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Investigation of Formation and Inhibition Mechanism of Cerium Conversion Films on Al 2024 Alloy 被引量:4
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作者 邵敏华 黄若双 +1 位作者 付燕 林昌健 《Journal of Rare Earths》 SCIE EI CAS CSCD 2002年第6期640-645,共6页
To study the mechanism of formation and inhibition of Ce conversion films on Al 2024-T3 alloy, scanning microreference electrode technique (SMRE) is used to probe the potential map on Al 2024-T3 in CeCl 3 solution, t... To study the mechanism of formation and inhibition of Ce conversion films on Al 2024-T3 alloy, scanning microreference electrode technique (SMRE) is used to probe the potential map on Al 2024-T3 in CeCl 3 solution, the localized corrosion of Al alloy decreases with immersion time and disappears finally, which results from the competition of Cl - aggression and Ce 3+ inhibition on alloy surface. The results of X-ray photoelectron spectroscopy (XPS) indicate that the Ce conversion films consist of Al 2O 3, CeO 2 and Ce 2O 3(Ce(OH) 3), and CeO 2/Ce 2O 3 ratio decreases with the immersion time. When a critical pH for Ce(OH) 3 formation was reached, Ce(OH) 3 will precipitate on the micro cathodic area on alloy surface. Consequently, H 2O 2, the product of the catholic reaction will oxidize a part of Ce(OH) 3 to CeO 2, which appears a better corrosion resistance for Al alloys. 展开更多
关键词 rare earths Ce conversion film Al 2024 alloy SMRE corrosion resistance
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Microstructure and mechanical properties of friction stir welded powder metallurgy AA2024 alloy 被引量:2
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作者 HAN Wei-hao LI Pei +6 位作者 LIU Nan CHEN Cun-guang DONG Shi-peng GUO Zhi-meng YANG Fang SUI Yan-li VOLINSKYAlex A 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第3期871-882,共12页
The extruded plate of powder metallurgy AA2024 aluminum alloy was successfully solid-state joined by friction stir welding(FSW) to demonstrate potential applications in the aerospace and automotive industries. For det... The extruded plate of powder metallurgy AA2024 aluminum alloy was successfully solid-state joined by friction stir welding(FSW) to demonstrate potential applications in the aerospace and automotive industries. For determining the optimal processing parameters of FSW, the microstructure, mechanical properties, and fracture behavior of FSW joints were evaluated. When the processing parameters were optimized with 2000 r/min rotation speed and100 mm/min traverse speed, high quality welds were achieved. The ultimate tensile strength yield strength and elongation of the joint can reach 415 MPa(85% of the base metal strength), 282 MPa, and 9.5%, respectively. The hardness of the joint gradually decreased from the alloy matrix to the heat-affected zone. The lowest strength and hardness appeared near the heat-affected zone because of the over-aging caused by heat flow from repeated stirring during FSW. The average grain size of the stir zone(2.15 μm) was smaller than that of the base metal(4.43 μm) and the heat-affected zone(5.03 μm), whose grains had <110> preferred orientation. 展开更多
关键词 high-strength aluminum alloy powder metallurgy AA2024 alloy friction stir welding mechanical properties
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Effect of casting speed on floating grains and macrosegregation ofdirect-chill cast 2024 alloy with intensive melt shearing 被引量:4
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作者 Xu-dong LIU Qing-feng ZHU +6 位作者 Zhi-meng LI Cheng ZHU Rui WANG Tao JIA Zhi-hao ZHAO Jian-zhong CUI Yu-bo ZUO 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2021年第3期565-575,共11页
The ingot was prepared by direct-chill(DC)casting technology with different casting speeds under the influence of intensive melt shearing to explore the effect of casting speed and intensive melt shearing on the float... The ingot was prepared by direct-chill(DC)casting technology with different casting speeds under the influence of intensive melt shearing to explore the effect of casting speed and intensive melt shearing on the floating grains and negative centerline segregation.The results indicate that the application of intensive melt shearing in DC casting process can distribute the floating grains uniformly,reduce the area fraction of the floating grains,alleviate the negative centerline segregation,and improve the uniformity of temperature field in the sump.It is also suggested that under the influence of intensive melt shearing,the casting speed plays a crucial role in the amounts and distribution of floating grains.At low casting speed,the intensive melt shearing can significantly reduce the area fraction of the floating grains and distribute them uniformly throughout the ingot.However,this effect gradually disappears with the increase of casting speed. 展开更多
