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Wear mechanism for spray deposited Al-Si/SiC_p composites under dry sliding condition 被引量:6
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作者 滕杰 李华培 陈刚 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第8期2875-2882,共8页
Al-Si/15%SiCp(volume fraction) composites with different silicon contents were fabricated by spray deposition technique, and typical microstructures of these composites were studied by optical microscopy(OM). Dry slid... Al-Si/15%SiCp(volume fraction) composites with different silicon contents were fabricated by spray deposition technique, and typical microstructures of these composites were studied by optical microscopy(OM). Dry sliding wear tests were carried out using a block-on-ring wear machine to investigate the effect of applied load range of 10-220 N on the wear and friction behavior of these composites sliding against SAE 52100 grade bearing steel. Scanning electron microscopy(SEM) and energy-dispersive X-ray microanalysis(EDAX) were utilized to examine the morphologies of the worn surfaces in order to observe the wear characteristics and investigate the wear mechanism. The results show that the wear behavior of these composites is dependent on the silicon content in the matrix alloy and the applied load. Al-Si/15%SiCp composites with higher silicon content exhibit better wear resistance in the applied load range. Under lower loads, the major wear mechanisms are oxidation wear and abrasive wear for all tested composites. Under higher loads, severe adhesive wear becomes the main wear mechanisms for Al-7Si/15%SiCp and Al-13Si/15%SiCp composites, while Al-20Si/15%SiCp presents a compound wear mechanism, consisting of oxidation, abrasive wear and adhesion wear. 展开更多
关键词 dry sliding wear wear mechanism Al-Si/SiC_p composites spray deposition
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Rolling of Al-SiC_p Composites
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作者 Rajesh Purohit Anil Kumar Das Rakesh Sagar 《厦门大学学报(自然科学版)》 CAS CSCD 北大核心 2002年第S1期103-105,共3页
Aluminum based metal matrix composites are offering o utstanding properties in a number of automotive and aircraft components and body structures. The major advantages of these composite materials are their high st re... Aluminum based metal matrix composites are offering o utstanding properties in a number of automotive and aircraft components and body structures. The major advantages of these composite materials are their high st rength to weight ratio, high stiffness, high hardness, wear resistance, low coef ficient of thermal expansion, superior dimensional stability and versatility to designer. In addition to these their isotropic properties, good forming characte ristics, easy availability of cheaper reinforcements along with the availability of comparatively low cost, high volume production methods have made them a prom ising material for future growth. Weight reduction is a major goal of automotive innovations. Lighter vehicles/ ai rcraft means less fuel consumption, reduced emissions, and improved performance. Components made from highly loaded aluminium matrix composites are attractive r elative to iron based materials because of their low density, high stiffness (eq uivalent to nodular iron) and better heat transfer characteristics. The basic co st of materials is higher with these advanced composites; however, manufacturing the part to near net shape may offset basic material costs. A good aluminium based material design can improves safety. The aluminium-based composites can give cars better acceleration and braking, improved handling, ex cellent durability, and ease of repair. Tha aluminum-based composite performs a s well or better in crash than conventional steel-structured cars because of th eir larger volume, which can absorb more crash energy. Another excellent advanta ge of Al-SiC p composite in auto design is better stability and response, and reduced noise, vibration/harshness (NHV). These advantages stem from reduced veh icle weight combined with high structural stiffness and also lead to improved st ability and turning response. In the present work Al-SiC p composite plates of 10 to 12 mm thickness w ere cast using sand casting as well as die casting process. The plates were furt her machined to 3 to 4 mm thicknesses. The machined plates were subjected to col d as well hot rolling. The cold rolling of Al-3 wt.