The carbon nanotubes(CNTs) reinforced Al-Cu matrix composites were prepared by hot pressing sintering and hot rolling, and the effects of Cu content on the interfacial reaction between Al and CNTs, the precipitation b...The carbon nanotubes(CNTs) reinforced Al-Cu matrix composites were prepared by hot pressing sintering and hot rolling, and the effects of Cu content on the interfacial reaction between Al and CNTs, the precipitation behavior of Cu-containing precipitates, and the resultant mechanical properties of the composites were systematically investigated. The results showed that the increase of Cu content can not only increase the number and size of Cu-containing precipitate generated during the composite fabrication processes, but also promote the interfacial reaction between CNTs and Al matrix, leading to the intensified conversion of CNTs into Al_(4)C_(3). As a result, the composite containing 1 wt.% Cu possesses the highest strength, elastic modulus and hardness among all composites, due to the maintenance of the original structure of CNTs. Moreover, the increase of Cu content can change the dominant strengthening mechanisms for the enhanced strength of the fabricated composites.展开更多
The deformation behaviors of as-sintered CNT/Al-Cu composites were investigated by isothermal compression tests performed in the temperature range of 300-550°C and strain rate range of 0.001-10 s-1 with Gleeble 3...The deformation behaviors of as-sintered CNT/Al-Cu composites were investigated by isothermal compression tests performed in the temperature range of 300-550°C and strain rate range of 0.001-10 s-1 with Gleeble 3500 thermal simulator system.Processing maps based on dynamic material model(DMM)were established at strains of 0.1-0.6,and microstructures before and after hot deformation were characterized by scanning electron microscopy(SEM),electron backscatter diffraction(EBSD)and high-resolution transmission electron microscopy(HRTEM).The results show that the strain has a significant influence on the processing maps,and the optimum processing domains are at temperatures of 375-425°C with strain rates of 0.4-10 s-1 and at 525-550°C with 0.02-10 s-1 when the strain is 0.6.An inhomogeneous distribution of large particles,as well as a high density of tangled dislocations,dislocation walls,and some sub-grains appears at low deformation temperatures and strain rates,which correspond to the instability domain.A homogeneous distribution of fine particles and dynamic recrystallization generates when the composites are deformed at 400 and 550°C under a strain rate of 10 s-1,which correspond to the stability domains.展开更多
An approach named direct reaction synthesis (DRS) has been developed to fabricate particulate composites with an extremely fine reinforcement size. ID situ Al matrix composites were fabri-cated by DRS. Extensive analy...An approach named direct reaction synthesis (DRS) has been developed to fabricate particulate composites with an extremely fine reinforcement size. ID situ Al matrix composites were fabri-cated by DRS. Extensive analysis of the composites microstructure using SEM and TEM identify that the reinforcement formed during the DRS process is Ti carbide (TiC) particle, generally less than 1.0 μm. The reacted, semisolid extruded samples exhibit a homogeneous distribution of fine TiC particles in Al-Cu matrix, Mechanical property evaluation of the composites has revealed a very high tensile strength relative to the matrix alloy. Fractographic analysis indicates ductile failure although the ductility and strength are limited by the presence of coarse titanium aluminides (Al3Ti).展开更多
Recyclable Sip/1199Al composites with high volume fraction of Si particles were fabricated by squeeze-casting method. The microstructure was observed and the thermal properties were tested and calculated by theoretica...Recyclable Sip/1199Al composites with high volume fraction of Si particles were fabricated by squeeze-casting method. The microstructure was observed and the thermal properties were tested and calculated by theoretical models.Sip/1199Al composites are all dense and macroscopically homogeneous without any particle clustering.The interface of Sip/1199Al is clean,smooth and free from any interfacial reaction products.Sip/1199Al composites have high thermal diffusivity(65.083 mm 2/s)and thermal conductivity (168.211 W/(m·℃)).The specific heat capacity of Sip/1199Al composites at constant pressure increases while the thermal diffusivity and thermal conductivity decrease with increasing temperature.Annealing treatment could improve the thermal properties.The results of Maxwell model and P.G.model are higher than those of experiment.展开更多
