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Microstructure and Mechanical Properties of Nb- and Nb+ Ti-Stabilised 18Cr-2Mo Ferritic Stainless Steels

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Acta Metallurgica Sinica(English Letters) 2020年第5期33卷 716-730页

作者： Jian Han Zhixiong Zhu Gang Wei Xingxu jiang Qian Wang Yangchuan Cai zhengyi jiang School of Materials Science and Engineering Tianjin University of TechnologyTianjin 300384China School of Materials Science and Engineering Hefei University of TechnologyHefei 230009China School of Mechanical Engineering and Automation University of Science and Technology LiaoningAnshan 114051China

To explore the optimum use of stabilised elements and study the influences of stabilisation in 18 Cr-2 Mo grades,the Nb and Nb+Ti microalloying investigation focused on the relationships of the microstructure and mechanical properties of the microalloyed 18 Cr-2 Mo ferritic stainless steel thick ***-Calc calculation was performed to predict the equilibrium phase ***,the microstructure,*** size and precipitation,of as-annealed specimens was analysed by means of optical microscopy,scanning electron microscopy and transmission electron microscopy,X-ray diffraction and energydispersive ***,electron backscatter diffraction mapping was constructed to characterise grain *** mechanical properties,including tensile strength and impact toughness,were tested to correlate with the *** results show that the grain sizes of Nb-stabilised steel are comparatively smaller,which is related to the fine precipitation at the grain boundaries and beneficial to the impact *** increase in its strength is not apparent due to the inhomogeneous grain *** grain boundary characters are similar,which is not the main factor related to their mechanical *** Ti is added,TiN forms above the liquidus,and large TiN particles evidently impair impact toughness.

关键词： Ferritic stainless steels Toughness Precipitation Microstructure

Influence of Zn Content on Microstructures,Mechanical Properties and Stress Corrosion Behavior of AA5083 Aluminum Alloy

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Acta Metallurgica Sinica(English Letters) 2020年第10期33卷 1369-1378页

作者： Zhixiong Zhu Xingxu jiang Gang Wei Xiaogang Fang Zhihong Zhong Kuijing Song Jian Han zhengyi jiang School of Materials Science and Engineering Hefei University of TechnologyHefei 230009China School of Materials Science and Engineering Tianjin University of TechnologyTianjin 300384China School of Mechanical Engineering and Automation University of Science and Technology LiaoningAnshan 114051China

To enhance the stress corrosion cracking(SCC)resistance,Zn was utilized as an alloy element to add in the AA5083 aluminum *** effects of Zn content on the microstructures,mechanical properties and SCC resistance were systematically *** results demonstrate that in the studied range adding Zn can significantly improve the SCC resistance of the AA5083 *** is related to the relatively low amount of continuous β(Al3Mg2)phase along grain boundary and the formation of Zn-containing phase such as Al5Mg11Zn4 *** on the results,the optimal Zn content with respect to SCC resistance is approximately 0.50 wt.%.Further increasing Zn content results in coarse precipitates discontinuously distributed along grain boundaries.

关键词： AA5083 aluminum alloy Slow strain rate test Precipitation Stress corrosion cracking

Modeling uniaxial tensile deformation of polycrystalline Al using CPFEM

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Journal of University of Science and Technology Beijing 2008年第1期15卷 43-47页

作者： Huachun pi Jingtao Han Chuanguo Zhang A. Kiet Tieu zhengyi jiang School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China School of Mechanical Materials ＆ Mechatronic Engineering University of Wollongong Wollongong NSW 2522 Australia Sinosteel Scie-Tech Development Company Beijing 100080 China

The crystal plasticity finite element modeling （CPFEM） is realized in commercial finite element code ABAQUS with UMAT subroutine on the basis of the crystal plasticity theory of rate dependent polycrystal constitutive relations in the mesoscopic scale. The initial orientations obtained by electron backscatter diffraction （EBSD） are directly input into the CPFEM to simulate the mechanical response of polycrystalline 1050 pure Al in uniaxial tensile deformation. Two polycrystal models and two tensile strain rates were used in the simulations. The stress-strain curves of tensile deformation were analyzed. The predictions and the corresponding experiment result show reasonable agreement and slight deviation with experiments. The flow true stress of strain rate 0.01 s^-1 is higher than that of strain rate 0.001 s^-1. At the strain less than 0.05, the stress saturated rate of the experiment is higher than the simulated results. However, the stress saturated rate of the experiment becomes gentler than the corresponding simulated predictions at the strain over 0.05. Also, necking was simulated by the two models, but the necking strain is not well predicted. Tensile textures at strain 0.25 were predicted at the low strain rate of 0.001 s^-1. The predictions are in good accord with the experimental results. 2008 University of Science and Technology Beijing. All rights reserved.

