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
Selective laser melting(SLM)is an emerging layer-wise additive manufacturing technique that can generate complex components with high performance.Particulate-reinforced aluminum matrix composites(PAMCs)are important m...Selective laser melting(SLM)is an emerging layer-wise additive manufacturing technique that can generate complex components with high performance.Particulate-reinforced aluminum matrix composites(PAMCs)are important materials for various applications due to the combined properties of Al matrix and reinforcements.Considering the advantages of SLM technology and PAMCs,the novel SLM PAMCs have been developed and researched in recent years.Therefore,the current research progress about the SLM PAMCs is reviewed.Firstly,special attention is paid to the solidification behavior of SLM PAMCs.Secondly,the important issues about the design and fabrication of high-performance SLM PAMCs,including the selection of reinforcement,the influence of parameters on the processing and microstructure,the defect evolution and phase control,are highlighted and discussed comprehensively.Thirdly,the performance and strengthening mechanism of SLM PAMCs are systematically figured out.Finally,future directions are pointed out on the advancement of high-performance SLM PAMCs.展开更多
Two kinds of unidirectional PAN M40 carbon fiber （55%, volume fraction） reinforced 6061Al and 5A06Al composites were fabricated by the squeeze-casting technology and their interface structure and thermal expansion p...Two kinds of unidirectional PAN M40 carbon fiber （55%, volume fraction） reinforced 6061Al and 5A06Al composites were fabricated by the squeeze-casting technology and their interface structure and thermal expansion properties were investigated. Results showed that the combination between aluminum alloy and fibers was well in two composites and interface reaction in M40/5A06Al composite was weaker than that in M40/6061Al composite. Coefficients of thermal expansion （CTE） of M40/Al composites varied approximately from （1.45-2.68）×10^-6 K^-1 to （0.35-1.44）×10^-6 K^-1 between 20℃ and 450℃, and decreased slowly with the increase of temperature. In addition, the CTE of M40/6061Al composite was lower than that of M40/SA06Al composite. It was observed that fibers were protruded significantly from the matrix after thermal expansion, which demonstrated the existence of interface sliding between fiber and matrix during the thermal expansion. It was believed that weak interracial reaction resulted in a higher CTE. It was found that the experimental CTEs were closer to the predicted values by Schapery model.展开更多
Pulsed magnetic field is generated when imposing pulse signal on high-frequency magnetic field. Distribution of the inner magnetic intensity in induction coils tends to be uniform. Furthermore oscillation and disturba...Pulsed magnetic field is generated when imposing pulse signal on high-frequency magnetic field. Distribution of the inner magnetic intensity in induction coils tends to be uniform. Furthermore oscillation and disturbance phenomena appear in the melt. In. situ Al2O3 and Al3Zr particulate reinforced aluminum matrix composites have been synthesized by direct melt reaction using AlZr（CO3）2 components under a foreign field. The size of reinforced particulates is 2-3 μm. They are well distributed in the matrix. Thermodynamic and kinetic analysis show that high-frequency pulsed magnetic field accelerates heat and mass transfer processes and improves the kinetic condition of in-situ fabrication.展开更多
Aluminum matrix composites reinforced by in situ Al2O3 and Al3Zr particles are fabricated from A356-Zr(CO3)2 system via magnetochemistry reaction,and the morphologies,sizes and distributions of the in situ particles a...Aluminum matrix composites reinforced by in situ Al2O3 and Al3Zr particles are fabricated from A356-Zr(CO3)2 system via magnetochemistry reaction,and the morphologies,sizes and distributions of the in situ particles as well as the microstructures,mechanical mechanisms of the composites are investigated by XRD,SEM,TEM and in situ tensile tests.The results indicate that with the pulsed magnetic field assistance,the morphologies of the in situ particles are mainly with ball-shape,the sizes are in nanometer scale and the distributions in the matrix are uniform.The interfaces between the in situ particles and the aluminum matrix are net and no interfacial outgrowth is observed.These are due to the strong vibration induced by the applied magnetic field in the aluminum melt,which in turn,accelerates the melt reactions.The effects of the magnetic field on the above contributions are discussed in detail.展开更多
Aluminum matrix composites reinforced with mechanical alloying particles(SiC_p) were fabricated by the semisolid stirring pouring method. The inf luence of mechanical alloying particles and Mg on the microstructure an...Aluminum matrix composites reinforced with mechanical alloying particles(SiC_p) were fabricated by the semisolid stirring pouring method. The inf luence of mechanical alloying particles and Mg on the microstructure and mechanical properties of the composites was investigated by means of optical microscopy(OM), X-ray diffraction scanning(XRD), electron microscopy(SEM) and energy dispersive spectroscopy(EDS). Results show that the addition of Mg converts the agglomerate mechanical al oying particles in ZL101 matrix composites into dispersed distribution in ZL101-Mg matrix composites, large matrix grains into f ine equiaxed matrix grains, and eutectic phase into f ine particles. So the mechanical properties of ZL101-Mg matrix composites are better than those of ZL101 matrix composites. The mechanical properties of ZL101/ZL101-Mg matrix composites are gradually increased with the increase of the volume fraction of mechanical alloying particles. When the volume fraction of mechanical alloying particles is 3%, the Vickers hardness and ultimate tensile strength of the ZL101/ZL101-Mg matrix composites reach their maximum values.展开更多