Three kinds of high volume fraction Sip/1199, Sip/4032 and Sip/4019 composites were fabricated by squeeze casting method. The results show that the clean Si /Al interfaces without interfacial reaction products can dec...Three kinds of high volume fraction Sip/1199, Sip/4032 and Sip/4019 composites were fabricated by squeeze casting method. The results show that the clean Si /Al interfaces without interfacial reaction products can decrease the interfacial thermal resistance. The composites have a low coefficient of thermal expansion (7.5×10-6℃-1) and high thermal conductivity ranging from 126 to 157.9 W/(m·℃). With increasing temperature, the specific capacity and the average coefficient of thermal expansion increases monotonically, the thermal diffusivity and the thermal conductivity decrease gradually. The specific capacity, average coefficient of thermal expansion, thermal diffusivity and the thermal conductivity of the composites decrease gradually with increasing Si content. The thermal conductivities of composites were calculated by theoretical models. Both Maxwell model and P.G model consider the reinforcement as nearly-round particles, and the interface thermal resistance of Sip/Al composite calculated by EMA method展开更多
Microstructural and mechanical behavior of heat treatable Al-4.6Cu binary alloy reinforced with graphene nanoplates(GNPs) in different heat treatment status were investigated in this paper.The addition of GNPs signifi...Microstructural and mechanical behavior of heat treatable Al-4.6Cu binary alloy reinforced with graphene nanoplates(GNPs) in different heat treatment status were investigated in this paper.The addition of GNPs significantly enhanced the yield strength and tensile strength of Al-Cu alloy regardless of the heattreatment conditions.It was also found that GNPs accelerated the formation of precipitates,leading to a greatly shortened aging time for GNPs/Al-4.6Cu composite to reach the peak hardness.However,aging treatment enhanced the strength of GNPs/Al-Cu composite very little,which could be explained by the interaction between GNPs,precipitates and dislocations.This work inspires us that the heat treatment process of aluminum alloy matrix composites should be designed independently with the matrix in quest of an optimum performance.展开更多
基金The financial supports from the National Natural Science Foundation of China (Nos. 52004101 and 52071269)the Chinese Postdoctoral Science Foundation (No. 2020T130246)+2 种基金the Fund of the State Key Laboratory of Solidification Processing in NWPU, China (No. SKLSP202121)the Guangdong Basic and Applied Basic Research Foundation, China (No. 2020A1515110621)the Fundamental Research Funds for the Central Universities, China (No. 11620345)。
文摘The carbon nanotubes(CNTs) reinforced Al-Cu matrix composites were prepared by hot pressing sintering and hot rolling, and the effects of Cu content on the interfacial reaction between Al and CNTs, the precipitation behavior of Cu-containing precipitates, and the resultant mechanical properties of the composites were systematically investigated. The results showed that the increase of Cu content can not only increase the number and size of Cu-containing precipitate generated during the composite fabrication processes, but also promote the interfacial reaction between CNTs and Al matrix, leading to the intensified conversion of CNTs into Al_(4)C_(3). As a result, the composite containing 1 wt.% Cu possesses the highest strength, elastic modulus and hardness among all composites, due to the maintenance of the original structure of CNTs. Moreover, the increase of Cu content can change the dominant strengthening mechanisms for the enhanced strength of the fabricated composites.
基金Project(KJ1601321)supported by Scientific and Technological Research Program of Chongqing Municipal Education Commission,ChinaProject(cstc2017jcyjAX0378)supported by the Chongqing Research Program of Basic Research and Frontier Technology,China
文摘The deformation behaviors of as-sintered CNT/Al-Cu composites were investigated by isothermal compression tests performed in the temperature range of 300-550°C and strain rate range of 0.001-10 s-1 with Gleeble 3500 thermal simulator system.Processing maps based on dynamic material model(DMM)were established at strains of 0.1-0.6,and microstructures before and after hot deformation were characterized by scanning electron microscopy(SEM),electron backscatter diffraction(EBSD)and high-resolution transmission electron microscopy(HRTEM).The results show that the strain has a significant influence on the processing maps,and the optimum processing domains are at temperatures of 375-425°C with strain rates of 0.4-10 s-1 and at 525-550°C with 0.02-10 s-1 when the strain is 0.6.An inhomogeneous distribution of large particles,as well as a high density of tangled dislocations,dislocation walls,and some sub-grains appears at low deformation temperatures and strain rates,which correspond to the instability domain.A homogeneous distribution of fine particles and dynamic recrystallization generates when the composites are deformed at 400 and 550°C under a strain rate of 10 s-1,which correspond to the stability domains.