% SiC composite plates was done on 2 high experimental cold rolling mill at Indian Oil Corporation Ltd., R esearch and Development centre, Faridabad. For hot rolling, the Al-5 weight % SiC p composite plates were heat treated at 500 ℃ temperature and Al-15 weight % SiC p composite plates were heat treate d at 550 ℃ temperature for 20 minutes. The plates were hot rolled on 2 high ro lling mill of one ton capacity at IIT Delhi. The maximum percentage reduction ob tained after hot rolling of Al-5 weight % SiC p composite and Al- 15 weight % SiC p composite plates for 10 passes was 11 % and 6 % respectively. During col d rolling of Al-SiC p composites cracks (particle fracture) were observed due to the low ductility of Al-SiC p composties at room temperature. The various m echanical properties such as tensile strength, hardness and wear resistance were measured for the rolled and un-rolled Al-SiC p composite plates. The tensile strength of un-rolled and rolled Al-5wt.% SiC p composites are shown in Tab. 1. Table shows that the tensile strength decreases after rolling. This may be du e to the damage of the bonding between aluminum and silicon carbide particulates . The Rockwell hardness values of Al-5 wt.% SiC p composites measured before a nd after hot rolling are shown in Tab.2. The hardness was found to decrease afte r hot rolling, which may be due to the annealing of composites during heating. T he Rockwell hardness values of Al-3 wt.% SiC p composites before and after cold rolling are shown in Tab.3. The Table shows that the Rockwell hardness of Al-SiC p compostes increases after cold rolling due to the workhardening effec t. The wear resistance of rolled and un-rolled Al-SiC p composites were teste d on reciprocating ball on flat wear testing machine. The wear resistance of Al -SiC p composites decreases after hot rolling due to decrease in hardness 展开更多
关键词 SIC Rolling of Al-SiC_p composites AL
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Synthesis and characterization of 356-SiC_p composites by stir casting and compocasting methods 被引量:21
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作者 S.AMIRKHANLOU B.NIROUMAND 《中国有色金属学会会刊:英文版》 CSCD 2010年第S3期788-793,共6页
Stir casting is one of the simplest ways of producing aluminum matrix composites.However,it suffers from poor incorporation and distribution of the reinforcement particles in the matrix.These problems become especiall... Stir casting is one of the simplest ways of producing aluminum matrix composites.However,it suffers from poor incorporation and distribution of the reinforcement particles in the matrix.These problems become especially significant as the reinforcement size decreases due to greater agglomeration tendency and reduced wettability of the particles with the melt.Development of new methods for addition of very fine particles to metallic melts which would result in more uniform distribution and effective incorporation of the reinforcement particles into the matrix alloy is therefore valuable.In this work,356-5%SiCp(volume fraction) composites,with average SiCp sizes of about 8 and 3 μm,were produced by injection of different forms of the reinforcement particles into fully liquid as well as semisolid slurries of 356 aluminum alloy and the effects of the injected reinforcement form and the casting method on distribution of the reinforcement particles as well as their porosity,hardness and impact strength were investigated.The results reveal that addition of SiC particles in the form of(Al-SiCp)cp composite powder and casting in semisolid state decreases the SiCp particle size,enhances the wettability between the molten matrix alloy and the reinforcements and improves the distribution of the reinforcement particles in the solidified matrix.It also increases the hardness and the impact energy of the composites and decreases their porosity. 展开更多
关键词 356-SiCp composite compocasting STIR CASTING REINFORCEMENT distribution mechanical properties
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Evolution of Thermoplastic Shear Localization and Related Microstructures in Al/SiC_p Composites Under Dynamic Compression 被引量:5
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作者 YongboXU ZhongLING 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2002年第6期504-508,共5页
The localized shear deformation in the 2024 and 2124 Al matrix composites reinforced with SiC particles was investigated with a split Hopkinson pressure bar (SHPB) at a strain rate of about 2.0×103 s-1. The resul... The localized shear deformation in the 2024 and 2124 Al matrix composites reinforced with SiC particles was investigated with a split Hopkinson pressure bar (SHPB) at a strain rate of about 2.0×103 s-1. The results showed that the occurrence of localized shear deformation is sensitive to the size of SiC particles. It was found that the critical strain, at which the shear localization occurs, strongly depends on the size and volume fraction of SiC particles. The smaller the particle size, the lower the critical strain required for the shear localization. TEM examinations revealed that Al/SiCp interfaces are the main sources of dislocations. The dislocation density near the interface was found to be high and it decreases with the distance from the particles. The Al matrix in shear bands was highly deformed and severely elongated at low angle boundaries. The AI/SiCp interfaces, particularly the sharp corners of SiC particles, provide the sites for microcrack initiation. Eventual fracture is caused by the growth and coalescence of microcracks along the shear bands. It is proposed that the distortion free equiaxed grains with low dislocation density observed in the center of shear band result from recrystallization during dynamic deformation. 展开更多