To extend the application of carbon nanotubes （CNTs） and explore novel aluminum matrix composites,CNTs were coated by molybdenum layers using metal organic chemical vapor deposition,and then Mo-coated CNT （Mo-CNT）...To extend the application of carbon nanotubes （CNTs） and explore novel aluminum matrix composites,CNTs were coated by molybdenum layers using metal organic chemical vapor deposition,and then Mo-coated CNT （Mo-CNT）/Al composites were prepared by the combination processes of powder mixing and spark plasma sintering.The influences of powder mixing and Mo-CNT content on the mechanical properties and electrical conductivity of the composites were investigated.The results show that magnetic stirring is better than mechanical milling for mixing the Mo-CNTs and Al powders.The electrical conductivity of the composites decreases with increasing Mo-CNT content.When the Mo-CNT content is 0.5wt%,the tensile strength and hardness of Mo-CNT/Al reach their maximum values.The tensile strength of 0.5wt% Mo-CNT/Al increases by 29.9%,while the electrical conductivity only decreases by 7.1%,relative to sintered pure Al.The phase analysis of Mo-CNT/Al composites reveals that there is no formation of Al carbide in the composites.展开更多
Aluminum matrix composite is one of the most attractive metal matrix composites.It is a kind of material with strong vitality emerging in response to the needs of modern scientific development.Compared with traditiona...Aluminum matrix composite is one of the most attractive metal matrix composites.It is a kind of material with strong vitality emerging in response to the needs of modern scientific development.Compared with traditional materials,aluminum matrix composites have the advantages of low density,good electric conductivity and heat conductivity,good wear resistance and oxidation resistance,high specific strength and stiffness,high temperature resistance,good heat treatment performance and flexible preparation process,which make them widely used in the fields of aviation,aerospace,and automobile.In this paper,the factors affecting the properties of aluminum matrix composites,the strengthening mechanism,classification and preparation methods of aluminum matrix composites are summarized.The research status,development direction and application prospect of aluminum matrix composites are briefly introduced.展开更多
Aluminum matrix composites(AMCs), reinforced with novel pre-synthesized Al/Cu Fe multi-layered coreshell particles, were fabricated by different consolidation techniques to investigate their effect on microstructure a...Aluminum matrix composites(AMCs), reinforced with novel pre-synthesized Al/Cu Fe multi-layered coreshell particles, were fabricated by different consolidation techniques to investigate their effect on microstructure and mechanical properties. To synthesize multi-layered Al/Cu Fe core-shell particles, Cu and Fe layers were deposited on Al powder particles by galvanic replacement and electroless plating method, respectively. The core-shell powder and sintered compacts were characterized by using X-ray diffraction(XRD), scanning electron microscopy(SEM) equipped with energy dispersive spectroscopy(EDX), pycnometer, microhardness and compression tests. The results revealed that a higher extent of interfacial reactions, due to the transformation of the deposited layer into intermetallic phases in spark plasma sintered composite, resulted in high relative density(99.26%), microhardness(165 HV0.3) and strength(572 MPa). Further, the presence of un-transformed Cu in the shell structure of hot-pressed composite resulted in the highest fracture strain(20.4%). The obtained results provide stronger implications for tailoring the microstructure of AMCs through selecting appropriate sintering paths to control mechanical properties.展开更多
Carbon fiber reinforced aluminum composites with ordered architectures of shear-induced aligned carbon fibers were fabricated by 3D printing.The microstructures of the printed and sintered samples and mechanical prope...Carbon fiber reinforced aluminum composites with ordered architectures of shear-induced aligned carbon fibers were fabricated by 3D printing.The microstructures of the printed and sintered samples and mechanical properties of the composites were investigated.Carbon fibers and aluminum powder were bonded together with resin.The spatial arrangement of the carbon fibers was fixed in the aluminum matrix by shear-induced alignment in the3D printing process.As a result,the elongation of the composites with a parallel arrangement of aligned fibers and the impact toughness of the composites with an orthogonal arrangement were 0.82%and 0.41 J/cm^(2),respectively,about 0.4 and 0.8 times higher than that of the random arrangement.展开更多
Aluminum alloys AA6061 reinforced with various amounts （0, 2.5% and 5%, mass fraction） of TiC particles were synthesized by the in situ reaction of inorganic salt K2TiF6 and ceramic particle SiC with molten aluminum...Aluminum alloys AA6061 reinforced with various amounts （0, 2.5% and 5%, mass fraction） of TiC particles were synthesized by the in situ reaction of inorganic salt K2TiF6 and ceramic particle SiC with molten aluminum. The casting was carried out at an elevated temperature and held for a longer duration to decompose SiC to release carbon atoms. X-ray diffraction patterns of the prepared AMCs clearly revealed the formation of TiC particles without the occurrence of any other intermetallic compounds. The microstructure of the prepared AA6061/TiC AMCs was studied using field emission scanning electron microscope （FESEM） and electron backscatter diffraction （EBSD）. The in situ formed TiC particles were characterized with homogeneous distribution, clear interface, good bonding and various shapes such as cubic, spherical and hexagonal. EBSD maps showed the grain refinement action of TiC particles on the produced composites. The formation of TiC particles boosted the microhardness and ultimate tensile strength （UTS） of the AMCs.展开更多
