Special Microstructures and Twin Features in Ti50Ni50-X(Pd,Au)X at Small Hysteresis

2011 ◽  
Vol 172-174 ◽  
pp. 105-110 ◽  
Author(s):  
Remi Delville ◽  
Hui Shi ◽  
Richard D. James ◽  
Dominique Schryvers
Keyword(s):  
Martensite Phase ◽  
Atomic Level ◽  
High Resolution Imaging ◽  
Composition Change ◽  
Twin Lamella ◽  
Atomic Displacements ◽  
Transmission Electron ◽  
Resolution Imaging ◽  
Two Phases ◽  
Deformation Compatibility

The breaking of symmetry due to atomic displacements in the austenite-martensite phase transformation generally leads to their crystallographic incompatibility. Energy minimizing accommodation mechanisms such as martensite twinning have been recently shown to be a source of hysteresis and irreversible plastic deformation. Compatibility between the two phases can however be achieved by carefully tuning lattice parameters through composition change. A dramatic drop in hysteresis and novel microstructures such as a lowering of the amount of twin lamella are then observed. Related theoretical and simulation works also support the existence of such microstructures including peculiar self-accommodating configurations at near-compatibility. We present the transmission electron microscopy (TEM) study of these novel microstructures for the alloy systems Ti50Ni50-xPdxand Ti50Ni50-xAuxwhere the composition was systemically tuned to approach perfect compatibility. High resolution imaging of the interface between austenite and martensite supplies evidences of compatibility at the atomic level.

Design and Applications of Environmental Cell Transmission Electron Microscope for In Situ Observations of Gas–Solid Reactions

2001 ◽  
Vol 7 (6) ◽  
pp. 494-506 ◽  
Author(s):  
Renu Sharma
Keyword(s):  
Chemical Vapor ◽  
Atomic Level ◽  
Chemical Information ◽  
Oxidation Reduction ◽  
Transmission Electron ◽  
Recent Developments ◽  
Level Information ◽  
Resolution Imaging ◽  
Electron Energy Loss

AbstractThe environmental transmission electron microscopy (E-TEM) is a budding technique for in situ study of gas–solid chemical reactions with numerous applications. Recent improvements in the design have made it possible not only to obtain atomic level information but also the chemical information during the reaction by incorporating an imaging filter or electron energy-loss spectrometer to an E-TEM. We have been involved in modifying a couple of microscopes to incorporate environmental cells in order to convert them into E-TEMs. These microscopes have been used to obtain atomic level information of the structural and chemical changes during dynamic processes by in situ electron diffraction, high-resolution imaging, and electron energyloss spectroscopy. The applications include, but are not limited to, oxidation, reduction, polymerization, nitridation, dehydroxylation, hydroxylation, chemical vapor deposition, etc. We report recent developments in the design and application along with the limitations of an E-TEM.

High Resolution Imaging of As-Grown Sapphire Surfaces

1985 ◽  
Vol 62 ◽  
Author(s):  
Tung Hsu ◽  
S. R. Nutt
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Structural Features ◽  
High Resolution Imaging ◽  
Sapphire Surface ◽  
Surface Steps ◽  
Transmission Electron ◽  
Reflection Electron Microscopy ◽  
Resolution Imaging ◽  
Surface Facets

ABSTRACTSurfaces of commercially grown edge-defined film-fed growth sapphire (EFG α-Al2O3) were studied in the electron microscope using both reflection electron microscopy (REM) and conventional transmission electron microscopy (TEM). The as-grown sapphire surface, ostensibly {1120}, was characterized by “rooftop” structures which were often locally periodic. These rooftop structures consisted of alternating {1120} facets and additional facets inclined a few degrees. The crystallography of the surface facets was analyzed using REM imaging of bulk specimens, and trace analysis of back-thinned plan section TEM specimens. Surface roughness was measured by stylus profilometry. and these measurements were compared to the electron microscopy observations. Fine structural features parallel to <0110> directions were also observed in both REM and TEM experiments, and these were attributed to surface steps of atomic scales.

