Icosahedral quasicrystals display irregular shape if it is embedded in bulk material. If it has free surface, it has well-defined facets, reflecting its unique 5-, 3-, and 2-fold rotational symmetries. In this study, ...Icosahedral quasicrystals display irregular shape if it is embedded in bulk material. If it has free surface, it has well-defined facets, reflecting its unique 5-, 3-, and 2-fold rotational symmetries. In this study, an Al-Cu-Fe alloy with nominal composition of Al65Cu20Fe15 was prepared by arc melting and the microstructure was studied by using Scanning Electron Microscope, Energy Dispersive X-ray Spectroscopy, and Electron Back Scattering Diffraction (EBSD). On the surface of λ crystalline phase, an extra layer is found. EBSD from this layer revealed 5-, 3-, and 2-fold rotational symmetries, demonstrating the icosahedral quasicrystalline structure. Further, it has been found that the icosahedral quasicrystalline extra layer and the λ substrate have orientation relationship revealed by the coincidences of Kikuchi bands and poles on the EBSD patterns. This report is important to future studies regarding the formation of icosahedral quasicrystalline phase and thin film preparation related to icosahedral quasicrystalline phase.展开更多
Experiment were conducted to unidirectional solidification pure copper during ECAP by route C, the samples were investigated by XRD and EBSD. The results shown that the effect of original microstructure on the subgrai...Experiment were conducted to unidirectional solidification pure copper during ECAP by route C, the samples were investigated by XRD and EBSD. The results shown that the effect of original microstructure on the subgrains orientation decrease with the increasing of strain. At low strain, in the column grain interiors first formed a band structure that the orientation quite different with the matrix. With the strain increasing, the boundaries of the band structure expanding towards to two sides, gradually partition the original column grains into subgrains, the distribution of the subgrains possesses a directional distribution characteristics and the twins occurring in subgrains. Keep on increasing strain, the original grain boundaries began to broken, low angles grain boundaries and high angles grain boundaries both occur simultaneously shows a diffusion distribution characteristics.展开更多
对七道次异步叠轧铜板采用220℃×30 m in和220℃×40 m in两种工艺进行退火,运用背散射电子衍射技术对两种铜板的再结晶程度、织构和晶界特征分布进行了研究。结果表明,经220℃×40 m in退火处理后,铜板的再结晶较完全,其...对七道次异步叠轧铜板采用220℃×30 m in和220℃×40 m in两种工艺进行退火,运用背散射电子衍射技术对两种铜板的再结晶程度、织构和晶界特征分布进行了研究。结果表明,经220℃×40 m in退火处理后,铜板的再结晶较完全,其织构为明显的{100}〈001〉立方织构;而经220℃×30 m in退火处理后,铜板内仍存在晶体缺陷,其织构为{123}〈412〉轧制织构及少量的{100}〈001〉立方织构。晶界特征分布图表明晶界都主要分布在Σ1、Σ3、Σ7、Σ9和Σ11位置上,采用220℃×40 m in退火处理后铜板中各主要晶界的含量明显高于采用220℃×30m in退火后的。展开更多
文摘Icosahedral quasicrystals display irregular shape if it is embedded in bulk material. If it has free surface, it has well-defined facets, reflecting its unique 5-, 3-, and 2-fold rotational symmetries. In this study, an Al-Cu-Fe alloy with nominal composition of Al65Cu20Fe15 was prepared by arc melting and the microstructure was studied by using Scanning Electron Microscope, Energy Dispersive X-ray Spectroscopy, and Electron Back Scattering Diffraction (EBSD). On the surface of λ crystalline phase, an extra layer is found. EBSD from this layer revealed 5-, 3-, and 2-fold rotational symmetries, demonstrating the icosahedral quasicrystalline structure. Further, it has been found that the icosahedral quasicrystalline extra layer and the λ substrate have orientation relationship revealed by the coincidences of Kikuchi bands and poles on the EBSD patterns. This report is important to future studies regarding the formation of icosahedral quasicrystalline phase and thin film preparation related to icosahedral quasicrystalline phase.
文摘Experiment were conducted to unidirectional solidification pure copper during ECAP by route C, the samples were investigated by XRD and EBSD. The results shown that the effect of original microstructure on the subgrains orientation decrease with the increasing of strain. At low strain, in the column grain interiors first formed a band structure that the orientation quite different with the matrix. With the strain increasing, the boundaries of the band structure expanding towards to two sides, gradually partition the original column grains into subgrains, the distribution of the subgrains possesses a directional distribution characteristics and the twins occurring in subgrains. Keep on increasing strain, the original grain boundaries began to broken, low angles grain boundaries and high angles grain boundaries both occur simultaneously shows a diffusion distribution characteristics.
文摘对七道次异步叠轧铜板采用220℃×30 m in和220℃×40 m in两种工艺进行退火,运用背散射电子衍射技术对两种铜板的再结晶程度、织构和晶界特征分布进行了研究。结果表明,经220℃×40 m in退火处理后,铜板的再结晶较完全,其织构为明显的{100}〈001〉立方织构;而经220℃×30 m in退火处理后,铜板内仍存在晶体缺陷,其织构为{123}〈412〉轧制织构及少量的{100}〈001〉立方织构。晶界特征分布图表明晶界都主要分布在Σ1、Σ3、Σ7、Σ9和Σ11位置上,采用220℃×40 m in退火处理后铜板中各主要晶界的含量明显高于采用220℃×30m in退火后的。