Two micron SiC particles with angular and spherical shape and the sub-micron Al2O3 particles with spherical shape were introduced to reinforce 6061 aluminium by squeeze casting technology. Microstructures and effect o...Two micron SiC particles with angular and spherical shape and the sub-micron Al2O3 particles with spherical shape were introduced to reinforce 6061 aluminium by squeeze casting technology. Microstructures and effect of thermal-cooling cycle treatment （TCCT） on the thermal expansion behaviors of three composites were investigated. The results show that the composites are free of porosity and SiC/Al2O3 particles are distributed uniformly. Inflections at about 300℃ are observed in coefficient of thermal expansion （CTE） versus temperature curves of two SiCp/Al composites, and this characteristic is not affected by TCCT. The TCCT has significant effect on thermal expansion behavior of SiCp/Al composites and CTE of them after 3 cycles is lower than that of 1 or 5 cycles. However, no inflection is observed in Al2O3p/Al composite, while TCCT has effect on CTE of Al2O3p/Al composite. These results should be due to different relaxation behavior of internal stress in three composites.展开更多
The microstructural features and the consequent mechanical properties were characterized in aluminium borate whisker(ABOw)(5, 10 and 15 wt.%) reinforced commercially-pure aluminium composites fabricated by conventiona...The microstructural features and the consequent mechanical properties were characterized in aluminium borate whisker(ABOw)(5, 10 and 15 wt.%) reinforced commercially-pure aluminium composites fabricated by conventional powder metallurgy technique. The aluminium powder and the whisker were effectively blended by a semi-powder metallurgy method. The blended powder mixtures were cold compacted and sintered at 600 ℃. The sintered composites were characterized for microstructural features by optical microscopy(OM), scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS), transmission electron microscopy(TEM) and X-ray diffraction(XRD) analysis. Porosity in the composites with variation in ABOw contents was determined. The effect of variation in content of ABOw on mechanical properties, viz. hardness, bending strength and compressive strength of the composites was evaluated. The dry sliding wear behaviour was evaluated at varying sliding distance at constant loads. Maximum flexural strength of 172 MPa and compressive strength of 324 MPa with improved hardness around HV 40.2 are obtained in composite with 10 wt.% ABOw. Further increase in ABOw content deteriorates the properties. A substantial increase in wear resistance is also observed with 10 wt.% ABOw. The excellent combination of mechanical properties of Al-10 wt.%ABOw composites is attributed to good interfacial bonds, less porosity and uniformity in the microstructure.展开更多
Stir casting was used to produce AA6061/15%TiC （mass fraction） aluminum matrix composites （AMCs）. An empirical relationship was developed to predict the effect of stir casting parameters on the ultimate tensile ...Stir casting was used to produce AA6061/15%TiC （mass fraction） aluminum matrix composites （AMCs）. An empirical relationship was developed to predict the effect of stir casting parameters on the ultimate tensile strength （UTS） of AA6061/TiC AMCs. A central composite rotatable design consisting of four factors and five levels was used to minimize the number of experiments, i.e., castings. The factors considered were stirring speed, stirring time, blade angle and casting temperature. The effect of those factors on the UTS of AA6061/TiC AMCs was derived using the developed empirical relationship and elucidated using microstructural characterization. Each factor significantly influenced the UTS. The variation in the UTS was attributed to porosity content, cluster formation, segregation of TiC particles at the grain boundaries and homogenous distribution in the aluminum matrix.展开更多
The liquid-phase coating method was used to deposit Y2O3 ceramic on the surface of α-Al2O3. The coated-Al2O3p/6061AI composites were produced using squeeze casting technology. The microstructure and tensile propertie...The liquid-phase coating method was used to deposit Y2O3 ceramic on the surface of α-Al2O3. The coated-Al2O3p/6061AI composites were produced using squeeze casting technology. The microstructure and tensile properties of the composites were analysed and studied. The results showed that the coated AI2O3 particles are able to disperse homogeneously in the aluminum liquid. The microstructure of the composites is more even in comparison with that of as-received powders. The tensile testing indicated that mechanical properties of the coated-AI2O3p/6061AI composites are better than those of uncoated particles. In the composite with 30% volume fraction, the tensile strength, yield strength as well as elongation is increased by 29.8%, 38.4% and 10.3%, respectively. The SEM analysis of fracture indicated that the dimples of the coated-Al2O3p/6061Al composites are more even.展开更多
Graphene-reinforced 7055 aluminum alloy composites with different contents of graphene were prepared by spark plasma sintering（SPS）. The structure and mechanical properties of the composites were investigated. Testi...Graphene-reinforced 7055 aluminum alloy composites with different contents of graphene were prepared by spark plasma sintering（SPS）. The structure and mechanical properties of the composites were investigated. Testing results show that the hardness, compressive strength, and yield strength of the composites are improved with the addition of 1wt% graphene. A clean, strong interface is formed between the metal matrix and graphene via metallurgical bonding on atomic scale. Harmful aluminum carbide（Al_4C_3） is not formed during SPS processing. Further addition of graphene（above 1wt%） results in the deterioration in mechanical properties of the composites. The agglomeration of graphene plates is exacerbated with increasing graphene content, which is the main reason for this deterioration.展开更多
