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Martensite Transformation and Its Control in DP,TRIP and TWIP Steels

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Journal of Iron and Steel Research International 2011年第S1期18卷 200-207页

作者： LI Lin 1,GAO Yi 2.SHI Wen 1,LIU Ren-dong 2.he Yan-lin 1,FU Ren-yu 1,ZHANG Mei 1,WANG Hua 1 (1.school of {2. science and Engineering,Shanghai university,Shanghai 2.0072.china 2.Ansteel Company,Anshan 114001 china Corresponding Author:school of {2. science and Engineering,Shanghai university,P.O.Box 15,149 Yanchang Road,Shanghai 2.0072.china) Shanghai Univ Sch Mat Sci & Engn Shanghai 200072 Peoples R China Ansteel Co Anshan 114001 Peoples R China

Designing of alloy concept and process for DP,TRIP and TWIP steels stressing at martensite transformation are *** DP steel,austenite volume percent and its carbon content at different intercritical temperatures are calculated as well as the tensile strength of the steel,which meet well with the experimental *** condition for dissolution of carbide is discussed by experiments and predicted by kinetic *** sample TRIP steels are prepared and their concentration profiles are calculated showing different diffusion characteristics of *** also shows carbon enrichment is successful in this stage through the quick diffusion of carbon from ferrite to *** order to maintain the austenite stability or to prevent precipitation of cementite,minimum cooling rate from the intercritical zone to over aging stage is obtained through kinetic *** transformation is estimated,which indicates the carbon rerichment from ferrite of bainite structure to austenite in this stage is also *** HCP martensite transformation and the strain induced martensite transformation in TWIP steel is *** between transformation and mechanical properties in the steel is also mentioned.

关键词： martensite transformation DP TRIP and TWIP steels thermal HCP martensite transformation

Effect of Nb on the Mechanical Properties of Ti/Al_2._3 Composite

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Journal of Wuhan university of technology({2. science) 2005年第1期20卷 30-32,36页

作者：王志 school of materials {2. and Engineering Ji'nan University Jinan 250022China State Key Laboratory of Advanced technology for materials Synt{2.sis and Proces sing Wuhan University of Techology Wuhan 430070China

Ti/Al 2. 3 composite with improved mechanical properties was synthesized by th e spark plasma sintering. The effect of Nb on the microstructure of the composit e was analyzed by TEM, SEM and so on. The experimental results indicate that the bending strength, fracture toughness, micro-hardness and relative density of t he composite are 897.2.MPa, 17.38MPa·m 1/2. 17.13GPa and 99.2.% respec tively when adding 1.5vol%Nb. The bending strength is improved by reason of form ing dislocation ring and transfering fracture mode from intergranular to mixture fracture of intergranular and transgranular. The crack propagating is mainly th e deflection bridging. It indicates a reduction of crack driving force and an in crease in crack growth resistance,which results in toughness enhanced.

关键词： spark plasma sintering Ti/Al 2. 3 composite niobium mechanical properti es

Study on Contact Fatigue Life and Failure Mechanism of Subquenched 42.rMo Steel

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材料热处理学报 2004年第5期25卷 260-262页

作者： heBo-lin YUYing-xia SHAOEr-yu schoolofMechanical＆ElectricalEngineering EastChinaJiaotongUniversityNanchangChina MaterialInstitute HenanUniversityofScienceandTechnologyLuoyangChina

The effect of undissolved ferrite amount in subcritically quenched 42.rMo steel on contact fatigue properties and failure mechanism were studied. The amount of undissolved ferrite in the steel were 0%,3%,10%,15% and 2.% in volume fraction, respectively. The experimental results show that the existence of undissolved ferrite can increase the contact fatigue life The contact fatigue life can be prolonged with increasing the amounts of undissolved ferrite The grain size can be fined by using subcritical quenching process and the area of phase boundaries can also be greatly increased. The stress relaxation and grain refinement due to occurring of plastic deformation are main reasons for improving the fatigue life. The existence of undissolved ferrite can increase the crack initiation period. Under the experiment conditions, when the amount of undissolved ferrite is 10%, the longest contact fatigue life can be the obtained.

