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Impact and mechanism of bisphosphonate depressant 1-hydroxypropane-1,1-diphosphonic acid on flotation decalcification of dolomite-rich magnesite ore
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作者 Wengang Liu Xudong Chen +3 位作者 Wenbao Liu Naixu Zhang Yong Mao Ying Guo 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2024年第7期1017-1032,共16页
Given the depletion of high-quality magnesite deposits and the rising demand for high-end magnesium materials,the separation and utilization of high-calcium magnesite ores have become essential.However,the similar sur... Given the depletion of high-quality magnesite deposits and the rising demand for high-end magnesium materials,the separation and utilization of high-calcium magnesite ores have become essential.However,the similar surface properties and solubility of semi-soluble salt-type minerals,pose significant challenges for the utilization of dolomite-rich magnesite resources.In this study,1-hydroxypropane-1,1-di phosphonic acid(HPDP)was identified for the first time as a high-performance depressant for dolomite.Various tests,including contact angle measurements,ζ potential analysis,X-ray photoelectron spectroscopy,and atomic force microscopy,were conducted to elucidate the interfacial interaction mechanisms of HPDP on the surfaces of the two minerals at different scales.Additionally,molecular modeling calculations were used to detail the spatial matching relationship between HPDP and the crystal faces of the two minerals.It was emphasized that HPDP specifically adsorbed onto the dolomite surface by forming calcium phosphonate,ensuring that the dolomite surface remained hydrophilic and sank.Moreover,it was found that the adsorption strength of HPDP on the mineral surfaces depended on the activity of the metal sites and their spatial distribution.These findings provide a theoretical foundation for the molecular design of flotation reagents for high-calcium magnesite ores. 展开更多
关键词 Depressant Interfacial mechanism MAGNESITE DOLOMITE DFT decalcification
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Deep decalcification of factory-provided freezing acidolysis solution to achieveα-high-strength gypsum
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作者 Wencai Ye Yulu Li +3 位作者 Yonggang Dong Lin Yang Yun Yi Jianxin Cao 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第5期143-151,共9页
The freezing acidolysis solution of the nitric acid-phosphate fertilizer process has a high calcium content,which makes it difficult to produce fine phosphate and high water-soluble phosphate fertilizer products.Here,... The freezing acidolysis solution of the nitric acid-phosphate fertilizer process has a high calcium content,which makes it difficult to produce fine phosphate and high water-soluble phosphate fertilizer products.Here,based on the potential crystallization principle of calcium sulfate in NH_(4)NO_(3)-H_(3)PO_(4)-H_(2)O,the deep decalcification(i.e.calcium removal)technology to achieveα-high-strength gypsum originated from freezing acidolysis-solutions has been firstly proposed and investigated.Typically,calcium can be removed from the factory-provided freezing acidolysis-solution by neutralizing it with ammonia,followed by the addition of ammonium sulfate solution.As a result,the formation of calcium sulfate in the reaction system undergoes the nucleation and growth of CaSO_(4)·2H_(2)O(DH),as well as its dissolution and crystallization into short columnarα-CaSO_(4)·0.5H_(2)O(α-HH).Remarkably,with the molar ratio of SO_(4)^(2-)/Ca^(2+)at 1.8,the degree of neutralization(NH_(3)/HNO_(3) molar ratio)at 1.7,the reaction temperature of 94℃,and the reaction time of 300 min,the decalcification rate can reach 86.89%,of which the high-strengthα-CaSO_(4)·0.5H_(2)O(α-HH)will be obtained.Noteworthy,the deep decalcification product meets the standards for the production of fine phosphates and highly water-soluble phosphate fertilizers.Consequently,the 2 h flexural strength ofα-HH is 5.3 MPa and the dry compressive strength is 36.8 MPa,which is up to the standard of commercialα-HH. 展开更多
关键词 Nitrophosphate Ammonia neutralization Deep decalcification High-strengthα-hemihydrate gypsum Controlled crystallization at atmospheric pressure
