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Effect of 2–6 at.% Mo addition on microstructural evolution of ti-44Al alloy

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Journal of Materials Science & technology 2018年第7期34卷 1196-1204页

作者： S.Z.Zhang Z.W.Song J.c.Han c.J.Zhang P.Lin d.d.Zhu F.t.Kong Y.Y.chen School of Materials Science and Engineering Taiyuan University of Technology Shanxi Key Laboratory of Advanced Magnesium-Based Materials Taiyuan University of Technology School of Mechanical Engineering Taiyuan University of Technology School of Mechanical Engineering Quzhou University State Key Laboratory for Advanced Welding and Jointing Harbin Institute of Technology

In order to understand the effect of Mo alloying on the microstructural evolution of tiAl alloy, the as-cast microstructure, heat treated microstructure characteristic, and hot compression microstructure evolution of ti-44Al alloy have been studied in this work. the as-cast microstructure morphology changes from （γ＋α2） lamellar colony and β/β0＋γ mixture structure to β/β0 phase matrix widmannstatten structure, when Mo content increases from 2 at.% to 6 at.%. Affected by the relationship between β phase and α90℃phase, the angles between the lamellar orientation and the block β/β0 phase are roughly at 0℃, 45℃ and 90℃. comparing with heat treatment microstructure, the hot compression microstructure contains less β/β0 phase, however, theβ/β0 phase containing 2Mo alloy and 3Mo alloy hot compressed at 1275 ℃ has the inverse tendency. In addition, （α2 ＋γ） colony is decomposed by the discontinuous transformation.2017 Published by Elsevier Ltd on behalf of the editorial office of Journal of Materials Science ＆ technology.

关键词： Phase transformation titanium aluminides Heat treatment Microstructure evolution,β/βo phase

Substrate selection and seasonal variation in abundance and size composition of isopod Lirceus fontinalis in Ontario streams, canada

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chinese Journal of Oceanology and Limnology 2007年第2期25卷 215-220页

作者： ZHAO Xiaoxia Michael G fox david c. LASENBY Alexis c. ARMIt dolly N. KOtHAWALA Watershed Ecosystems Graduate Program Trent University Peterborough Ontario K9J 7B8 Canada Environmental ＆ Resource Studies Program and department of Biology Trent University Peterborough ON K9J 7B8 Canada department of Biology Trent University Peterborough ON K9J 7B8 Canada

the abundance and size composition of stream isopods Lirceusfontinalis were investigated from April 2001 to August 2002 in 3 streams in southem Ontario, canada. Effects of current speed was released from the analysis by choosing slow flowing water. the effects of substrate, season and water depth on the abundance, distribution and size composition of the isopods were analyzed. It was found that substrate and season influence isopods the most. the rocky substrate with attached filamentous macro-algae contains an isopod abundance 7.05 times that of bare rock substrate and 14.6 times that of free-sand and mud substrate. there was a large variation with respect to seasonali .ty in both abundance and size composition of the isopods, with the highest abundance occumng in summer and the lowest in winter and spring; individual isopods also tend to be larger in the winter and spring. In all substrates, shallow areas tend to support higher densities of isopods than deeper areas.

关键词： isopods Lirceusfontinalis, size abundance substrate seasonal variation Ontario

Micromorphology of Surface crusts in the Knersvlakte,South Africa

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Journal of Mountain Science 2009年第2期6卷 189-196页

作者： Sarah-Jane c.fox Anthony J.Mills Rosa M.Poch department of Soil Science Stellenbosch UniversityStellenbosch South Africa department of Environment and Soil Science University of LleidaRovira Roure 191 Lleida

Soils in the Knersvlakte are particularly prone to crusting and have lower inherent infiltrability than other soils across western southern Africa. Micromorphological techniques were used to examine the structure and porosity of soil crusts in the Knersvlakte to ascertain why crusting is so intense in this region. Quantile regression using boundary lines was employed to examine the relationships between infiltrability and soil properties for all samples （n = 67）. this analysis showed that infiltrability is potentially maximal at low water- dispersible ＇clay plus silt＇ content and low silt content （r^2 = 0.72 and 0.64; respectively, n = 67）（Figure 2）. the strength of crusts, pH, Ec, clay mineralogy, and water-dispersible clay, silt and ＇clay plus silt＇ content were compared, and a pore analysis using optical microscopy was undertaken on images of six soil thin sections （n = 6）（circular and parallel polarizers）. Pore analysis was further undertaken on five horizontal slices of equal dimensions taken through each soil thin section. the porosity samples with low infiltrability （〈 100 mm·hr^-1, n = 4） had greater crust strength, lower porosity （both total and in the least porous slice） and greater water-dispersible ＇day plus silt＇ and silt content than the porosity samples with high infiltrability （〉 100mm·hr^-1, n = 2）. the porosity samples with low infiltrability showed a trend of lower pH and greater water dispersible clay percentage. Porosity varied within the porosity samples due to the presence of dense clay/silt bands （〈 0.5 mm in width） with relatively few air vesicles. the porosity samples with horizontal slices of low porosity （but large numbers of air vesicles） had low infiltrability, while those without slices of low porosity （and relatively few air vesicles） had high infiltrability. We conclude that the intense crusting and resultant low infiltrability of soils in the Knersvlakte appears to be related to the formation of thin, dense clay/silt bands in the