关键词 Al/SiCp composites Shear localization RECRYSTALLIZATION Dislocations
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Role of particle stimulated nucleation in recrystallization of hot extruded Al 6061/SiC_p composites 被引量:5
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作者 C.S.RAMESH R.KESHAVAMURTHY +1 位作者 Praveennath G.KOPPAD K.T.KASHYAP 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第1期53-58,共6页
Studies on texture and microstructure evolution in hot extruded Al 6061 aluminium alloy reinforced with uncoated and nickel coated SiC p were carried out by electron backscattered diffraction technique.Textures of bot... Studies on texture and microstructure evolution in hot extruded Al 6061 aluminium alloy reinforced with uncoated and nickel coated SiC p were carried out by electron backscattered diffraction technique.Textures of both the alloy and its composite with nickel coated SiC p do exhibit strong β fiber with its axis parallel to the direction of extrusion.In addition to the dominant cube texture(001) 100,fully recrystallized grains with partially equiaxed structure have been observed in the alloy reinforced with uncoated SiC p.The recrystallization texture of this composite can be attributed to the particle stimulated nucleation(PSN) due to the presence of SiC p with size less than 5 μm.Under these conditions,the low value of Zener-Hollomon,Z(~1012s-1) confirms that PSN is one of the dominant mechanisms for recrystallization and is governed by formation of deformation zone rather than stored energy. 展开更多
关键词 metal matrix composites 6061/SiC p composite EXTRUSION particle stimulated nucleation RECRYSTALLIZATION stored energy
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Effects of compocasting process parameters on microstructural characteristics and tensile properties of A356-SiC_p composites 被引量:6
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作者 Hamed KHOSRAVI Hamed BAKHSHI Erfan SALAHINEJAD 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第8期2482-2488,共7页
The effects of compocasting process parameters on some structural and tensile characteristics of the A356-10% SiCp (volume fraction) composites were studied. Semisolid stirring was carried out at temperatures of 590, ... The effects of compocasting process parameters on some structural and tensile characteristics of the A356-10% SiCp (volume fraction) composites were studied. Semisolid stirring was carried out at temperatures of 590, 600 and 610 °C with stirring speeds of 200, 400 and 600 r/min for 10, 20 and 30 min. The distribution of the SiC particles within the matrix, porosity content and tensile properties of the obtained samples were examined. The structural evaluations show that by increasing the stirring time and decreasing the stirring temperature, the uniformity in the particle distribution is improved;however, by increasing the stirring speed the homogeneity firstly increases and then declines. It is also found that by increasing all of the processing parameters, the porosity content is enhanced. From the tensile characteristics viewpoint, the optimum values of the speed, temperature and time are found to be 400 r/min, 590 °C and 30 min, respectively. The contribution of the reinforcement distribution uniformity prevails over that of the porosity level to the tensile properties. 展开更多
关键词 A356-SiC_p composite semisolid stirring compocasting POROSITY reinforcement distribution tensile properties
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Corrosion influence on surface appearance and microstructure of compo cast ZA27/SiC_p composites in sodium chloride solution 被引量:2
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作者 Biljana BOBIC Jelena BAJAT +1 位作者 Ilija BOBIC Bore JEGDIC 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第6期1512-1521,共10页
The influence of corrosion on the surface appearance and microstructure of particulate ZA27/SiCp composites was examined after 30 d immersion in a sodium chloride solution with the access of atmospheric oxygen. The co... The influence of corrosion on the surface appearance and microstructure of particulate ZA27/SiCp composites was examined after 30 d immersion in a sodium chloride solution with the access of atmospheric oxygen. The composites with different contents of SiC micro-particles were synthesized via compo casting. Microstructural studies by means of optical microscopy (OM) and scanning electron microscopy (SEM) showed that corrosion occurred in the composite matrices, preferentially in regions of the η phase, rich in zinc. The corrosion processes did not affect the silicon carbide particles incorporated in the matrix alloy. According to the results of electrochemical polarization measurements, an increase in the content of SiC particles in the composite matrice has led to the lower corrosion resistance in the composites. 展开更多
