检索结果-南通市图书馆

Microstructure and formation mechanism of twins of laths of austenite with high nitrogen

Science china(Technological Sciences) 2007年第6期50卷 755-764页

作者： WU CuiLan1,2 & LUO ChengPing2 1 Center for High Resolution Electron Microscopy, college of Materials Science and engineering, Hunan university, Changsha 410082, china 2 college of mechanical engineering, south china university of technology, guangzhou 510641, china 1. Center for High Resolution Electron Microscopy College of Materials Science and Engineering Hunan University Changsha 410082 China 2. college of mechanical engineering South China University of Technology Guangzhou 510641 China

The microstructure of composite diffusion layer of the nitrided and chromized 0.2% carbon steel is investigated using TEM and EDS. It is found that laths of austenite with high nitrogen (γ N) precipitate from α-ferrite matrix in the deeper zone of the diffusion layer. These γ N laths are all twins, with their {111} twinning planes parallel to the lath axis, thus forming a characteristic "back-to-back" morphology. There are two types of γN lath. The first is a genuinely {111} twin, and γ N and α keep the accurate K-S relationship, and each γ N and α form a sharp and smooth γ N/α inter- face of {335}γN//{341}α, namely habit plane {335}fcc. The second is a pseudo-twin, with micro-twins {111} or faults formed within the two twin components. Localized lattice deformation (relaxation) seems to have occurred at the interfaces of the second type of γ N due to the formation of micro-twins or faults within the twin components. These micro-twins or faults make the orientation relationship (OR) between each of the γN and the α-matrix deviate from the accurate K-S OR, and the OR between two γ N twin components deviate from the genuine {111} twin relation- ship. In addition, the γ N/α interface of the second type of γ N is not as sharp or smooth as that of the first one.

关键词： austenite containing nitrogen, twins, steel 20, nitriding, composite chromizing

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Microstructure and Properties of Low Temperature Composite Chromized Layer on H13 Tool Steel

引用

Journal of Materials Science & technology 2005年第2期21卷 251-255页

作者： Cuilan WU, Chengping LUO and Ganfeng ZOU college of mechanical engineering, south china university of technology, guangzhou 510641, china Coll. of Mech. Eng. South China Univ. of Technol. Guangzhou 510641 China

Low temperature composite chromizing is a process composed of a plain ion-carbonitriding or ion-nitriding at 550-580℃, followed by a low-temperature chromizing in a salt-bath of 590℃. The microstructure and properties of the low temperature composite chromized layer on H13 tool steel were investigated using metallography, X-ray diffraction, microanalysis, hardness and wear tests. It was found that this low temperature process was thermo-dynamically and kinetically possible, and the composite chromized layer on H13 steel, with a thickness of 3-6 μm, consisted of three sub-layers (bands), viz. the outer Cr-rich one, the intermediate (black) one, and the inner, original white layer. After chromizing, the former diffusion layer was thickened. The results of X-ray diffraction showed that the composite chromized layer contained such nitrides and carbides of chromium as CrN, Cr2N, (Cr, Fe)23C6, and (Cr, Fe)7C3, as well as plain α-(Fe, Cr). A high surface microhardness of 1450-1550 HV0.025, which is much higher than that obtained by the conventional ion carbonitriding and ion nitriding, was obtained. In addition, an excellent wear resistance was gained on the composite chromized layer.

关键词： H13 tool steel Low temperature composite chromizing Nitride and carbide of chromium Microhardness Wear resistance

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

DIMPLE FORMATION ON FRACTURE SURFACE OF STEEL 55SiMnMo

引用

Acta Metallurgica Sinica(English Letters) 1993年第2期6卷 140-143页

作者： LIANG Sizu LIANG Yaoneng LIU Zhengyi south china university of technology,guangzhou,china Lecturer,Department of mechanical engineering No.2,south china university of technology,guangzhou 510641,china south china Univ of technology Guangzhou China

The fracture surface of the normalized steel 55SiMnMo was observed,under tensile device at- tached on the SEM,to be of ductile dimple feature on the bainite which is composed of lath ferrite and austenite *** dimple is essentially nucleated in the *** the austenitic plastic deformation is remarkable during fracturing,the tear ridge of dimple is very sharp.

关键词： dimple plastic deformation ductile fracture steel 55SiMnMo

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A mechanical MODEL FOR THE CHIP SIDE DEFORMATION IN ALUMINIUM ALLOY CUTTING

引用

中国有色金属学会会刊：英文版 1995年第4期5卷 168-172页

作者： Xia Wei Li Yuanyuan Zhou Zehua(Department of mechanical engineering,south china university of technology,guangzhou 510641) south china Univ of technology Guangzhou China

ＡＭＥＣＨＡＮＩＣＡＬＭＯＤＥＬＦＯＲＴＨＥＣＨＩＰＳＩＤＥＤＥＦＯＲＭＡＴＩＯＮＩＮＡＬＵＭＩＮＩＵＭＡＬＬＯＹＣＵＴＴＩＮＧＸｉａＷｅｉ；ＬｉＹｕａｎｙｕａｎ；ＺｈｏｕＺｅｈｕａ（ＤｅｐａｒｔｍｅｎｔｏｆＭｅｃｈ... 详细信息