文摘An approach named direct reaction synthesis (DRS) has been developed to fabricate particulate composites with an extremely fine reinforcement size. ID situ Al matrix composites were fabri-cated by DRS. Extensive analysis of the composites microstructure using SEM and TEM identify that the reinforcement formed during the DRS process is Ti carbide (TiC) particle, generally less than 1.0 μm. The reacted, semisolid extruded samples exhibit a homogeneous distribution of fine TiC particles in Al-Cu matrix, Mechanical property evaluation of the composites has revealed a very high tensile strength relative to the matrix alloy. Fractographic analysis indicates ductile failure although the ductility and strength are limited by the presence of coarse titanium aluminides (Al3Ti).
基金Project(HITQNJS.2008.057)supported by Development Program for Outstanding Young Teachers in Harbin Institute of Technology,China
文摘Recyclable Sip/1199Al composites with high volume fraction of Si particles were fabricated by squeeze-casting method. The microstructure was observed and the thermal properties were tested and calculated by theoretical models.Sip/1199Al composites are all dense and macroscopically homogeneous without any particle clustering.The interface of Sip/1199Al is clean,smooth and free from any interfacial reaction products.Sip/1199Al composites have high thermal diffusivity(65.083 mm 2/s)and thermal conductivity (168.211 W/(m·℃)).The specific heat capacity of Sip/1199Al composites at constant pressure increases while the thermal diffusivity and thermal conductivity decrease with increasing temperature.Annealing treatment could improve the thermal properties.The results of Maxwell model and P.G.model are higher than those of experiment.
基金Project(2003AA305110) supported by the Hi-tech Research and Development Program of China
文摘Three kinds of high volume fraction Sip/1199, Sip/4032 and Sip/4019 composites were fabricated by squeeze casting method. The results show that the clean Si /Al interfaces without interfacial reaction products can decrease the interfacial thermal resistance. The composites have a low coefficient of thermal expansion (7.5×10-6℃-1) and high thermal conductivity ranging from 126 to 157.9 W/(m·℃). With increasing temperature, the specific capacity and the average coefficient of thermal expansion increases monotonically, the thermal diffusivity and the thermal conductivity decrease gradually. The specific capacity, average coefficient of thermal expansion, thermal diffusivity and the thermal conductivity of the composites decrease gradually with increasing Si content. The thermal conductivities of composites were calculated by theoretical models. Both Maxwell model and P.G model consider the reinforcement as nearly-round particles, and the interface thermal resistance of Sip/Al composite calculated by EMA method
基金financially support by the Equipment Advance Research Fund (Grant No. 61409220102)the Chinese National Science Fund for Distinguished Young Scholars (Grant No. 52025015)+2 种基金the Chinese National Natural Science Foundation (Grant No. 51771130, 52071230)the Tianjin youth talent support program, the Tianjin Natural Science Funds for Distinguished Young Scholars (Grant No. 17JCJQJC44300)the Tianjin Science and Technology Support Project (Grant No. 17ZXCLGX00060)。
文摘Microstructural and mechanical behavior of heat treatable Al-4.6Cu binary alloy reinforced with graphene nanoplates(GNPs) in different heat treatment status were investigated in this paper.The addition of GNPs significantly enhanced the yield strength and tensile strength of Al-Cu alloy regardless of the heattreatment conditions.It was also found that GNPs accelerated the formation of precipitates,leading to a greatly shortened aging time for GNPs/Al-4.6Cu composite to reach the peak hardness.However,aging treatment enhanced the strength of GNPs/Al-Cu composite very little,which could be explained by the interaction between GNPs,precipitates and dislocations.This work inspires us that the heat treatment process of aluminum alloy matrix composites should be designed independently with the matrix in quest of an optimum performance.