关键词 direct-chill casting intensive melt shearing MACROSEGREGATION floating grains casting speed 2024 aluminum alloy
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Evaluation of surface roughness and optimization of cutting parameters in turning of AA2024 alloy under different cooling-lubrication conditions using RSM method 被引量:3
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作者 Seyed Hasan MUSAVI Behnam DAVOODI Behzad ESKANDARI 《Journal of Central South University》 SCIE EI CAS CSCD 2020年第6期1714-1728,共15页
In the present study,the effect of reduction of cutting fluid consumption on the surface quality and tool wear was studied.Mathematical models were developed to predict the surface roughness using response surface met... In the present study,the effect of reduction of cutting fluid consumption on the surface quality and tool wear was studied.Mathematical models were developed to predict the surface roughness using response surface methodology(RSM).Analysis of variance(ANOVA)was used to investigate the significance of the developed regression models.The results showed that the coefficient of determination values(R^2)for the developed models was 97.46%for dry,89.32%for flood mode(FM),and 99.44%for MQL,showing the high accuracy of fitted models.Also,under the minimum quantity lubrication(MQL)condition,the surface roughness improved by 23%−44%and 19%−41%compared with dry and FM,respectively,and the SEM images of machined surface proved the statement.The prepared SEM images of tool rake face also showed a considerable decrease in adhesion wear.Built-up edge and built-up layer were the two main products of the adhesion wear,and energy-dispersive X-ray spectroscopy(EDX)analysis of specific points on the tool faces helped to discover the chemical compositions of adhered materials.By changing dry and FM to MQL mode,dominant mechanism of tool wear in machining aluminum alloy was significantly decreased.Breakage wear that led to early failure of cutting edge was also controlled by MQL technique. 展开更多
关键词 cooling-lubrication methods surface roughness minimum quantity lubrication response surface methodology AA2024 aluminum alloy
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Visualization and simulation of plastic material flow in friction stir welding of 2024 aluminium alloy plates 被引量:12
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作者 武传松 张文斌 +1 位作者 石磊 陈茂爱 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第6期1445-1451,共7页
Thin copper sheets as marker material were embedded into weld path of 2024 aluminium alloy plates and their final position after friction stir welding was examined by metallographic techniques. Referring to the visual... Thin copper sheets as marker material were embedded into weld path of 2024 aluminium alloy plates and their final position after friction stir welding was examined by metallographic techniques. Referring to the visualized material flow patterns, a three-dimensional model was developed to conduct the numerical simulation of the temperature profile and plastic material flow in friction stir welding. The calculated velocity contour of plastic flow in close proximity of the tool is generally consistent with the visualized results. As the tool rotation speed increases at a constant tool travel speed, the material flow near the pin gets stronger. The predicted shape and size of the weld nugget zone match with the experimentally measured ones. 展开更多
关键词 2024 aluminium alloy numerical simulation VISUALIZATION friction stir welding material flow heat transfer
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Effects of magnesium chloride-based multicomponent salts on atmospheric corrosion of aluminum alloy 2024 被引量:6
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作者 王彬彬 王振尧 +2 位作者 韩薇 汪川 柯伟 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第4期1199-1208,共10页