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To improve robustness of mechanical properties of semi-solid cast A356 alloy using taguchi design method
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作者 Yi-wu Xu Hong-yi Zhan +4 位作者 Wei Tong Jin-ping Li Le-peng Zhang De-jiang Li Xiao-qin Zeng 《China Foundry》 SCIE EI CAS CSCD 2024年第2期175-184,共10页
Mechanical properties of semi-solid casting are dependent on multiple processing parameters,and improper processing parameters will not only reduce mean data but also increase variations.The present study investigated... Mechanical properties of semi-solid casting are dependent on multiple processing parameters,and improper processing parameters will not only reduce mean data but also increase variations.The present study investigated the impact of parameters in slurry preparation and heat treatment on the yield strength and ductility of T6 heat-treated A356 Al-Si alloy using rapid slurry forming(RSF)semi-solid casting.The focus was primarily on the robustness of mechanical properties based on Taguchi design method.By analyzing signal-to-noise ratio and minimum value calculated from-3S,the optimum slurry preparation parameters and heat treatment parameters were determined to be no quench,enthalpy exchange material(EEM)temperature of 140℃,EEM-to-melt ratio of 6mass%,stirring time of 18 s,solution heat treated at 520℃ for 2 h,and ageing heat treated at 190℃ for 6 h.In a small batch validation,the-3S yield strength and-3S elongation reach 256.1 MPa and 5.03% respectively,showing a satisfactory robustness.The hardness and microstructure of heat-treated samples with the best and worst properties were characterized to gain insight into the underlying mechanisms affecting the mean value and variations of mechanical properties. 展开更多
关键词 semi-solid casting taguchi design method signal-to-noise ratio mechanical property MICROSTRUCTURE
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Microstructure evolution of Ti_(48)Zr_(27)Cu_(6)Nb_(5)Be_(14)amorphous alloy after semi-solid isothermal treatment
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作者 Xin-hua Huang Jing-wen Pu +1 位作者 Yong-xin Luo Yue-jun Ouyang 《China Foundry》 SCIE EI CAS CSCD 2024年第3期287-294,共8页
The as-cast amorphous Ti_(48)Zr_(27)Cu_(6)Nb_(5)Be_(14)composites,comprising in situ formedβ-Ti ductile crystalline precipitates,were prepared by water cooled copper mold suction casting.Then,the semi-solid composite... The as-cast amorphous Ti_(48)Zr_(27)Cu_(6)Nb_(5)Be_(14)composites,comprising in situ formedβ-Ti ductile crystalline precipitates,were prepared by water cooled copper mold suction casting.Then,the semi-solid composites were obtained after the as-cast composites were treated by semi-solid isothermal treatment.The microstructure evolution and kinetics of the composites were examined.Results show that the microstructures of both the as-cast and semi-solid composites comprise ofβ-Ti crystal phases and amorphous matrix phases.Before and after treatment,the crystals evolve from fine granular or fine dendritic crystals to coarse crystals.As the treatment temperature increasing or the time prolonging,the average crystal size gradually increases and the surface morphology of the crystals gradually becomes regular.By studying the microstructural evolution and dynamics during the isothermal treatment process,it is found that the final morphology ofβ-Ti crystals is influenced by the isothermal treatment temperature and time(t),and theβ-Ti evolution rate increases with an increase in treatment temperature.In addition,a linear relationship was observed between the size of cubicβ-Ti crystals(D^(3))and t;the growth kinetics factor K is 3.8μm^(3)·s^(-1).As the K value closes to 4μm^(3)·s^(-1),it is inferred the morphology evolution ofβ-Ti crystals is a coarsening behavior controlled by the diffusion of solute elements. 展开更多
关键词 Ti_(48)Zr_(27)Cu_(6)Nb_(5)Be_(14) amorphous matrix composites semi-solid as-cast microstructure
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Research on Decalcification Degradation Process of Cement Stone
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作者 余海燕 YANG Jiujun RONG Hui 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2015年第2期369-374,共6页
