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Inhomogeneity of density and mechanical properties of A357 aluminum alloy backward extruded in semi-solid state 被引量:6
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作者 杜之明 陈刚 +1 位作者 程远胜 谢水生 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第10期2285-2293,共9页
The inhomogeneity of density and mechanical properties of A357 aluminum alloy in the semi-solid state were investigated.Numerical simulation and backward extrusion were adopted to study the preparation of cup shells.T... The inhomogeneity of density and mechanical properties of A357 aluminum alloy in the semi-solid state were investigated.Numerical simulation and backward extrusion were adopted to study the preparation of cup shells.The results show that the relative density of the wall is the lowest in samples,and that of the base is the highest.With increasing the billet height,more time is needed for relative density of the corner to reach the maximum value,and the relative densities in every region improve evidently with increasing the pressure.The tensile stress was simulated to be the largest at the corner,and the hot tearings were forecasted to mainly appear at the corner too.By employing proper billet height and pressure,the extruded samples consisted of fine and uniform microstructures,and can obtain excellent mechanical properties and Brinell hardness. 展开更多
关键词 A357 aluminum alloy INHOMOGENEITY semi-solid state backward extrusion numerical simulation
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Isothermal grain growth of reactive spray formed 7075 alloys in semi-solid state 被引量:5
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作者 HuiminLiu HuaCuit BinYang JishanZhang 《Journal of University of Science and Technology Beijing》 CSCD 2004年第5期411-414,共4页
The grain growth behavior in reactive spray formed 7075+2.91 vol percent TiCAl alloy was studied and compared with that of spray formed 7075 Al alloy at semi-solid state. Theeffects of in-situ TiC particles on the mic... The grain growth behavior in reactive spray formed 7075+2.91 vol percent TiCAl alloy was studied and compared with that of spray formed 7075 Al alloy at semi-solid state. Theeffects of in-situ TiC particles on the microstructure of spray formed 7075 Al alloy were alsoinvestigated. The specimens were heat-treated isothermally at various temperatures between thesolidus and liquidus of 7075 Al alloy for times in the range of 10-60 min, then quenched in water.The microstructure of reheated specimens was characterized using scanning electron microscopy andoptical microscopy. The grain size was measured using a mean linear intercept method. Results showthat the in-situ TiC particles can effectively retard grain growth and refine the grain at a limitedsize. The grain growth exponent in Arrhenius equation increases from 2 to 3, which indicates thatthe in-situ TiC particles have the significant pinning effect on grain coarsening in the semi-solidstate. 展开更多
关键词 reactive spray forming semi-solid state grain growth in-situ TiC particles
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Mechanical behavior of Al-Zn-Mg-Cu alloy under tension in semi-solid state 被引量:2
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作者 陈刚 张宇民 杜之明 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第3期643-648,共6页
In order to study the hot fractures in relation to the semi-solid processing, the tensile tests of an extruded 7075 aluminum alloy which is based on Al?Zn?Mg?Cu system were carried out in the high temperature solid an... In order to study the hot fractures in relation to the semi-solid processing, the tensile tests of an extruded 7075 aluminum alloy which is based on Al?Zn?Mg?Cu system were carried out in the high temperature solid and semi-solid states at different strain rates. The results show that the tensile behavior can be divided into three regimes with increasing the liquid fraction. The alloy first behaves in a ductile character, and as the temperature increases, the fracture mechanism changes from ductile to brittle which is determined by both of liquid and solid, and lastly the fracture mechanism is brittle which is totally dominated by liquid. At strain rates of 1×10?4, 1×10?3 and 1×10?2 s?1, the brittle temperature ranges are 515?526, 519?550 and 540?580 °C, respectively. Two equations which are critical for tensile behavior are proposed. 展开更多
关键词 Al-Zn-Mg-Cu alloy mechanical behavior semi-solid processing FRACTURE
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Mechanical behaviour of Al/Al_(2)O_(3) composite in pseudo-semi-solid state during isothermal compression 被引量:2
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作者 CHENG Yuan-sheng LUO Shou-jing 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2009年第S02期368-372,共5页
