检索结果-南通市图书馆

Annealing Texture Evolution of Ti-IF Steel during Batch Annealing

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and materials 1998年第3期12卷 175-179页

作者： Jing Shi Xianjin Wang(Material science and engineering School, University of science and technology beijing, beijing 100083, china) Material science and engineering School University of Science and Technology Beijing Beijing 100083 China

Texture development and recrystallization behavior of Ti-IF steel during Batch Annealing (BA) were investigared with X-ray diffraction and EBSP in lab, and the results were compared with research work on continu ous annealing (CA) with rapid heating rate. The basic tendencies are similar that eary nucleation takes place in ND fibers, RD fibers are consumed at the end of recrystallization, and ND texture dominates over annealing texture. However, the detailed texture transformation during batch annealing is different and somewhat more compicated than tha in rapid-heating process. Moreover, misorientation plays an important role in texture transformation of BA In addition, the results of EBSP are consistent with that of ODF well.

关键词： Ti-IF steel texture batch annealing X-ray diffraction EBSP

PRECIPITATION HARDENING IN B2.ORDERED NiAl BY Ni_(2.AlTi COMPOUND

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2001年第5期14卷 313-318页

作者： W.H. Tian, K. Ohishi and M. Nemoto 1)Department of materials Physics and Chemistry, University of science and {2. beijing, beijing 100083, china 2.Department of materials science and engineering, Faculty of engineering 36, Kyushu University, Fuk Dept. of Mat. Phys. and Eng. Univ. of Sci. and Technol. Beijing Beijing 100083 China

Microstructural variations and correlated hardness changes in B2.ordered NiAl containing fine precipitation of Ni2.lTi have been investigated by means of transmission electron microscopy (TEM) and hardness tests. The amount of age hardening is not large as compared to the large microstructural variations during aging. TEM observations have revealed that the L2.-type Ni2.lTi precipitates keep a lattice coherency with the NiAl matrix at the beginning of aging. By longer periods of aging Ni2.lTi precipitates lose their coherency and change their morphology to the globular ones surrounded by misfit dislocations. The temperature dependence of the yield strength of precipitate-containing B2.ordered NiAl was investigated by compression tests over the temperature range of 873-12.3 K. The fine precipitation of Ni2.lTi was found to enhance greatly the yield strength and the high-temperature strength is comparable with that of superalloy Mar-M2.0.

关键词： Aluminum Hardening Mechanical properties Nickel Precipitation (chemical)

Investigation of Al-based Alloys for Brazing SiC_p/Al Composites

在线全文

学校读者我要写书评

暂无评论

稀有金属材料与工程 2011年第S3期40卷 132-135页

作者： Wu Mao1,2. Chang Lingling2. Peng Zirong2. Feng Zelong2. Yong Weina2. Wang Wei2. He Xinbo1,2. Qu Xuanhui1,2.1State Key Laboratory for Advanced Metals and materials, University of science and {2. beijing 100083, china 2.beijing Key Laboratory for Powder Metallurgy and Particulate materials, University of science and {2. beijing, beijing 100083, china Univ Sci & Technol beijing State Key Lab Adv Met & Mat Beijing 100083 Peoples R China Univ Sci & Technol beijing Beijing Key Lab Powder Met & Particulate Mat Beijing 100083 Peoples R China

The brazing of SiCp/Al composites is limited owing to the unavailability of suitable commercial intermediate temperature brazes. Adding a third constituent of copper to aluminum-silicon brazing alloy can depress the melting point sharply. While, it generates a large volume fraction of the hard Al2.u intermetallic compounds (IMCs), which makes the alloy brittle and reduces its corrosion resistance. A quaternary addition of nickel that partly substitute for copper can refine grain size significantly, improve the mechanical properties, and without altering the melting range of aluminum-silicon-copper alloy. Al-Cu-Ni-Si braze alloy has been prepared and a fluxless process has been employed to braze SiCp/Al composites that leads to a good bonding strength of brazing joint.