关键词 metal-matrix composites ZA27 alloy CORROSION MICROSTRUCTURE polarization resistance corrosion rate
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Comparison of microstructure and wear resistance of A356-SiC_p composites processed via compocasting and vibrating cooling slope 被引量:5
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作者 H.KHOSRAVI F.AKHLAGHI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第8期2490-2498,共9页
The influences of SiC content on the microstructure, porosity, hardness and wear resistance of A356?SiCp composites processed via two different methods of compocasting and vibrating cooling slope (VCS) were compare... The influences of SiC content on the microstructure, porosity, hardness and wear resistance of A356?SiCp composites processed via two different methods of compocasting and vibrating cooling slope (VCS) were compared with each other. In the as-cast condition, the matrix of VCS and compocast processed composites exhibited globular and dendritric structures, respectively. While a more uniform distribution of SiC particulates in the matrix alloy as well as higher hardness values were obtained for the VCS processed samples, the composites produced via compocasting exhibited less porosity. The increased SiC content (up to 20% in volume fraction) resulted in a more uniform distribution of SiC particles within the matrix alloy and improved wear resistance for both the composite series. However, for the VCS processed composites, the increased SiC content, resulted in the decreased size and shape factor of globules as well as better tribological properties when compared with compocast composites. It was concluded that the improved properties of the VCS processed composites when compared with their compocast counterparts was a consequence of a more uniform distribution of SiC particulates in the matrix alloy as well as the globular microstructure generated during the VCS process. 展开更多
关键词 Al-A356/SiCp composite compocasting vibrating cooling slope MICROSTRUCTURE particle distribution POROSITY hardness wear resistance
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Ductility and hardness of chloride cleaned AA6011/SiC_p composites 被引量:1
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作者 S.O.ADEOSUN E.I.AKPAN +1 位作者 O.P.GBENEBOR S.A.BALOGUN 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第2期339-347,共9页
Theductility and hardness of AA6011/SiCp composites using NaCl, SnCl2, NH4Cl and PdCl2 as wetting reagents were investigated. SiCp was cleaned with the wetting reagents, and used as reinforcement in AA6011 alloy using... Theductility and hardness of AA6011/SiCp composites using NaCl, SnCl2, NH4Cl and PdCl2 as wetting reagents were investigated. SiCp was cleaned with the wetting reagents, and used as reinforcement in AA6011 alloy using the stir casting method. Ductility and hardness responses of the composites were measured using standard methods. Microstructural features were examined using scanning electron microscopy and the phases were determined with the help of an X-ray diffractometer. The results show that for all wetting agents, the increase in cleaning time leads to initial increase in ductility to a certain value, but a decrease afterwards with further increase in cleaning time. The best combination of hardness (BHN 57.88) and ductility (11.91%) was shown under conditions of 40 g/L SnCl2and cleaning time of 60 min. A minor formation of Al4C3was noted in diffraction patterns, indicating that the formation of deleterious precipitate was hindered by the cleaning process. 展开更多
关键词 aluminium alloy composite silicon carbide wetting agent DUCTILITY HARDNESS REINFORCEMENT
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Properties and microstructures of 7075/SiC_p composites prepared by spray deposition 被引量:6
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作者 袁武华 陈振华 +2 位作者 徐海洋 张福全 傅定发 《中国有色金属学会会刊:英文版》 CSCD 2003年第5期1160-1163,共4页
