检索结果-南通市图书馆

Thermal Stress in Free-standing Diamond Films with Cr Interlayer Destroyed

在线全文

学校读者我要写书评

暂无评论

Journal of Materials science & technology 2010年第11期26卷 991-995页

作者： Zheng Liu,Liangxian Chen,Chengming Li,Lifu Hei,Jianhua Song,Guangchao Chen,Weizhong Tang and Fanxiu Lv school of Materials science and {2.,university of science and technology beijing,beijing 100083,china [a] school of Materials science and {2. university of science and {2. beijing beijing 100083 china

Thermal stress in large area free-standing diamond films was remarkable during the post-deposition cooling of direct current （DC） arc plasma jet chemical vapor deposition （CVD） *** this research,the stress release caused by delamination of Cr interlayer was of great importance to ensure the integrity of free-standing diamond *** effects of Cr interlayer on Mo substrate,namely composite substrate,on thermal stress were ***-mechanical coupling analysis of the thermal stress was applied by finite element analysis （FEA） using ANSYS *** was found that the interlayer could be destroyed first by the large thermal stress,and then the stress could be released and the probability of diamond film crack initiation would be *** stress concentration at the bent edge of diamond film was also *** addition,diamond films deposited on Mo substrates with and without Cr interlayer were prepared by DC arc plasma jet CVD system and experimental measurements were used to characterize these *** was found that composite substrate could be an effective method of growing free-standing crack-free diamond films by DC arc plasma jet CVD system when there is no special requirement to the film strength.

关键词： CVD diamond film Cr interlayer Thermal stress Finite element analysis

Functionally Gradient Material Made by IncrementalMelting and Solidification Process

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 1999年第3期13卷 205-207页

作者： Chengchang Jia Hongbo Tian Tao Lin Zhimeng Guo Nobuyoshi Sasaki(Material science and engineering {2.. university of science and technology beijing. beijing, 100083. china)(CADIC Cooperation. Kawasaki, 2.3. Japan) Material science and engineering {2. University of Science and Technology Beijing Beijing 100083 China CADIC Cooperation Kawasaki 213 Japan

A new technique IMS (Incremental Melting and Solidification Process) has been introduced. A kind of cast steel high Mn foundry alloy gradient rnalerial was produced by this process. The microstructure and mechanical properties of the alloy were tested. Fe and Mn in the samples were measured by EPMA. The experimental results show that the content and hardness of Fe-Mn alloy vary continuously and the IMS process is an alternative way in producing metal matrix gradient material. It is possible for these materials to be made into some parts such as camshaft.

关键词： IMS process FGM melting solidification

Two-Sublattice Thermodynamic Model on Carbonitride Precipitation in Microalloyed Steels Bearing Nb-V-Ti

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2011年第S1期18卷 271-277页

作者： XIANG Song 1,3,LIU Guo-quan 2.(1.school of Materials and Metallurgy,Guizhou university,Guiyang 550003,Guizhou,{2. 2.school of Materials science and engineering,university of science and technology,beijing,beijing 100083,{2. 3.The Key Laboratory for mechanical Behavior and Microstructure of Materials,Guizhou Province,Guiyang 550003,Guizhou,{2.) Guizhou Univ Sch Met & Mat Guiyang 550003 Guizhou Peoples R China Univ Sci & Technol beijing Sch Mat Sci & Engn Beijing 100083 Peoples R China Key Lab Mech Behav & Microstruct Mat Guiyang 550003 Guizhou Peoples R China

Based on the two sublattice model of the regular solution,one being metal atom sublattice and another being interstitial atom sublattice,a thermodynamic model for the precipitates of niobium carbonitride,vanadium carbonitride and titanium carbonitride was established to study the starting-temperature of precipitates and the austenite compositions at given temperature in a low carbon *** calculation results show that starting-temperature of the precipitation of niobium carbonitride,vanadium carbonitride and titanium carbonitride are 1100℃,92.℃ and 1340℃,respectively,the mole fraction of carbonitride precipitates is 8.65×10-4 in the 0.053C-0.002.N-1.2.Mn-0.008S-0.031Al-0.046Nb-0.008Ti0.02.V-Fe *** the N content is from 0.002.% to 0.0056%,the starting-temperature of the precipitation of the titanium carbonitride changes from 1340℃ to 1430℃.And the C content is from 0.053% to 0.07%,the startingtemperature of the precipitation of the titanium carbonitride hardly changes,but the atomic fraction of niobium in the carbonitride obviously increases.