Atmospheric corrosion of aluminum alloy 2024 (AA2024) with salt lake water was simulated through a laboratory- accelerated test of cyclic wet-dry and electrochemical techniques. Effects of the soluble magnesium salt... Atmospheric corrosion of aluminum alloy 2024 (AA2024) with salt lake water was simulated through a laboratory- accelerated test of cyclic wet-dry and electrochemical techniques. Effects of the soluble magnesium salt contained in the salt water were investigated by scanning electron microscope (SEM), transmission electron microscope (TEM), energy dispersive spectrometer (EDS), electron probe micro analyzer (EPMA), X-ray diffraction (XRD), infrared transmission spectroscope (IR), and atmospheric corrosion monitor (ACM). The results showed that, with the deposition, atmospheric corrosion of AA2024 could occur when the relative humidity (RH) was lower than 30%. A main crystalline component of corrosion products, layered double hydroxides (LDH), [Mg1-xAlx(OH)2]^x+ Clx-·mH2O (LDH-C1), was determined, which meant that magnesium ion played an important role in the corrosion process. It not only facilitated the corrosion as a result of deliquescence, but also was involved in the corrosion process as a reactant. 展开更多
关键词 aluminum alloy 2024 atmospheric corrosion magnesium chloride relative humidity corrosion products
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Effects of non-isothermal annealing on microstructure and mechanical properties of severely deformed 2024 aluminum alloy 被引量:8
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作者 Saeed KHANI MOGHANAKI Mohsen KAZEMINEZHAD 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2017年第1期1-9,共9页
Microstructure and mechanical properties of AA2024 after severe plastic deformation (SPD) and non-isothermal annealing were investigated. The non-isothermal treatment was carried out on the severely deformed AA2024,... Microstructure and mechanical properties of AA2024 after severe plastic deformation (SPD) and non-isothermal annealing were investigated. The non-isothermal treatment was carried out on the severely deformed AA2024, and the interaction between restoration and precipitation phenomena was investigated. Differential scanning calorimetry, hardness and shear punch tests illustrate that static recovery and dissolution of GPB zones/Cu-Mg co-clusters occur concurrently through non-isothermal annealing. Scanning electron microscope and electron backscatter diffraction illustrate that non-isothermal annealing of deformed AA2024 up to 250 ℃ promotes the particle-free regions and also particle stimulated nucleation. Results show that through heating with the rate of 10 ℃/min up to 250 ℃, the ultimate shear strength and the hardness are maximum due to the presence of S'/S phases which have been detected during non-isothermal differential scanning calorimetry experiment. Also, recrystallization phenomenon occurs in temperature range which includes the dissolution of S'/S phases. The concurrent recrystallization and dissolution of S'/S phase at 380 ℃ have been verified by differential scanning calorimetry, mechanical properties, and optical microscope. 展开更多
关键词 AA2024 alloy severe plastic deformation non-isothermal annealing MICROSTRUCTURE mechanical properties
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Parametric optimization and microstructural characterization of friction welded aeronautic aluminum alloy 2024 被引量:5
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作者 Pei-hao GENG Guo-liang QIN +1 位作者 Jun ZHOU Chang-an LI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2019年第12期2483-2495,共13页
Continuous drive friction welding was employed to join the aeronautic aluminum alloy 2024.Parametric optimization and microstructural characterization were investigated.Results show that friction pressure is the most ... Continuous drive friction welding was employed to join the aeronautic aluminum alloy 2024.Parametric optimization and microstructural characterization were investigated.Results show that friction pressure is the most significant factor influencing the tensile strength of joints.To obtain a high joint efficiency,the combination of moderate friction pressure,less friction time and higher upset pressure is recommended.The optimized joint efficiency from Taguchi analysis reaches 92% of base metal.Under the optimized experimental condition,the interfacial peak temperature is calculated analytically in the range of 779-794 K,which is validated by experimental data.Fine recrystallized grains caused by the high temperature and plastic deformation are observed in the friction interface zone.The grain refinement is limited in the thermo-mechanically affected zone,where most of matrix grains are deformed severely.The extensive dissolution and limited re-precipitation of strengthening phases result in a lower microhardness in the friction interface zone than that in the thermo-mechanically affected zone. 展开更多
