Tungsten inert gas（TIG） welding was applied to creating a composite layer on the surface of cast aluminum alloy A380. Different mixtures of Al, Si and SiC powders mixed with sodium silicate solution were pasted on s...Tungsten inert gas（TIG） welding was applied to creating a composite layer on the surface of cast aluminum alloy A380. Different mixtures of Al, Si and SiC powders mixed with sodium silicate solution were pasted on substrates. Surface melting was conducted by TIG welding to produce Al-SiC layer on the surface. Microstructural evolution was investigated by X-ray diffractometry（XRD）, optical and scanning electron microscopy（SEM） and elemental microanalysis（EDS）. Properties of clad layers were studied by microhardness and sliding wear testing. The results showed a uniform distribution of SiC particles in dendritic aluminum matrix. Addition of excess silicon caused the formation of eutectic crystals and coarse silicon particles in the clad layer which resulted in higher hardness and wear resistance of clad layers.展开更多
Al-cladded Al-Zn-Mg-Cu sheets were compressed up to70%reduction on a Gleeble-3500thermo-mechanical simulatorwith temperatures ranging from380to450°C at strain rates between0.1and30s-1.The microstructures of the A...Al-cladded Al-Zn-Mg-Cu sheets were compressed up to70%reduction on a Gleeble-3500thermo-mechanical simulatorwith temperatures ranging from380to450°C at strain rates between0.1and30s-1.The microstructures of the Al cladding and theAl-Zn-Mg-Cu matrix were characterized by electron back-scattered diffraction(EBSD)and X-ray diffraction(XRD).Themicrostructure is closely related to the level of recovery and recrystallization,which can be influenced by deformation temperature,deformation pass and deformation rate.The level of recovery and recrystallization are different in the Al cladding and theAl-Zn-Mg-Cu matrix.Higher deformation temperature results in higher degree of recrystallization and coarser grain size.Staticrecrystallization and recovery can happen during the interval of deformation passes.Higher strain rate leads to finer sub-grains atstrain rate below10s-1;however,dynamic recovery and recrystallization are limited at strain rate of30s-1due to shorter duration atelevated temperatures.展开更多
Calcium carbonate,which is widely employed as a filler added into the polymer matrix,has large numbers of applications owing to the excellent properties such as low cost,non-toxicity,high natural reserves and biocompa...Calcium carbonate,which is widely employed as a filler added into the polymer matrix,has large numbers of applications owing to the excellent properties such as low cost,non-toxicity,high natural reserves and biocompatibility.Nevertheless,in order to obtain the good filling effect,calcium carbonate needs to be surface modified by organic molecules so as to enhance the dispersion and compatibility within the composites.This review paper systematically introduces the theory,methods,and applications progress of calcium carbonate with surface modification.Additionally,the key factors that affect the properties of the composites as well as the current difficulties and challenges are highlighted.The current research progress and potential application prospects of calcium carbonate in the fields of plastics,rubber,paper,medicine and environmental protection are discussed as well.Generally,this review can provide valuable reference for the modification and comprehensive utilization of calcium carbonate.展开更多
文摘Tungsten inert gas（TIG） welding was applied to creating a composite layer on the surface of cast aluminum alloy A380. Different mixtures of Al, Si and SiC powders mixed with sodium silicate solution were pasted on substrates. Surface melting was conducted by TIG welding to produce Al-SiC layer on the surface. Microstructural evolution was investigated by X-ray diffractometry（XRD）, optical and scanning electron microscopy（SEM） and elemental microanalysis（EDS）. Properties of clad layers were studied by microhardness and sliding wear testing. The results showed a uniform distribution of SiC particles in dendritic aluminum matrix. Addition of excess silicon caused the formation of eutectic crystals and coarse silicon particles in the clad layer which resulted in higher hardness and wear resistance of clad layers.
基金Projects(2016YFB0300901,2016YFB0700401) supported by the National Key Research and Development Program of ChinaProjects(106112015CDJXY130003,106112015CDJXZ138803) supported by the Fundamental Research Funds for the Central Universities,China
文摘Al-cladded Al-Zn-Mg-Cu sheets were compressed up to70%reduction on a Gleeble-3500thermo-mechanical simulatorwith temperatures ranging from380to450°C at strain rates between0.1and30s-1.The microstructures of the Al cladding and theAl-Zn-Mg-Cu matrix were characterized by electron back-scattered diffraction(EBSD)and X-ray diffraction(XRD).Themicrostructure is closely related to the level of recovery and recrystallization,which can be influenced by deformation temperature,deformation pass and deformation rate.The level of recovery and recrystallization are different in the Al cladding and theAl-Zn-Mg-Cu matrix.Higher deformation temperature results in higher degree of recrystallization and coarser grain size.Staticrecrystallization and recovery can happen during the interval of deformation passes.Higher strain rate leads to finer sub-grains atstrain rate below10s-1;however,dynamic recovery and recrystallization are limited at strain rate of30s-1due to shorter duration atelevated temperatures.
基金Project(AA18242008)supported by the Guangxi Science&Technology Major Project,ChinaProject(HZXYKFKT201904)supported by the Opening Project of Guangxi Key Laboratory of Calcium Carbonate Resources Comprehensive Utilization,China。
文摘Calcium carbonate,which is widely employed as a filler added into the polymer matrix,has large numbers of applications owing to the excellent properties such as low cost,non-toxicity,high natural reserves and biocompatibility.Nevertheless,in order to obtain the good filling effect,calcium carbonate needs to be surface modified by organic molecules so as to enhance the dispersion and compatibility within the composites.This review paper systematically introduces the theory,methods,and applications progress of calcium carbonate with surface modification.Additionally,the key factors that affect the properties of the composites as well as the current difficulties and challenges are highlighted.The current research progress and potential application prospects of calcium carbonate in the fields of plastics,rubber,paper,medicine and environmental protection are discussed as well.Generally,this review can provide valuable reference for the modification and comprehensive utilization of calcium carbonate.