关键词： microalloyed steel carbonitride precipitation two sublattice model thermodynamics

Laser Shock Processing of an Austenitic Stainless Steel and a Nickel-base Superalloy

在线全文

学校读者我要写书评

暂无评论

Journal of Materials science & technology 2003年第5期19卷 402-404页

作者： Huaming WANG, Xijun SUN and Xiaoxuan LILaboratory of Laser Materials Processing and Surface engineering, {2. of Materials science and engineering, Beihang university (formerly beijing university of Aeronautics and Astronautics), beijing 100083, china Lab. of Laser Mat. Proc. Sch. of Mat. Sci. and Eng. Beijing Univ. of Aero. and Astron. Beijing 100083 China

An austenitic stainless steel 1Cr18Ni9Ti and a solid solution-strengthened Ni-base superalloy GH30 were shock processed using a Q-switched pulsed Nd-glass laser. Microstructure, hardness and residual stress of the laser shock processed surface were investigated as functions of laser processing parameters. Results show that high density of dislocations and fine deformation twins are produced in the laser shock processed surface layers in both the austenitic stainless steel and the nickel-base superalloy. Extensive strain-induced martensite was also observed in the laser shock processed zone of the austenitic steel. The hardness of the laser shock processed surface was significantly enhanced and compressive stress as high as 400 MPa was produced in the laser shock processed surface.

关键词： Laser shock processing Austenitic stainless steel Nickel-base superalloy Surface mechanical properties Residual stress

Effects of Composition and Thermal Cycle on Transformation Behaviors,Thermal Stability and mechanical Properties of CuAlAg Alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Materials science & technology 2003年第5期19卷 431-434页

作者： Yunqing MA, Chengbao JIANG, Lifen DENG and Huibin xuDepartment of Materials science and {2., beijing university of Aeronautics and Astronautics, beijing 100083, china Dept. of Mat. Sci. and Eng. Beijing Univ. of Aero. and Astron. Beijing 100083 China

The phase transformation behavior, mechanical properties, and the thermal stability of CuAlAg alloy were studied and minor rare earth (0.1 wt pct La+Ce) was added to improve the mechanical property of the studied alloy. It was found that Ag addition in the CuAl binary alloy can improve the stability of martensitic transformation and high Al content leads to the disappearing of martensitic transformation. The tensile strength and strain of the Cu-10.6AI-5.8Ag (wt pct) alloy were measured to be 383.5 MPa and 0.86%, respectively. With rare earth addition, the tensile strain increased from 0.86% to 1.47%. The CuAlAg alloy did not exhibit martensitic transformation on the second heating process. Its poor thermal stability still needs to be improved.

关键词： High temperature shape memory alloys CuAlAg Transformation behavior Thermal cycle Thermal stability Rare earth mechanical property

Microstructure and Properties of W-Cu Alloys Prepared with mechanically Activated Powder

在线全文

学校读者我要写书评

暂无评论

Journal of university of science and technology beijing 2001年第2期8卷 129-132页

作者： Chengchang Jia, Xiuhu Guan, xuekuan Su, Changheng Hou, Shimin Fan, Jun Zhao, Zizhang Xie (Material science and {2. school, university of science and technology beijing, beijing 100083, china) (beijing Research Institute of Powder Metallurgy, Beiji Univ Sci & Technol beijing Mat Sci & Engn Sch Beijing 100083 Peoples R China beijing Res Inst Powder Met Beijing 100053 Peoples R China beijing Polytech Univ Beijing 100022 Peoples R China

W-15% Cu (mass fraction) alloys were sintered with mechanically activated powder in order to develop new preparing processes and improve properties of alloys. The microstructures of the activated powder and the sintered alloy were observed. Properties such as density were measured. The results show that through mechanical activation, the particle size of the powder becomes finer to sub-micron or nanometer level, some copper was soluble in tungsten, and high density W-Cu alloys can be obtained by mechanically activated powder for its action to the activation sintering.

