大约单层薄的非晶态氮化硅的组织,是在nc-(Al_(1-x)Ti_x)N/a-Si_3N_4超硬纳米复合涂层沉积过程中形成的,具有良好的结构与硬度。在温度低于1100℃时,能有效地避免fcc-(Al_(1-x)Ti_x)亚稳溶液的分解和软化,形成富钛fcc(Ti_(1-δ)Al_δ)N...大约单层薄的非晶态氮化硅的组织,是在nc-(Al_(1-x)Ti_x)N/a-Si_3N_4超硬纳米复合涂层沉积过程中形成的,具有良好的结构与硬度。在温度低于1100℃时,能有效地避免fcc-(Al_(1-x)Ti_x)亚稳溶液的分解和软化,形成富钛fcc(Ti_(1-δ)Al_δ)N纤锌矿型h-(A l N)。如果没有氮化硅涂层,(Al_(1-x)Ti_x)N的软化和分解将会发生在800~900℃之间。展开更多
A new kind of laminar metal matrix nanocomposite（MMC） was fabricated by an electrodeposition process with copper and superaligned carbon nanotubes film（SACNT film）.The SACNT film was put on a titanium plate and th...A new kind of laminar metal matrix nanocomposite（MMC） was fabricated by an electrodeposition process with copper and superaligned carbon nanotubes film（SACNT film）.The SACNT film was put on a titanium plate and then a layer of copper was electrodeposited on it.By repeating the above process,the laminar Cu/SACNT composite which contains dozens or hundreds of layers of copper and SACNT films was obtained.The thickness of a single copper layer was controlled by adjusting the process parameter easily and the thinnest layer is less than 2 μm.The microscopic observation shows that the directional alignment structure of SACNT is retained in the composite perfectly.The mechanical and electrical properties testing results show that the tensile and yield strengths of composites are improved obviously compared with those of pure copper,and the high conductivity is retained.This technology is a potential method to make applicable MMC which characterizes high volume fraction and directional alignment of carbon nanotubes.展开更多
Magnesium matrix nanocomposite reinforced with carbon nanotubes(CNTs/AZ91D) was fabricated by mechanical stirring and high intensity ultrasonic dispersion processing.The microstructures and mechanical properties of th...Magnesium matrix nanocomposite reinforced with carbon nanotubes(CNTs/AZ91D) was fabricated by mechanical stirring and high intensity ultrasonic dispersion processing.The microstructures and mechanical properties of the nanocomposite were investigated.The results show that CNTs are well dispersed in the matrix and combined with the matrix very well.As compared with AZ91D magnesium alloy matrix,the tensile strength,yield strength and elongation of the 1.5%CNTs/AZ91D nanocomposite are improved by 22%,21%and 42%respectively in permanent mold casting.The strength and ductility of the nanocomposite are improved simultaneously.The tensile fracture analysis shows that the damage mechanism of nanocomposite is still brittle fracture.But the CNTs can prevent the local crack propagation to some extent.展开更多
文摘大约单层薄的非晶态氮化硅的组织,是在nc-(Al_(1-x)Ti_x)N/a-Si_3N_4超硬纳米复合涂层沉积过程中形成的,具有良好的结构与硬度。在温度低于1100℃时,能有效地避免fcc-(Al_(1-x)Ti_x)亚稳溶液的分解和软化,形成富钛fcc(Ti_(1-δ)Al_δ)N纤锌矿型h-(A l N)。如果没有氮化硅涂层,(Al_(1-x)Ti_x)N的软化和分解将会发生在800~900℃之间。
基金Project(20111080980)supported by the Initiative Scientific Research Program,Tsinghua University,China
文摘A new kind of laminar metal matrix nanocomposite（MMC） was fabricated by an electrodeposition process with copper and superaligned carbon nanotubes film（SACNT film）.The SACNT film was put on a titanium plate and then a layer of copper was electrodeposited on it.By repeating the above process,the laminar Cu/SACNT composite which contains dozens or hundreds of layers of copper and SACNT films was obtained.The thickness of a single copper layer was controlled by adjusting the process parameter easily and the thinnest layer is less than 2 μm.The microscopic observation shows that the directional alignment structure of SACNT is retained in the composite perfectly.The mechanical and electrical properties testing results show that the tensile and yield strengths of composites are improved obviously compared with those of pure copper,and the high conductivity is retained.This technology is a potential method to make applicable MMC which characterizes high volume fraction and directional alignment of carbon nanotubes.
文摘Magnesium matrix nanocomposite reinforced with carbon nanotubes(CNTs/AZ91D) was fabricated by mechanical stirring and high intensity ultrasonic dispersion processing.The microstructures and mechanical properties of the nanocomposite were investigated.The results show that CNTs are well dispersed in the matrix and combined with the matrix very well.As compared with AZ91D magnesium alloy matrix,the tensile strength,yield strength and elongation of the 1.5%CNTs/AZ91D nanocomposite are improved by 22%,21%and 42%respectively in permanent mold casting.The strength and ductility of the nanocomposite are improved simultaneously.The tensile fracture analysis shows that the damage mechanism of nanocomposite is still brittle fracture.But the CNTs can prevent the local crack propagation to some extent.