The influence of volume fraction on damping capacities at room temperature for amorphous carbon fiber reinforced aluminum matrix composites was investigated.At room temperature,the dislocation damping is the primary d...The influence of volume fraction on damping capacities at room temperature for amorphous carbon fiber reinforced aluminum matrix composites was investigated.At room temperature,the dislocation damping is the primary damping mechanism.Meanwhile,the dislocation damping exhibits dynamic hysteresis at low strain amplitudes and static hysteresis at high strain amplitudes.Moreover,the damping capacity is rather sensitive to the volume fraction.Compared to unreinforced aluminum alloy,the additions of amorphous carbon fibers into the aluminum matrix can improve damping capacity below the volume fraction of 30%,whereas worsen above the volume fraction of 40%.展开更多
Using nickel catalyst supported on aluminum powders, carbon nanotubes （CNTs） were successfully synthesized in aluminum powders by in-situ chemical vapor deposition at 650 ℃. Structural characterization revealed tha...Using nickel catalyst supported on aluminum powders, carbon nanotubes （CNTs） were successfully synthesized in aluminum powders by in-situ chemical vapor deposition at 650 ℃. Structural characterization revealed that the as-grown CNTs possessed higher graphitization degree and straight graphite shell. By this approach, more homogeneous dispersion of CNTs in aluminum powders was achieved compared with the traditional mechanical mixture methods. Using the in-situ synthesized CNTs/Al composite powders and powder metallurgy process, CNTs/Al bulk composites were prepared. Performance testing showed that the mechanical properties and dimensional stability of the composites were improved obviously, which was attributed to the superior dispersion of CNTs in aluminum matrix and the strong interfacial bonding between CNTs and matrix.展开更多
Welding is a vital component of several industries such as automotive,aerospace,robotics,and construction.Without welding,these industries utilize aluminum alloys for the manufacturing of many components or systems.Ho...Welding is a vital component of several industries such as automotive,aerospace,robotics,and construction.Without welding,these industries utilize aluminum alloys for the manufacturing of many components or systems.However,fusion welding of aluminum alloys is challenging due to several factors,including the presence of non-heat-treatable alloys,porosity,solidification,and liquation of cracks.Many manufacturers adopt conventional in-air friction stir welding(FSW)to weld metallic alloys and dissimilar materials.Many researchers reported the drawbacks of this traditional in-air FSW technique in welding metallic and polymeric materials in general and aluminum alloys and aluminum matrix composites in specific.A number of FSW techniques were developed recently,such as underwater friction stir welding(UFSW),vibrational friction-stir welding(VFSW),and others,for welding of aluminum alloy joints to overcome the issues of welding using conventional FSW.Therefore,the main objective of this review is to summarize the recent trends in FSW process of aluminum alloys and aluminum metal matrix composites(Al MMCs).Also,it discusses the effect of welding parameters of the traditional and state-of-the-art developed FSW techniques on the welding quality and strength of aluminum alloys and Al MMCs.Comparison among the techniques and advantages and limitations of each are considered.The review suggests that VFSW is a viable option for welding aluminum joints due to its energy efficiency,economic cost,and versatile modifications that can be employed based on the application.This review also illustrated that significantly less attention has been paid to FSW of Al-MMCs and considerable attention is demanded to produce qualified joint.展开更多
One of the most desired strengthening mechanisms in the carbon nanotube reinforced aluminum matrix composites(CNT/Al)composites is the load transfer strengthening mechanism(LTSM).However,a fundamental issue concerning...One of the most desired strengthening mechanisms in the carbon nanotube reinforced aluminum matrix composites(CNT/Al)composites is the load transfer strengthening mechanism(LTSM).However,a fundamental issue concerning the LTSM is that quantitative measurements of load partitioning in these composites during loading are very limited.In this study,in-situ neutron diffraction study on the tensile deformation of the 3 vol.%CNT/2009 Al composite and the unreinforced 2009 Al alloy was conducted.The{311}and{220}diffraction elastic constants(DECs)of the 2009 Al alloy were determined.Using those DECs the average stress in the 2009 Al matrix of the composite was calculated.Then the average stress in the CNTs was separated by using the stress equilibrium condition.Computational homogenization models were also applied to explain the stress evolution in each phase.Predicted results agree with experimental data.In the present case,the average stress in the CNTs reaches 1630 MPa at the yield strength of the composite based on linear regression of the measured data,which leads to an increment of yield strength by about 37 MPa.As the result of this work,an approach to quantify load partitioning in the CNTs is developed for the CNT/Al composites,which can be applied to optimize the mechanical properties of the composites.展开更多
基金the Key Projects of Equipment Pre-research Foundation of the Ministry of Equipment Development of the Central Military Commission of China (No.6140922010201)the Key R&D Plan of Zhenjiang in 2018(No.GY2018021)。
文摘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.