关键词： powder metallurgy mechanical activation W-Cu alloys sintering

Shape Character of Fusion-solidification Zone of EBW Joints for Titanium Alloy

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S4期40卷 74-78页

作者： Fu Pengfei1,2.Mao Zhiyong2.Wang Yajun3,Gong Shuili2.Liu Xin2.1school of Materials science and {2.,Huazhong university of science and technology,Wuhan 430074,china 2.1} and technology on Power Beam Processes Laboratory,beijing Aeronautical Manufacturing technology Research Institute,beijing 10002.,china3school of mechanical {2. and Automation,beijing university of Aeronautics and Astronautics,beijing 100191,china beijing Aeronaut Mfg Technol Res Inst Sci & Technol Power Beam Proc Lab Beijing 100024 Peoples R China Huazhong Univ Sci & Technol Sch Mat Sci & Engn Wuhan 430074 Peoples R China beijing Univ Aeronaut & Astronaut Sch Mech Engn & Automat Beijing 100191 Peoples R China

Shape character of fusion-solidification zone of electron beam welding (EBW) joints was studied for TC4 *** typical shapes of the fusion-solidification zone were gained by appropriate welding *** shapes and dimensions of the fusion-solidification zone of TC4 titanium joints were apparently influenced by processing parameters,focusing state and power density *** on the analyses of processing parameters,focusing state and power density distribution,the integrated parameters of n1 and n2.were put forward,which represented the distribution and intensity of electron beam *** a series of the formulations are developed to predict the shape of fusion-solidification zone by the processing parameters.

关键词： electron beam welding (EBW) titanium alloy fusion-solidification zone mathematical model

Effect of Alloying Element on Process Control of High Strength Hot-Rolled Dual Phase Steel

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2011年第S1期18卷 792-795页

作者： ZHOU Le-yu,LIU Ya-zheng,HU xue-wen,ZHANG Da-wei (school of Materials {2. and engineering,university of {2. and technology beijing,beijing 100083,china) Univ Sci & Technol beijing Sch Mat Sci & Engn Beijing 100083 Peoples R China

Microstructure evolution of C-Si-Mn-Nb,C-Si-Mn-Cr-Nb and C-Si-Mn-Cr-Mo-Nb tested steels during step-cooling process were *** of alloying element and process data on microstructure and mechanical properties of high strength Nb bearing DP steel were analyzed,to illustrate the relationship between alloy composition design and process control stability during DP microstructure and property *** is shown that,700MPa ferrite and martensite DP steel is obtained respectively by three kinds of composition tested steel under different step-cooling process.C-Si-Mn-Nb steel with simple alloying design of low cost is provided with low hardenability,and has strong process sensibility during microstructure *** microstructure of ferrite and martensite of C-Si-Mn-Nb steel just can be obtained by coiling at low temperature of 2.0℃.The process control stability of C-Si-Mn-Cr-Nb steel is stronger than that of C-Si-Mn-Nb steel,to obtain DP microstructure by coiling at low temperature.C-Si-Mn-Cr-Mo-Nb steel with complex alloying design of high cost is provided with excellent process control *** element Mo can promote stabilizing of metastable austenite to obtain F+M DP microstructure by coiling at medium temperature of 600℃.

关键词： hot-rolled DP steel process control step-cooling microstructure evolution

Indentation Size Effect on the mechanical Properties of Supersonic Plasma Sprayed NiCr-Cr_3C_2.Coating

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 2012年第S1期41卷 296-298页

作者： Zhu Lina1,2.xu Binshi2.Wang Haidou2.Wang Chengbiao1 1 school of {2. and technology,china university of Geosciences,beijing 100083,china 2.National Key Laboratory for Remanufacturing,Academy of Armored Forces {2.,beijing 100072.china Acad Armored Forces Engn Natl Key Lab Remfg Beijing 100072 Peoples R China china Univ Geosci Sch Engn & Technol Beijing 100083 Peoples R China

In this paper,NiCr-Cr3C2.coating was deposited onto AISI 1045 steel substrate by employing supersonic plasma spraying *** surface and cross-section morphologies of the NiCr-Cr3C2.coating were observed by *** phase constituents of the coating were identified by *** SEM images showed that the coating was very dense,and it had a low porosity *** XRD pattern implied that the coating was mainly composed of NiCr,Cr3C2.and *** tests were performed on the coating surface by a Nano *** widely used Oliver-Pharr method was adopted to extract the mechanical properties of the *** hardness exhibited a strong peak-load-dependence,*** size effect;the elastic modulus was not affected by indentation size effect.

关键词： nanoindentation mechanical property indentation size effect