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Progress of Nonequilibrium Solidification Theory

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Journal of Materials Science & Technology 1998年第6期14卷 497-505页

作者： Li, Qingchun cui, chengsong Xu, Daming Yuan, Xiaoguang Harbin Inst Technol Harbin 150001 Peoples R China Jilin Univ Technol Changchun 130025 Peoples R China

The theory related to nucleation, interface kinetics, micromorphology evolution and microscopic growth during nonequilibrium alloy solidification was reviewed. Methods for quantitative analysis of nucleation rate, the criterion of marginal stability, nonequilibrium partition coefficient, as well as the relationship between growth rate with undercooling and dendrite tip radius were presented. Some limitations and future developments of nonequilibrium theory were presented. (Edited author abstract) 55 Refs.

关键词： Alloys

Microstructure of Rapidly Solidified Al-3.8Li-0.8Mg-0.4Cu-0.13Zr Alloy by Spray Deposition Processing

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Journal of Materials Science & Technology 1998年第5期14卷 407-410页

作者： cui, chengsong Fan, Hongbo Xu, Daming Jiang, Zuling Li, Qingchun Harbin Inst Technol Sch Mat Sci & Engn Harbin 150001 Peoples R China

The grains are 5-20 mu m in size, and the microstructure exhibits the rapid solidification merits. Shrinkage porosities have been avoided, and the formation of prior particle boundary has been prevented to a large extent. But there still exist some micropores with various shapes. The relative density of the as-deposited material is 94% on average. The main precipitates in the tested alloy are delta (AlLi), S(Al//2CuMg) and delta prime (Al//3Li) phases. (Edited author abstract) 10 Refs.

关键词： Aluminum alloys

Microstructure and Properties of Spray Deposited 2024-20Si-5Fe Alloy

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Journal of Materials Science & Technology 1998年第5期14卷 402-406页

作者： Yuan, Xiaoguang Ren, Luquan cui, chengsong Xu, Daming Li, Qingchun Jilin Univ Technol Engn Bion Res Inst Changchun 130025 Peoples R China Harbin Inst Technol Sch Mat Sci & Engn Harbin 150001 Peoples R China

A rapidly solidified Al-Si-Fe-Cu-Mg alloy was prepared by spray deposition. The microstructure of the alloy includes silicon phase and delta -(Al,Fe,Si), Al//8Si//6Mg//3Fe, FeAl//2 and small FeSi//2 phases. The reasons of the formation of silicon and delta -(Al,Fe,Si) phase were analyzed. The tensile properties at the room temperature to 350 degree C were investigated, and the strengthening mechanism was suggested. The wear resistance and cutability of the alloy were measured as well. (Edited author abstract) 11 Refs.

关键词： Aluminum alloys

Drinking water quality & health risk assessment of secondary water supply systems in residential neighborhoods

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Frontiers of Environmental Science & Engineering 2024年第2期18卷 47-62页

作者： Yating Wei Dong Hu chengsong Ye Heng Zhang Haoran Li Xin Yu College of the Environment&Ecology Xiamen UniversityXiamen 361102China School of Public Health Shandong First Medical University&Shandong Academy of Medical SciencesJinan 250117China

Secondary water supply systems(SWSSs)are important components of the water supply infrastructure that ensure residents’drinking water *** are characterized by long detention time,warm temperature,and unreasonable management,which may trigger the deterioration of water quality and increase *** this study,drinking water quality index(DWQI)and health risk assessment(HRA)were selected and modified to quantitatively assess the water quality and health risks of SWSSs in residential *** total,121 seasonal water samples were *** was observed that the water quality was excellent with the DWQI of 0.14±0.04,excluding one sample,which was extremely poor owing to its excessive total bacterial *** HRA results revealed that the health risks were low:negligible non-carcinogenic risk for any population;negligible and acceptable carcinogenic risk for children aged 6–17 and ***,samples revealed higher carcinogenic risk(7.63×10−5±3.29×10−6)for children aged 0–5,and arsenic was the major *** samples had poor water quality and higher health risks,which called for *** further investigate the water quality and health risks of SWSSs,monthly sampling was conducted during *** 24 water samples were qualified in Chinese standard(GB 5749-2022)and characterized as excellent *** HRA results were consistent with the seasonal samples’and the health risks were mainly concentrated in ***,our study provides a suitable framework for water quality security,advice for managers,and references for administrators in other cities.

关键词： Drinking water quality Water quality index Health risk assessment Secondary water supply systems Heavy metals

Modeling of the Shape Forming of Composite Roll

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Journal of Materials Science & Technology 2000年第3期16卷 337-340页

作者： chengsong cui, Zhenyu LI, Fuyang CAO and Qingchun LI (School of Materials Science and Engineering, Harbin Institute of Technology, 150001, China) School of Materials Science and Engineering Harbin Institute of Technology China

A shape modeling of spray formed composite roll, which is utilized to predict the shape and dimension of roll during spray forming process, is developed in this paper. The influences of the principal spray forming parameters, such as the spatial distribution of melt mass flux, spray distance, rotating and translating speeds of substrate bar etc. , on the geometry and dimension of spray formed product were investigated.