The 7075/SiC p composites were prepared by spray deposition, extrusion and heat treatment technologies. The microstructures of the deposit, the extruded and heat treated bars were analyzed. And the mechanical properti... The 7075/SiC p composites were prepared by spray deposition, extrusion and heat treatment technologies. The microstructures of the deposit, the extruded and heat treated bars were analyzed. And the mechanical properties and wearing resistance were tested and compared with other aluminum alloys. The results show that the spray deposited preform presents fine microstructure and uniformly distributed SiC particles. Compared with the matrix alloy, the yield strength, modulus and wearing resistance of the peak aged composites are improved markedly with 50% reduction of elongation. It indicates that the addition of SiC particles greatly contributes to the refining of microstructure and the altering of fracture and wearing mechanisms. 展开更多
关键词 显微组织 7075/SiCp混合物 铝复合物 快速凝固 喷射沉积
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Microstructure and mechanical properties of Al-Fe-V-Si/SiC_p composites 被引量:1
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作者 陈振华 贺毅强 +3 位作者 严红革 郝亮 陈志钢 陈刚 《中国有色金属学会会刊:英文版》 CSCD 2007年第A01期238-243,共6页
The characteristics of microstructures and mechanical properties of the multi-layer spray deposited SiCP/Al-6.5Fe-0.6V-1.3Si,SiCP/Al-8.5Fe-1.3V-1.7Si and SiCP/Al-10Fe-1.3V-2Si composite sheets obtained by rolling afte... The characteristics of microstructures and mechanical properties of the multi-layer spray deposited SiCP/Al-6.5Fe-0.6V-1.3Si,SiCP/Al-8.5Fe-1.3V-1.7Si and SiCP/Al-10Fe-1.3V-2Si composite sheets obtained by rolling after extruding were investigated. The evolution of the grain and phases of these composites during processing were examined,and the influence of the microstructures on the mechanical properties was analyzed. The experimental results show that the ultimate tensile strengths σb of the three kinds of composite sheets are 420,535,470 MPa respectively at room temperature,and 232,285,300 MPa at 315 ℃ and 148,180,200 MPa at 400 ℃. The excellent mechanical properties can be attributed to the high solid solubility,fine grain size,Al12(Fe,V)3Si precipitation particles and the SiC particles. And the composition of the matrix alloy has an obvious effect on the mechanical properties of the as-rolled sheets. 展开更多
关键词 抗热合金 合成物 沉积物 金属材料
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Effect of Heat Treatment on Microstructure and Mechanical Properties of Multiscale SiC_p Hybrid Reinforced 6061 Aluminum Matrix Composites
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作者 吴健铭 许晓静 +3 位作者 ZHANG Xu LUO Yuntian LI Shuaidi HUANG Lin 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第1期174-181,共8页
The performance of solid solution aging treatment on aluminum matrix composites prepared by powder metallurgy and reinforced with 6061 aluminum alloy powder as matrix;meanwhile, nano silicon carbide particles(nm Si Cp... The performance of solid solution aging treatment on aluminum matrix composites prepared by powder metallurgy and reinforced with 6061 aluminum alloy powder as matrix;meanwhile, nano silicon carbide particles(nm Si Cp), submicron silicon carbide particles(1 μm Si Cp) and Ti particles were studied. The Al/Si Cp composite powder was prepared by high-energy ball milling, and then cold-pressed, sintered, hotextruded, and then heat-treated with different solution temperatures and aging times for the extruded composites. Optical microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy(EDS), X-ray diffractometer(XRD) and extrusion testing were used to analyze and test the microstructure and mechanical properties of aluminum matrix composites. The results show that after the multi-stage solid solution at 530 ℃×2 h+535 ℃×2 h+540 ℃×2 h, the particles are mainly equiaxed grains and uniformly distributed. There is no reinforcement agglomeration, and the surface is dense and the insoluble phase is basically dissolved. In the matrix, the strengthening effect is good, and the hardness and compressive strength are 179.43 HV and 680.42 MPa, respectively. Under this solution process, when the aluminum matrix composites are aged at 170 ℃ for 10 h, the hardness and compressive strength can reach their peaks and increase to 195.82 HV and 721.48 MPa, respectively. 展开更多
关键词 aluminum matrix composites Si C particles multiscale hybrid enhancement heat treatment mechanical properties
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SiC_p分布对SiC_p/2024Al复合材料组织和性能及变形行为的影响
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作者 薛鹏鹏 邓坤坤 +2 位作者 聂凯波 史权新 刘力 《材料工程》 EI CAS CSCD 北大核心 2024年第4期164-175,共12页
采用半固态搅拌铸造法制备出SiC_(p)/2024Al复合材料,并通过热挤压和多向锻造(MDF)的多步变形调控SiC_(p)的分布,研究SiC_(p)分布对SiC_(p)/2024Al复合材料组织和性能的影响。研究结果表明:热挤压变形促使SiC_(p)沿挤压方向(ED)排布;而... 采用半固态搅拌铸造法制备出SiC_(p)/2024Al复合材料,并通过热挤压和多向锻造(MDF)的多步变形调控SiC_(p)的分布,研究SiC_(p)分布对SiC_(p)/2024Al复合材料组织和性能的影响。研究结果表明:热挤压变形促使SiC_(p)沿挤压方向(ED)排布;而经过多向锻,SiC_(p)分布得到显著改善,由定向排布转变为均匀分布。经过1MDF后,沿ED定向排布的SiC_(p)向无序分布转变,同时材料的力学性能急剧下降。3MDF后SiC_(p)分布均匀性提高,材料的力学性能大幅提高。随着锻造道次增加至6道次,虽然SiC_(p)分布均匀性进一步提高,但伴随着部分SiC_(p)发生破碎,材料的力学性能下降。其中,当锻造次数为3时,复合材料的力学性能最优,其屈服强度、极限抗拉强度和伸长率分别为264,387 MPa和7%。与定向分布的复合材料相比,均匀分布的SiC_(p)可有效缓解局部应力集中,合金基体能存储更多的位错。此外,当SiC_(p)分布均匀性提高时,也伴随着Al_(2)Cu相的细化。弥散分布的Al_2Cu相阻碍了位错的滑移,导致均匀分布的复合材料具有更高的加工硬化率和内应力。为了研究SiC_(p)分布对复合材料加工软化行为的影响,对复合材料进行循环应力松弛实验。在应力循环过程中,由于均匀分布的SiC_(p)和弥散分布的Al_(2)Cu相,导致均匀分布SiC_(p)/2024Al复合材料的抗应力松弛性能更好。 展开更多