To gain a better understanding of thixoforging for the Al_(2)O_(3)-37%Al composite,its mechanical behavior in the pseudo-semi-solid state was studied by isothermal compression tests.The results show that the values of... To gain a better understanding of thixoforging for the Al_(2)O_(3)-37%Al composite,its mechanical behavior in the pseudo-semi-solid state was studied by isothermal compression tests.The results show that the values of peak stress obviously decrease with increasing temperature and decreasing strain rate.The compressive true stress-strain curves of the Al_(2)O_(3)-37%Al composite can be divided into four stages.They are rapidly ascending,decreasing,steady and slowly ascending.Moreover,the main deformation mechanism controlling deformation of the composite in the pseudo-semi-solid state is the sliding or rotary movement between solid particles. 展开更多
关键词 COMPOSITE pseudo-semi-solid state mechanical behaviour stress—strain curve
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Effects of Organic Fertilizer Application Amount on Seedling Quality under No-tillage Semi-Solid State Direct Seeding
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作者 LI Jing-yi HUANG Huang +4 位作者 LIANG Yu-gang WANG Ren WU Jia LV Guang-dong YANG Fei-xiang 《Agricultural Science & Technology》 CAS 2019年第2期1-10,共10页
With early rice variety Zhongzao 39 as test material,this paper investigated the effects of organic fertilizer application rate on seedling quality under no-tillage semi-solid state direct seeding.The results showed t... With early rice variety Zhongzao 39 as test material,this paper investigated the effects of organic fertilizer application rate on seedling quality under no-tillage semi-solid state direct seeding.The results showed that the seedling quality of no-tillage semi-solid direct seeding was better than that of traditional direct seeding,and different application rates of organic fertilizer under no-tillage semi-solid direct seeding also had signi ficant effects on seedling emergence rate,dry matter weight in ground and underground,stem base width,root activity,chlorophyll content and seedling growth index of rice seedlings.When the organic fertilizer dosage was A4(0.10∶1),it was most beneficial to the growth and development of rice seedlings under no-tillage semi-solid state direct seeding,it could effectively improve the quality of rice seedlings and enhance their resistances,the cultivated seedlings could lay a good foundation for high yield of rice in late stage. 展开更多
关键词 RICE NO-TILLAGE semi-solid state direct seeding Organic fertilizer Seedling quality
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Microstructure evolution of hot pressed AZ91D alloy chips reheated to semi-solid state
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作者 许红雨 吉泽升 +1 位作者 胡茂良 王振宇 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第12期2906-2912,共7页
AZ91D magnesium alloy chips, which were directly collected on the spot of machining process, were recycled to prepare billet via hot pressing for semi-solid processing. The semi-solid microstructure evolution of the b... AZ91D magnesium alloy chips, which were directly collected on the spot of machining process, were recycled to prepare billet via hot pressing for semi-solid processing. The semi-solid microstructure evolution of the billet during reheating was investigated. The results indicate that there are three stages during reheating to semi-solid state: the dissolution of Mg17Al12 and diffusion of Al into α-Mg matrix, the melting of the region with high content of solute and formation of isolated solid particles, and spheroidization and growth of solid particles. Meanwhile, a number of entrapped liquid droplets form within solid particles. In addition, the number and size of entrapped liquid droplets rely on the holding time in the semi-solid temperature range. With increasing isothermal holding time, the solid fraction remains unchanged when the solid-liquid system reaches the dynamic equilibrium at last, while the solid particles become more globular and the average size of solid particles increases owing to the decreasing of interfacial energy and the effect of interfacial tension. 展开更多
关键词 AZ91D alloy CHIPS semi-solid microstructure microstructure evolution RECYCLING entrapped liquid droplet interfacial energy interfacial tension
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Microstructure evolution and mechanical properties of ZK60 magnesium alloy produced by SSTT and RAP route in semi-solid state
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作者 王长朋 张营营 +3 位作者 李迪凡 梅华生 张帷 刘杰 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第12期3621-3628,共8页