关键词 AA2024 alloy continuous drive friction welding Taguchi analysis microstructure evolution mechanical properties
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TLP bonding of Ti-6Al-4V to Al 2024 using thermal spray Babbitt alloy interlayer 被引量:5
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作者 H.NAEIMIAN M.A.MOFID 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2020年第5期1267-1276,共10页
Thermal spray assisted transient liquid phase(TLP) bonding of Ti-6 Al-4 V to Al2024 alloys was investigated, where the interlayer was 80 μ m Babbitt thermal spray coat on Al substrate. Thermal spray creates a rough a... Thermal spray assisted transient liquid phase(TLP) bonding of Ti-6 Al-4 V to Al2024 alloys was investigated, where the interlayer was 80 μ m Babbitt thermal spray coat on Al substrate. Thermal spray creates a rough and clean surface which leads to establishing a joint with higher strength. The optimized parameters were bonding temperature of 580 ℃ and bonding time of 30 and 60 min. Microstructural observation together with XRD patterns confirmed the existence of Al2 Cu, Al2 Cu Mg, Cu3 Ti, Ti Al3, Ti Al and Mg2 Sn intermetallic compounds formed in Al weld side. On the other hand, Ti3 Al, Sn3 Ti5 and Ti3 Sn intermetallic compounds formed in Ti side. With increasing bonding time from 30 to 60 min, although the interlayer was not completely consumed, the thickness of remained Babbitt interlayer decreased to approximately 15 μ m. The study showed that shear strength of the joint reaches the high value of 57 MPa obtained at larger bonding time of 60 min. 展开更多
关键词 transient liquid phase Al 2024 alloy Ti-6Al-4V alloy thermal spray shear strength
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Microstructure evolution and mechanical properties of ultrasonic-assisted soldering joints of 2024 aluminum alloys 被引量:2
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作者 李远星 赵维巍 +3 位作者 冷雪松 付秋娇 王雷 闫久春 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第9期1937-1943,共7页
Ultrasonic-assisted soldering of 2024 aluminum alloys using a filler metal of Zn-5Al alloy was investigated at the temperature of 400 ℃,which is lower than the solution strengthening temperature of Al-Cu alloys.The u... Ultrasonic-assisted soldering of 2024 aluminum alloys using a filler metal of Zn-5Al alloy was investigated at the temperature of 400 ℃,which is lower than the solution strengthening temperature of Al-Cu alloys.The ultrasonic vibration with power of 200 W and vibration amplitude of 15 μm at the frequency of 21 kHz was applied on the top samples.The ultrasonic vibration promoted the dissolution of Al elements in the base metal.The reduction of volume fraction of the eutectic phases in the bonds was investigated by increasing ultrasonic vibration time.As the ultrasonic vibration time increased from 3 s to 30 s,the volume fraction of the eutectic phase in the bonds decreased from 12.9% to 0.9%,and the shear strength of the joints was up to 149-153 MPa,increased by 20%.The improvement of the mechanical properties of joints was discussed based on the modulus and hardness of the phases in the bonds and the fracture of the joints. 展开更多
关键词 2024 aluminum alloys BRAZING SOLDERING ultrasonic-assisted soldering Zn-5Al filler metal
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Corrosion behavior of 2024 Al-Cu-Mg alloy of various tempers 被引量:11
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作者 K.S.GHOSH Md.HILAL Sagnik BOSE 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第11期3215-3227,共13页