关键词：亚临界灭弧接触疲劳失效机理铁素体 42.rMo钢

Thermodynamic Analysis of the Preparation Process of EB-PVD SiC Coating

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Journal of Wuhan university of technology({2. science) 2009年第3期24卷 363-366页

作者：易剑 school of Mechatronics Engineering Taizhou University Laser Processing Center Tianjin Polytechnic University Center for Composite materials Harbin Institute of Technology

The process of preparing SiC coating by electron beam-physical vapor deposition （EB-PVD） was discussed from viewpoint of thermodynamis. Results show that within the temperature range of 2.700-3 300 K, the ratio of SiC in the SiC coating doesn＇t change much and keeps around 0.7. Purity of the as-deposited SiC coating is not high. To improve the purity of the SiC coating, the SiC ingot is required to not be, necessary in full density but be fine-grained.

关键词： thermodynamics SiC coating EB-PVD ratio of SiC purity

Nano-apatite/Polymer Biocomposite for Tissue Engineering

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Journal of Wuhan university of technology({2. science) 2005年第B12期20卷 126-128页

作者：魏杰 Institute of Biomaterials East China University of Science and Technology Shanghai 200237China

A new kind of tissue engineering scaffold materials of nano-apatite （ NA ） and polyamide6 （ PA6 ） biocomposite was prepared by means of the co-solution method. The NA crystals uniforndy distribute in the composite with a size of 10-30 nm in diameter by 50-90 nm in length. The NA/ PA6 composite has good homogeneity and high NA content, and excellent mechanical properties close to those of natural bone. The porous 3-D scaffold has not only macropores, but also micropores on the walls of macropores with porosity of about 80% and the size of pore diameter of about 300μm made by injection foam. The biocomposite can be used for bone repair and as scaffolds in tissue engineering.

关键词： biocomposite nano apatite tissue engineering scaffold material

Microstructure and properties of Al_2._3-13%TiO_2.coatings sprayed using nanostructured powders

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Rare Metals 2007年第4期26卷 391-397页

作者： ZHANG Jianxin he Jining DONG Yanchun LI Xiangzhi YAN Dianran school of materials {2. and Engineering Hebei University of Technology Tianjin 300130 China

The microstructure and wear performance of M2.3-13% TiO2.coatings prepared by plasma spraying of agglom- erated nanoparticle powders were investigated. SEM analysis showed that the as-sprayed Al2.3-TiO2.coatings comprise of two kinds of typical region： fully melted region and unmelted/partially melted nanostructured region, which is different than the conventional coating with lamellar structure. It is shown that the microhardness of the nanostructured coatings was about 15%-30% higher than that of the conventional coating and the wear resistance is significantly improved, especially under a high wear load. The nanostructured coating sprayed at a lower power shows a lower wear resistance than the coatings produced at a higher power, because of the presence of pores and microstructural defects which are detrimental to the fracture toughness of the coatings.

关键词： surface coating nanostructured coating plasma spray microhardness wear resistance

Microstructure Characteristic of In-situ Ti/TiC Composites

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Journal of materials science & {2. 2001年第1期17卷 103-104页

作者： Bo YANG beijing institute of Aeronauticul materials, beijing 100095, china Erlin ZHANG Yunxue JIN Zhaojun ZHU and Songyan ZENG National Key Lab. of Precision Hot Processing of Metals, Harbin institute of technology, Harbin 150001, china Inst. of Aeronaut. Mater. Beijing 100095 China

TiC reinforced titanium composites has been produced with different Al content and C content by XDTM. The results have shown that TiC particles are of two different morphologies f coarse dendritical primary TiC and short bar-shape eutectic TiC. Al content has great effects on the morphology of TiC. With the increasing of Al content, the morphology of primary TiC changes from coarse developed dendrite into short bar-shape or plate--shape TiC with 35%Al. Meanwhile, the structure of the matrix changes from single Ti to Ti and Ti3Al, and to Ti3Al and TiAl. However, the C content has no influence on the microstructure of matrix. When the C content is less than 1.2., the dendrite TiC disappears and only short bar-shape or plate-shape TiC exists in the composites. In addition, the effect of he3t treatment on the morphology of TiC has also Studied.