关键词： crystal plasticity f'mite element method electron backscatter diffraction (EBSD) uniaxial tensile deformation

Mechanical and Electrical Properties of Y-containing Al-Zr Heat-resistant Alloy Produced by Dynamic ECAE Process

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Journal of Wuhan University of Technology(Materials Science) 2022年第1期37卷 123-129页

作者： ZHOU Tianguo XIE Haibo jiang zhengyi School of Materials Science and Engineering Yangtze Normal UniversityChongqing 408100China School of Mechanical MaterialsMechatronic and Biomedical EngineeringUniversity of WollongongWollongongNSW 2522Australia

The influence of rare earth Y on the microstructure and mechanical properties of Al-Zr alloy produced by dynamic ECAE was studied by OLYMPUS-BX51M optical microscope(OM),S4800 energy disperse spectroscopy(EDS)and SANS CMT5105 electronic universal material testing machine,and the corresponding equivalent conductivity was also investigated by using QJ48 DC electric *** results show that the tensile strength of Al-Zr conductor first increases and then decreases with the increase of the aging time and temperature,and the highest tensile value can be obtained under the aging temperature of 160°C for 4 *** ductility and the resistivity of the Al-Zr alloy have inverse proportion to the aging *** rare earth Y has significantly improved the electrical and mechanical properties of Al-0.3%Zr heat-resistant *** this study,the tensile strength and the elongation of the Al-0.3%Zr-0.2%Y alloy,after aging treatment at 220°C for 14 h,are about 278.49 MPa and 6.7%,respectively,and the equivalent conductivity is about 59.6 *** the synthetical properties of the Y-containing alloy are significantly improved compared with traditional Al-0.3%Zr alloy.

关键词： Al-Zr heat-resistant alloy ECAE process equivalent conductivity aging treatment

Experimental Investigation on Micro Deep Drawing of Stainless Steel Foils with Different Microstructural Characteristics

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Chinese Journal of Mechanical Engineering 2021年第2期34卷 179-189页

作者： Jingwei Zhao Tao Wang Fanghui Jia Zhou Li Cunlong Zhou Qingxue Huang zhengyi jiang College of Mechanical and Vehicle Engineering Taiyuan University of TechnologyTaiyuan 030024China Engineering Research Center of Advanced Metal Composites Forming Technology and Equipment Ministry of EducationTaiyuan 030024China TYUT-UOW Joint Research Center Taiyuan University of TechnologyTaiyuan 030024China TYUT-UOW Joint Research Center University of WollongongWollongongNSW 2522Australia School of Mechanical MaterialsMechatronic and Biomedical EngineeringUniversity of WollongongWollongongNSW 2522Australia Shanxi Provincial Key Laboratory on Metallurgical Device Design and Theory Taiyuan University of Science and TechnologyTaiyuan 030024China

In the present work,austenitic stainless steel(ASS)304 foils with a thickness of 50μm were first annealed at temperatures ranging from 700 to 1100℃for 1 h to obtain different microstructural *** the effects of microstructural characteristics on the formability of ASS 304 foils and the quality of drawn cups using micro deep drawing(MDD)were studied,and the mechanism involved was *** results show that the as-received ASS 304 foil has a poor formability and cannot be used to form a cup using *** wrinkling problem occurs on the drawn cup,and the height profile distribution on the mouth and the symmetry of the drawn cup is quite non-uniform when the annealing temperature is 700℃.At annealing temperatures of 900 and 950℃,the drawn cups are both characterized with very few wrinkles,and the distribution of height profile,symmetry and mouth thickness are uniform on the mouths of the drawn *** wrinkling becomes increasingly significant with a further increase of annealing temperature from 950 to 1100℃.The optimal annealing temperatures obtained in this study are 900 and 950℃for reducing the generation of wrinkling,and therefore improving the quality of drawn *** non-optimized microstructure,the distribution of the compressive stress in the circumferential direction of the drawn foils becomes inhomogeneous,which is thought to be the cause of the occurrence of localized deformation till wrinkling during MDD.

关键词： Microforming Micro deep drawing Stainless steel foils Wrinkling Annealing Microstructure

Microstructural evolution of hybrid aluminum matrix composites reinforced with SiC nanoparticles and graphene/graphite prepared by powder metallurgy

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Progress in Natural Science:Materials International 2020年第2期30卷 192-199页

作者： jiangshan Zhang Qing Liu Shufeng Yang Zhixin Chen Qiang Liu zhengyi jiang State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing School of Mechanical MaterialsMechatronic and Biomedical EngineeringUniversity of Wollongong

The dispersion of ceramic nanoparticles is of significance to the microstructure and properties of particulate reinforced metal matrix *** this study,two hybrid enhancers,SiC-graphite and SiC-graphene nanosheets（GNSs）,were incorporated into aluminum matrix composites using powder *** dispersion of the reinforcements and microstructural evolution of the composites were characterized by using Scanning Electron Microscopy,X-Ray Diffraction,Transmission Electron Microscopy,and Raman *** results show that thin GNSs accelerated the deformation of the aluminum particles,and defects were introduced into the carbonaceous phases during the ball milling ***;C;needles generated during hot pressing,and were observed to bridge the aluminum *** with graphite,GNSs were more uniformly dispersed throughout the composite,which in turn restrained grain *** a result,a nanostructured composite（57.7 nm） was successfully produced upon the addition of SiC-GNSs.