基金Project(GJHZ20190822095418365)supported by Shenzhen International Cooperation Research,ChinaProject(2019011)supported by NTUT-SZU Joint Research Program,China+2 种基金Project(2019040)supported by Natural Science Foundation of Shenzhen University,ChinaProject(JCYJ20190808144009478)supported by Shenzhen Fundamental Research Fund,ChinaProject(ZDYBH201900000008)supported by Shenzhen Bureau of Industry and Information Technology,China。
文摘Selective laser melting(SLM)is an emerging layer-wise additive manufacturing technique that can generate complex components with high performance.Particulate-reinforced aluminum matrix composites(PAMCs)are important materials for various applications due to the combined properties of Al matrix and reinforcements.Considering the advantages of SLM technology and PAMCs,the novel SLM PAMCs have been developed and researched in recent years.Therefore,the current research progress about the SLM PAMCs is reviewed.Firstly,special attention is paid to the solidification behavior of SLM PAMCs.Secondly,the important issues about the design and fabrication of high-performance SLM PAMCs,including the selection of reinforcement,the influence of parameters on the processing and microstructure,the defect evolution and phase control,are highlighted and discussed comprehensively.Thirdly,the performance and strengthening mechanism of SLM PAMCs are systematically figured out.Finally,future directions are pointed out on the advancement of high-performance SLM PAMCs.
基金Project(DL09BB23) supported by the Fundamental Research Funds for the Central Universities in China
文摘Two kinds of unidirectional PAN M40 carbon fiber （55%, volume fraction） reinforced 6061Al and 5A06Al composites were fabricated by the squeeze-casting technology and their interface structure and thermal expansion properties were investigated. Results showed that the combination between aluminum alloy and fibers was well in two composites and interface reaction in M40/5A06Al composite was weaker than that in M40/6061Al composite. Coefficients of thermal expansion （CTE） of M40/Al composites varied approximately from （1.45-2.68）×10^-6 K^-1 to （0.35-1.44）×10^-6 K^-1 between 20℃ and 450℃, and decreased slowly with the increase of temperature. In addition, the CTE of M40/6061Al composite was lower than that of M40/SA06Al composite. It was observed that fibers were protruded significantly from the matrix after thermal expansion, which demonstrated the existence of interface sliding between fiber and matrix during the thermal expansion. It was believed that weak interracial reaction resulted in a higher CTE. It was found that the experimental CTEs were closer to the predicted values by Schapery model.
基金This work was financially supported by the Foundation for Key Program of the Ministry of Education of China (No.207038)the Technological Achievement Conversion Program of Jiangsu Province in China (No.BA2005054)+1 种基金the High Technology Research Program of Jiangsu Province (No.BG2005026)the Natural Science Foundation of the Higher Education Institutions of Jiangsu Province, China (No. 05KJD450043).
文摘Pulsed magnetic field is generated when imposing pulse signal on high-frequency magnetic field. Distribution of the inner magnetic intensity in induction coils tends to be uniform. Furthermore oscillation and disturbance phenomena appear in the melt. In. situ Al2O3 and Al3Zr particulate reinforced aluminum matrix composites have been synthesized by direct melt reaction using AlZr（CO3）2 components under a foreign field. The size of reinforced particulates is 2-3 μm. They are well distributed in the matrix. Thermodynamic and kinetic analysis show that high-frequency pulsed magnetic field accelerates heat and mass transfer processes and improves the kinetic condition of in-situ fabrication.
基金Project(2007AA03Z548) supported by High-Tech Research and Development Program of ChinaProject(50971066) supported by the National Natural Science Foundation of ChinaProject(1283000349) supported by the Jiangsu University Research Fund for Advanced Scholars,China
文摘Aluminum matrix composites reinforced by in situ Al2O3 and Al3Zr particles are fabricated from A356-Zr(CO3)2 system via magnetochemistry reaction,and the morphologies,sizes and distributions of the in situ particles as well as the microstructures,mechanical mechanisms of the composites are investigated by XRD,SEM,TEM and in situ tensile tests.The results indicate that with the pulsed magnetic field assistance,the morphologies of the in situ particles are mainly with ball-shape,the sizes are in nanometer scale and the distributions in the matrix are uniform.The interfaces between the in situ particles and the aluminum matrix are net and no interfacial outgrowth is observed.These are due to the strong vibration induced by the applied magnetic field in the aluminum melt,which in turn,accelerates the melt reactions.The effects of the magnetic field on the above contributions are discussed in detail.