An accelerated laboratory method(saturated ammonium nitrate solution immersion method) was used to analyze the degradation of cement decalcification process. By studying the changes of intensity, volume, elastic mod... An accelerated laboratory method(saturated ammonium nitrate solution immersion method) was used to analyze the degradation of cement decalcification process. By studying the changes of intensity, volume, elastic modulus, quality, p H value, the Ca/Si, and mineral phase, it could be found that the first cement decalcification degradation process was the decalcification of calcium hydroxide, and then CSH gel, AFm, etc. The secondary ettringite deposition happened and the decalcification degradation depth was proportional to the square root of time. Moreover, the corresponding strength of cement would be gradually reduced, cement rock volume shrinkage occurred, p H values decreased, the surface elastic modulus decreased down to a certain level, and slightly changed and the Ca/Si was 3.1 from the beginning and lasted down to 1.3. 展开更多
关键词 accelerated test decalcification Ca/Si ratio degradation process
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Mechanical properties and microstructural evolution of rheocast A356 semi-solid slurry prepared by annular electromagnetic stirring 被引量:1
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作者 Mohammad Taghi Asadi Khanouki 《China Foundry》 SCIE CAS CSCD 2023年第4期315-328,共14页
Nowadays,having an effective technique in preparing semi-solid slurries for rheocasting process seems to be an essential requirement.In this study,semi-solid slurry of A356 aluminum alloy was prepared by three-phase a... Nowadays,having an effective technique in preparing semi-solid slurries for rheocasting process seems to be an essential requirement.In this study,semi-solid slurry of A356 aluminum alloy was prepared by three-phase annular electromagnetic stirring(A-EMS)technique under different conditions.The effects of stirring current,pouring temperature and stirring time on microstructural evolution,mean particle size,shape factor and solid fraction were investigated.The rheocasting process was carried out by using a drop weight setup and to inject the prepared semi-solid slurry in optimal conditions into the step-die cavity.The filling behavior and mechanical properties of parts were studied.Microstructural evolution showed that the best semi-solid slurry which had fine spherical particles with the average size of~27μm and a shape factor of~0.8 was achieved at the stirring current of 70 A,melt pouring temperature of 670℃,and stirring time of 30 s.Under these conditions,the step-die cavity was completely filled at die preheating temperature of 470℃.The hardness increases by decreasing step thickness as well as die preheating temperature.Moreover,the tensile properties are improved at lower die preheating temperatures.The fracture surface,which consists of a complex topography,indicates a typical ductile fracture. 展开更多
关键词 semi-solid slurry annular electromagnetic stirring rheocast A356 aluminum alloy microstructural evolution mechanical properties magnetic flux density
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Microstructure characteristics and thermodynamic properties of A357-SiCp/A357 layered composites prepared by semi-solid vacuum stirring suction casting
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作者 Zhen-lin Zhang Ying Xiao +3 位作者 Jun Xu Feng-liang Tan Li Wang Min He 《China Foundry》 SCIE CAS CSCD 2023年第2期108-114,共7页
A357-SiCp/A357 layered composites were prepared using a semi-solid vacuum stirring suction casting method.The microstructures,mechanical properties,and thermal conductivities of the composites fabricated under differe... A357-SiCp/A357 layered composites were prepared using a semi-solid vacuum stirring suction casting method.The microstructures,mechanical properties,and thermal conductivities of the composites fabricated under different suction casting processes were compared.Additionally,the microstructural evolution characteristics and performance enhancement mechanism of the A357-SiCp/A357 layered composites were discussed.The results demonstrate that suction casting at 610°C with a low solid phase ratio can significantly enhance the material density and reduce the agglomeration of SiCp.The A357-SiC_(p)/A357 interface is clear and straight with good bonding.With an increase in the suction casting temperature,the bending resistance and thermal conductivity of the A357-SiC_(p)/A357 layered composites exhibit a trend of significantly increase at first and then slowly decrease owing to casting defects,interface bonding,and SiCp distribution.Compared with SiCp/A357 composites,the bending strength,deflection,and thermal conductivity of the A357-SiCp/A357 layered composites increase from 257 MPa,1.07 mm,and 155.72 W·(m·K)^(-1) to 298 MPa,2.1 mm,and 169.86 W·(m·K)^(-1),respectively.This study provides a reference for improving the rheological casting of aluminum matrix layered composites. 展开更多