关键词： SiCp/Al composites Al-based brazes brazing intermetallic compounds (IMCs)

PRECIPITATION BEHAVIOUR AND HARDENING OFB2.ORDERED Ni(Al, Ta)

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 1997年第2期10卷 99-104页

作者： W.H. Tian and M. Nemoto2.Department of materials Physics, University of science and {2. beijing, beijing 100083, china)(Department of materials science and engineering, Faculty of engineering, Kyushu University, 812.Fukuoka, Japan) Univ of science and technology Beijing Beijing China

Precipitation of Ni2.l in supersaturated NiAl containing Ta and corresponding hardening have been investigated by hardness measurements and by transmission electron microscope observations. Selected area electron diffraction, high resolution electron microscopy and energy dispersive X-ray spectrometer analysis have shown that the Ni2.l with a hexagonal structure precipitates coherently in the B2.NiAl matrix. Ni2.l is an ordered phase with a. unit cell parameter, aNi2.ll=aNiAl and CNi2.l= aNiAl. The orientation relationship between the Ni2.l precipitate and the B2.NiAl matrix is (0001)Ni2.l (111)NiAl and [112.]Ni2.l[110]NiAl. NiAlhardens appreciably by the precipitation of Ni2.l phase.

关键词： intermetallic compound precipitation hardening TEM HREM,EDS

Hot Corrosion of Iron in the Presence of Salt Mixture Deposit Containing NaCl and V_2._5 at 600℃

在线全文

学校读者我要写书评

暂无评论

Journal of materials science & {2. 1996年第6期12卷 445-451页

作者： Lingchuan LI (Dept. of materials science and {2., Tsinghua University beijing 100084, china)Rizhang ZHU (Dept. of Surface science and Corrosion {2., University of science and technology beijing, beijing 100083, china)(To whom correspondenc Dept. of materials science and {2. Tsinghua University Beijing 100084 China Dept. of Surface science and Corrosion engineering University of Science and Technology Beijing Beijing 100083 China Instiuto di Chimica Facolta di Ingegneria Università di Genova Fiera del Mare Pad.D 16129 Genova Italy

Iron suffered low temperature hot corrosion (LTHC) in the presence of salt deposits of Na2.O4,Na2.O4 mixed with NaCl and Na2.O4 mixed with V2.5 in a combustion gas at 600℃. The additions of NaCl to Na2.O4 and of V2.5 to Na2.O4 changed the corrosion kinetics significantly and modified the scale structure markedly It is proposed that trivalent iron ions were more favored than divalent ions in the eutectic responsible for the occurrence of LTHC when NaCl was present, while the reaction between Na2.O4 mixed with V2.5 and the gas formed (Na2.)xV2.4(V2.5)6-x providing directly the liquid required by LTHC. The suphide formation in the inner FeO larer was related to the sites of the reduction step wher SO2.was released.

关键词： SO NaCl

Preparation and characterization of nano-crystalline diamond films on glass substrate

在线全文

学校读者我要写书评

暂无评论

Journal of University of science and technology {2. 2004年第3期11卷 216-220页

作者： Fanxiu Lu Wubao Yang Zhilin Liu Weizhong Tang Yumei Tong materials science and {2. School, University of science and technology beijing, beijing 100083, china materials science and {2. School University of Science and Technology Beijing Beijing 100083 China

Adherent nano diamond films were successfully deposited on glass substrate bymicrowave plasma assisted CVD method in H_2.CH_4 and Ar-CH_4 environment. Raman, AFM (Atomic ForceMicroscope), TEM (Transmission Electron Microscope), FTIR, and Nano Indentation techniques were usedfor characterization of the obtained nano diamond films. It was found that the average grain sizewas less than 100 nm with a surface roughness value as low as 2.nm. The nano diamond films werefound to have excellent transparency in visible and IR spectrum range, and were as hard as naturaldiamond. Experimental results were presented. Mechanisms for nano diamond film deposition werediscussed.