Corrosion behavior of 2024 Al-Cu-Mg alloy of different tempers was assessed by potentiodynamic polarization studies in 3.5% NaCl solution, 3.5% NaCI+I.0% H2O2 solution and 3.5% NaCl solution at pH 12. Polarization cu... Corrosion behavior of 2024 Al-Cu-Mg alloy of different tempers was assessed by potentiodynamic polarization studies in 3.5% NaCl solution, 3.5% NaCI+I.0% H2O2 solution and 3.5% NaCl solution at pH 12. Polarization curves showed shifting of corrosion potential (φPcor) towards more negative potential with increasing ageing time and shifting of φcorr in the positive direction with the addition of H2O2 in NaCl solution. Polarization curves in 3.5% NaCl solution at pH 12 exhibited distinct passivity phenomenon. Optical micrographs of the corroded surfaces showed general corrosion, extensive pitting and intergranular corrosion as well. Cyclic potentiodynamic polarization curves exhibited wide hysteresis loop and the mode of corrosion attack confirmed that the alloy states are susceptible to pit growth damage. Attempts were made to explain the observed corrosion behavior of the alloy of various tempers in different electrolytes with the help of microstructural features. 展开更多
关键词 2024 Al-Cu-Mg alloy ageing behavior electrochemical polarization PASSIVITY pitting potential
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Numerical simulation for macrosegregation in direct-chill casting of 2024 aluminum alloy with an extended continuum mixture model 被引量:9
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作者 Hai-jun LUO Wan-qi JIE +1 位作者 Zhi-ming GAO Yong-jian ZHENG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2018年第5期1007-1015,共9页
An extended continuum mixture model for macrosegregation is applied to predicting Cu and Mg segregation in large-size ingot of 2024 aluminum alloy during direct chill casting(DC). A microsegregation model using the ... An extended continuum mixture model for macrosegregation is applied to predicting Cu and Mg segregation in large-size ingot of 2024 aluminum alloy during direct chill casting(DC). A microsegregation model using the approximate phase diagram data was coupled with macroscopic transport equations for macrosegregation profiles. Then, the impacts of transport mechanisms on the formation of macrosegregation were discussed. It is found that copper and magnesium have a similar segregation configuration from the billet center to surface. Negative segregation is observed in the centerline and subsurface, whereas positive segregation is obtained in the surface and somewhat underestimated positive segregation in the middle radius. Further, the discrepancy between the predicted and experimental results was discussed in detail. The results show that the magnesium to some extent alleviates the copper segregation in ternary alloy, compared with that in binary alloy. The predicted results show good agreement with measured experimental data obtained from literatures. 展开更多
关键词 direct-chill casting MACROSEGREGATION numerical simulation continuum model 2024 aluminum alloy
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Microstructure characteristics and solidification behavior of wrought aluminum alloy 2024 rheo-diecast with self-inoculation method 被引量:15
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作者 Li Yanlei Li Yuandong +1 位作者 Li Chun Wu Huihui 《China Foundry》 SCIE CAS 2012年第4期328-336,共9页
One important problem in casting wrought aluminum alloys is the high tendency to the formation of hot tears in the solidification process.By using semi-solid metal(SSM) processing,the hot tearing tendency of alloys ca... One important problem in casting wrought aluminum alloys is the high tendency to the formation of hot tears in the solidification process.By using semi-solid metal(SSM) processing,the hot tearing tendency of alloys can be minimized during casting.In the present research,the semi-solid slurry of wrought aluminum alloy 2024 was firstly prepared with a novel self-inoculation method(SIM),and then the microstructure characteristics of the semi-solid slurry and the rheo-diecastings cast with the semi-solid slurry were investigated.The results indicate that finer and more uniform globular primary α-Al particles can be obtained when the semi-solid slurry are isothermally held for a short period within the semi-solid temperature range,and the primary α-Al particles without entrapped liquid are uniformly fine,globular grains in the rheo-diecastings.The holding temperature and time affect the solid fraction,particle size,and shape factor.After the semi-solid slurry is held at 625 ℃ for 3 min and 5 min,the optimal values for the average equivalent diameter are 70.80 μm and 74.15 μm,and for the shape factor are 1.32 and 1.42,respectively.The solidification process of the rheo-diecastings is composed of the following two distinct stages:primary solidification process and secondary solidification process.The secondary solidification process consists further of the following three stages:(1) direct growth of secondary primary(α 2) phase from the surface of the primary α-Al phase particles without re-nucleation,(2) independent nucleation and growth of α 3 phase from the residual liquid,and(3) eutectic reaction at the end. 展开更多