The microstructure evolution and mechanical properties of a ZK60 magnesium alloy produced by the semi-solid thermal transformation (SSTT) route and the recrystallization and partial melting (RAP) route were studie... The microstructure evolution and mechanical properties of a ZK60 magnesium alloy produced by the semi-solid thermal transformation (SSTT) route and the recrystallization and partial melting (RAP) route were studied, respectively. The microstructure evolution during partial remelting was studied at different temperatures for different time. The tensile mechanical properties of thixoformed components by the two routes at room temperature were examined. The results show that coalescence is dominant in the SSTT alloy and Ostwald ripening is dominant in the RAP alloy. Compared with the SSTT route, the RAP route can produce finer semi-solid microstructure under the similar isothermal holding condition. The microstructure of the RAP alloy is much more spheroidized compared with the SSTT alloy. Thixoforming for the ZK60 magnesium alloy produced by the SSTT and RAP route results in successful filling of the die, and the thixoforming process improves the mechanical properties of ZK60 magnesium alloy. The RAP alloy shows significantly advantageous mechanical properties over that of the SSTT alloy. 展开更多
关键词 ZK60 magnesium alloy semi-solid thermal transformation (SSTT) recrystallization and partial melting (RAP) route microstructure evolution mechanical properties
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Reheating microstructure of refined AZ91D magnesium alloy in semi-solid state 被引量:17
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作者 姜巨福 罗守靖 《中国有色金属学会会刊:英文版》 CSCD 2004年第6期1074-1081,共8页
By means of equal channel angular extrusion (ECAE) test, upsetting test and metalloscope, reheating microstructures of raw casting ingots, materials prepared by SIMA and materials extruded by ECAE in semi-solid state ... By means of equal channel angular extrusion (ECAE) test, upsetting test and metalloscope, reheating microstructures of raw casting ingots, materials prepared by SIMA and materials extruded by ECAE in semi-solid state were investigated. The results show that compared with those of raw casting ingots and materials prepared by SIMA, reheating microstructure of materials extruded by ECAE is the best and the final grain size is the finest. With increasing holding time, a growing phenomenon occurs in reheating microstructure of materials extruded by ECAE, which can be described by Ostwald ripening law. The average grain size increases firstly, subsequently decreases and the shape factor of grains approaches to 1 as the reheating temperature increases. With increasing equivalent strain, the average grain size decreases. This demonstrates that reheating material extruded by ECAE technology is a good method to prepare AZ91D magnesium alloy semi-solid billets. 展开更多
关键词 再加热 微观结构 ECAE 半固态 AZ91D镁合金
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Structure of miniature components from steel produced by forming in semi-solid state 被引量:1
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作者 B.MASEK D.AISMAN +1 位作者 M.BEHULOVA H.JIRKOVA 《中国有色金属学会会刊:英文版》 CSCD 2010年第S3期1037-1041,共5页
To obtain new unconventional structures with specific mechanical and physical properties is possible not only by the development of new types of materials but also by treatment of conventional materials using unconven... To obtain new unconventional structures with specific mechanical and physical properties is possible not only by the development of new types of materials but also by treatment of conventional materials using unconventional innovative technological procedures.One of these technologies is the forming in semi-solid state involving rapid solidification of miniature components from steels.Production of such components is complicated by a number of technical problems.To explain phenomena of the process and structure development,the production of miniature components from the tool steel X210Cr12 difficult to form was experimentally tested.The structure of this originally ledeburite steel consisted of 95 % of metastable austenite after the treatment.Metastable austenite was located particularly in globular and polygonal grains while the remaining interspaces were filled by lamellar network.The detected high stability of extremely high fraction of metastable austenite was tested under different conditions of thermal exposition and mechanical loading. 展开更多
关键词 semi-solid state semi-solid FORMING rapid cooling METASTABLE AUSTENITE mini-thixoforming
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Thixoforming of SiC ceramic matrix composites in pseudo-semi-solid state 被引量:1
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作者 程远胜 罗守靖 杜之明 《中国有色金属学会会刊:英文版》 EI CSCD 2005年第5期1062-1066,共5页