关键词： TiC Microstructure Characteristic of In-situ Ti/TiC Composites

Controllable synthesis of Ni-catalyzed tetragonal tungsten nanowires via chemical vapor deposition

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Progress in Natural science:materials International 2012年第5期22卷 514-519页

作者： Chao Wang a,Yuehui he a,Chaoqun Peng b,Shiliang Wang a,c,Xinli Liu a a State Key Laboratory of Powder Metallurgy,Central South university,Changsha 410083,{2. b school of Material science and Engineering,Central South university,Changsha 410083,{2. c school of Physics science and technology,Central South university,Changsha 410083,{2. State Key Laboratory of Powder Metallurgy Central South University Changsha 410083 China school of Material science and Engineering Central South University Changsha 410083 China school of Physics science and {2. Central South University Changsha 410083 China

Tetragonal single-crystal tungsten nanowires were successfully synthesized by chemical vapor deposition(CVD) catalyzed by Ni *** influences of the catalysts,temperature and growth time on the formation of the nanowires were *** was found that the tetragonal tungsten nanowires(WNWs) arrays were obtained by deterministic growth from the ordered Ni catalyst particles with one-to-one relation in size and position between the catalysts and *** large-scale tungsten nanowire arrays were synthesized at the low temperature of 950℃.Samples were characterized by X-ray diffraction(XRD),field-emission scanning electron microscopy(FE-SEM),transmission electron microscopy(TEM) and high-resolution transmission electron microscopy(HRTEM).Increasing growth time at 950℃,the tip of the WNWs changed from four(2.1) planes to four(110) *** controls of the orientation and structure of WNWs arrays were important for adjusting their properties to satisfy different requirements of potential nanodevices.

关键词： Tungsten nanowires Ni catalysts Chemical vapor deposition Nanostructures

Durability of Asphalt Mixture in Different Corrosion Solution

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Journal of Wuhan university of technology({2. science) 2011年第6期26卷 1200-1204页

作者：陈拴发关博文 Key Laboratory for Special Area Highway Engineering of Ministry of Education Chang’an University school of materials {2. and Engineering Chang’an University

The corrosion to asphalt mixture under different kinds of corrosion solution, such as pH=2.solution, pH=12.solution, pH = 12.solution and 10% Na2.O4 solution, was studied. The performance attenuation of asphalt mixture was analyzed under the normal environment and the freeze-thaw environment, and the analysis was given on the sensitivity of the test results to the evaluation index. The experimental results show that the performance of asphalt mixture is attenuated faster under the acidic solution, alkaline solution and sulfate solution. Corrosion factor Kc, freeze-thaw corrosion factor Kf, and freeze-thaw effect factor Kfc are proposed to evaluate asphalt mixture resistance to corrosion in different kinds of corrosion solution. The values of Kc and Kfc decrease with the increasing of corrosion time. The change rule of Kf show that the rate of corrosion is decreased by the action of freeze-thaw in acidic solution and in alkaline solution, but is increased by the action of freeze-thaw in sulfate solution. The microscopic analysis indicates that acid solution reacts with aggregate of asphalt mixture, alkaline solution reacts with asphalt cement of asphalt mixture, the surface tension of sulfate solution and crystallization of sulfate are the main reasons which weak the performance of asphalt mixture.

关键词： asphalt mixture corrosion damage corrosion mechanism corrosion evaluation