检索结果-南通市图书馆

Effect of aging treatment on the microstructures and mechanical properties evolution of 25Cr-20Ni austenitic stainless steel weldments with different nb contents

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2019年第4期35卷 520-529页

作者： Xu Zhang Dianzhong Li Yiyi Li Shanping Lu Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of Sciences School of Materials Science and Engineering University of Science and Technology of China Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences

The microstructure evolutions and the mechanical properties of the 25Cr-20Ni austenitic stainless steel weld metals with different nb contents were investigated during the long term aging treatment at 700~?C.M_(23)C_6,nb(C,N),α-Cr phase and nb-nitride phase(Z phase)were observed in the microstructures of the aged weld metals.The results showed that theα-Cr phase precipitated in the interdendritic regions of the weld metals after being exposed to~ 700?C for 500 h and the element nb accelerated the precipitation of theα-Cr phase significantly.The density of theα-Cr phase decreased with the increase of the distance away from the primary nb(C,N).Additionally,theα-Cr phase showed a crystallographic relationship with the austenitic matrix,■.It was observed that the Z phase precipitated in the periphery of the nb(C,N)and may replace the nb(C,N)after long term exposure to high temperature.The transformation of the nb(C,N)into Z phase suggested that the Z phase had a higher stability than the nb(C,N)par^ticles at 700?C for long term aging.The tensile strength of the nb-bearing weld metal showed a continuous decrease at the initial stage of the aging treatment and then went up slightly with the prolonged aging time.However,the elongations and the impact energies of the weld metals decreased monotonously with the increase of the aging time.

关键词： 25Cr-20Ni steel Weld metal nb Aging treatment α-Cr phase Mechanical property

An experimental determination of W,nb,and Ta partition coefficients between P-rich peraluminous granitic melt and coexisting aqueous fluid

在线全文

学校读者我要写书评

暂无评论

Chinese Journal Of Geochemistry 2015年第2期34卷 194-200页

作者： Yong Tang Hui Zhang Laboratory for High Temperature and High Pressure Study of the Earth's Interior Institute of GeochemistryChinese Academy of Sciences

The partition coefficients of W,nb,and Ta between the P-rich peraluminous granitic melt and the coexisting aqueous fluid were determined at 800-850 °C and 0.5-1.5 kbar.The experimental results showed that the partition coefficients D_w,D_(nb) and D_(Ta)(D_i^(v/m) = C_i^V/C_i^m,where C_i^V and C_i^m denote the concentrations of an element,i,in the aqueous fluid and the melt,respectively) were less than 0.1.All partition coefficients were affected by pressure,but there was no evidence for the complexation of P2O5 with these elements in the granitic melt or aqueous fluid,except for with W in the fluid.The results showed that W,nb,and Ta tended to partition into the granitic melt and,in the late period of crystallization of P-rich magma,they formed independent minerals.

关键词：分配系数实验测定水流体过铝质熔体 nb 共存钽

Effect of nb and Mo on the Microstructure, Mechanical Properties and Ductility-Dip Cracking of Ni–Cr–Fe Weld Metals

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2016年第10期29卷 928-939页

作者： Xu Zhang Dian-Zhong Li Yi-Yi Li Shan-Ping Lu Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences School of Materials Science and Engineering University of Science and Technology of China Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal Research Chinese Academy of Sciences

A series of Ni-Cr-Fe welding wires with different nb and Mo contents were designed to investigate the effect of nb and Mo on the rnicrostructure, mechanical properties and the ductility-dip cracking susceptibility of the weld metals by optical microscopy （OM）, scanning electron microscopy, X-ray diffraction as well as the tensile and impact tests. Results showed that large Laves phases formed and distributed along the interdendritic regions with high nb or Mo addition. The Cr-carbide （M23C6） was suppressed to precipitate at the grain boundaries with high nb addition. Tensile testing indicates that the ultimate strength of weld metals increases with nb or Mo addition. However, the voids formed easily around the large Laves phases in the interdendritic area during tensile testing for the weld metal with high Mo content. It is found that the tensile fractographs of high Mo weld metals show a typical feature of interdendritic fracture. The high nb or Mo addition, which leads to the formation of large Laves phases, exposes a great weakening effect on the impact toughness of weld metals. In addition, the ductility-dip cracking was not found by OM in the selected cross sections of weld metals with different nb additions. High nb addition can eliminate the ductility-dip cracking from the Ni-Cr-Fe weld metals effectively.