A new forming process, ceramic matrix composites thixoforming in pseudo-semi-solid state, was proposed based on powder metallurgy technology combined with the semi-solid metal forming process. The satellite angle-fram... A new forming process, ceramic matrix composites thixoforming in pseudo-semi-solid state, was proposed based on powder metallurgy technology combined with the semi-solid metal forming process. The satellite angle-frames were prepared by this technology with Al_p and SiC_p materials mixed with different volume fractions. It is proved that it is feasible for the forming of the ceramic matrix composites by this technology through metallographic analyses and tensile tests. The results also show that the microstructures of samples are homogeneous and they have high hardness and certain plasticity. 展开更多
关键词 SIC 碳化硅 金属陶瓷 复合材料 金相学 强度 塑性
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Tensile properties of as-deformed 2A50 aluminum alloy in semi-solid state 被引量:8
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作者 杜之明 陈刚 +1 位作者 柳君 谢水生 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第9期1597-1602,共6页
Tensile properties of as-deformed 2A50 aluminum alloy were investigated in the high temperature solid and semi-solid states. The results show that temperature has almost no effect on the maximum tensile stress between... Tensile properties of as-deformed 2A50 aluminum alloy were investigated in the high temperature solid and semi-solid states. The results show that temperature has almost no effect on the maximum tensile stress between 500 ℃ and 530 ℃, and the maximum tensile stress decreases rapidly when the temperature is above 532 ℃. The ductility decreases with increasing temperature and has an obvious fall when the temperature is above solidus temperature. This alloy almost has no ductility above 537 ℃, and cannot sustain tensile stress above 550℃. A brittle temperature range in which this alloy is prone to form microcracks was derived. The relation between microstructure, fraction solid and tensile properties were also investigated by examining the metallograph and fracture surface morphology of tested specimens, which could provide reference for forecasting the microcracks in this alloy occurring in semi-solid processing. 展开更多
关键词 tensile properties aluminum alloy semi-solid MICROCRACKS FORECAST
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High temperature deformation behavior and microstructure evolution of wrought nickel-based superalloy GH4037 in solid and semi-solid states 被引量:6
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作者 Ju-fu JIANG Guan-fei XIAO +2 位作者 Ying WANG Ying-ze LIU Ying ZHANG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2020年第3期710-726,共17页
Cylindrical samples of Ni-based GH4037 alloy were compressed at solid temperatures(1200,1250 and 1300℃) and semi-solid temperatures(1340,1350,1360,1370 and 1380℃) with different strain rates of 0.01,0.1 and 1 s-1.Hi... Cylindrical samples of Ni-based GH4037 alloy were compressed at solid temperatures(1200,1250 and 1300℃) and semi-solid temperatures(1340,1350,1360,1370 and 1380℃) with different strain rates of 0.01,0.1 and 1 s-1.High temperature deformation behavior and microstructure evolution of GH4037 alloy were investigated.The results indicated that flow stress decreased rapidly at semi-solid temperatures compared to that at solid temperatures.Besides,the flow stress continued to increase after reaching the initial peak stress at semi-solid temperatures when the strain rate was 1 s-1.With increasing the deformation temperature,the size of initial solid grains and recrystallized grains increased.At semi-solid temperatures,the grains were equiaxed,and liquid phase existed at the grain boundaries and inside the grains.Discontinuous dynamic recrystallization(DDRX) characterized by grain boundary bulging was the main nucleation mechanism for GH4037 alloy. 展开更多
关键词 nickel-based superalloy high temperature deformation semi-solid microstructure evolution dynamic recrystallization
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Deformation mechanism and forming properties of 6061Al alloys during compression in semi-solid state 被引量:6
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作者 尚淑珍 路贵民 +2 位作者 唐小玲 赵祖欣 吴成明 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第9期1725-1730,共6页
