A TEM Study of Dynamic Continuous Recrystallization in a Superplastic AL-4MG-0.3SC Alloy

1999 ◽  
Vol 601 ◽  
Author(s):  
L.M. Dougherty ◽  
I.M. Robertson ◽  
J.S. Vetrano
Keyword(s):  
True Strain ◽  
Orientation Imaging Microscopy ◽  
Superplastic Forming ◽  
Orientation Imaging ◽  
Transmission Electron ◽  
In Situ Experiments ◽  
Continuous Recrystallization ◽  
Cold Rolled ◽  
Nominal Temperature

AbstractAn Al-4Mg-0.3Sc alloy, aged at 280°C for 8 hours and cold rolled to a 70% reduction, exhibited dynamic recrystallization during superplastic forming at 460°C and at a strain rate of 10−3sec−1. To understand the progression of recrystallization during forming, specimens were deformed under these same conditions to 0.1, 0.2, 0.4 and 0.8 true strain and studied postmortem using optical microscopy, transmission electron microscopy and orientation imaging microscopy. The microstructural evolution that occurred between each strain state was directly observed during deformation experiments at a nominal temperature of 460°C in the transmission electron microscope. These in-situ experiments showed the migration, coalescence, disintegration and annihilation of subboundaries. This combination of post-mortem analysis of specimens strained in bulk with real time observations made during these in-situ experiments allows the mechanisms operating during dynamic continuous recrystallization to be ascertained.

A computer-control program for TEM in situ fatigue experiments

1989 ◽  
Vol 47 ◽  
pp. 620-621
Author(s):  
Kenneth S. Vecchio ◽  
John A. Hunt
Keyword(s):  
Slow Crack Growth ◽  
Computer Control ◽  
Control Program ◽  
Video Tape ◽  
Computer Control System ◽  
Transmission Electron ◽  
In Situ Experiments ◽  
Tremendous Amount ◽  
And Control

In-situ experiments conducted within a transmission electron microscope provide the operator a unique opportunity to directly observe microstructural phenomena, such as phase transformations and dislocation-precipitate interactions, “as they happen”. However, in-situ experiments usually require a tremendous amount of experimental preparation beforehand, as well as, during the actual experiment. In most cases the researcher must operate and control several pieces of equipment simultaneously. For example, in in-situ deformation experiments, the researcher may have to not only operate the TEM, but also control the straining holder and possibly some recording system such as a video tape machine. When it comes to in-situ fatigue deformation, the experiments became even more complicated with having to control numerous loading cycles while following the slow crack growth. In this paper we will describe a new method for conducting in-situ fatigue experiments using a camputer-controlled tensile straining holder.The tensile straining holder used with computer-control system was manufactured by Philips for the Philips 300 series microscopes. It was necessary to modify the specimen stage area of this holder to work in the Philips 400 series microscopes because the distance between the optic axis and holder airlock is different than in the Philips 300 series microscopes. However, the program and interfacing can easily be modified to work with any goniometer type straining holder which uses a penrmanent magnet motor.

scholarly journals Randomly oriented twin domains in electrodeposited silver dendrites

2015 ◽  
Vol 80 (1) ◽  
pp. 107-113 ◽  
Author(s):  
Evica Ivanovic ◽  
Nebojsa Nikolic ◽  
Velimir Radmilovic
Keyword(s):  
Electron Microscopy ◽  
Orientation Imaging Microscopy ◽  
Dark Field ◽  
High Angle ◽  
Orientation Imaging ◽  
Transmission Electron ◽  
Annular Dark Field ◽  
Silver Dendrites ◽  
Z Contrast ◽  
Scanning Electron

Silver dendrites were prepared by electrochemical deposition. The structures of Ag dendrites, the type of twins and their distribution were investigated by scanning electron microscopy (SEM), Z-contrast high angle annular dark field transmission electron microscopy (HAADF), and crystallografically sensitive orientation imaging microscopy (OIM). The results revealed that silver dendrites are characterized by the presence of randomly distributed 180? rotational twin domains. The broad surface of dendrites was of the {111} type. Growth directions of the main dendrite stem and all branches were of <112> type.