scholarly journals Recent Advances in Transmission Electron Microscopy for Materials Science at the EMAT Lab of the University of Antwerp

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1304 ◽  
Author(s):  
Giulio Guzzinati ◽  
Thomas Altantzis ◽  
Maria Batuk ◽  
Annick De Backer ◽  
Gunnar Lumbeeck ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Materials Science ◽  
Electron Tomography ◽  
High Resolution Imaging ◽  
Rapid Progress ◽  
Transmission Electron ◽  
The World ◽  
Resolution Imaging ◽  
The University

The rapid progress in materials science that enables the design of materials down to the nanoscale also demands characterization techniques able to analyze the materials down to the same scale, such as transmission electron microscopy. As Belgium’s foremost electron microscopy group, among the largest in the world, EMAT is continuously contributing to the development of TEM techniques, such as high-resolution imaging, diffraction, electron tomography, and spectroscopies, with an emphasis on quantification and reproducibility, as well as employing TEM methodology at the highest level to solve real-world materials science problems. The lab’s recent contributions are presented here together with specific case studies in order to highlight the usefulness of TEM to the advancement of materials science.

A novel mosaic-like structure in SrTiO3 thin films on a Pt(001) surface revealed by transmission electron microscopy

1996 ◽  
Vol 11 (11) ◽  
pp. 2777-2784 ◽  
Author(s):  
S. Takeno ◽  
S. Nakamura ◽  
K. Abe ◽  
S. Komatsu
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
High Resolution Imaging ◽  
Antiphase Boundaries ◽  
Growth Modes ◽  
Transmission Electron ◽  
Interfacial Structures ◽  
Resolution Imaging ◽  
Means Of Transmission

A novel mosaic-like structure in SrTiO3 thin films was discovered and characterized by means of transmission electron microscopy (TEM). The films were deposited on a (001) oriented Pt surface. The orientation relationship between SrTiO3 film and Pt substrate was determined, and four types of growth modes were revealed. These four growth modes formed four types of domains, respectively, and these domains and Pt formed peculiarly ordered interfacial structures, i.e., near coincidence site lattices. Antiphase boundaries between two adjacent domains were also observed by high-resolution imaging.

Atomic Structure of Interfaces in Epitaxial NiSi2 on (001) Silicon

1992 ◽  
Vol 263 ◽  
Author(s):  
W.J. Chen ◽  
F.R. Chen ◽  
L.J. Chen
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Atomic Structure ◽  
Imaging Technique ◽  
Interface Structure ◽  
High Resolution Imaging ◽  
Image Simulation ◽  
Transmission Electron ◽  
Resolution Imaging ◽  
Boundary Core

ABSTRACTHigh resolution transmission electron microscopy (HRTEM) has been applied to study the atomic structure of NiSi2 /(001)Si interface. Previous HRTEM result suggested that Ni atoms in the boundary core are six-fold coordinated and Si atoms are everywhere tetrahedrally coordinated. In this work, high resolution imaging technique and computer image simulation were used to study the atomic structure of NiSi2 /(001)Si interfaces and a new interface structure was found. For the new interface structure, Ni and Si atoms are also six-fold and tetrahedrally coordinated, respectively, with an extra layer of fourfold planar bonded Si atoms present at the interface.

SiAlON Microstructures

2008 ◽  
Vol 403 ◽  
pp. 265-268
Author(s):  
L.K.L. Falk
Keyword(s):  
Grain Shape ◽  
Ceramic Materials ◽  
Liquid Phase Sintering ◽  
High Resolution Imaging ◽  
Size Distributions ◽  
Fine Scale ◽  
Quantitative Microscopy ◽  
Transmission Electron ◽  
Resolution Imaging ◽  
Shape And Size

This paper is focussed on the development of microstructure during liquid phase sintering and post-densification crystallisation heat treatment of ceramic materials based on the α- and β-Si3N4 structures. Grain shape and size distributions, assessed by quantitative microscopy in combination with stereological methods, and fine scale microstructures, investigated by electron diffraction and high resolution imaging and microanalysis in the transmission electron microscope, are discussed in relation to the fabrication process and the overall composition of the ceramic material.

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