The 6061 semi-solid aluminium alloy feedstocks prepared by near-liquidus casting were compressed in semi-solid state by means of Gleeble-3500 thermal-mechanical simulator.The relationship between the true stress and t... The 6061 semi-solid aluminium alloy feedstocks prepared by near-liquidus casting were compressed in semi-solid state by means of Gleeble-3500 thermal-mechanical simulator.The relationship between the true stress and the true strain at different temperatures and strain rates was studied with the deformation degree of 70%.The microstructures during the deformation process were characterized.The deformation mechanism and thixo-forming properties of the semi-solid alloys were analyzed.The results show that the homogeneous and non-dendrite microstructures of semi-solid 6061Al alloy manufactured by near-liquidus casting technology could be transformed into semi-solid state with the microstructure suitable for thixo-forming which are composed of near-spherical grains and liquid phase with eutectic composition through reheating process.The deformation temperature and strain rate affect the peak stress significantly rather than steady flow stress.The resistance to deformation in semi-solid state decreases with the increase of the deformation temperature and decrease of the strain rate.At steady thixotropic deformation stage, the thixotropic property is uniform, and the main deformation mechanism is the rotating or sliding between the solid particles and the plastic deformation of the solid particles. 展开更多
关键词 semi-solid processing 6061Al alloy compression deformation microstructural evolution thixotropic property
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Structural evolution of spray-formed Al-70wt.%Si alloys during iso-thermal holding in the semi-solid state 被引量:2
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作者 ZHANG Di CUI Hua +3 位作者 WEI Yanguang ZHANG Jishan ZHANG Yongan XIONG Baiqing 《Rare Metals》 SCIE EI CAS CSCD 2005年第4期317-324,共8页
The grain growth behavior of spray-formed Al-70wt.%Si alloys was studied in the semi-solid state. The specimens were isothermally heat-treated at various temperatures between the solidus and liquidus of Al-Si alloys a... The grain growth behavior of spray-formed Al-70wt.%Si alloys was studied in the semi-solid state. The specimens were isothermally heat-treated at various temperatures between the solidus and liquidus of Al-Si alloys and then quenched in water. The microstructure of reheated specimens was characterized using optical and scanning electron microscopies. The isothermal holding experiment was carried out to investigate grain growth behavior as a function of holding time and temperature in the semi-solid state. The coarsening mechanism and the effect of porosity on microstructure were also studied. 展开更多
关键词 materials science grain growth behavior spray forming Al-70wt.%Si alloys semi-solid processing
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Effects of Extrusion Processing on Microstructure of 7075Al Alloy in the Semi-solid State 被引量:2
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作者 SONG Yang ZHANG Zhiming +2 位作者 WANG Kai LI Hongxu ZHU Zizong 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2019年第6期1433-1443,共11页
A recrystallization and partial melting(RAP) process was introduced to prepare the semi-solid 7075 aluminum alloy used for thixoforming. In order to obtain an ideal semi-solid microstructure, a series of extrusion exp... A recrystallization and partial melting(RAP) process was introduced to prepare the semi-solid 7075 aluminum alloy used for thixoforming. In order to obtain an ideal semi-solid microstructure, a series of extrusion experiments were conducted to comparatively investigate the optimum extrusion process parameters. Commercial 7075 Al alloy samples were firstly extruded with varying extrusion ratios below the recrystallization temperature followed by homogenization, then these samples were reheated to the semi-solid state and held in the range of 5 to 50 minutes. The experimental results show that varying process cause the difference in the deformation degree and microstructure for as-extruded samples, resulting in various semi-solid microstructure. It is verified that the formation of equiaxed grains in semi-solid microstructure depends on recrystallization behavior of extruded samples during partial melting. Both relative high extrusion temperature and low extrusion ratio lead to high volume fraction of recrystallized area, thus entirely equiaxed solid grains in semi-solid 7075 Al alloy samples can be obtained finally. In addition, Ostwald ripening was determined as the dominate coarsening mechanism of solid grains in semi-solid state for this 7075 Al alloy during the RAP route. The influence of predeformation on recrystallization behavior of this 7075 Al alloy was discussed in detail. 展开更多
关键词 aluminum alloys extrusion process recrystallization and partial melting(RAP) semi-solid microstructure coarsening mechanism
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Rheological behavior of Al_2O_ 3n/Al_μ composite in pseudo-semi-solid state
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作者 程远胜 杜之明 罗守靖 《中国有色金属学会会刊:英文版》 CSCD 2005年第S2期142-146,共5页