关键词 self-inoculation method wrought aluminum alloy 2024 solidification behavior secondary solidification
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Anodizing of 2024-T3 aluminum alloy in sulfuric-boric-phosphoric acids and its corrosion behavior 被引量:19
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作者 M. SAEEDIKHANI M. JAVIDI A. YAZDANI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第9期2551-2559,共9页
The corrosion resistance of 2024-T3 aluminum alloy was improved by anodizing treatment in a mixed electrolyte containing 10% sulfuric acid, 5% boric acid and 2% phosphoric acid. Electrochemical impedance spectroscopy ... The corrosion resistance of 2024-T3 aluminum alloy was improved by anodizing treatment in a mixed electrolyte containing 10% sulfuric acid, 5% boric acid and 2% phosphoric acid. Electrochemical impedance spectroscopy (EIS) technique was used to study the corrosion behavior of the anodized alloy. Using Tafel plot and salt spray techniques, it is revealed that the anodizing treatment of 2024-T3 aluminum alloy in sulfuric-boric-phosphoric acids provides better corrosion resistance and durability in comparison with the anodizing treatment in phosphoric acid or sulfuric-boric acids. This electrolyte can be a suitable alternative for chromate baths which are generally used in the anodizing of aluminum alloys. 展开更多
关键词 ANODIZING 2024-T3 aluminum alloy mixed electrolyte EIS
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Corrosion performance of friction stir welded AA2024 aluminium alloy under salt fog conditions 被引量:7
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作者 R.SEETHARAMAN V.RAVISANKAR V.BALASUBRAMANIAN 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第5期1427-1438,共12页
Aluminium alloy(AA) 2024 is an important engineering material due to its widespread use in the aerospace industry. However, it is very prone to corrosion attack in chloride containing media. In the present investiga... Aluminium alloy(AA) 2024 is an important engineering material due to its widespread use in the aerospace industry. However, it is very prone to corrosion attack in chloride containing media. In the present investigation, AA2024 aluminium alloy rolled plates of 5 mm in thickness were friction stir welded. Corrosion performances of the specimens were evaluated by conducting salt fog tests in Na Cl solution at different p H values, chloride ion concentrations and spraying time. In addition, an empirical relationship was established to predict the corrosion rate of friction stir welds of AA2024 aluminium alloy. A central composite rotatable design including three factors and five levels was used to minimize the number of experiments. Response surface methodology(RSM) was used to develop the relationship. The corrosion rate decreased under neutral p H conditions. The corrosion rate increased in acidic and basic conditions. It was also found that the corrosion rate decreased with the increase of spraying time, but the corrosion tended to be uniform with the increment of time and with the increase in the chloride ion concentration, and the corrosion rate increased in the salt spray corrosion test. 展开更多
关键词 AA2024 aluminium alloy friction stir welding salt fog test response surface methodology corrosion rate
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A STUDY ON MICRO-PLASTIC DEFORMATION BEHAVIOR OF 2024 A1 ALLOY 被引量:5
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作者 F. Yang C. H. Wu D. L. Sun 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2000年第2期502-507,共6页
