An 2024Al matrix composite reinforced with 36%(volume fraction)β-Si_(3)N_(4) particles was fabricated by pressure infiltration method,and its microstructure and the effect of annealing treatment on thermo-conductivit...An 2024Al matrix composite reinforced with 36%(volume fraction)β-Si_(3)N_(4) particles was fabricated by pressure infiltration method,and its microstructure and the effect of annealing treatment on thermo-conductivity were discussed.Si_(3)N_(4) particles distribute uniformly without any particle clustering and no apparent particle porosity or significant casting defects are observed in the composites.The combination of particles and matrix is well.The raw Si_(3)N_(4) particles are regular cylindrical polyhedron with flat surface and change to serrated surface in composite due to reactions during fabrication.Thermal conductivity of as-cast Si_(3)N_(4)p/2024 composite is 90.125 W/(m·K)at room temperature,and increases to 94.997 W/(m·K)after annealing treatment. The calculated results of thermal conductivity of the Si_(3)N_(4p)/Al composite by Maxwell model,H-S model and PG model are lower than experimental results while that by ROM model is higher.展开更多
Graphite fiber reinforced magnesium matrix(Grf/Mg)composites were fabricated by squeeze casting technology.M40 graphite fibers were reinforced to AZ91D and ZM6,their thermal expansion behaviors of M40/AZ91D and M40/ZM...Graphite fiber reinforced magnesium matrix(Grf/Mg)composites were fabricated by squeeze casting technology.M40 graphite fibers were reinforced to AZ91D and ZM6,their thermal expansion behaviors of M40/AZ91D and M40/ZM6 composites in the temperature range from 20 to 490℃were investigated.The results show that the interfacial species and thermal stress have significant influence on the thermal expansion behavior of the composites.Simultaneously,the longitudinal coefficient of thermal expansion of Grf/Mg composites are affected by the thermal stress,interfacial species and yield strength of matrix alloy,it also decreases with increasing temperature and descending rate of longitudinal coefficient of thermal expansion(CTEs)of Grf/Mg composites changed in different temperature ranges.In terms of different descending rates,the curve of coefficient of thermal expansion vs temperature can be divided into three stages.The matrix alloys M40/AZ91D and M40/ZM6 yield at 170 and 155℃in the thermal expansion,respectively.展开更多
TiB_(2p)/Cu composites with high reinforcement content(φ_(p)=50%,58%and 65%)for electronic packaging applications were fabricated by squeeze casting technology.The microstructures and thermo-physical properties of th...TiB_(2p)/Cu composites with high reinforcement content(φ_(p)=50%,58%and 65%)for electronic packaging applications were fabricated by squeeze casting technology.The microstructures and thermo-physical properties of the TiB_(2p)/Cu composites were investigated.The results show that TiB2 particles are homogeneous and distribute uniformly,and the TiB2-Cu interfaces are clean and free-from interfacial reaction products and amorphous layers,the densifications of the TiB_(2p)/Cu composites are higher than 98.2%. The mean linear coefficients of thermal expansion at 20-100℃for TiB_(2p)/Cu composites range from 8.3×10^(-6)to 10.8×10^(-6)/K and decrease with increasing volume fraction of TiB2.The experimental coefficients of thermal expansion agree well with the predicted values based on Turner’s model.The thermal conductivities of TiB_(2p)/Cu composites range from 167.3 to 215.4 W/(m·K),decreasing with increasing volume fraction TiB2.展开更多
Si_(3)N_(4p)/2024Al composite was fabricated by squeeze casting method and treated by extrusion deformation.Microstructure analyses indicate that Si_(3)N_(4) particles in the composite are in cylindrical polyhedron sh...Si_(3)N_(4p)/2024Al composite was fabricated by squeeze casting method and treated by extrusion deformation.Microstructure analyses indicate that Si_(3)N_(4) particles in the composite are in cylindrical polyhedron shape.Extrusion deformation is beneficial to uniform distribution of Si_(3)N_(4) particles and improves the relative density of Si_(3)N_(4p)/2024Al composite.Tensile strength of Si_(3)N_(4p)/2024Al composite increases by 76.6%after T6 treatment,and after extrusion and T6 treatment it is by 57.6%more than T6 treatment only.Elastic modulus of Si_(3)N_(4p)/2024Al composite increases a little after T6 treatment but increases by 33.5%after extrusion deformation.展开更多
基金Project(2003AA305110)supported by the Hi-tech Research and Development Program of China。
文摘An 2024Al matrix composite reinforced with 36%(volume fraction)β-Si_(3)N_(4) particles was fabricated by pressure infiltration method,and its microstructure and the effect of annealing treatment on thermo-conductivity were discussed.Si_(3)N_(4) particles distribute uniformly without any particle clustering and no apparent particle porosity or significant casting defects are observed in the composites.The combination of particles and matrix is well.The raw Si_(3)N_(4) particles are regular cylindrical polyhedron with flat surface and change to serrated surface in composite due to reactions during fabrication.Thermal conductivity of as-cast Si_(3)N_(4)p/2024 composite is 90.125 W/(m·K)at room temperature,and increases to 94.997 W/(m·K)after annealing treatment. The calculated results of thermal conductivity of the Si_(3)N_(4p)/Al composite by Maxwell model,H-S model and PG model are lower than experimental results while that by ROM model is higher.