In-Situ Annealing of Metal Thin Films on Silicon

1981 ◽  
Vol 39 ◽  
pp. 164-165
Author(s):  
L. J. Chen ◽  
J. W. Mayer
Keyword(s):  
Thin Films ◽  
Device Fabrication ◽  
Electron Gun ◽  
Specimen Thickness ◽  
Metal Thin Films ◽  
Thin Foils ◽  
Transmission Electron ◽  
In Situ Experiments ◽  
Annealing Study

In-situ dynamical experiments in the transmission electron microscope (TEM) have long interested electron microscopists. In designing and performing the experiments, it is important to minimize the influences of the factors, which include the specimen thickness, electron beam heating, electron irradiation and specimen environments that may affect the validity of in-situ experiments. Comparisons of the results with those of other experiments are also very desirable.In microelectronic device fabrication process, it has become increasingly common to react a few hundred Å in thickness metal films with silicon substrate to form silicide contacts. Ni thin films on silicon have been chosen for in-situ annealing study since this system has been extensively investigated by Rutherford backscattering and glancing angle x-ray experiments. In-situ annealing of Co, Mo, Ti, Pd and W thin films on silicon have also been performed.Ni films, 300 and 400 Å thick, were electron gun deposited on (001) n-type silicon. Thin foils for TEM examination were chemically polished from silicon side. A JEOL 100B microscope equipped with a side entry, single tilt hot stage was used for TEM study.

Observation of grain superstructure in thin aluminum films by orientation imaging microscopy

1995 ◽  
Vol 53 ◽  
pp. 436-437
Author(s):  
Roger Alvis ◽  
David Dingley ◽  
David Field
Keyword(s):  
Aluminum Alloy ◽  
Orientation Imaging Microscopy ◽  
Test Structure ◽  
Al Alloy ◽  
X Ray Diffraction ◽  
Aluminum Films ◽  
Orientation Imaging ◽  
Reliability Parameters ◽  
Transmission Electron ◽  
Thin Aluminum

The correlation of aluminum alloy reliability data to microstructure has long been the goal of those scientists seeking to model electromigration behavior of interconnects. Traditionally, microstructural information has been acquired through x-ray diffraction , and transmission electron microscopy (TEM). However, each of these techniques is capable of delivering only part of the characterization whole. We describe the application of orientation imaging microscopy (OIM) to thin aluminum alloy films and demonstrate its versatility in providing the key microstructural reliability parameters: namely texture and grain size, as well as providing insight to the microstructure of grain boundaries.OIM was performed on an electromigration test structure (figure 1). The Al-alloy was deposited on titanium and capped with an anti-reflective titanium nitride. Subsequently, the test structure was patterned and capped with a multilayer blanket consisting of silicon nitride (SiN), and SiO2. The structure was annealed after the SOG deposition at 450° C for 90 minutes, seeing no electrical stressing. The die was removed from the package and deprocessed before the OIM was acquired.

Microstructural Coarsening during Annealing of Cold Rolled Aluminum

2004 ◽  
Vol 467-470 ◽  
pp. 209-216 ◽  
Author(s):  
Q. Xing ◽  
X. Huang ◽  
Niels Hansen
Keyword(s):  
Lamellar Structure ◽  
True Strain ◽  
Rolling Texture ◽  
Recrystallization Temperature ◽  
Commercial Purity ◽  
Microstructural Coarsening ◽  
Transmission Electron ◽  
Rolled Aluminum ◽  
Cold Rolled ◽  
Commercial Purity Aluminum

The microstructural evolution during annealing below the recrystallization temperature of a commercial purity aluminum (99wt.% purity) cold rolled to a true strain of 2 has been investigated by transmission electron microscopy concentrating on microstructural and orientational aspects. The deformation microstructure was a typical lamellar structure with extended lamellar boundaries, GNBs (geometrical necessary boundaries), and short interconnecting boundaries, IDBs (incidental dislocation boundaries). The microstructure was divided into regions representing typical rolling texture orientations and regions of other orientations. During annealing the structure coarsened towards an equiaxed structure and it was observed that this coarsening was significantly slower in regions of rolling texture orientations than in regions of other orientations. This difference was discussed based on the characteristics of the deformation structure.

scholarly journals Microstructure characterization of a duplex stainless steel weld by electron backscattering diffraction and orientation imaging microscopy techniques

2015 ◽  
Vol 20 (1) ◽  
pp. 212-226 ◽  
Author(s):  
Isabela Viegas Aguiar ◽  
Diana Pérez Escobar ◽  
Dagoberto Brandão Santos ◽  
Paulo J. Modenesi
Keyword(s):  
Electron Microscopy ◽  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Electron Backscatter Diffraction ◽  
Orientation Imaging Microscopy ◽  
Orientation Distribution ◽  
Orientation Imaging ◽  
Transmission Electron ◽  
Ebsd Technique ◽  
Microscopy Techniques

This paper describes the electron backscatter diffraction (EBSD) technique used to characterize the microstructure (especially the morphology and constitution) of the base metal (BM), the heat-affected zone (HAZ) and the fusion zone (FZ) on a lean duplex stainless steel (LDX). This technique provides advantages due to its simplicity of use and greater depth of information, thereby increasing the amount of information obtained by traditional characterization techniques such as optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The use of EBSD together with orientation imaging microscopy (OIM) as a tool to understand phase transformation paths and ferrite-austenite variant selection was discussed. Vickers microhardness measurements were performed and no significance difference between the different zones was found. Orientation distribution function (ODF) results show that there are no significant changes on the crystallographic texture of the samples after welding. The advantages of using SEM together with EBSD for microstructure analyzing and texture development were also discussed.