关键词： nb Mo Laves phase Microstructure Mechanical properties

AN IN-SITU STUDY ON DISLOCATION BEHAVIOR OF CRACK-TIP IN Ti_3Al-nb ALLOY

在线全文

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 1997年第3期7卷 31-37页

作者： Wu, Y Zhen, L Yang, DZ Liang, W HARBIN INST TECHNOL SCH MAT SCI & ENGN HARBIN 150001 PEOPLES R CHINA TAIYUAN UNIV TECHNOL DETECTING CTR TAIYUAN 030024 PEOPLES R CHINA

ＡＮＩＮＳＩＴＵＳＴＵＤＹＯＮＤＩＳＬＯＣＡＴＩＯＮＢＥＨＡＶＩＯＲＯＦＣＲＡＣＫＴＩＰＩＮＴｉ３ＡｌＮｂＡＬＬＯＹ①ＷｕＹｉｎｇ，ＺｈｅｎＬｉａｎｇ，ＹａｎｇＤｅｚｈｕａｎｇＳｃｈｏｏｌｏｆＭａｔｅｒｉａｌｓ... 详细信息

ＡＮＩＮＳＩＴＵＳＴＵＤＹＯＮＤＩＳＬＯＣＡＴＩＯＮＢＥＨＡＶＩＯＲＯＦＣＲＡＣＫＴＩＰＩＮＴｉ３ＡｌＮｂＡＬＬＯＹ①ＷｕＹｉｎｇ，ＺｈｅｎＬｉａｎｇ，ＹａｎｇＤｅｚｈｕａｎｇＳｃｈｏｏｌｏｆＭａｔｅｒｉａｌｓＳｃｉｅｎｃｅａｎｄＥｎｇｉｎｅｒ...

关键词： Ti 3Al nb alloy tensile deformation crack propagation dislocation

The Electric-Field Controllable Non-Volatile 35° Rotation of Magnetic Easy Axis in Magnetoelectric CoFeB/(001)-Cut Pb(Mg_(1/3)nb_(2/3))O_3-25%PbTiO_3 Heterostructure

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2016年第6期33卷 141-144页

作者：何浩赵江涛罗震林杨远俊徐晗洪宾王亮鑫王瑞雪高琛 Department of Materials Science and Engineering and CAS Key Laboratory of Materials for Energy ConversionUniversity of Science and Technology of China National Synchrotron Radiation Laboratory University of Science and Technology of China Condensed Matter Science and Technology Institute Harbin Institute of Technology

Using in situ electric-field-modulated anisotropic magnetoresistance measurement, a large reversible and non- volatile in-plane rotation of magnetic easy axis of -35° between the positive and negative electrical poling states is demonstrated in C040Fe40B20//（001）-cut Pb（Mgl/3nb2/3）O3-25PbTiO3 （PMN-PT）. The specific magneto- electric coupling mechanism therein is experimentally verified to be related to the synchronous in-plane strain rotation induced by 109° ferroelastic domain switching in the （001）-cut PMN-PT substrate.

关键词： in PT is of PMN O3-25%PbTiO3 Heterostructure Rotation of Magnetic Easy Axis in Magnetoelectric CoFeB The Electric-Field Controllable Non-Volatile 35 Mg nb

Evaluation of Mechanical Properties According to nb Content of High Strength Steel Manufactured in VIM

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2008年第5期24卷 793-796页

作者： Byung-Hui Choi Byung-Ki Choi Department of Mechanical Engineering Graduate SchoolChosun UniversityKorea Department of Mechanical Engineering Chosun UniversityGwang-ju 501-750Korea

As the aircraft and aerospace industry and the automobile industry are developed, the demand of reliable materials with high strength and high toughness is steadily increased. The grain miniature method which improves the ductility and the toughness simultaneously under high strength is the miniature of the casting microstructure. In this paper, the nb which affects the austenite grain miniature is added by 0.00%, 0.03% and 0.06% in this steel and the ingot is manufactured in a vacuum induction melting furnace （VIM）. The casting microstructure and the mechanical property of the maraging steel according to nb contents are analyzed by conducting the solution annealing and the age hardening after hot rolling. In this result, a specimen containing 0.03% nb is most miniature. When it does the long time age hardening, the precipitation estimated as the carbide is appeared. The mechanical properties are excellent if a specimen containing 0.06% nb does the age hardening during 8 h in 482℃.