关键词： nano diamond films microwave plasma assisted CVD characterization glasssubstrate

Surface hardening of Fe-based alloy powders by Nd:YAG laser cladding followed by electrospark deposition with WC-Co cemented carbide

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2010年第4期29卷 380-384页

作者： WANG Jiansheng,MENG Huimin,YU Hongying,FAN Zishuan,and SUN Dongbai School of materials science and {2.,University of science and technology beijing,beijing 100083,china School of materials science and {2. University of Science and Technology Beijing Beijing China

This paper presents the results of a study concerned with the surface hardening of Fe-based alloys and WC-8Co cemented carbide by inte- grating laser cladding and the electrospark deposition processes. Specimens of low carbon steel were processed firstly by laser cladding with Fe-based alloy powders and then by electrospark deposition with WC-SCo cemented carbide. It is shown that, for these two treatments, the electrospark coating possesses finer microstructure than the laser coating, and the thickness and surface hardness of the electrospark coating can be substantially increased.

关键词： laser cladding electrospark deposition surface hardening Fe-based alloy cemented carbide

Numerical prediction of the incremental melting and solidification process

在线全文

学校读者我要写书评

暂无评论

Journal of University of science and technology {2. 2003年第4期10卷 50-54页

作者： Jun Wang, Chengchang Jia, and Sheng Yinmaterials science and {2. School, University of science and technology beijing, beijing 100083, china Mat. Sci. and Eng. Sch. Univ. of Sci. and Technol. Beijing Beijing 100083 China

A mathematical formulation is applied to represent the phenomena in theincremental melting and solidification process (IMSP), and the temperature and electromagneticfields and the depth of steel liquid phase are calculated by a finite difference technique using thecontrol volume method. The result shows that the predicted values are in good agreement with theobservations. In accordance with the calculated values for different kinds of materials anddifferent size of molds, the technological parameter of the IMS process such as the power supply andthe descending speed rate can be determined.

关键词： incremental melting and solidification process (IMSP) numerical prediction electromagnetic field temperature field technological parameter

Boundary conditions for the bending of a piezoelectric beam

在线全文

学校读者我要写书评

暂无评论

science china(Physics,Mechanics & Astronomy) 2008年第7期51卷 847-856页

作者： GAO Yang1, XU SiPeng2.& ZHAO BaoSheng3 1 college of science,{2. Agricultural University, beijing 100083,{2. 2.college of engineering, Ocean University of{2., Qingdao 2.6071,{2. 3 School of Mechanical engineering, University of science and technology Liaoning, Anshan 114044,{2. 1. college of science China Agricultural University Beijing 100083 China 2. college of engineering Ocean University of China Qingdao 266071 China 3. School of Mechanical engineering University of Science and Technology Liaoning Anshan 114044 China

For beam bending in transversely isotropic piezoelectric media, the reciprocal theorem and the general solution of piezoelasticity are applied in a novel way to obtain the appropriate stress and mixed boundary conditions accurate to all orders for the beam of general edge geometry and loadings. By generalizing the method developed by Gregory and Wan, a set of necessary conditions on the edge-data for the existence of a rapidly decaying solution is established. The prescribed edge-data of the beam must satisfy these conditions in order that they could generate a decaying state within the beam. When stress and mixed conditions are imposed on the beam edge, these decaying state conditions for the case of bending deformation of piezoelectric beam are derived explicitly. They are then used for the correct formulation of boundary conditions for the beam theory solution (or the interior solution). Besides, an analytical solution of elastic beam is formulated to verify validity of our boundary conditions. For the stress data, our boundary conditions coincide with those obtained in conventional forms of beam theories. More importantly, the appropriate boundary conditions with two sets of mixed edge-data are obtained for the first time.

关键词： boundary conditions beam bending piezoelectric media decaying states regular states