关键词： Infiltrability optical microscopy porosity air vesicles

A Hybrid Joining technology for Aluminum/Zinc coated Steels in Vehicles

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Journal of Materials Science & technology 2010年第9期26卷 858-864页

作者： c.Y.choi d.c.Kim d.G.Nam Y.d.Kim Y.d.Park School of Materials Science and Engineering Pusan National UniversityBusan Advanced Welding & Joining R&d division Institute of Industrial technology Incheon dongnam technology Service division Korea Institute of Industrial TechnologyBusan department of Advanced Materials Engineering Dong-Eui UniversityBusan

currently,in the automotive industry,joining of the aluminum alloys with the steel is a crucial problem to be *** joining techniques including resistance spot and gas metal arc welding are not acceptable for those applications due to a number of metallurgical *** investigation was carried out to develop the hybrid joining process combining the resistance spot welding and *** this study,an attempt was made to apply hybrid process to the joining of dissimilar sheet metals,Al-Mg-Si（6000 series） alloy and low carbon steel *** process（resistance spot weld/brazing） using filler metal was found to be effective to overcome the incompatibility between aluminum alloy and *** hybrid joining process of Al alloy sheet and steel sheet did not produce acceptable bond strength,it was proved to have reasonable interfacial bond layer if the optimal process condition was applied.

关键词： Hybrid joining Aluminum alloy Steel Resistance welding Brazing

ISOcHRONOUS StRESS-StRAIN cURVES OF LOW ALLOY StEEL cROSS-WELd-SPEcIMEN At HIGH tEMPERAtURE

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Acta Metallurgica Sinica(English Letters) 2004年第4期17卷 612-617页

作者： c.W.Ma F.Z.Xuan Z.d.Wang S.t.tu East china University of Science and technology Shanghai 200237 ChinaEast China University of Science and Technology Shanghai 200237 ChinaEast China University of Science and Technology Shanghai 200237 ChinaEast China University of Science and Technology Shanghai 200237 China Nanjing University of Technology Nanjing 210009 China

In this work, a parametric approach is presented and utilized to determine the creep properties of weldments; then the model of creep strain for cross weld specimen is given. On the basis of the experimental results, attempt has been made to establish equations of the isochronous stress-strain for weld joint that can predict the function of loading and service time in use of the creep data of base metal and weld metal.

关键词： isochronous stress-strain curve creep deformation high temperature welded joint low alloy steel

climate change and groundwater resources in Mekong delta, Vietnam

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Journal of Groundwater Science and Engineering 2017年第1期5卷 76-90页

作者： duong d Bui Nghia c Nguyen Nuong t Bui Anh t t Le dao t Le National center for Water Resources Planning and Investigation MONRE Vietnam tokyo Metropolitan University Japan center for Environmental Fluid dynamics Hanoi University of Science Vietnam

Groundwater resources have considerable influences on the human population and socioeconomic development of Vietnam and the Mekong River delta(MRd). this paper presents an overview of the relationship between climate change and groundwater in the MRd, including the challenges, strategies and technical measures. Our results showed that groundwater levels are related to other climate and hydrological variables(i.e., rainfall, river levels, etc.); therefore, the impacts of climate change on the groundwater resources of the Mekong delta are significant, especially on groundwater recharge. Based on the results of this study, it is recommended that groundwater development in the future should focus on reducing groundwater harvesting, enhancing groundwater quantity by establishing artificial works and exploiting surface water. this study suggests that the Artificial Neural Network(ANN) model is an effective tool for forecasting groundwater levels in periods of 1 month and 3 months for aquifers in the natural and tidal regime areas of the delta.

