Investigations of Fine Grained Metallic Materials by Means of Orientation Maps in Transmission Electron Microscope

2012 ◽  
Vol 186 ◽  
pp. 53-57 ◽  
Author(s):  
Magdalena Bieda
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Quantitative Description ◽  
Ccd Camera ◽  
Microscopic Investigation ◽  
Automated System ◽  
Fine Grained ◽  
Transmission Electron ◽  
Orientation Maps ◽  
Diffraction Patterns

New subdivision of microscopic investigation called Orientation Microscopy (OM) is already well known in scanning electron microscope (SEM). Needs for investigation in nanoscale contribute to development of an appropriate method for transmission electron microscope (TEM). Automated acquisition and indexing of diffraction patterns, necessary for creation of orientation maps in TEM, cause more difficulties then in SEM. Nevertheless, the techniques of OM are also being developed in the Transmission Electron Microscope (TEM). Microdiffraction has been successfully introduced for creating such maps. Individual orientation measurements, which appeared in the convergent beam mode, can be used for quantitative description of microstructure of fine grained and deformed materials. The idea of the operation of the automated system in transmission electron microscope (TEM) which is developed in IMIM PAS relies on an automatic (with control position of the beam) acquisition of diffraction patterns using digital CCD camera, and indexing them, and then on the analysis of the set of individual crystallographic orientations. The graphic presentation of received sets of orientation can be analysed in order to obtain parameters and characteristics such as texture characteristics, characteristics of grain boundaries (based on orientation relationship) or the stereological characteristics. To illustrate application of this system, orientation maps measured in cold-rolled polycrystalline aluminium and its alloy 6013, and in multi-phase alloys of Fe-Cr-Co system after severe plastic deformation are presented.

Automatic Crystallographic Characterization in a Transmission Electron Microscope: Applications to Twinning Induced Plasticity Steels and Al Thin Films

2013 ◽  
Vol 19 (3) ◽  
pp. 693-697 ◽  
Author(s):  
M. Galceran ◽  
A. Albou ◽  
K. Renard ◽  
M. Coulombier ◽  
P.J. Jacques ◽  
...  
Keyword(s):  
Thin Films ◽  
Electron Microscope ◽  
Electron Diffraction ◽  
Transmission Electron Microscope ◽  
Microstructural Characterization ◽  
Fine Grained ◽  
Mapping Tool ◽  
Transmission Electron ◽  
Kikuchi Lines ◽  
Diffraction Patterns

AbstractA new automated crystallographic orientation mapping tool in a transmission electron microscope technique, which is based on pattern matching between every acquired electron diffraction pattern and precalculated templates, has been used for the microstructural characterization of nondeformed and deformed aluminum thin films and twinning-induced plasticity steels. The increased spatial resolution and the use of electron diffraction patterns rather than Kikuchi lines make this tool very appropriate to characterize fine grained and deformed microstructures.

An Automated System for Maintaining Liquid Nitrogen Levels in the Gatan Cryostage.

2000 ◽  
Vol 6 (S2) ◽  
pp. 290-291
Author(s):  
S.J. Robinson ◽  
G. Fried ◽  
J. Pulokas
Keyword(s):  
Electron Microscope ◽  
Liquid Nitrogen ◽  
Transmission Electron Microscope ◽  
Ccd Camera ◽  
Automated System ◽  
Automated Control ◽  
Nitrogen Levels ◽  
Transmission Electron ◽  
Current Implementation

For several years we have been developing a system for the automated control and acquisition of images from a transmission electron microscope [1,2,3]. The system has been developed around a Philips CM200 equipped with a Gatan cryostage and a Gatan MSC CCD camera. One of the primary motivations in developing this software is to provide for a system that can acquire many hundreds of images over several days of completely unattended operation.The current implementation of our automated system allows data to be automatically collected from the TEM for more than 36 hours. There is no intervention required from the operator except for one critical exception, refilling the Gatan cryostage. The cryostage, which maintains the temperature of the vitreous ice specimens, must be refilled with liquid nitrogen (LN2) approximately every two hours.

Crystalline to Amorphous Transformation of Fe3B By 1 MeV Electron Irradiation

1981 ◽  
Vol 7 ◽  
Author(s):  
A. Mogro-Campero ◽  
E.L. Hall ◽  
J.L. Walter ◽  
A.J. Ratkowski
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Electron Irradiation ◽  
Room Temperature ◽  
Ion Irradiation ◽  
Rapid Quenching ◽  
Al Alloy ◽  
Bright Field ◽  
Transmission Electron ◽  
Diffraction Patterns

ABSTRACTSpecimens of amorphous Fe75B25 produced by rapid quenching from the melt were annealed to complete crystallization and subjected to 1 MeV electron irradiation in a transmission electron microscope at room temperature and at 130 K. The irradiation was interrupted at various intervals in order to obtain bright field images and diffraction patterns. The Fe3B crystals did not become amorphous at room temperature, even after damage levels of several dpa, whereas at 130 K the crystalline to amorphous transformation was observed to be complete at damage levels below 1 dpa. The results are combined with those of ion irradiation work on Fe3B; qualitative agreement is found between Fe3B and previous work on the Zr3Al alloy concerning their response to displacement damage by electron and ion irradiation.