基金financially supported by the National Natural Science Foundation of China(No.51474153)
文摘Aluminum matrix composites reinforced with mechanical alloying particles(SiC_p) were fabricated by the semisolid stirring pouring method. The inf luence of mechanical alloying particles and Mg on the microstructure and mechanical properties of the composites was investigated by means of optical microscopy(OM), X-ray diffraction scanning(XRD), electron microscopy(SEM) and energy dispersive spectroscopy(EDS). Results show that the addition of Mg converts the agglomerate mechanical al oying particles in ZL101 matrix composites into dispersed distribution in ZL101-Mg matrix composites, large matrix grains into f ine equiaxed matrix grains, and eutectic phase into f ine particles. So the mechanical properties of ZL101-Mg matrix composites are better than those of ZL101 matrix composites. The mechanical properties of ZL101/ZL101-Mg matrix composites are gradually increased with the increase of the volume fraction of mechanical alloying particles. When the volume fraction of mechanical alloying particles is 3%, the Vickers hardness and ultimate tensile strength of the ZL101/ZL101-Mg matrix composites reach their maximum values.
基金supported by the National High-Tech Research and Development Program of China (No.2009AA03Z116)the National Natural Science Foundation of China (No.50971020)
文摘To extend the application of carbon nanotubes （CNTs） and explore novel aluminum matrix composites,CNTs were coated by molybdenum layers using metal organic chemical vapor deposition,and then Mo-coated CNT （Mo-CNT）/Al composites were prepared by the combination processes of powder mixing and spark plasma sintering.The influences of powder mixing and Mo-CNT content on the mechanical properties and electrical conductivity of the composites were investigated.The results show that magnetic stirring is better than mechanical milling for mixing the Mo-CNTs and Al powders.The electrical conductivity of the composites decreases with increasing Mo-CNT content.When the Mo-CNT content is 0.5wt%,the tensile strength and hardness of Mo-CNT/Al reach their maximum values.The tensile strength of 0.5wt% Mo-CNT/Al increases by 29.9%,while the electrical conductivity only decreases by 7.1%,relative to sintered pure Al.The phase analysis of Mo-CNT/Al composites reveals that there is no formation of Al carbide in the composites.
基金Thanks for the support of the National Natural Science Foundation of China(51661021)Thanks for the support of Key Research and Development Projects of Gansu Province(18YF1GA061)China Postdoctoral Science Foundation(2019M653896XB).
文摘Aluminum matrix composite is one of the most attractive metal matrix composites.It is a kind of material with strong vitality emerging in response to the needs of modern scientific development.Compared with traditional materials,aluminum matrix composites have the advantages of low density,good electric conductivity and heat conductivity,good wear resistance and oxidation resistance,high specific strength and stiffness,high temperature resistance,good heat treatment performance and flexible preparation process,which make them widely used in the fields of aviation,aerospace,and automobile.In this paper,the factors affecting the properties of aluminum matrix composites,the strengthening mechanism,classification and preparation methods of aluminum matrix composites are summarized.The research status,development direction and application prospect of aluminum matrix composites are briefly introduced.
文摘Aluminum matrix composites(AMCs), reinforced with novel pre-synthesized Al/Cu Fe multi-layered coreshell particles, were fabricated by different consolidation techniques to investigate their effect on microstructure and mechanical properties. To synthesize multi-layered Al/Cu Fe core-shell particles, Cu and Fe layers were deposited on Al powder particles by galvanic replacement and electroless plating method, respectively. The core-shell powder and sintered compacts were characterized by using X-ray diffraction(XRD), scanning electron microscopy(SEM) equipped with energy dispersive spectroscopy(EDX), pycnometer, microhardness and compression tests. The results revealed that a higher extent of interfacial reactions, due to the transformation of the deposited layer into intermetallic phases in spark plasma sintered composite, resulted in high relative density(99.26%), microhardness(165 HV0.3) and strength(572 MPa). Further, the presence of un-transformed Cu in the shell structure of hot-pressed composite resulted in the highest fracture strain(20.4%). The obtained results provide stronger implications for tailoring the microstructure of AMCs through selecting appropriate sintering paths to control mechanical properties.
基金supported by the Projects of National Key Research and Development Program of China(2018YFA0703300,2018YFB1105100,2018YFC2001300)the National Natural Science Foundation of China(5167050531,51822504,91848204)+1 种基金Key Scientific and Technological Project of Jilin Province(20180201051GX)Program for JLU Science and Technology Innovative Research Team(2017TD-04)。
文摘Carbon fiber reinforced aluminum composites with ordered architectures of shear-induced aligned carbon fibers were fabricated by 3D printing.The microstructures of the printed and sintered samples and mechanical properties of the composites were investigated.Carbon fibers and aluminum powder were bonded together with resin.The spatial arrangement of the carbon fibers was fixed in the aluminum matrix by shear-induced alignment in the3D printing process.As a result,the elongation of the composites with a parallel arrangement of aligned fibers and the impact toughness of the composites with an orthogonal arrangement were 0.82%and 0.41 J/cm^(2),respectively,about 0.4 and 0.8 times higher than that of the random arrangement.
