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Shao‐Pu Tsai Shih‐Ning Tsai Yu‐Ting Tsai Yu‐Wen Chen Po‐Yen Tung Jer‐Ren Yang Hsueh‐Ren Chen Chih‐Yuan Chen Yuan‐Tsung Wang Ching‐Yuan Huang 《Microscopy research and technique》2019,82(1):4-11
Convergent beam electron diffraction (CBED) in transmission electron microscopy (TEM) was applied to determine local carbon concentrations in low‐carbon transformation‐induced plasticity (TRIP) steels. High‐order Laue‐zone (HOLZ) lines were experimentally obtained for comparison with simulation results. A new procedure for calculating carbon content is thus proposed. Retained austenite (RA) is classified into three types by morphology; the relationship between the carbon content and the corresponding RA morphology is discussed based on CBED results. Furthermore, results of X‐Ray diffractometry measurements are also used for comparison. 相似文献
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The use of a surface developer, pyrocatechol, to process transmission electron microscope negatives has been shown to have significant advantages over the conventional D-19 process. The process described here is tolerant of a large margin of error in the electron exposure and produces a negative that not only retains details both in the highlight as well as the faint regions, but also preserves local contrast. These characteristics are particularly useful in convergent beam electron diffraction applications where one encounters a wide contrast range. Improved acuteness and an enhanced signal to noise ratio due to the prolonged exposures associated with this process have also been observed. 相似文献
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This paper investigates the interfacial structure in hot-wall CVD TiN/κ-Al2O3 multilayer coatings using both HREM and DFT modeling. Two multilayers with different thicknesses of the TiN layers (50 and 600 nm) separating the κ-Al2O3 layers are analyzed. The general microstructure of the two multilayers is relatively similar. The TiN layer in the thicker TiN/κ-Al2O3 coating is thick enough to be several TiN grains high. This means that epitaxial columns, which are often found in the thinner TiN/κ-Al2O3 coatings, are not present. However, the orientation relationships at the TiN/κ-Al2O3 interfaces are the same in both multilayers. The HREM investigations show that κ-Al2O3 (001) planes can grow directly on flat (111) TiN faces, without any other phases or detectable amounts of impurities, such as sulphur, present. Where the TiN layers are more curved, γ-Al2O3 can be grown, at least partly stabilized by the cube-on-cube orientation relationship between γ-Al2O3 and the underlying TiN. The DFT calculations show very similar adsorption strengths for an O monolayer positioned on Ti-terminated TiC(111) and TiN(111) surfaces, with preferred adsorption in the fcc site. O adsorption on N-terminated TiN(111) is much weaker, with preferred adsorption in the top site. Calculated elastic-energy contributions yield a higher stability for κ-Al2O3 on TiN(111) than on TiC(111) and a higher stability for κ-Al2O3 than for α-Al2O3 on both TiC and TiN. This indicates that the observed higher stability of κ-Al2O3 on TiC(111) than on TiN(111) is not due to the lattice mismatch, while the preferred epitaxial growth of κ-Al2O3 over α-Al2O3 can be partly attributed to the mismatch. 相似文献
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John Mansfield 《Microscopy research and technique》1989,13(1):3-15
The purpose of this article is to present a practical guide to the identification of phases in the analytical electron microscope with the aid of convergent beam electron diffraction. There is included a step-by-step approach to phase analysis, from the possible choices of the form of the specimen through how to explore reciprocal space in order to perform a full phase identification, either by symmetry analysis or by simple comparison of a pattern observed in the microscope with a previously recorded pattern (fingerprinting). There is a strong emphasis on practical hints and useful shortcuts. 相似文献
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Takuma Suzuki Hang-Ju Ko Agus Setiawan Jung-Jin Kim Koh Saitoh Masami Terauchi Takafumi Yao 《Materials Science in Semiconductor Processing》2003,6(5-6):519-521
We report the successful growth of Ga-polar GaN epilayers on O-polar ZnO templates pre-deposited on c-sapphire. Prior to GaN growth, NH3 is exposed onto the ZnO template. The polarity of the GaN layers is confirmed by etching of the surface and by conversion beam electron diffraction (CBED), while the O-polar ZnO is confirmed by CBED. It is suggested that the NH3 pre-exposure helps form a Zn3N2 layer, which possesses inversion symmetry and inverts the crystal from anion polar to cation polar. 相似文献
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This study deals with the uncertainty of the measurement of lattice parameters by CBED using the kinematic approximation. The analysis of a large number of diffraction patterns acquired on a silicon sample at 93 K with a LaB6 TEM without energy filter shows the presence of both the systematic and the random parts of errors. It is established that random errors follow the normal statistical distribution and that the precision quantified by the relative standard deviation is about 3–4×10−4 for lattice parameter measurements made from single pattern. The error sources are analyzed, different ways of enhancement are reviewed, and a new approach is proposed. It is shown that both accuracy and precision can be simply improved by taking into account multiple patterns analysis for the determination of the actual voltage, the single lattice parameter “a” or the complete set of lattice parameters. The precision of about 1.5–2×10−4 can be reached using a minimum of three HOLZ line patterns for the single “a” parameter and about 5×10−4 for the complete set of lattice parameters using six diffraction patterns. The use of multiple patterns also allows overcoming the non-uniqueness of solution linked to the CBED studies. 相似文献
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本文采用对称多束会聚柬电子衍射图确定了一种尺度为数10nm至1μm的显微沉积相的晶体结构,指出会聚束衍射。尤其是对称多柬会聚束衍射图,是确定晶体材料中显微相结构的极其有用的方法。 相似文献
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Determination of residual strains with CBED/LACBED techniques 总被引:1,自引:0,他引:1
Theresidualstressesaregeneratedinmetalmatrixcomposites(MMCs)becauseofadifferenceinthermalexpansioncoefficientsbetweenthereinforcementandthematrixwhencoolingfromhighprocessingtemperatures.Themagnitudeoftheseresidualstressesissignificant,especiallyintheM… 相似文献