关键词 SiC_p分布 铝基复合材料 软化行为 多向锻造 加工硬化
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Ti_(3)C_(2)T_(x) MXene/carbon composites for advanced supercapacitors:Synthesis,progress,and perspectives 被引量:1
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作者 Yanqing Cai Xinggang Chen +4 位作者 Ying Xu Yalin Zhang Huijun Liu Hongjuan Zhang Jing Tang 《Carbon Energy》 SCIE EI CAS CSCD 2024年第2期113-142,共30页
MXenes are a family of two-dimensional(2D)layered transition metal carbides/nitrides that show promising potential for energy storage applications due to their high-specific surface areas,excellent electron conductivi... MXenes are a family of two-dimensional(2D)layered transition metal carbides/nitrides that show promising potential for energy storage applications due to their high-specific surface areas,excellent electron conductivity,good hydrophilicity,and tunable terminations.Among various types of MXenes,Ti_(3)C_(2)T_(x) is the most widely studied for use in capacitive energy storage applications,especially in supercapacitors(SCs).However,the stacking and oxidation of MXene sheets inevitably lead to a significant loss of electrochemically active sites.To overcome such challenges,carbon materials are frequently incorporated into MXenes to enhance their electrochemical properties.This review introduces the common strategies used for synthesizing Ti_(3)C_(2)T_(x),followed by a comprehensive overview of recent developments in Ti_(3)C_(2)T_(x)/carbon composites as electrode materials for SCs.Ti_(3)C_(2)T_(x)/carbon composites are categorized based on the dimensions of carbons,including 0D carbon dots,1D carbon nanotubes and fibers,2D graphene,and 3D carbon materials(activated carbon,polymer-derived carbon,etc.).Finally,this review also provides a perspective on developing novel MXenes/carbon composites as electrodes for application in SCs. 展开更多
关键词 electrochemical performance MXene/carbon composites SUPERCAPACITORS
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Mechanical behaviors of backfill-rock composites: Physical shear test and back-analysis 被引量:1
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作者 Jie Xin Quan Jiang +5 位作者 Fengqiang Gong Lang Liu Chang Liu Qiang Liu Yao Yang Pengfei Chen 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第3期807-827,共21页
The shear behavior of backfill-rock composites is crucial for mine safety and the management of surface subsidence.For exposing the shear failure mechanism of backfill-rock composites,we conducted shear tests on backf... The shear behavior of backfill-rock composites is crucial for mine safety and the management of surface subsidence.For exposing the shear failure mechanism of backfill-rock composites,we conducted shear tests on backfill-rock composites under three constant normal loads,compared with the unfilled rock.To investigate the macro-and meso-failure characteristics of the samples in the shear tests,the cracking behavior of samples was recorded by a high-speed camera and acoustic emission monitoring.In parallel with the experimental test,the numerical models of backfill-rock composites and unfilled rock were established using the discrete element method to analyze the continuous-discontinuous shearing process.Based on the damage mechanics and statistics,a novel shear constitutive model was proposed to describe mechanical behavior.The results show that backfill-rock composites had a special bimodal phenomenon of shearing load-deformation curve,i.e.the first shearing peak corresponded to rock break and the second shearing peak induced by the broken of aeolian sand-cement/fly ash paste backfill.Moreover,the shearing characteristic curves of the backfill-rock composites could be roughly divided into four stages,i.e.the shear failure of the specimens experienced:stage I:stress concentration;stage II:crack propagation;stage III:crack coalescence;stage IV:shearing friction.The numerical simulation shows that the existence of aeolian sand-cement/fly ash paste backfill inevitably altered the coalescence type and failure mode of the specimens and had a strengthening effect on the shear strength of backfillrock composites.Based on damage mechanics and statistics,a shear constitutive model was proposed to describe the shear fracture characteristics of specimens,especially the bimodal phenomenon.Finally,the micro-and meso-mechanisms of shear failure were discussed by combining the micro-test and numerical results.The research can advance the better understanding of the shear behavior of backfill-rock composites and contribute to the safety of mining engineering. 展开更多
关键词 Physical simulation Backfill-rock composites Shear failure CRACKING Shear constitutive model