关键词： Microstructure Aluminum matrix composite SiC nanoparticle SiC-Graphene nanosheets Powder metallurgy

Molecular Dynamics Simulation on Mobility and Aggregation of Macromolecular Lubricant Oxidation Products and Their Influences on Base Stock

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China Petroleum Processing & Petrochemical Technology 2020年第3期22卷 101-108页

作者： Xia Lei Li Yan Zhang Hongmei jiang zhengyi Long Jun School of Material and Metallurgy University of Science and Technology LiaoningAnshan 114051 State Key Laboratory of Metal Material for Marine Equipment and Application Anshan 114009 Iron&Steel Research Institutes of Ansteel Group Corporation Anshan 114009 School of Mechanical MaterialsMechatronic and Biomedical EngineeringUniversity of WollongongWollongongNSW 2522Australia SINOPEC Research Institute of Petroleum Processing Beijing 100083

The mobility and aggregation behavior of macromolecular lubricant oxidation products and their influences on the performance of base stock were probed by molecular dynamics(MD)*** mean square displacement(MSD)of molecules was calculated to explore the mobility of *** distribution appearance of lubricant oxidation products in models was acquired to explore the aggregation of *** results show that the mobility of macromolecular oxidation products is lower than that of base *** MSD of macromolecular oxidation products reduces with an increasing macromolecular *** oxidation products can also decrease the mobility of base *** interaction energy between the macromolecules and the base stock soars with the increase of macromolecular *** with a larger molecular weight can affect more base stock molecules with stronger restriction,which leads to lower mobility of base stock *** are aggregates formed among macromolecular oxidation products,and the molecules in aggregates are connected by hydrogen *** quantity of hydrogen bonds in aggregates is related to temperature.

关键词： molecular dynamics simulation lubricant oxidation aggregation mobility

Modeling texture development during cold rolling of IF steel by crystal plasticity finite element method

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Journal of University of Science and Technology Beijing 2008年第6期15卷 696-701页

作者： Hejie Li Jingtao Han Huachun Pi zhengyi jiang Dongbin Wei A. Kiet Tieu School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China Department of Mechanic ＆ Electricity Tangshan College Tangshan 063000 China Sinosteel Scie-tech Development Company Beijing 100031 China School of Mechanical Materials ＆ Mechatronic Engineering University of Wollongong Wollongong NSW 2522 Australia

With the consideration of slip deformation mechanism and various slip systems of body centered cubic （BCC） metals, Taylor-type and finite element polycrystal models were embedded into the commercial finite element code ABAQUS to realize crystal plasticity finite element modeling, based on the rate dependent crystal constitutive equations. Initial orientations measured by electron backscatter diffraction （EBSD） were directly input into the crystal plasticity finite element model to simulate the develop- ment of rolling texture of interstitial-free steel （IF steel） at various reductions. The modeled results show a good agreement with the experimental results. With increasing reduction, the predicted and experimental rolling textures tend to sharper, and the results simulated by the Taylor-type model are stronger than those simulated by finite element model.＇Conclusions are obtained that rolling textures calculated with 48 { 110} 〈 111 〉＋ { 112 } 〈 111〉＋ { 123 } 〈 111 〉 slip systems are more approximate to EBSD results.

关键词： interstitial-free steel (IF steel) crystal plasticity field emission microscopy (FEM) electron backscatter diffraction(EBSD) rolling texture

Molecular Simulation of Chain Initiation Mechanism in Oxidation of Lubricant Base Stock

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China Petroleum Processing & Petrochemical Technology 2021年第4期23卷 105-112页

作者： Xia Lei Li Yan Zhang Hongmei jiang zhengyi Long Jun School of Material and Metallurgy University of Science and Technology LiaoningAnshan 114051 State Key Laboratory of Metal Material for Marine Equipment and Application Anshan 114009 Iron&Steel Research Institutes of Ansteel Group Corporation Anshan 114009 SINOPEC Research Institute of Petroleum Processing Beijing 100083

Chain initiation reactions in the oxidation process of lubricant base stock molecules were studied by molecular *** ways to initiate lubricant oxidation were *** included the dissociation of chemical bonds in base stock molecules and the reaction between base stock molecules and oxygen(O_(2)),*** activation energy of above methods was *** results show that C‒C bonds are more likely to break than C‒H bonds to generate free radicals by the pyrolysis of chemical *** C‒C bonds with tertiary carbon atoms are preferential positions to ***,their bond dissociation energy is above 360 kJ/mol,which is difficult to occur under lubricant working *** chain initiation is more likely to occur by the way that O_(2) attacks the two atoms in C‒H bonds at the same time,and is then embedded into the C‒H bond to produce hydrocarbon *** then,the O‒O bond is cracked to form hydroxyl radicals and alkoxy *** C‒H bonds with tertiary carbon atoms are preferential reaction sites,the reaction activation energy of which is about 190.11 kJ/mol.

关键词： molecular simulation lubricant base stock oxidation chain initiation