon atoms and the strengthening effect of lowered isothermal temperature on supercooled austenite.PM and its adjacent bainitic laths have nearly the same crystallographic orientation and belong to the same block.The pre-formation of martensite largely refines the bainitic blocks/laths and retained austenite.The specimens with PM show relatively uniform strain partitioning among various phases,contrasting with the specimens without PM,for which strains are highly concentrated in the bainite region nearby fresh martensite/austenite(M/A)blocks or between adjacent M/A blocks.The impact absorption energies of the specimens with PM,when austempered at 30-60℃ below Ms,are more than twice higher than those of the specimens without PM,at no expense of tensile properties.

关键词： Bainite Martensite Impact toughness transformation kinetics Strain partitioning

Roles of Al in enhancing the thermal stability of reverted austenite and mechanical properties of a medium-Mn TRIP steel containing 2.7 Mn

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2023年第36期167卷 119-136页

作者： Wenlu Yu Lihe Qian Xu Peng Tongliang Wang Kaifang Li Chaozhang Wei Zhaoxiang Chen Fucheng Zhang Jiangying Meng State Key Laboratory of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao 066004China National Engineering Research Center for Equipment and Technology of Cold Strip Rolling Yanshan UniversityQinhuangdao 066004China School of Mechanical Engineering Yanshan UniversityQinhuangdao 066004China

Often,the addition of more than 4 wt.%Mn to medium-Mn steels is necessary to enhance the thermal stability of intercritical austenite for achieving sufficient amounts of retained austenite(RA)at room tem-perature.In this paper,a medium-Mn steel with Mn content as low as 2.7 wt.%was designed via alloying with a small amount of Al,and the microstructure and mechanical properties of the steel,subjected to intercritical annealing(IA)at 745°C for different times followed by oil quenching,were investigated.Results show that the volume fraction of RA increases first and then decreases with IA time,with the maximum of 0.36 obtained at IA time of 50 min.It is demonstrated that Al addition slows down the in-terface migration and growth kinetics of reverted austenite via retarding C diffusion in ferrite during IA,which,hence,decreases the amount and size of the reverted austenite and partitions more C and Mn into it.This suggests that Al plays a favorable role in enhancing the thermal stability of reverted austenite and increasing the amount of austenite retained at room temperature.Due to the presence of large amounts of RA and the strong transformation-induced plasticity effect generated during plastic deformation,the steel exhibits persistent high strain hardening and superior mechanical properties,comparable to those of reported medium-Mn steels containing higher Mn content.The present result offers a new insight into the role of Al in adjusting microstructure-property relationships and opens a promising way for designing low-cost,high performance medium-Mn steels with low Mn content for industrial applications.

关键词： Medium-Mn steel transformation-induced plasticity transformation kinetics Austenite thermal stability Mechanical properties

Characteristics of microstructural evolution during deformation-enhanced ferrite transformation in Nb-microalloyed HSLA steel

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2007年第1期14卷 36-40页

作者： Guoan Chen Wangyue Yang Shouzhen Guo Zuqing Sun State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 China Materials Science and Engineering School University of Science and Technology Beijing Beijing 100083 China

Microstructure evolution during deformation of undercooled austenite at 760℃ was investigated in Nb-microalloyed steel by using SEM （scanning electron microscope）, TEM （transmission electron microscope）, and EBSD （electron backscattered diffraction）. It is indicated that during deformation-enhanced ferrite transformation （DEFT） in Nb-microalloyed steel, the incubation period is prolonged, and the higher strain is needed to accomplish ferrite transformation. Therefore, the transformation kinetics curves move to high strain parallelly; and the transformation kinetics curves of Nb-microalloyed steel can be divided into three stages. At the fast stage, the solute drag effect of Nb and the consumption of strain energy for the dynamic precipitation of Nb（CN） led to a long incubation period, and at the second stage, ferrite transformation was accelerated significantly and fine Nb（CN） precipitates restrict the grain growth of ferrite effectively. The results also showed that DEFT in Nb-microalloyed steel is still a nucleation dominated process, and during the microstructure evolution the interchange of 〈001〉 and 〈111〉 texture was obtained.

关键词： Nb-microalloyed steel deformation-enhanced ferrite transformation （DEFT） microstructure evolution transformation kinetics texture

Effect of austempering time on microstructure and properties of a low-carbon bainite steel

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2020年第3期27卷 340-346页

作者： Man Liu Guang Xu Jun-yu Tian Qing Yuan Xin Chen The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and Technology

The effect of austempering time after the bainitic transformation on the microstructure and property in a low-carbon bainite steel was investigated by metallography and dilatometry. The results showed that by prolonging the austempering time after the bainite transformation, the amount of large-size martensite/austenite islands decreased, but no significant change of the amount and morphology of bainite were observed. In addition, more austenite with a high carbon content was retained by prolonging the holding time at the bainite transformation temperature.Moreover, with a longer holding time, the elongation was improved at the expense of a small decrease in tensile strength. Finally, the Avrami equation B(RF) = 1-exp(-0.0499 × t^0.7616) for bainite reaction at 350℃ was obtained for the tested steel. The work provided a reference for tailoring the properties of low-carbon steels.

关键词： austempering time retained austenite martensite/austenite island low-carbon bainite transformation kinetics

Formation of Omega-like Nanocrystalline in the Melt-Spun Nd_(85)Al_(15) Alloy by Phase transformation

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2002年第5期18卷 462-464页

作者： JiaZHANG WenshengSUN MingxiuQUAN ZhuangqiHU Lab. for Mat. Sci. Inst. of Metal Res. Chinese Acad. of Sci. Shenyang 110016 China

Microstructure and subsequent phase transformations on heating of the melt-spun Nd85Al15 alloy have been studied by X-ray diffraction, transmission electron microscopy and differential scanning calorimetry. The melt-spun Nd85Al15 alloy shows two-stage transformation processes as follows: amorphous+72 nm supersaturated bcc-Nd(AI) solid solution-7 nm omega-like phase-AINd3+hexagonal Nd. The activation energies for the first and second transformation were found to be 100 kj/mol and 188 kj/mol, respectively. The formation mechanism of nanoscale omega-like phase is discussed.

关键词： Melt-spun Nd85Al15 alloy Omega-like phase transformation kinetics

Computer Simulation of Ferrite transformation during Hot Working of Low Carbon Steel

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2004年第5期20卷 497-500页

作者： Yunbo XU, Yongmei YU, Xianghua LIU and Guodong WANGState Key Laboratory of Rolling and Automation, Northeastern University, P.O. Box 105, Shenyang 110004, China Lab. of Rolling and Automat. Northeastern Univ. P.O. Box 105 Shenyang 110004 China

On the basis of transformation kinetics and thermodynamics, the austenite-ferrite transformation start temperature during deformation was predicted for several grades of low-carbon steels under different processing conditions. Results indicate that Ar3d temperature mostly depended on alloying composition and processing parameters. Ar3d increased as strain rate or strain increased for the same steel grade. In view of enhancement of deformation on transformation, the basic kinetics model was established to simulate deformation induced transformation behavior, using which the influence of the deformation stored energy and effective deformation ledge on the nucleation and growth can be considered. The simulated results are in good agreement with experiment results.

关键词： Computer simulation transformation kinetics Ultrafine ferrite Deformation induced transformation