ＡＭＥＣＨＡＮＩＣＡＬＭＯＤＥＬＦＯＲＴＨＥＣＨＩＰＳＩＤＥＤＥＦＯＲＭＡＴＩＯＮＩＮＡＬＵＭＩＮＩＵＭＡＬＬＯＹＣＵＴＴＩＮＧＸｉａＷｅｉ；ＬｉＹｕａｎｙｕａｎ；ＺｈｏｕＺｅｈｕａ（ＤｅｐａｒｔｍｅｎｔｏｆＭｅｃｈａｎｉｃａｌＥｎｇｉｎｅｅｒｉｎｇ...

关键词： metal cutting mechanical model cutting force chip side deformation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Vector bundle constraint for particle swarm optimization and its application to active contour modeling

引用

Progress in Natural Science:Materials International 2007年第10期17卷 1220-1225页

作者： Zeng Delu, Zhou Zhiheng and Xie Shengli(college of Electronic and Information engineering, south china university of technology, guangzhou 510641, china) college of Electronic and Information engineering South China University of Technology Guangzhou 510641 China

Active contour modeling (ACM) has been shown to be a powerful method in object boundary extraction. In this paper, a new ACM based on vector bundle constraint for particle swarm optimization (VBCPSO-ACM) is proposed. Different from the traditional particle swarm optimization (PSO), in the process of velocity update, a vector bundle is predefined for each particle and velocity update of the particle is restricted to its bundle. Applying this idea to ACM, control points on the contour are treated as particles in PSO and the evolution of the contour is driven by the particles. Meanwhile, global searching is shifted to local searching in ACM by decreasing the number of neighbors and inertia. In addition, the addition and deletion of particles on the active contour make this new model possible for representing the real boundaries more precisely. The proposed VBCPSO-ACM can avoid self-intersection during contour evolving and also extract inhomogeneous boundaries. The simulation results proved its great performance in performing contour extraction.

关键词： boundary extraction active contour modeling particle swarm optimization velocity update vector bundle.

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

A MECHANICS MODEL FOR CIRCULAR FORM TOOL CUTTING

引用

中国有色金属学会会刊：英文版 1996年第2期6卷 86-90,94页

作者： Xia Wei Li Yuanyuan Zhou Zehua (Department of mechanical engineering,south china university of technology, guangzhou 510641) S china UNIV TECHNOL DEPT MECH ENGNGUANGZHOU 510641PEOPLES R CHINA

ＡＭＥＣＨＡＮＩＣＳＭＯＤＥＬＦＯＲＣＩＲＣＵＬＡＲＦＯＲＭＴＯＯＬＣＵＴＴＩＮＧＸｉａＷｅｉ；ＬｉＹｕａｎｙｕａｎ；ＺｈｏｕＺｅｈｕａ（ＤｅｐａｒｔｍｅｎｔｏｆＭｅｃｈａｎｉｃａｌＥｎｇｉｎｅｅｒｉｎｇ，Ｓｏｕｔｈ... 详细信息

ＡＭＥＣＨＡＮＩＣＳＭＯＤＥＬＦＯＲＣＩＲＣＵＬＡＲＦＯＲＭＴＯＯＬＣＵＴＴＩＮＧＸｉａＷｅｉ；ＬｉＹｕａｎｙｕａｎ；ＺｈｏｕＺｅｈｕａ（ＤｅｐａｒｔｍｅｎｔｏｆＭｅｃｈａｎｉｃａｌＥｎｇｉｎｅｅｒｉｎｇ，ＳｏｕｔｈＣｈｉｎａＵｎｉｖｅｒｓｉｔｙｏｆ...

关键词： metal cutting mechanical medel circular form tcol

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A NOVEL INTERPRETATION OF CONCENTRATION DEPENDENCE OF VISCOSITY OF DILUTE POLYMER SOLUTION

引用

Chinese Journal of Polymer Science 2000年第1期18卷 57-67页

作者： Yan Pan Rong-shi Cheng college of Material Science and engineering, south china university of technology, guangzhou 510641, china college of Chemistry and Chemical engineering, Nanjing university, Nanjing 210093, china S china Univ Technol Coll Mat Sci & Engn Guangzhou 510641 Peoples R China Nanjing Univ Coll Chem & Chem Engn Nanjing 210093 Peoples R China

The concentration dependence of the reduced viscosity of dilute polymer solution is interpreted in the light of a new concept of the self-association of polymer chains in dilute solution. The apparent self-association constant is defined as the molar association constant divided by the molar mass of individual polymer chain and is numerically interconvertible with the Huggins coefficient. The molar association constant is directly proportional to the effective hydrodynamic volume of the polymer chain in solution and is irrespective of the chain architecture. The effective hydrodynamic volume accounts for the non-spherical conformation of a short polymer chain in solution and is a product of a shape factor and hydrodynamic volume. The observed enhancement of Huggins coefficient for short chain and branched polymer is satisfactorily interpreted by the concept of self-association. The concept of self-association allows us to predict the existence of a boundary concentration C-s(dynamic contact concentration) which divides the dilute polymer solution into two regions.