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Ultraviolet‑Irradiated All‑Organic Nanocomposites with Polymer Dots for High‑Temperature Capacitive Energy Storage 被引量:1
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作者 Jiale Ding Yao Zhou +5 位作者 Wenhan Xu Fan Yang Danying Zhao Yunhe Zhang Zhenhua Jiang Qing Wang 《Nano-Micro Letters》 SCIE EI CSCD 2024年第3期398-406,共9页
Polymer dielectrics capable of operating efficiently at high electric fields and elevated temperatures are urgently demanded by next-generation electronics and electrical power systems.While inorganic fillers have bee... Polymer dielectrics capable of operating efficiently at high electric fields and elevated temperatures are urgently demanded by next-generation electronics and electrical power systems.While inorganic fillers have been extensively utilized to improved high-temperature capacitive performance of dielectric polymers,the presence of thermodynamically incompatible organic and inorganic components may lead to concern about the long-term stability and also complicate film processing.Herein,zero-dimensional polymer dots with high electron affinity are introduced into photoactive allyl-containing poly(aryl ether sulfone)to form the all-organic polymer composites for hightemperature capacitive energy storage.Upon ultraviolet irradiation,the crosslinked polymer composites with polymer dots are efficient in suppressing electrical conduction at high electric fields and elevated temperatures,which significantly reduces the high-field energy loss of the composites at 200℃.Accordingly,the ultraviolet-irradiated composite film exhibits a discharged energy density of 4.2 J cm^(−3)at 200℃.Along with outstanding cyclic stability of capacitive performance at 200℃,this work provides a promising class of dielectric materials for robust high-performance all-organic dielectric nanocomposites. 展开更多
关键词 High-temperature energy storage Polymer dots Ultraviolet irradiation All-organic composite dielectrics
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Self‑Assembly of Binderless MXene Aerogel for Multiple‑Scenario and Responsive Phase Change Composites with Ultrahigh Thermal Energy Storage Density and Exceptional Electromagnetic Interference Shielding 被引量:1
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作者 Chuanbiao Zhu Yurong Hao +8 位作者 Hao Wu Mengni Chen Bingqing Quan Shuang Liu Xinpeng Hu Shilong Liu Qinghong Ji Xiang Lu Jinping Qu 《Nano-Micro Letters》 SCIE EI CSCD 2024年第3期367-382,共16页
The severe dependence of traditional phase change materials(PCMs)on the temperature-response and lattice deficiencies in versatility cannot satisfy demand for using such materials in complex application scenarios.Here... The severe dependence of traditional phase change materials(PCMs)on the temperature-response and lattice deficiencies in versatility cannot satisfy demand for using such materials in complex application scenarios.Here,we introduced metal ions to induce the self-assembly of MXene nanosheets and achieve their ordered arrangement by combining suction filtration and rapid freezing.Subsequently,a series of MXene/K^(+)/paraffin wax(PW)phase change composites(PCCs)were obtained via vacuum impregnation in molten PW.The prepared MXene-based PCCs showed versatile applications from macroscale technologies,successfully transforming solar,electric,and magnetic energy into thermal energy stored as latent heat in the PCCs.Moreover,due to the absence of binder in the MXene-based aerogel,MK3@PW exhibits a prime solar-thermal conversion efficiency(98.4%).Notably,MK3@PW can further convert the collected heat energy into electric energy through thermoelectric equipment and realize favorable solar-thermal-electric conversion(producing 206 mV of voltage with light radiation intensity of 200 mw cm^(−2)).An excellent Joule heat performance(reaching 105℃with an input voltage of 2.5 V)and responsive magnetic-thermal conversion behavior(a charging time of 11.8 s can achieve a thermal insulation effect of 285 s)for contactless thermotherapy were also demonstrated by the MK3@PW.Specifically,as a result of the ordered arrangement of MXene nanosheet self-assembly induced by potassium ions,MK3@PW PCC exhibits a higher electromagnetic shielding efficiency value(57.7 dB)than pure MXene aerogel/PW PCC(29.8 dB)with the same MXene mass.This work presents an opportunity for the multi-scene response and practical application of PCMs that satisfy demand of next-generation multifunctional PCCs. 展开更多
关键词 Self-assembly Multiple-scenario Phase change composites Thermal energy storage Electromagnetic interference shielding
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Highly Aligned Graphene Aerogels for Multifunctional Composites 被引量:1
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作者 Ying Wu Chao An +4 位作者 Yaru Guo Yangyang Zong Naisheng Jiang Qingbin Zheng Zhong‑Zhen Yu 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第6期276-342,共67页