关键词 semi-solid vacuum stirring suction casting SiCp/A357 layered composites thermodynamic properties rheological casting
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Microstructures and mechanical properties of semi-solid squeeze casting ZL104 connecting rod 被引量:10
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作者 王永飞 赵升吨 张晨阳 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2018年第2期235-243,共9页
Semi-solid squeeze casting(SSSC) and liquid squeeze casting(LSC) processes were used to fabricate a ZL104 connecting rod, and the influences of the process parameters on the microstructures and mechanical properti... Semi-solid squeeze casting(SSSC) and liquid squeeze casting(LSC) processes were used to fabricate a ZL104 connecting rod, and the influences of the process parameters on the microstructures and mechanical properties were investigated. Results showed that the tensile strength and elongation of the SSSC-fabricated rod were improved by 22% and 17%, respectively, compared with those of the LSC-fabricated rod. For SSSC, the average particle size(APS) and the shape factor(SF) increased with the increase of re-melting temperature(Tr), whereas the tensile strength and elongation increased first and then decreased. The APS increased with increasing the mold temperature(Tm), whereas the SF increased initially and then decreased, which caused the tensile strength and elongation to increase initially and then decrease. The APS decreased and the SF increased as squeezing pressure(ps) increased, and the mechanical properties were enhanced. Moreover, the optimal Tr, ps and Tm are 848 K, 100 MPa and 523 K, respectively. 展开更多
关键词 aluminum alloy semi-solid squeeze casting semi-solid microstructure tensile strength ELONGATION connecting rod
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Microstructure evolution and grain growth behavior of Ti14 alloy during semi-solid isothermal process 被引量:6
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作者 陈永楠 魏建锋 +1 位作者 赵永庆 郑晶 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第5期1018-1022,共5页
Microstructure evolution of Ti14 (α+Ti2Cu) alloy during semi-solid isothermal process at different temperatures was investigated. The results reveal that both the temperature and holding time have effect on the gr... Microstructure evolution of Ti14 (α+Ti2Cu) alloy during semi-solid isothermal process at different temperatures was investigated. The results reveal that both the temperature and holding time have effect on the grain growth behavior. The grains grow obviously and the degree of globularity increases with the increase of holding time. According to the statistic analysis of experimental data, the grain growth indices are 0.88 and 0.97 at 1 000 ℃ and 1 050 ℃, respectively, which indicates that increasing isothermal temperature would accelerate microstructural evolution. 展开更多
关键词 titanium alloy Ti14 alloy semi-solid microstructure grain growth index
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Effect of cooling condition on microstructure of semi-solid AZ91 slurry produced via ultrasonic vibration process 被引量:10
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作者 张亮 吴国华 +1 位作者 王少华 丁文江 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第10期2357-2363,共7页
