scholarly journals In situ TEM observations of interface sliding and migration in a refined lamellar TiAl alloy

2004 ◽  
Vol 12 (7-9) ◽  
pp. 727-732 ◽  
Author(s):  
L.M. Hsiung ◽  
A.J. Schwartz ◽  
T.G. Nieh
Keyword(s):  
Tial Alloy ◽  
In Situ Tem ◽  
And Migration ◽  
Interface Sliding

scholarly journals In-Situ Tem Study of Interface Sliding and Migration in an Ultrafine Lamellar Structure

2005 ◽  
Vol 880 ◽  
Author(s):  
Luke L.M. Hsiung ◽  
T.G. Nieh
Keyword(s):  
Lamellar Structure ◽  
In Situ Tem ◽  
Tial Alloys ◽  
Cooperative Movement ◽  
Transmission Electron ◽  
Interfacial Dislocations ◽  
And Migration ◽  
The Stability ◽  
Interface Sliding

AbstractThe stability of interfaces in an ultrafine TiAl-(y)/Ti3Al-(α2) lamellar structure by straining at room temperature has been investigated using in-situ straining techniques performed in a transmission electron microscope. The purpose of this study is to obtain experimental evidence to support the previously proposed creep mechanisms in ultrafine lamellar TiAl alloys based upon the interface sliding in association with a cooperative movement of interfacial dislocations. The results have revealed that both the sliding and migration of lamellar interfaces can take place simultaneously as a result of the cooperative motion of interfacial dislocations.

In situ transmission electron microscope study of interface sliding and migration in an ultrafine lamellar structure

2006 ◽  
Vol 21 (10) ◽  
pp. 2453-2459 ◽  
Author(s):  
L.M. Hsiung ◽  
J. Zhou ◽  
T.G. Nieh
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Lamellar Structure ◽  
Cooperative Movement ◽  
Transmission Electron ◽  
Transmission Electron Microscope Study ◽  
Interfacial Dislocations ◽  
And Migration ◽  
Interface Sliding

The instability of interfaces in an ultrafine TiAl-(γ)/Ti3Al-(α2) lamellar structure by straining at room temperature has been investigated using in situ straining techniques performed in a transmission electron microscope. The purpose of this study was to obtain experimental evidence to support the creep mechanisms based upon the interface sliding in association with a cooperative movement of interfacial dislocations, which was proposed previously to rationalize a nearly linear creep behavior of ultrafine lamellar TiAl alloys. The results reveal that the sliding and migration of lamellar interfaces can take place simultaneously as a result of the cooperative movement of interfacial dislocations, which can lead to an adverse effect in the performance of ultrafine lamellar TiAl alloy.

scholarly journals In situ TEM observation of void formation and migration in phase change memory devices with confined nanoscale Ge2Sb2Te5

2020 ◽  
Vol 2 (9) ◽  
pp. 3841-3848
Author(s):  
Sang Ho Oh ◽  
Kyungjoon Baek ◽  
Sung Kyu Son ◽  
Kyung Song ◽  
Jang Won Oh ◽  
...  
Keyword(s):  
Phase Change ◽  
Phase Change Memory ◽  
Void Formation ◽  
In Situ Tem ◽  
Memory Devices ◽  
Device Failure ◽  
And Migration ◽  
Change Memory

Void formation and migration that drive the device failure of Ge2Sb2Te5 (GST)-based practical devices were revealed via in situ TEM.

scholarly journals Interfacial Control of Creep Deformation in Ultrafine Lamellar TiAl

2002 ◽  
Vol 740 ◽  
Author(s):  
L. M. Hsiung
Keyword(s):  
Creep Resistance ◽  
Solute Segregation ◽  
In Situ Tem ◽  
Two Phase ◽  
Deformation Substructure ◽  
Linear Creep ◽  
Interfacial Dislocations ◽  
Interface Sliding ◽  
Creep Regime

ABSTRACTSolute effect on the creep resistance of two-phase lamellar TiAl with an ultrafine microstructure creep-deformed in a low-stress (LS) creep regime [where a nearly linear creep behavior was observed] has been investigated. The resulted deformation substructure and in-situ TEM experiment reveals that interface sliding by the motion of pre-existing interfacial dislocations is the predominant deformation mechanism in LS creep regime. Solute segregation at interfaces and interfacial precipitation caused by the segregation result in an increase of creep resistance in LS creep regime.