Structure Transformations of the Decagonal and Icosahedral Phases in Quaternary Alloys.

1991 ◽  
Vol 235 ◽  
Author(s):  
R. Perez ◽  
J. Reyes-Gasga ◽  
M. Jose-Yacaman
Keyword(s):  
Electron Microscope ◽  
Electron Diffraction ◽  
Transmission Electron Microscope ◽  
Icosahedral Phase ◽  
Electron Radiation ◽  
Quaternary Alloys ◽  
Decagonal Phase ◽  
Icosahedral Phases ◽  
Transmission Electron ◽  
Diffraction Patterns

ABSTRACTAn investigation of the phase transformations experienced by the decagonal and icosahedral phases in two different quaternary -alloys is carried out. The transformation in the decagonal phase of Al-Cu-Co-Si alloy is induced by the electron radiation in a transmission electron microscope. However, in the icosahedral phase of Al-Cu-Co-Fe alloy this transformation is induced by annealing. Electron diffraction patterns obtained from both phases suggest that the deformation mechanism involved in these kind of transitions is related with twinning

In-situ Observations of Martensitic Transformation in Pure Ti Thin Films using the Dynamical Transmission Electron Microscope (DTEM)

2005 ◽  
Vol 907 ◽  
Author(s):  
Thomas Bradley LaGrange ◽  
Geoffrey H. Campbell ◽  
Jeffrey D. Colvin ◽  
Wayne E. King ◽  
Nigel D. Browning ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Martensitic Transformation ◽  
Electron Diffraction ◽  
Transmission Electron Microscope ◽  
Diffusion Mechanism ◽  
Single Shot ◽  
Transmission Electron ◽  
Texture Modification ◽  
Diffraction Patterns ◽  
Ti Films

AbstractWe have measured the transient events of the α-β martensitic transformation in nanocrystalline Ti films via single shot electron diffraction patterns with 1.5 ns temporal resolution. This was accomplished with a newly constructed dynamic transmission electron microscope (DTEM), which combines pulsed laser systems and pump-probe techniques with a conventional TEM. The DTEM thereby enables studies of transformations that are (1) far too fast to be captured by conventional bulk techniques, and (2) difficult to study with current ultrafast electron diffraction (UED) instruments (which typically require an accumulation of multiple shots for each diffraction pattern). Martensitic transformations in nanocrystalline materials meet both criteria, with their rapid nucleation, characteristic interface velocities ∼1 km/s, and significant irreversible microstructural changes. Free-standing 40-nm-thick Ti films were laser-heated at a rate of ∼1010 K/s to a temperature above the 1155 K transition point, then probed at various time intervals with a 1.5-ns-long intense electron pulse. Diffraction patterns show an almost complete transition to the β phase within 500 ns. Post-mortem analysis (after the sample is allowed to cool) shows a reversion to the α phase coupled with substantial grain growth, lath formation, and texture modification. The cooled material also shows a complete lack of apparent dislocations, suggesting the possible importance of a "massive" short-range diffusion mechanism.

Synthesis of Core-Shell Cu-Au Nanoparticles via a Redox-Transmetalation Method in Reverse Microemulsion

2013 ◽  
Vol 815 ◽  
pp. 465-468
Author(s):  
Jun Jie Jing ◽  
Ji Min Xie ◽  
Gao Yuan Chen ◽  
Wen Hua Li ◽  
Ming Mei Zhang
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Au Nanoparticles ◽  
Shell Morphology ◽  
Reverse Microemulsion ◽  
Pure Gold ◽  
Core Shell ◽  
Visible Absorption ◽  
Transmission Electron ◽  
Diffraction Patterns

Core-shell Cu-Au nanoparticles were chemically synthesized through a redox-transmetalation method in reverse microemulsion. The powder X-ray diffraction patterns revealed the presence of crystalline gold and copper and the absence of any copper oxides or other byproducts. The core shell structure could be clearly observed by the transmission electron microscope (TEM). In addition, the Cu cores and the gold shells were further verified by the high-resolution transmission electron microscope (HRTEM). The diameter of the nanoparticles ranged from 15 to 25 nm, with 5-10 nm core diameters and 10-15 nm shell thickness. The UV-visible absorption spectra of these nanoparticles showed a red shift (relative to pure gold nanoparticles), also in agreement with the gold shell morphology.

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