关键词： Modeling of the Shape Forming of Composite Roll

Modeling of Heat Transfer and Solidification Process of Spray Formed Billet

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Journal of Materials Science & Technology 2001年第1期17卷 101-102页

作者： Fuyang CAO chengsong cui and QingChun LI School of Materials Science and Engineering, Harbin institute of Technology, Harbin 150001, China Sch. of Mater. Sci. Harbin Inst. of Technol. Harbin 150001 China

In this paper, modeling of heat transfer and solidification process of spray formed billet was established. Thermal profiles of billet at various spray time and under various spray forming conditions were calculated n... 详细信息

关键词： Solidification Process solidification process simulation results spray forming heat transfer

Modeling of Heat Transfer and Solidification of Composite Roll

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Journal of Materials Science & Technology 2001年第1期17卷 87-88页

作者： chengsong cui Fuyang CAO Zhenyu LI and Qingchun LI School of Materials Science and Engineering, Harbin institute of Technology, Harbin 150001, China Sch. of Mater. Sci. Harbin Inst. of Technol. Harbin 150001 China

Modeling of heat transfer and solidification of composite roll was established and used to predict the thermal history and solidification process of roll during spray forming. Evolution of temperature field of the preform and cooling rate in the growing deposit during spray deposition and post-deposition were numerically simulated.

关键词： Modeling of Heat Transfer and Solidification of Composite Roll

MICROSTRUCTURE　AND　TENSILE　PROPERTIES　OF　RAPIDLY　SOLIDIFIED　Al－3．8Li－0．8Mg－0．4Cu－0．13Zr　ALLOY　PREPARED　BY　SPRAY　DEPOSITION

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Acta Metallurgica Sinica(English Letters) 1996年第1期9卷 37-43页

作者： cui chengsong FAN Hongbo SHEN Jun JIANG Zuling LI Qingchun(Department of Metallic Materials and Technology,Harbin Institute of Technology,Harbin 150001,China) Harbin Inst of Technology Harbin China

Al-3.8Li-0.8Mg-0.4Cu-0.13Zr alloy was prepared by a novel spray deposition technique,and its microstructure and tensile properties after various aging treatments have been investigated. The experimental results show that the alloy,under study has very fine equiaxed grains about 5-20μm in diameter and a relative density of(94±3)% on *** in the as-extruded alloy are'brick-like'in morphology,and few oxide particles have been found al the grain boundaries.δ' particles with irregular shape and'δ'-β''coprecipitates appear in the aged *** coarsening of δ'particles is fast,and the distance between the particles does not widen so obviously as that of IM(ingot-casting method) alloys with increasing aging *** spray deposited Al-Li *** the peak-aged condition in a short time(10 h al 190℃) when the best properties(σb=534 MPa, σ0.2=480 MPa.δ=10%) are *** with RSPM(rapid solidification processing method)Al-Li alloy,the ductility of the tested alloy has been *** while a comparable tensile strength is maintained.

关键词： spray deposition rapid solidification Al-Li alloy microstructure tensile property

Change of pore water near the freezing front during soil freezing: Migration and mechanisms

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Pedosphere 2024年第4期34卷 770-782页

作者： Yajun SHI Wei MA Lianhai ZHANG chengsong YANG Fei SHANG Cheng CHEN State Key Laboratory of Frozen Soil Engineering Northwest Institute of Eco-Environment and Resources Chinese Academy of Sciences University of Chinese Academy of Sciences Department of Joint NMR Laboratory for Freeze-Thaw Processes in Soils of State Key Laboratory of Frozen Soil Engineering and Suzhou Niumag Analytical Instrument Corporation

The formation and growth of segregation ice dominate the frost heave during soil freezing, which is closely related to water migration. To analyze segregation ice during soil freezing for different soils, a freezing-thawing experiment was conducted with Lanzhou loess(LZL) and Qinghai-Tibet Plateau silty clay(QSC) using a novel layered nuclear magnetic resonance approach. During LZL freezing, the unfrozen water content first increased and then decreased with decreasing temperature near the freezing front, but decreased with decreasing temperature in other layers, whereas during the freezing of QSC, the unfrozen water content in different layers(including the freezing front) decreased with decreased temperature. Notably, the increased liquid water near the freezing front during LZL freezing was primarily adsorbed water. In addition to the temperature gradient, the squeezing action during soil freezing was another important factor affecting water migration, especially at the early stage of soil freezing. However, which of the two factors, squeezing action and temperature gradient, was the dominant one causing water migration depended on soil structure. At the early stage of soil freezing, the squeezing action had a significant effect on the water migration of LZL, but no significant effect on that of QSC. Furthermore, water accumulation of LZL near the freezing front due to squeezing action at the early stage of freezing limited the formation and growth of segregation ice. This study provided an improved understanding for ice segregation and water migration during soil freezing.

关键词： frozen soil nuclear magnetic resonance segregation ice unfrozen water water migration