关键词： High strength steel Maraging steel nb Vacuum induction melting furnace （VIM）

Investigation of matrix effects in the MC-ICP-MS induced by nb, W, and Cu: Isotopic case studies of iron and copper

在线全文

学校读者我要写书评

暂无评论

Chinese Journal Of Geochemistry 2013年第1期32卷 1-6页

作者： SUN Jian ZHU Xiangkun TANG Suohan CHEN Yuelong Laboratory of Isotope Geology MLR State Key Laboratory of Continental Dynamics Institute of Geology CAGS School of Earth Sciences and Resources China University of Geosciences

Some elements normally occur at trace levels while the majority of natural geological materials may be exceedingly enriched in some special cases, such as the Bayan Obo ore deposit where REE and nb are extremely enriched. These elements may not be removed completely during purification. Therefore, matrix effects will be caused during stable isotope ratio measurement in the MC-ICP-MS. Experiments have shown that the established methods of chromatographic separation of Cu, Fe, and Zn using AG MP-1 Anion Exchange Resin cannot make ef-fective separation of nb, W, and Cu from Fe using 20 mL 6 M HCl. It is also observed that the elution curves of W and Cu overlap at working conditions and thus W is present in measurable amounts in some sample solutions. Matrix effects in the MC-ICP-MS induced by nb, W, and Cu during Fe isotope ratio measurements and by W during Cu isotope ratio measurements were thus investigated by examining their changes in delta values between doped and undoped standards. The results show that the effects of the matrix elements nb, W, or Cu on Fe isotope ratio measurements are minimal in the case of m(nb)/m(Fe)nb can be removed during purification, demonstrates that the methods of chromatographic separation of Fe established before are suitable for Bayan Obo ore samples and that the methods can be simplified when Cu elution is unnecessary. The effects of the matrix element W on Cu isotope determinations are minimal in the case of m(W)/m(Cu)<0.7. Therefore, W exerts no significant effect on the measurements of Cu isotopes for the majority of natural geological materials.

关键词：同位素比值基体效应 Cu nb 诱导阴离子交换树脂铁比率测量

Selective propylene epoxidation in liquid phase using highly dispersed nb catalysts incorporated in mesoporous silicates

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2018年第6期26卷 1278-1284页

作者： Wenjuan Yan Yuhui Wu Xiang Feng Chaohe Yang Xin Jin Jian Shen State Key Laboratory of Heavy Oil Processing College of Chemical EngineeringChina University of Petroleum Department of Environmental Science and Engineering Xiangtan University

Selective propylene epoxidation to propylene oxide(PO) with hydrogen peroxide(H_2O_2) was carried out in a catalytic semi-batch reactor.High propylene epoxidation activity(44 h^(-1)) was observed over nb based mesoporous silicate materials nb-TUD-1 under mild operating conditions.The physical and chemical properties of the nb based silicates characterized using BET,FTIR,TPD,TEM and UV–Vis revealed that the site isolation and surface acidity are crucial for PO production.Catalyst synthesis methods were investigated for their effects on PO productivity,PO selectivity and H_2O_2 utilization efficiency.It is found that nb-TUD-1 material synthesized by the sol–gel method is more active and selective than impregnated materials for liquid phase propylene epoxidation.Surface characterization confirms that thus synthesized nb-TUD-1 catalysts have more Lewis acidity and less Bronsted acidity compared to the catalysts by impregnation.

关键词：硅酸盐材料催化剂丙烯 nb 氢过氧化物液体合并化学性质

Effect of nb on Structure and Mechanical Properties of Chilled Cast Iron at Room and Elevated Temperatures

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3期20卷 301-303页

作者： QijieZHAI LiFU HuayingZHAI SchoolofMaterialsScienceandEngineering ShanghaiUniversityShanghai200072China SchoolofMaterialsScienceandEngineering ShenyangUniversityShenyang110044China SchoolofMaterialsScienceandEngineering UniversityofScienceandTechnologyBeijingBeijing100083China

Effect of nb on microstructure and mechanical properties of chilled cast iron at room and elevated temperatures isstudied in this research. The results demonstrate that the cast structure and mechanical properties of chilled castiron at room and elevated temperatures are improved with the addition of trace amount of nb. However, if nb wasadded too much, the cast structure and mechanical properties of chilled cast iron would deteriorate. The suitablecontent of nb in chilled cast iron is about 0.05% (mass fraction). Except the dissolution in the matrix of cast ironthe excessive nb will form nb-rich phases in three morphologies. Those are lumpy nbC, complicated strip-like phaseand compound with pearlite structure.

关键词： nb Chilled cast iron Structure Properties