文摘Aluminum alloys AA6061 reinforced with various amounts （0, 2.5% and 5%, mass fraction） of TiC particles were synthesized by the in situ reaction of inorganic salt K2TiF6 and ceramic particle SiC with molten aluminum. The casting was carried out at an elevated temperature and held for a longer duration to decompose SiC to release carbon atoms. X-ray diffraction patterns of the prepared AMCs clearly revealed the formation of TiC particles without the occurrence of any other intermetallic compounds. The microstructure of the prepared AA6061/TiC AMCs was studied using field emission scanning electron microscope （FESEM） and electron backscatter diffraction （EBSD）. The in situ formed TiC particles were characterized with homogeneous distribution, clear interface, good bonding and various shapes such as cubic, spherical and hexagonal. EBSD maps showed the grain refinement action of TiC particles on the produced composites. The formation of TiC particles boosted the microhardness and ultimate tensile strength （UTS） of the AMCs.
基金Project(20080430895) supported by China Postdoctoral Science FoundationProject(2008RFQXG045) supported by Special Fund of Technological Innovation of HarbinProject(HITQNJS.2009.021) supported by Development Program for Outstanding Young Teachers in Harbin Institute of Technology
文摘Two micron SiC particles with angular and spherical shape and the sub-micron Al2O3 particles with spherical shape were introduced to reinforce 6061 aluminium by squeeze casting technology. Microstructures and effect of thermal-cooling cycle treatment （TCCT） on the thermal expansion behaviors of three composites were investigated. The results show that the composites are free of porosity and SiC/Al2O3 particles are distributed uniformly. Inflections at about 300℃ are observed in coefficient of thermal expansion （CTE） versus temperature curves of two SiCp/Al composites, and this characteristic is not affected by TCCT. The TCCT has significant effect on thermal expansion behavior of SiCp/Al composites and CTE of them after 3 cycles is lower than that of 1 or 5 cycles. However, no inflection is observed in Al2O3p/Al composite, while TCCT has effect on CTE of Al2O3p/Al composite. These results should be due to different relaxation behavior of internal stress in three composites.
基金support provided by the Central Instrument Facility Centre(CIFC)of IIT(BHU)the Department of Ceramic Engineering especially Advance Refractory Lab(ARL)of IIT(BHU)Varanasi。
文摘The microstructural features and the consequent mechanical properties were characterized in aluminium borate whisker(ABOw)(5, 10 and 15 wt.%) reinforced commercially-pure aluminium composites fabricated by conventional powder metallurgy technique. The aluminium powder and the whisker were effectively blended by a semi-powder metallurgy method. The blended powder mixtures were cold compacted and sintered at 600 ℃. The sintered composites were characterized for microstructural features by optical microscopy(OM), scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS), transmission electron microscopy(TEM) and X-ray diffraction(XRD) analysis. Porosity in the composites with variation in ABOw contents was determined. The effect of variation in content of ABOw on mechanical properties, viz. hardness, bending strength and compressive strength of the composites was evaluated. The dry sliding wear behaviour was evaluated at varying sliding distance at constant loads. Maximum flexural strength of 172 MPa and compressive strength of 324 MPa with improved hardness around HV 40.2 are obtained in composite with 10 wt.% ABOw. Further increase in ABOw content deteriorates the properties. A substantial increase in wear resistance is also observed with 10 wt.% ABOw. The excellent combination of mechanical properties of Al-10 wt.%ABOw composites is attributed to good interfacial bonds, less porosity and uniformity in the microstructure.
文摘Stir casting was used to produce AA6061/15%TiC （mass fraction） aluminum matrix composites （AMCs）. An empirical relationship was developed to predict the effect of stir casting parameters on the ultimate tensile strength （UTS） of AA6061/TiC AMCs. A central composite rotatable design consisting of four factors and five levels was used to minimize the number of experiments, i.e., castings. The factors considered were stirring speed, stirring time, blade angle and casting temperature. The effect of those factors on the UTS of AA6061/TiC AMCs was derived using the developed empirical relationship and elucidated using microstructural characterization. Each factor significantly influenced the UTS. The variation in the UTS was attributed to porosity content, cluster formation, segregation of TiC particles at the grain boundaries and homogenous distribution in the aluminum matrix.
基金This investigation was supported by the National Natural Science Foundation of China(No.59771014 and 50071019).The supports are gratefully acknowledged.
文摘The liquid-phase coating method was used to deposit Y2O3 ceramic on the surface of α-Al2O3. The coated-Al2O3p/6061AI composites were produced using squeeze casting technology. The microstructure and tensile properties of the composites were analysed and studied. The results showed that the coated AI2O3 particles are able to disperse homogeneously in the aluminum liquid. The microstructure of the composites is more even in comparison with that of as-received powders. The tensile testing indicated that mechanical properties of the coated-AI2O3p/6061AI composites are better than those of uncoated particles. In the composite with 30% volume fraction, the tensile strength, yield strength as well as elongation is increased by 29.8%, 38.4% and 10.3%, respectively. The SEM analysis of fracture indicated that the dimples of the coated-Al2O3p/6061Al composites are more even.