文摘Graphite fiber reinforced magnesium matrix(Grf/Mg)composites were fabricated by squeeze casting technology.M40 graphite fibers were reinforced to AZ91D and ZM6,their thermal expansion behaviors of M40/AZ91D and M40/ZM6 composites in the temperature range from 20 to 490℃were investigated.The results show that the interfacial species and thermal stress have significant influence on the thermal expansion behavior of the composites.Simultaneously,the longitudinal coefficient of thermal expansion of Grf/Mg composites are affected by the thermal stress,interfacial species and yield strength of matrix alloy,it also decreases with increasing temperature and descending rate of longitudinal coefficient of thermal expansion(CTEs)of Grf/Mg composites changed in different temperature ranges.In terms of different descending rates,the curve of coefficient of thermal expansion vs temperature can be divided into three stages.The matrix alloys M40/AZ91D and M40/ZM6 yield at 170 and 155℃in the thermal expansion,respectively.
基金Project(20080430895)supported by China Postdoctoral Science FoundationProject(2008RFQXG045)supported by the Special Fund of Technological Innovation of Harbin,China。
文摘TiB_(2p)/Cu composites with high reinforcement content(φ_(p)=50%,58%and 65%)for electronic packaging applications were fabricated by squeeze casting technology.The microstructures and thermo-physical properties of the TiB_(2p)/Cu composites were investigated.The results show that TiB2 particles are homogeneous and distribute uniformly,and the TiB2-Cu interfaces are clean and free-from interfacial reaction products and amorphous layers,the densifications of the TiB_(2p)/Cu composites are higher than 98.2%. The mean linear coefficients of thermal expansion at 20-100℃for TiB_(2p)/Cu composites range from 8.3×10^(-6)to 10.8×10^(-6)/K and decrease with increasing volume fraction of TiB2.The experimental coefficients of thermal expansion agree well with the predicted values based on Turner’s model.The thermal conductivities of TiB_(2p)/Cu composites range from 167.3 to 215.4 W/(m·K),decreasing with increasing volume fraction TiB2.
基金Project(HITQNJS.2008.057)Supported by Development Program for Outstanding Young Teachers in Harbin Institute of Technology,China。
文摘Si_(3)N_(4p)/2024Al composite was fabricated by squeeze casting method and treated by extrusion deformation.Microstructure analyses indicate that Si_(3)N_(4) particles in the composite are in cylindrical polyhedron shape.Extrusion deformation is beneficial to uniform distribution of Si_(3)N_(4) particles and improves the relative density of Si_(3)N_(4p)/2024Al composite.Tensile strength of Si_(3)N_(4p)/2024Al composite increases by 76.6%after T6 treatment,and after extrusion and T6 treatment it is by 57.6%more than T6 treatment only.Elastic modulus of Si_(3)N_(4p)/2024Al composite increases a little after T6 treatment but increases by 33.5%after extrusion deformation.