The effects of cooling conditions on the microstructure of semi-solid AZ91 slurry produced via ultrasonic vibration process were investigated. AZ91 melts were subjected to ultrasonic vibration in different temperature... The effects of cooling conditions on the microstructure of semi-solid AZ91 slurry produced via ultrasonic vibration process were investigated. AZ91 melts were subjected to ultrasonic vibration in different temperature ranges under different cooling rates. The results show that fine and spherical α-Mg particles are obtained under ultrasonic vibration at the nucleation stage, which is mainly attributed to the cavitation and acoustic streaming induced by the ultrasonic vibration. The reduction of lower limit of ultrasonic vibration temperature between the liquidus and solidus increases the solid volume fraction and average particle size. Increasing cooling rate increases the solid volume fraction and reduces the average shape factor of particles. The appropriate temperature range for ultrasonic vibration is from 605 °C to 595 °C or 590 °C, and the suitable cooling rate is 2-3 °C/min. 展开更多
关键词 AZ91 alloy semi-solid ultrasonic vibration MICROSTRUCTURE cooling condition
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Preparation of semi-solid 7075 aluminum alloy slurry by serpentine pouring channel 被引量:15
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作者 朱文志 毛卫民 涂琴 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第4期954-960,共7页
The semi-solid slurry of 7075 aluminum alloy was prepared by a serpentine pouring channel (SCP). Influences of pouring temperature and the number of turns on the microstructure of semi-solid 7075 alloy slurry were i... The semi-solid slurry of 7075 aluminum alloy was prepared by a serpentine pouring channel (SCP). Influences of pouring temperature and the number of turns on the microstructure of semi-solid 7075 alloy slurry were investigated. The results demonstrated that the semi-solid 7075 aluminum alloy slurry with satisfied quality could be generated by a serpentine pouring channel when the pouring temperature was in the range of 680-700 ℃. At a given pouring temperature, the equivalent size of the primaryα(Al) grains decreased and the shape factor increased with the increase of the number of turns. During the slurry preparation of semi-solid 7075 aluminum alloy, the flow direction of alloy melt changed many times when it flowed in a curved and closed serpentine channel. With the effect of“stirring”in it , the primary nuclei gradually evolved into spherical and near-spherical grains. 展开更多
关键词 7075 aluminum alloy semi-solid slurry serpentine channel primary α(Al)
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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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Microstructure evolution of semi-solid 7075 Al alloy slurry during temperature homogenization treatment 被引量:7
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作者 杨斌 毛卫民 宋晓俊 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第12期3592-3597,共6页
Semi-solid 7075 Al slurry was prepared by inverted cone-shaped pouring channel process (ICSPC) and temperature homogenization (TH) treatment was combined to make the slurry uniform and have a controllable solid fr... Semi-solid 7075 Al slurry was prepared by inverted cone-shaped pouring channel process (ICSPC) and temperature homogenization (TH) treatment was combined to make the slurry uniform and have a controllable solid fraction suitable for the follow-up rheocasting. The influence of cooling rate on the microstructure evolution of primary α(Al) during TH treatment was investigated. The results show that as the cooling rate of the slurry after being prepared reduces, the growth of primaryα(Al) in the slurry tends to be nearly spherical and the uniformity of the organization is also enhanced. This may be due to the fact that lower cooling rate plays an important role in achieving the uniformity of temperature and composition in the remaining liquid, which is crucial to the formation of the spherical and homogeneous microstructure. However, a too low cooling rate will lead to a significant increase in grain growth time, which makes too coarse grains and more particles coalesce, so a certain abnormal growth of grain appears and the shape factor decreases slightly. 展开更多
关键词 semi-solid slurry 7075 Al alloy MICROSTRUCTURE primaryα(Al)
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Application of cyclic upsetting-extrusion to semi-solid processing of AZ91D magnesium alloy 被引量:3
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作者 陶健全 姜巨福 +5 位作者 陈红 肖远伦 张荣朝 胡庆华 赵军 赵强 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第4期909-915,共7页