基金financially supported by the National Natural Science Foundation of China (No. 51271012)
文摘Graphene-reinforced 7055 aluminum alloy composites with different contents of graphene were prepared by spark plasma sintering（SPS）. The structure and mechanical properties of the composites were investigated. Testing results show that the hardness, compressive strength, and yield strength of the composites are improved with the addition of 1wt% graphene. A clean, strong interface is formed between the metal matrix and graphene via metallurgical bonding on atomic scale. Harmful aluminum carbide（Al_4C_3） is not formed during SPS processing. Further addition of graphene（above 1wt%） results in the deterioration in mechanical properties of the composites. The agglomeration of graphene plates is exacerbated with increasing graphene content, which is the main reason for this deterioration.
文摘The influence of volume fraction on damping capacities at room temperature for amorphous carbon fiber reinforced aluminum matrix composites was investigated.At room temperature,the dislocation damping is the primary damping mechanism.Meanwhile,the dislocation damping exhibits dynamic hysteresis at low strain amplitudes and static hysteresis at high strain amplitudes.Moreover,the damping capacity is rather sensitive to the volume fraction.Compared to unreinforced aluminum alloy,the additions of amorphous carbon fibers into the aluminum matrix can improve damping capacity below the volume fraction of 30%,whereas worsen above the volume fraction of 40%.
基金Projects(51071107,51001080,51201056)supported by the National Natural Science Foundation of ChinaProject(2010CB934703)supported by the National Basic Research Program of China+1 种基金Project(13211027)supported by Science and Technology Plan Project of Hebei Province,ChinaProject(2011008)supported by Outstanding Youth Science and Technology Innovation Fund of Hebei University of Technology,China
文摘Using nickel catalyst supported on aluminum powders, carbon nanotubes （CNTs） were successfully synthesized in aluminum powders by in-situ chemical vapor deposition at 650 ℃. Structural characterization revealed that the as-grown CNTs possessed higher graphitization degree and straight graphite shell. By this approach, more homogeneous dispersion of CNTs in aluminum powders was achieved compared with the traditional mechanical mixture methods. Using the in-situ synthesized CNTs/Al composite powders and powder metallurgy process, CNTs/Al bulk composites were prepared. Performance testing showed that the mechanical properties and dimensional stability of the composites were improved obviously, which was attributed to the superior dispersion of CNTs in aluminum matrix and the strong interfacial bonding between CNTs and matrix.
基金United Arab Emirates University (UAEU), Al-Ain, UAE, and Sultan Qaboos University (SQU), Muscat, Sultanate of Oman, for providing research support through a collaborative research project (UAEU: 31N270)。
文摘Welding is a vital component of several industries such as automotive,aerospace,robotics,and construction.Without welding,these industries utilize aluminum alloys for the manufacturing of many components or systems.However,fusion welding of aluminum alloys is challenging due to several factors,including the presence of non-heat-treatable alloys,porosity,solidification,and liquation of cracks.Many manufacturers adopt conventional in-air friction stir welding(FSW)to weld metallic alloys and dissimilar materials.Many researchers reported the drawbacks of this traditional in-air FSW technique in welding metallic and polymeric materials in general and aluminum alloys and aluminum matrix composites in specific.A number of FSW techniques were developed recently,such as underwater friction stir welding(UFSW),vibrational friction-stir welding(VFSW),and others,for welding of aluminum alloy joints to overcome the issues of welding using conventional FSW.Therefore,the main objective of this review is to summarize the recent trends in FSW process of aluminum alloys and aluminum metal matrix composites(Al MMCs).Also,it discusses the effect of welding parameters of the traditional and state-of-the-art developed FSW techniques on the welding quality and strength of aluminum alloys and Al MMCs.Comparison among the techniques and advantages and limitations of each are considered.The review suggests that VFSW is a viable option for welding aluminum joints due to its energy efficiency,economic cost,and versatile modifications that can be employed based on the application.This review also illustrated that significantly less attention has been paid to FSW of Al-MMCs and considerable attention is demanded to produce qualified joint.
基金the National Key R&D Program of China(No.2017YFB0703104)the National Natural Science Foundation of China(Nos.51871214 and 51931009)the“Key Research Program of Frontier Sciences,CAS”(No.QYZDJ-SSWJSC015)。
文摘One of the most desired strengthening mechanisms in the carbon nanotube reinforced aluminum matrix composites(CNT/Al)composites is the load transfer strengthening mechanism(LTSM).However,a fundamental issue concerning the LTSM is that quantitative measurements of load partitioning in these composites during loading are very limited.In this study,in-situ neutron diffraction study on the tensile deformation of the 3 vol.%CNT/2009 Al composite and the unreinforced 2009 Al alloy was conducted.The{311}and{220}diffraction elastic constants(DECs)of the 2009 Al alloy were determined.Using those DECs the average stress in the 2009 Al matrix of the composite was calculated.Then the average stress in the CNTs was separated by using the stress equilibrium condition.Computational homogenization models were also applied to explain the stress evolution in each phase.Predicted results agree with experimental data.In the present case,the average stress in the CNTs reaches 1630 MPa at the yield strength of the composite based on linear regression of the measured data,which leads to an increment of yield strength by about 37 MPa.As the result of this work,an approach to quantify load partitioning in the CNTs is developed for the CNT/Al composites,which can be applied to optimize the mechanical properties of the composites.