关键词： self-association polymer solution viscosity concentration dependence

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Microwave peak absorption frequency of liquid

引用

Science china(Physics,Mechanics & Astronomy) 2008年第9期51卷 1254-1263页

作者： HAN GuangZe1 & CHEN MingDong2 1 Department of Physics,south china university of technology,guangzhou 510640,china 2 guangzhou Auto college,south china university of technology,guangzhou 510800,china 1. Department of Physics South China University of Technology Guangzhou 510640 China 2. guangzhou Auto college South China University of Technology Guangzhou 510800 China

Microwave-assisted extraction is a new effective method which has practical ap-plications in many fields. Microwave heating is one of its physical mechanisms,and it also has the characteristic of selectivity. When the applied microwave fre-quency equals a certain absorption frequency of the material (or specific compo-nent),the material will intensively absorb microwave energy. This is also known as resonant absorption,and the frequency is called the peak absorption frequency which depends on the physical structure of the material. In this work,dynamic hy-drogen bond energy was included in molecular activation energy; with the liquid cell model,the expression of interaction energy between dipolar molecules was derived. The rotational relaxation time was gotten from the Eyring viscosity formula. Then based on the relationship between dielectric dissipation coefficient and re-laxation time,the expression of microwave peak absorption frequency as a func-tion of the material physical structure,rotational inertia and electrical dipole mo-ment of molecules was established. These theoretical formulas were applied to water and benzene,and the calculated results agree fairly well with the experi-mental data. This work can not only deepen the study of the interaction between microwave and material,but also provide a possible guide for the experiment of microwave-assisted extraction.

关键词： microwave-assisted extraction microwave heating relaxation time liquid viscosity peak absorption fre-quency

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

mechanically Driven Alloying and Structural Evolution of Nanocrystalline Fe_(60)Cu_(40) Powder

引用

Journal of Materials Science & technology 1997年第4期13卷 354-358页

作者： Yuanda DONG and Xueming MA(School of Materials Science and engineering, Shanghai university, Shanghai 200072, china)Yuanzheng YANG(Dept. of mechanical engineering(2), south china university of technology, guangzhou 510641, china)Fangxin LIU and Genmiao WA School of Materials Science and engineering Shanghai University Shanghai 200072 China Dept. of mechanical engineering(2) South China University of Technology Guangzhou 510641 China Lab. of Structure Analysis University of Science and Technology of China Hefei 230026 China

Highly supersaturated nanocrystalline fcc Fe60Cu40 alloy has been prepared by mechanical alloying of elemental powders. The phase transformation is monitored by X-ray diffraction (XRD),Mossbauer spectroscopy and extended X-ray absorption fine structure (EXAFS). The powder obtained after milling is of single fcc structure with grain size of nanometer order. The Mossbauer spectra of the milled powder can be fitted by two subspectra whose hyperfine magnetic fields are 16 MA/m and 20 MA/m while that of pure Fe disappeared. EXAFS results show that the radial structure function (RSF) of Fe K-edge changed drastically and finally became similar to that of reference Cu K-edge, while that of Cu K-edge nearly keeps unchanged in the process of milling. These imply that bcc Fe really transforms to fcc structure and alloying between Fe and Cu occurs truly on an atomic scale. EXAFS results indicate that iron atoms tend to segregate at the boundaries and Cu atoms are rich in the fcc lattice. Annealing experiments show that the Fe atoms at the interfaces are easy to cluster to α-Fe at a lower temperature, whereas the iron atoms in the lattice will form γ-Fe first at temperature above 350℃, and then transform to bcc Fe

关键词： mechanically Driven Alloying and Structural Evolution of Nanocrystalline Fe MA Cu Powder Figure

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

ARTIFICIAL NEURAL NETWORK AND FUZZY LOGIC CONTROLLER FOR GTAW MODELING AND CONTROL

引用

Chinese Journal of mechanical engineering 2002年第1期15卷 53-56页

作者： Gao Xiangdong Faculty of mechanical and Electrical engineering，Guangdong university of technology， guangzhou 510090，china Huang Shisheng south china university of technology Faculty of mechanical and Electrical engineering Guangdong University of Technology Guangzhou 510090 China

An artificial neural network(ANN) and a self-adjusting fuzzy logiccontroller(FLC) for modeling and control of gas tungsten arc welding(GTAW) process are *** discussion is mainly focused on the modeling and control of the weld pool depth with ANN and theintelligent control for weld seam tracking with FLC. The proposed neural network can produce highlycomplex nonlinear multi-variable model of the GTAW process that offers the accurate prediction ofwelding penetration depth. A self-adjusting fuzzy controller used for seam tracking adjusts thecontrol parameters on-line automatically according to the tracking errors so that the torch positioncan be controlled accurately.

关键词： Artificial neural network Fuzzy logic control Weld pool depth Seamtracking

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：