关键词： Groundwater management climate change ANN model Mekong River delta

PREdIctION OF cARBON cONcENtRAtION ANd FERRItE VOLUME FRActION OF HOt-ROLLEd StEEL StRIP dURING LAMINAR cOOLING

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Acta Metallurgica Sinica(English Letters) 2007年第4期20卷 251-257页

作者： Y.t. Zhang c.Z. Wang d.Z. Li Y.Y. Li School of Material Science and Engineering Shenyang Ligong University Shenyang 110168 China Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China

A phase transformation model was presented for predicting the phase fraction transformed and the carbon concentration in austenite for austenite to ferrite transformation during laminar cooling on run-out table in hot rolling strip mill. In this model, the parameter k in Avrami equation was developed for carbon steels. the wide range of chemical composition, the primary austenite grain size, and the retained strain were taken into account. It can be used to predict the ferrite volume fraction and the carbon concentration in austenite of hot-rolled steel strip during laminar cooling on run-out table. the coiling temperature controlling model was also presented to calculate the temperature of steel strip. the transformation kinetics of austenite to ferrite and the evolution of carbon concentration in austenite at different temperatures during cooling were investigated in the hot rolled Q235B strip for thickness of 9.35, 6.4, and 3.2mm. the ferrite volume fraction along the length of the strip was also calculated. the calculated ferrite volume fraction was compared with the log data from hot strip mill and the calculated results were in agreement with the experimental ones. the present study is a part of the prediction of the mechanical properties of hot-rolled steel strip, and it has already been used on-line and off-line in the hot strip mill.

关键词： carbon concentration ferrite volume fraction laminar cooling hot rolling

Exploring the light-quark interaction

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chinese Physics c 2009年第12期33卷 1189-1196页

作者：常雷 Ian c. cLOЁt Bruno El-BENNIcH thomas KLHN craig d. ROBERtS Institute of Applied Physics and computational Mathematics department of Physics University of Washington Seattle WA 98195 USA Physics division Argonne National Laboratory Argonne Illinois 60439 USA department of Physics Peking University

two basic motivations for an upgraded JLab facility are the needs： to determine the essential nature of light-quark confinement and dynamical chiral symmetry breaking （dcSB）; and to understand nucleon structure and spectroscopy in terms of Qcd＇s elementary degrees of freedom. during the next ten years a programme of experiment and theory will be conducted that can address these questions. We present a dyson- Schwinger equation perspective on this effort with numerous illustrations, amongst them： an interpretation of string^breaking; a symmetry-preserving truncation for mesons; the nucleon＇s strangeness σ-term; and the neutron＇s charge distribution.

关键词： Bethe-Salpeter equations bound-states confinement dynamical chiral symmetry breaking,dyson-Schwinger equations Faddeev equation nucleon electromagnetic form factors

Microstructural Evolution of Infrared Brazed cP-ti Using ti-cu-Ni Brazes

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Journal of Materials Science & technology 2011年第2期27卷 131-138页

作者： c.t.chang t.Y.Yeh R.K.Shiue c.S.chang department of Mechanical Engineering National Hualien Industrial Vocational Senior High SchoolHualien 970TaiwanChina department of Materials Science and Engineering National Taiwan UniversityTaipei 106TaiwanChina Engineered Materials Solutions 39 Perry AvenueMS 4-1AttleboroMA 02703-2410USA

Microstructural evolution of infrared vacuum brazed cP-ti using two ti-based braze alloys,ti-15cu-15Ni and ti-15cu-25Ni,has been *** infrared brazed joint consisted of eutectic ti 2 cu/ti 2 Ni intermetallic compounds and ti-rich *** eutectic ti 2 cu/ti 2 Ni intermetallic compounds disappeared from the joint after being annealed at 900 c for 1 *** contrast,the depletion rate of both cu and Ni from the braze alloy into cP-ti substrate at 750 c annealing was greatly decreased as compared with that annealed at 900 *** ti 2 cu/ti 2 Ni phases were observed even if the specimen was annealed at 750 c for 15 *** the Ni content of the ti-15cu-25Ni braze alloy is much higher than that of the ti-15cu-15Ni alloy,the amount of eutectic ti 2 cu/ti 2 Ni phases in ti-15cu-25Ni brazed joint is more than that in ti-15ci-15Ni brazed ***,similar microstructural evolution can be obtained from the infrared brazed joint annealed at various temperatures and/or time for both filler metals.

关键词： Infrared Brazing cP-ti ti-cu-Ni fillers Microstructure