The microstructural evolution of AZ91D magnesium alloy prepared by means of the cyclic upsetting-extrusion and partial remelting was investigated. The effects of remelting temperature and holding time on microstructur... The microstructural evolution of AZ91D magnesium alloy prepared by means of the cyclic upsetting-extrusion and partial remelting was investigated. The effects of remelting temperature and holding time on microstructure of semi-solid AZ91D magnesium alloy were studied. Furthermore, tensile properties of thixoextruded AZ91D magnesium alloy components were determined. The results show that the cyclic upsetting-extrusion followed by partial remelting is effective in producing semi-solid AZ91D magnesium alloy for thixofonning. During the partial remelting, with the increase of remelting temperature and holding time, the solid grain size increases and the degree of spheroidization tends to be improved. The tensile mechanical properties of thixoextruded AZ91D magnesium alloy components produced by cyclic upsetting-extrusion and partial remelting are better than those of the same alloy produced by casting. 展开更多
关键词 AZ91D magnesium alloy semi-solid processing cyclic upsetting-extrusion mechanical properties MICROSTRUCTURE
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Influence of serpentine channel pouring process parameters on semi-solid A356 aluminum alloy slurry 被引量:7
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作者 陈正周 毛卫民 吴宗闯 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第5期985-990,共6页
Semi-solid A356 aluminum alloy slurry was prepared by using serpentine channel pouring process, and the influences of the channel diameters and pouring temperatures on the semi-solid A356 aluminum alloy slurry were in... Semi-solid A356 aluminum alloy slurry was prepared by using serpentine channel pouring process, and the influences of the channel diameters and pouring temperatures on the semi-solid A356 aluminum alloy slurry were investigated. The experimental results show that when the channel diameter is 20 and 25 mm, respectively, and the pouring temperature is 640-680 ℃, the average diameter of primary α(Al) grains in the prepared A356 aluminum alloy slurry is 50-75 and 55-78 μm, respectively, and the average shape factor of primary α(Al) grains is 0.89-0.76 and 0.86-0.72, respectively. With the decline in the pouring temperature, the microstructure of semi-solid A356 aluminum alloy slurry is more desirable and a serpentine channel with smaller diameter is also advantageous to the microstructure imProvement. During the preparation of semi-solid A356 aluminum alloy slurry, a large number of nuclei can be produced by the chilling effect of the serpentine channel, and owing to the combined effect of the chilled nuclei separation and melt self-stirring, primary α(Al) nuclei can be multiplied and spheroidized finally. 展开更多
关键词 semi-solid A356 aluminum alloy serpentine channel primary α(Al)
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Microstructure and properties of electronic packaging box with high silicon aluminum-base alloy by semi-solid thixoforming 被引量:10
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作者 贾琪瑾 刘俊友 +1 位作者 李艳霞 王文韶 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第1期80-85,共6页
The electronic packaging box with high silicon aluminum-base alloy was prepared by semi-solid thixoforming technique.The flow characteristic of the Si phase was analyzed.The microstructures of different parts of the b... The electronic packaging box with high silicon aluminum-base alloy was prepared by semi-solid thixoforming technique.The flow characteristic of the Si phase was analyzed.The microstructures of different parts of the box were observed by optical microscopy and scanning electron microscopy,and the thermophysical and mechanical properties of the box were tested.The results show that there exists the segregation phenomenon between the primary Si phase and the liquid phase during thixoforming,the liquid phase flows from the box,and the primary Si phase accumulates at the bottom of the box.The volume fraction of primary Si phase decreases gradually from the bottom to the walls.Accordingly,the thermal conductivities of bottom center and walls are 107.6 and 131.5 W/(m·K),the coefficients of thermal expansion(CTE) are 7.9×10-6 and 10.6×10-6 K-1,respectively.The flexural strength increases slightly from 167 to 180 MPa.The microstructures and properties of the box show gradient distribution overall. 展开更多