Dimensional stability properties of hot extruded 2024 Al alloy bar in T4 and T6 aging states and dif- ferent extruded directions were investigated by testing micro-yield strength (MYS), stress relaxation resistance (S... Dimensional stability properties of hot extruded 2024 Al alloy bar in T4 and T6 aging states and dif- ferent extruded directions were investigated by testing micro-yield strength (MYS), stress relaxation resistance (SRR), and dimensional change in thermal cycling and unloading conditions.The results show that micro-plastic deformation resistance in longitudinal(parallel to the axis of the extruded bar) direction is higher than that in transverse(perpendicular to the axis of the extruded bar) direction. Testing in short-term loading condition MYS value corresponding to micro-plastic strain of 1 *10m^(-5)in longitudinal direction is 1.4 times than that in transverse.Compared with the results of MYS and dimensional change in thermal cycling and unloading conditions, the values in T6 state are higher than that in T4 state. Using TEM the microstructures before micro-plastic deformation were observed.The analyses confirm that stability of thermodynamics condition and dislocation results in dimensional stability of the alloy. 展开更多
关键词 2024 Al alloy dimensional stability AGING micro-yield strength stress relaxation
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Nonmechanical criteria proposed for prediction of hot tearing sensitivity in 2024 aluminum alloy 被引量:4
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作者 M.H.GHONCHEH S.G.SHABESTARI +1 位作者 A.ASGARI M.KARIMZADEH 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2018年第5期848-857,共10页
Two theoretical criteria represented by Katgerman, and Clyne and Davies for prognosticating hot tearing sensitivity were compared. Both unrefined and grain-refined samples of Al2024 alloy were solidified at various co... Two theoretical criteria represented by Katgerman, and Clyne and Davies for prognosticating hot tearing sensitivity were compared. Both unrefined and grain-refined samples of Al2024 alloy were solidified at various cooling rates ranging from 0.4 to 17.5 °C/s. Thermal analysis was used to detect dendrite coherency point and temperature of eutectic reaction. Curves of solid and liquid fractions were plotted based on Newtonian method to determine hot tearing susceptible areas. The experimental results show that the most susceptible zone in which hot tearing can occur in Al2024 is where Al_2CuMg intermetallic compound forms as a eutectic phase at last stage of mushy-state interval. Also, both criteria are in a good agreement with each other at high cooling rates used in direct-chill casting process while Clyne and Davies' model is more acceptable to determine hot tearing tendency from low to medium cooling rates. 展开更多
关键词 2024 aluminum alloy dendrite coherency direct-chill casting thermal analysis hot tearing
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EFFECT OF LOW-FREQUENCY ELECTROMAGNETIC FIELD ON THE AS-CASTING MICROSTRUCTURES AND MECHANICAL PROPERTIES OF HDC 2024 ALUMINUM ALLOY 被引量:4
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作者 Q.F. Zhu Z.H. Zhao J.Z. Cui Y.B. Zuo F. Qu 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2008年第3期205-210,共6页
The influences of the low frequency electromagnetic field on the horizontal direct chill casting process were investigated experimentally. Ingots of 2024 aluminum alloy with a cross size of 40 mm× 200 mm were pro... The influences of the low frequency electromagnetic field on the horizontal direct chill casting process were investigated experimentally. Ingots of 2024 aluminum alloy with a cross size of 40 mm× 200 mm were produced by the conventional horizontal chill casting process and low frequency electromagnetic horizontal chill casting processre- spectively. The as-cast structures and the mechanical property of the ingots were examined. The results showed that the low frequency electromagnetic field could sub- stantially refine the microstructures and pronouncedly reduce the macrosegregation in the horizontal direct chill casting process. Moreover, the surface quality of the ingot was prominently improved by the low frequency electromagnetic field. The fracture strength and elongation percentage of the ingot was increased with the low frequency electromagnetic field. 展开更多
关键词 Horizontal direct chill casting Low frequency electromagnetic field 2024 aluminum alloy MICROSTRUCTURES MACROSEGREGATION
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Multi-axial Fatigue of 2024-T4 Aluminum Alloy 被引量:7
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作者 WANG Xiaogui GAO Zengliang +2 位作者 QIU Baoxiang WANG Limei JIANG Yanyao 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2011年第2期195-201,共7页