A new technology for ceramics matrix composites-ceramics matrix composite thixoforming in pseudo-semi-solid state based on semi-solid metal process and powder metallurgy technology were proposed. The rheological behav... A new technology for ceramics matrix composites-ceramics matrix composite thixoforming in pseudo-semi-solid state based on semi-solid metal process and powder metallurgy technology were proposed. The rheological behavior of Al2O 3n/Alμ composite was studied by isothermal compression in pseudo-semi-solid state. The variation rules of the true stress-true strain, rheological behavior and the influencing factors were also analyzed. The results show that the flow stress decreases evidently with the increasing pseudo-semi-solid temperature, and that the trend of the true stress-true strain curve of the composite in pseudo-semi-solid state can be divided into four stages: increase, decline, re-increase and re-decline. 展开更多
关键词 Al2O 3n/Alμ COMPOSITE pseudo-semi-solid state ISOTHERMAL compression RHEOLOGICAL behavior
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The Compressive Deformation Behavior and Deformation Mechanism of Ti14 Alloy in Semi-solid State
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作者 陈永楠 WANG Jiao +1 位作者 WEI Jianfeng ZHAO Yongqing 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2014年第1期143-147,共5页
The semi-solid deformation behavior of Til4 was investigated using compression tests at deformation temperatures between 1 273 and 1 423 K with strain rate of 5×10^-2 s^-1. Moreover, the fraction solid at differe... The semi-solid deformation behavior of Til4 was investigated using compression tests at deformation temperatures between 1 273 and 1 423 K with strain rate of 5×10^-2 s^-1. Moreover, the fraction solid at different temperatures was also measured by image analysis. The results showed that the deformation temperature had strong effects on the flow stress, and the stress increased with the decrease of deformation temperature. The maximum stress depended greatly on the fraction solid, and a sharp decrease in stress occurred at a solid fraction between 0.94 and 0.98 (temperature from 1 323 to 1 373 K). This decrease was related to the decrease in the amount of solid bridges between grains. Because of the partial solid/liquid segregation during deformation, the experimental strain rates were much lower than those calculated by the flow of liquid incorporating solid particles, which suggested that the main deformation mechanism between 1 323 and 1 373 K was still plastic deformation of solid particles. 展开更多
关键词 titanium alloy semi-solid microstructure MICROMECHANICS deformation mechanism
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Morphology and valence state evolution of Cu:Unraveling the impact on nitric oxide electroreduction 被引量:1
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作者 Ting Sun Fengyu Gao +4 位作者 Ya Wang Honghong Yi Qingjun Yu Shunzheng Zhao Xiaolong Tang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第4期276-286,共11页
Ammonia(NH3)serves as a critical component in the fertilizer industry and fume gas denitrification.However,the conventional NH3production process,namely the Haber-Bosch process,leads to considerable energy consumption... Ammonia(NH3)serves as a critical component in the fertilizer industry and fume gas denitrification.However,the conventional NH3production process,namely the Haber-Bosch process,leads to considerable energy consumption and waste gas emissions.To address this,electrocatalytic nitric oxide reduction reaction(NORR)has emerged as a promising strategy to bridge NH3consumption to NH3production,harnessing renewable electricity for a sustainable future.Copper(Cu)stands out as a prominent electrocatalyst for NO reduction,given its exceptional NH3yield and selectivity.However,a crucial aspect that remains insufficiently explored is the effects of morphology and valence states of Cu on the NORR performance.In this investigation,we synthesized CuO nanowires(CuO-NF)and Cu nanocubes(Cu-NF)as cathodes through an in situ growth method.Remarkably,CuO-NF exhibited an impressive NH3yield of 0.50±0.02 mg cm^(-2)h^(-1)at-0.6 V vs.reversible hydrogen electrode(RHE)with faradaic efficiency of29,68%±1,35%,surpassing that of Cu-NF(0.17±0.01 mg cm^(-2)h^(-1),16.18%±1.40%).Throughout the electroreduction process,secondary cubes were generated on the CuO-NF surface,preserving their nanosheet cluster morphology,sustained by an abundant supply of subsurface oxygen(s-O)even after an extended duration of 10 h,until s-O depletion ensued.Conversely,Cu-NF exhibited inadequate s-O content,leading to rapid crystal collapse within the same timeframe.The distinctive current-potential relationship,akin to a volcano-type curve,was attributed to distinct NO hydrogenation mechanisms.Further Tafel analysis revealed the exchange current density(i0)and standard heterogeneous rate constant(k0)for CuO-NF,yielding 3.44×10^(-6)A cm^(-2)and 3.77×10^(-6)cm^(-2)s^(-1)when NORR was driven by overpotentials.These findings revealed the potential of CuO-NF for NO reduction and provided insights into the intricate interplay between crystal morphology,valence states,and electrochemical performance. 展开更多