Stemming from the unique in-plane honeycomb lattice structure and the sp^(2)hybridized carbon atoms bonded by exceptionally strong carbon–carbon bonds,graphene exhibits remarkable anisotropic electrical,mechanical,an... Stemming from the unique in-plane honeycomb lattice structure and the sp^(2)hybridized carbon atoms bonded by exceptionally strong carbon–carbon bonds,graphene exhibits remarkable anisotropic electrical,mechanical,and thermal properties.To maximize the utilization of graphene’s in-plane properties,pre-constructed and aligned structures,such as oriented aerogels,films,and fibers,have been designed.The unique combination of aligned structure,high surface area,excellent electrical conductivity,mechanical stability,thermal conductivity,and porous nature of highly aligned graphene aerogels allows for tailored and enhanced performance in specific directions,enabling advancements in diverse fields.This review provides a comprehensive overview of recent advances in highly aligned graphene aerogels and their composites.It highlights the fabrication methods of aligned graphene aerogels and the optimization of alignment which can be estimated both qualitatively and quantitatively.The oriented scaffolds endow graphene aerogels and their composites with anisotropic properties,showing enhanced electrical,mechanical,and thermal properties along the alignment at the sacrifice of the perpendicular direction.This review showcases remarkable properties and applications of aligned graphene aerogels and their composites,such as their suitability for electronics,environmental applications,thermal management,and energy storage.Challenges and potential opportunities are proposed to offer new insights into prospects of this material. 展开更多
关键词 Highly aligned graphene aerogels Quantitative characterization of alignment Multifunctional composites Anisotropic properties Multifunctional applications
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中高体积分数SiC_p/Al复合材料的力学性能及强化机制
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作者 崔岩 廖家杰 +1 位作者 曹雷刚 杨越 《材料工程》 EI CAS CSCD 北大核心 2024年第4期110-119,共10页
采用热等静压粉末冶金工艺,以2024和6061铝合金为基体,分别制备体积分数为35%,45%,55%的中高体积分数SiC_(p)/Al复合材料。探究基体合金与SiC体积分数对复合材料力学性能的影响。结果表明:相同体积分数时,以2024铝合金为基体的复合材料... 采用热等静压粉末冶金工艺,以2024和6061铝合金为基体,分别制备体积分数为35%,45%,55%的中高体积分数SiC_(p)/Al复合材料。探究基体合金与SiC体积分数对复合材料力学性能的影响。结果表明:相同体积分数时,以2024铝合金为基体的复合材料具有更高的弯曲强度和弹性模量;但以6061铝合金为基体的复合材料则呈现出了更高的断裂应变。随着体积分数的增加,两类复合材料力学性能的变化规律相同,弯曲强度呈先增大后减小的趋势,当体积分数为45%时达到峰值,分别为656.54 MPa和548.00 MPa;弹性模量呈持续上升趋势,当体积分数为55%时分别达到202 GPa和188 GPa。基体合金差异对力学性能的影响在体积分数较低时更为明显,提高体积分数将会弱化这种差异。结合理论公式计算发现,对于微米级的增强体颗粒,Orowan机制带来的强化效应极小,可忽略不计;其他各类强化机制的强化效果将随着增强体体积分数的增加呈现不同程度的提高;几何必须位错强化和热错配强化对材料屈服强度的贡献始终占据主导地位。 展开更多
关键词 SIC_P/AL复合材料 体积分数 力学性能 强化机制
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Effects of Sinusoidal Vibration of Crystallization Roller on Composite Microstructure of Ti/Al Laminated Composites by Twin-Roll Casting
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作者 李励 杜凤山 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第1期196-205,共10页
A new,innovative vibration cast-rolling technology of “electromagnetic stirring+dendrite breaking+asynchronous rolling” was proposed with the adoption of sinusoidal vibration of crystallization roller to prepare Ti/... A new,innovative vibration cast-rolling technology of “electromagnetic stirring+dendrite breaking+asynchronous rolling” was proposed with the adoption of sinusoidal vibration of crystallization roller to prepare Ti/Al laminated composites,and the effect of sinusoidal vibration of crystallization roller on composite microstructure was investigated in detail.The results show that the metallurgical bonding of titanium and aluminum is realized by mesh interweaving and mosaic meshing,instead of transition bonding by forming metal compound layer.The meshing depth between titanium and aluminum layers (6.6μm) of cast-rolling materials with strong vibration of crystallization roller (amplitude 0.87 mm,vibration frequency 25 Hz) is doubled compared with that of traditional cast-rolling materials (3.1μm),and the composite interfacial strength(27.0 N/mm) is twice as high as that of traditional cast-rolling materials (14.9 N/mm).This is because with the action of high-speed superposition of strong tension along the rolling direction,strong pressure along the width direction and rolling force,the composite linearity evolves from "straight line" with traditional casting-rolling to "curved line",and the depth and number of cracks in the interface increases greatly compared with those with traditional cast-rolling,which leads to the deep expansion of the meshing area between interfacial layers and promotes the stable enhancement of composite quality. 展开更多
关键词 laminated composites sinusoidal vibration composite microstructure
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