Only the fatigue initiation is considered by the safe-life design approach,while fatigue crack propagation is paid more attention by the damage tolerance approach.The reasonable fatigue design method and durability as... Only the fatigue initiation is considered by the safe-life design approach,while fatigue crack propagation is paid more attention by the damage tolerance approach.The reasonable fatigue design method and durability assessment standard should give these two phases equivalent concerns.To develop a unified model of fatigue initiation and crack propagation,a great deal of baseline fatigue properties of a material should be obtained by fatigue experiments.However,there is lack of thorough and comprehensive experiment study on the fatigue properties of 2024-T4 aluminum alloy,which is widely used as load-bearing components in aircraft industry.In this paper,strain-controlled uniaxial,torsion,and combined axial-torsion fatigue experiments are conducted on 2024-T4 aluminum alloy in ambient air.Fully reversed uniaxial and pure torsion experiments employ solid cylindrical specimens.Fatigue experiments under the fully reversed shear loading with a static axial stress,proportional axial-torsion loading,and 90°out-of-phase axial-torsion nonproportional loading are conducted by using thin-walled tubular specimens.The experimental results show that the mean stress has a significant influence on the fatigue strength of the material.A tensile mean stress decreases the fatigue life dramatically,while a compressive mean stress increases the fatigue life.The strain-life fatigue results obtained from the fully reversed uniaxial fatigue experiments can be represented by one smooth curve of a three-parameter equation.However,two fitting curves are needed for characterizing the results of the fully reversed pure torsion fatigue tests because of the existence of an obvious kink.The baseline fatigue properties of 2024-T4 aluminum alloy obtained from the fatigue experiments have applications for the fatigue design and safe assessment of engineering components. 展开更多
关键词 2024-T4 aluminum alloy fatigue life loading path multiaxial fatigue SWT fatigue parameter
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Tensile properties and microstructure of 2024 aluminum alloy subjected to the high magnetic field and external stress 被引量:3
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作者 李桂荣 薛飞 +4 位作者 王宏明 郑瑞 朱弋 储强泽 程江峰 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第10期262-270,共9页
In order to explore the dependence of plasticity of metallic material on a high magnetic held,the effects of the different magnetic induction intensities(H = 0 T,0.5 T,1 T,3 T,and 5 T) and pulses number(N = 0,10,20... In order to explore the dependence of plasticity of metallic material on a high magnetic held,the effects of the different magnetic induction intensities(H = 0 T,0.5 T,1 T,3 T,and 5 T) and pulses number(N = 0,10,20,30,40,and 50) on tensile strength(σ;) and elongation(δ) of 2024 aluminum alloy are investigated in the synchronous presences of a high magnetic held and external stress.The results show that the magnetic held exerts apparent and positive effects on the tensile properties of the alloy.Especially under the optimized condition of H;=1 T and N;=30,the σ;and 8 are 410 MPa and 17% that are enhanced by 9.3% and 30.8% respectively in comparison to those of the untreated sample.The synchronous increases of tensile properties are attributed to the magneto-plasticity effect on a quantum scale.That is,the magnetic held will accelerate the state conversion of radical pair generated between the dislocation and obstacles from singlet to the triplet state.The bonding energy between them is meanwhile lowered and the moving flexibility of dislocations will be enhanced.At H;= 1 T and N;= 30,the dislocation density is enhanced by 1.28 times.The relevant minimum grain size is 266.1 nm,which is reduced by 35.2%.The grain rehning is attributed to the dislocation accumulation and subsequent dynamic recrystallization.The(211) and(220) peak intensities are weakened.It is deduced that together with the recrystallization,the hne grains will transfer towards the slip plane and contribute to the slipping deformation. 展开更多
关键词 2024 aluminum alloy tensile strength ELONGATION magneto plasticity effect
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