Crystallographic Mapping in Scanning and Transmission Electron Micrsocopy with Application to Semiconductor Materials

1998 ◽  
Vol 523 ◽  
Author(s):  
D. J. Dingley ◽  
S. I. Wright ◽  
D. J. Dingley
Keyword(s):  
Electron Microscope ◽  
Electron Backscatter Diffraction ◽  
Orientation Imaging Microscopy ◽  
Lattice Parameter ◽  
Dark Field ◽  
Polycrystalline Materials ◽  
Orientation Imaging ◽  
Transmission Electron ◽  
Dark Field Microscopy ◽  
Backscatter Diffraction

AbstractThe two sister techniques, Electron Backscatter Diffraction and Orientation Imaging Microscopy which operate in a scanning electron microscope, are well established tools for the characterization of polycrystalline materials. Experiment has shown that the limiting resolution for mapping is the order of 0.1 microns. The basic techniques have been extended to include multiphase mapping. Whereas it has been possible to distinguish between phases of different crystal systems easily, it has not been possible to distinguish between phases that differ in lattice parameter by less than 5 %.An equivalent transmission electron microscope procedure has been developed. The technique couples standard hollow cone microscopy procedures with dark field microscopy. All possible dark field images that can be produced by tilting the electron beam are scanned to detect under what settings each crystal is brought into a diffracting condition. Subsequent analysis permits determination of both crystal phase and orientation.

Orientation Mapping Study on the Inhomogeneous Microstructure Evolution during Annealing of 6013 Aluminum Alloy

2010 ◽  
Vol 163 ◽  
pp. 13-18 ◽  
Author(s):  
M. Bieda-Niemiec ◽  
Krzystof Sztwiertnia ◽  
A. Korneva ◽  
Tomasz Czeppe ◽  
R. Orlicki
Keyword(s):  
Aluminum Alloy ◽  
Particle Distribution ◽  
Phase Particle ◽  
Second Phase ◽  
Transmission Electron ◽  
Orientation Mapping ◽  
Initial Stage ◽  
Second Phase Particles ◽  
Cold Rolled

Orientation mapping in transmission electron microscope was successfully applied to study microstructural changes at the initial stage of recrystallization in the aluminum alloy with a bimodal second-phase particle distribution. The alloy samples were reversibly cold rolled resulting in the formation of laminar structure with zones of localized strain around large second-phase particles. Orientation mapping and in-situ investigations carry information about the processes which are active in the deformation zones during annealing.

Possibility of an integrated transmission electron microscope: enabling complex in-situ experiments

2021 ◽  
Vol 56 (9) ◽  
pp. 5309-5320
Author(s):  
Khalid Hattar ◽  
Katherine L. Jungjohann
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Extreme Environments ◽  
Structure Property ◽  
Multispectral Data ◽  
Transmission Electron ◽  
Holistic Understanding ◽  
In Situ Experiments ◽  
Scanning Transmission

Abstract Multimodal in-situ experiments are the wave of the future, as this approach will permit multispectral data collection and analysis during real-time nanoscale observation. In contrast, the evolution of technique development in the electron microscopy field has generally trended toward specialization and subsequent bifurcation into more and more niche instruments, creating a challenge for reintegration and backward compatibility for in-situ experiments on state-of-the-art microscopes. We do not believe this to be a requirement in the field; therefore, we propose an adaptive instrument that is designed to allow nearly simultaneous collection of data from aberration-corrected transmission electron microscopy (TEM), probe-corrected scanning transmission electron microscopy, ultrafast TEM, and dynamic TEM with a flexible in-situ testing chamber, where the entire instrument can be modified as future technologies are developed. The value would be to obtain a holistic understanding of the underlying physics and chemistry of the process-structure–property relationships in materials exposed to controlled extreme environments. Such a tool would permit the ability to explore, in-situ, the active reaction mechanisms in a controlled manner emulating those of real-world applications with nanometer and nanosecond resolution. If such a powerful tool is developed, it has the potential to revolutionize our materials understanding of nanoscale mechanisms and transients. Graphical Abstract

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