关键词 NORR Ammonia Synthesis COPPER MORPHOLOGY Valence states Mechanism
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Assessment of Wet Season Precipitation in the Central United States by the Regional Climate Simulation of the WRFG Member in NARCCAP and Its Relationship with Large-Scale Circulation Biases 被引量:1
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作者 Yating ZHAO Ming XUE +2 位作者 Jing JIANG Xiao-Ming HU Anning HUANG 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第4期619-638,共20页
Assessment of past-climate simulations of regional climate models(RCMs)is important for understanding the reliability of RCMs when used to project future regional climate.Here,we assess the performance and discuss pos... Assessment of past-climate simulations of regional climate models(RCMs)is important for understanding the reliability of RCMs when used to project future regional climate.Here,we assess the performance and discuss possible causes of biases in a WRF-based RCM with a grid spacing of 50 km,named WRFG,from the North American Regional Climate Change Assessment Program(NARCCAP)in simulating wet season precipitation over the Central United States for a period when observational data are available.The RCM reproduces key features of the precipitation distribution characteristics during late spring to early summer,although it tends to underestimate the magnitude of precipitation.This dry bias is partially due to the model’s lack of skill in simulating nocturnal precipitation related to the lack of eastward propagating convective systems in the simulation.Inaccuracy in reproducing large-scale circulation and environmental conditions is another contributing factor.The too weak simulated pressure gradient between the Rocky Mountains and the Gulf of Mexico results in weaker southerly winds in between,leading to a reduction of warm moist air transport from the Gulf to the Central Great Plains.The simulated low-level horizontal convergence fields are less favorable for upward motion than in the NARR and hence,for the development of moist convection as well.Therefore,a careful examination of an RCM’s deficiencies and the identification of the source of errors are important when using the RCM to project precipitation changes in future climate scenarios. 展开更多
关键词 NARCCAP Central United states PRECIPITATION low-level jet large-scale environment diurnal variation
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Thermal safety boundary of lithium-ion battery at different state of charge 被引量:1
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作者 Hang Wu Siqi Chen +8 位作者 Yan Hong Chengshan Xu Yuejiu Zheng Changyong Jin Kaixin Chen Yafei He Xuning Feng Xuezhe Wei Haifeng Dai 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第4期59-72,共14页
Thermal runaway(TR)is a critical issue hindering the large-scale application of lithium-ion batteries(LIBs).Understanding the thermal safety behavior of LIBs at the cell and module level under different state of charg... Thermal runaway(TR)is a critical issue hindering the large-scale application of lithium-ion batteries(LIBs).Understanding the thermal safety behavior of LIBs at the cell and module level under different state of charges(SOCs)has significant implications for reinforcing the thermal safety design of the lithium-ion battery module.This study first investigates the thermal safety boundary(TSB)correspondence at the cells and modules level under the guidance of a newly proposed concept,safe electric quantity boundary(SEQB).A reasonable thermal runaway propagation(TRP)judgment indicator,peak heat transfer power(PHTP),is proposed to predict whether TRP occurs.Moreover,a validated 3D model is used to quantitatively clarify the TSB at different SOCs from the perspective of PHTP,TR trigger temperature,SOC,and the full cycle life.Besides,three different TRP transfer modes are discovered.The interconversion relationship of three different TRP modes is investigated from the perspective of PHTP.This paper explores the TSB of LIBs under different SOCs at both cell and module levels for the first time,which has great significance in guiding the thermal safety design of battery systems. 展开更多
关键词 Lithium-ion battery Battery safety Thermal runaway state of charge Numerical analysis
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