关键词 high silicon aluminum-base alloy electronic packaging semi-solid thixoforming thermal conductivity coefficient of thermal expansion
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Preparation of semi-solid A380 aluminum alloy slurry by serpentine channel 被引量:8
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作者 刘志勇 毛卫民 +1 位作者 王伟番 郑志凯 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第5期1419-1426,共8页
The semi-solid slurry of A380 aluminum alloy was prepared by the serpentine channel. The effects of pouring temperature, curve number and curve diameter of the serpentine channel on the microstructure of the semi-soli... The semi-solid slurry of A380 aluminum alloy was prepared by the serpentine channel. The effects of pouring temperature, curve number and curve diameter of the serpentine channel on the microstructure of the semi-solid A380 aluminum alloy slurry were investigated. The results show that the satisfactory semi-solid A380 aluminum alloy slurry could be obtained when the pouring temperature ranged from 630 to 650 °C. Under the same conditions, increasing the curve number or reducing the curve diameter of the serpentine channel would decrease the average diameter and increase the shape factor of the primary α(Al) grains. The "self-stirring" of the alloy melt in the serpentine channel was beneficial to the ripening of the dendrites and the spheroidizing of the primary α(Al) grains. 展开更多
关键词 A380 aluminum alloy semi-solid slurry serpentine channel primary α(Al)
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Effects of processing parameters on microstructure of semi-solid slurry of AZ91D magnesium alloy prepared by gas bubbling 被引量:3
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作者 张扬 吴国华 +3 位作者 刘文才 张亮 庞松 丁文江 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第7期2181-2187,共7页
The semi-solid slurry of AZ91 D magnesium alloy was prepared by gas bubbling process.The effect of processing parameters,including gas flow rate,cooling rate and stirring end temperature,on microstructure of AZ91 D se... The semi-solid slurry of AZ91 D magnesium alloy was prepared by gas bubbling process.The effect of processing parameters,including gas flow rate,cooling rate and stirring end temperature,on microstructure of AZ91 D semi-solid slurry was investigated.With increasing the gas flow rate from 0 to 5 L/min,the average size of primary α-Mg particles decreases from 119.1 to77.2μm and the average shape factor increases continuously from 0.1 to 0.596.The formation of non-dendritic primary α-Mg particles during gas bubbling is the result of combined effects of dendrite fragmentation and copious nucleation.With increasing the cooling rate from 3.6 to 14.6℃/min,the average particle size of primary α-Mg phase decreases from 105.0 to 68.1μm while the average shape factor peaks at 9.1℃/min.Both high and low cooling rates can induce dendritic growth of primary α-Mg particles.Changing the stirring end temperature from 590 to 595℃ has little effect on the average size and shape factor of primary α-Mg particles in AZ91 D semi-solid slurry.The insensitivity of semi-solid microstructures to the stirring end temperature is attributed to the sufficient quantity of primary particles formed in the melt. 展开更多
关键词 AZ91D magnesium alloy semi-solid slurry gas bubbling MICROSTRUCTURE
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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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无托槽隐形矫治中牙釉质脱矿情况的临床调查
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作者 胡丹艳 陈慧芬 +3 位作者 吴峻青 李琥 严斌 韶青华 《口腔医学》 CAS 2024年第10期742-746,共5页
目的调查无托槽隐形矫治过程中牙釉质脱矿的发病率及脱矿严重程度,为临床医疗护理工作提供参考依据。方法收集2015年-2022年于我院进行无托槽隐形矫治的151例患者(3507颗牙齿),对比观察其治疗前后的牙釉质脱矿情况,使用釉质脱矿指数(ena... 目的调查无托槽隐形矫治过程中牙釉质脱矿的发病率及脱矿严重程度,为临床医疗护理工作提供参考依据。方法收集2015年-2022年于我院进行无托槽隐形矫治的151例患者(3507颗牙齿),对比观察其治疗前后的牙釉质脱矿情况,使用釉质脱矿指数(enamel decalcification index,EDI)评估脱矿程度,对患者牙釉质脱矿的发病率和脱矿严重程度进行统计分析,比较不同性别、年龄及牙位之间的差异。结果治疗过程中有84例患者出现釉质脱矿,发病率为55.63%,性别及治疗时间对发病率无影响,青少年患者发病率高于成年患者。在被调查的3507颗牙齿中有601颗出现釉质脱矿,发病率为17.14%,其中上颌前牙和下颌后牙的发病率较高,右侧牙齿的发病率显著高于左侧牙齿,粘接附件后釉质脱矿的发病率也显著增加。88%的牙釉质脱矿病损程度为1~2度,男女患者釉质脱矿程度相似,青少年的釉质脱矿程度显著高于成年患者,上颌前牙的平均EDI值明显大于下颌,上颌后牙的平均EDI值明显小于下颌,右侧的平均EDI值明显大于左侧。结论无托槽隐形矫治过程中出现牙釉质脱矿的发病率较高,且青少年是易感人群,不同牙位之间的脱矿情况有显著差异,粘结附件会增加牙齿釉质脱矿风险。因此医护人员应在釉质脱矿的防治工作中采取积极有效的措施。 展开更多
关键词 正畸 无托槽隐形矫治 牙釉质脱矿
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