Tracking sodium migration in TiS2 using in situ TEM

Nanoscale ◽  
2019 ◽  
Vol 11 (15) ◽  
pp. 7474-7480 ◽  
Author(s):  
Bo Han ◽  
Shulin Chen ◽  
Jian Zou ◽  
Ruiwen Shao ◽  
Zhipeng Dou ◽  
...  
Keyword(s):  
Structural Evolution ◽  
In Situ Tem ◽  
Migration Dynamics ◽  
And Migration

Using in situ TEM, the structural evolution and migration dynamics are revealed during sodium migration in TiS2.

In situ TEM studies of irradiation effects for materials improvement

1991 ◽  
Vol 49 ◽  
pp. 452-453
Author(s):  
Charles W. Allen
Keyword(s):  
Nuclear Reactor ◽  
Austenitic Stainless Steels ◽  
High Energy ◽  
Point Of View ◽  
In Situ Tem ◽  
Irradiation Effects ◽  
Tem Analysis ◽  
Radiation Induced ◽  
Analytical Tools

Irradiation effects studies employing TEMs as analytical tools have been conducted for almost as many years as materials people have done TEM, motivated largely by materials needs for nuclear reactor development. Such studies have focussed on the behavior both of nuclear fuels and of materials for other reactor components which are subjected to radiation-induced degradation. Especially in the 1950s and 60s, post-irradiation TEM analysis may have been coupled to in situ (in reactor or in pile) experiments (e.g., irradiation-induced creep experiments of austenitic stainless steels). Although necessary from a technological point of view, such experiments are difficult to instrument (measure strain dynamically, e.g.) and control (temperature, e.g.) and require months or even years to perform in a nuclear reactor or in a spallation neutron source. Consequently, methods were sought for simulation of neutroninduced radiation damage of materials, the simulations employing other forms of radiation; in the case of metals and alloys, high energy electrons and high energy ions.

In situ TEM measurements of the electrical properties of interface dislocations

1992 ◽  
Vol 50 (2) ◽  
pp. 1338-1339
Author(s):  
F. M. Ross ◽  
R. Hull ◽  
D. Bahnck ◽  
J. C. Bean ◽  
L. J. Peticolas ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Electronic Device ◽  
In Situ Tem ◽  
Device Performance ◽  
Misfit Dislocations ◽  
Electrical Characteristics ◽  
Strained Layer ◽  
Transmission Electron ◽  
Interfacial Dislocations

We describe an investigation of the electrical properties of interfacial dislocations in strained layer heterostructures. We have been measuring both the structural and electrical characteristics of strained layer p-n junction diodes simultaneously in a transmission electron microscope, enabling us to correlate changes in the electrical characteristics of a device with the formation of dislocations.The presence of dislocations within an electronic device is known to degrade the device performance. This degradation is of increasing significance in the design and processing of novel strained layer devices which may require layer thicknesses above the critical thickness (hc), where it is energetically favourable for the layers to relax by the formation of misfit dislocations at the strained interfaces. In order to quantify how device performance is affected when relaxation occurs we have therefore been investigating the electrical properties of dislocations at the p-n junction in Si/GeSi diodes.

In situ TEM Studies of agglomeration of sub-nanometer Ru layers in Ru/C multilayers

1992 ◽  
Vol 50 (1) ◽  
pp. 256-257
Author(s):  
Tai D. Nguyen ◽  
Ronald Gronsky ◽  
Jeffrey B. Kortright
Keyword(s):  
Layered Structure ◽  
Driving Force ◽  
High Energy ◽  
Superior Performance ◽  
In Situ Tem ◽  
Rayleigh Instability ◽  
Practical Applications ◽  
Transmission Electron ◽  
Diffraction Patterns

Nanometer period Ru/C multilayers are one of the prime candidates for normal incident reflecting mirrors at wavelengths < 10 nm. Superior performance, which requires uniform layers and smooth interfaces, and high stability of the layered structure under thermal loadings are some of the demands in practical applications. Previous studies however show that the Ru layers in the 2 nm period Ru/C multilayer agglomerate upon moderate annealing, and the layered structure is no longer retained. This agglomeration and crystallization of the Ru layers upon annealing to form almost spherical crystallites is a result of the reduction of surface or interfacial energy from die amorphous high energy non-equilibrium state of the as-prepared sample dirough diffusive arrangements of the atoms. Proposed models for mechanism of thin film agglomeration include one analogous to Rayleigh instability, and grain boundary grooving in polycrystalline films. These models however are not necessarily appropriate to explain for the agglomeration in the sub-nanometer amorphous Ru layers in Ru/C multilayers. The Ru-C phase diagram shows a wide miscible gap, which indicates the preference of phase separation between these two materials and provides an additional driving force for agglomeration. In this paper, we study the evolution of the microstructures and layered structure via in-situ Transmission Electron Microscopy (TEM), and attempt to determine the order of occurence of agglomeration and crystallization in the Ru layers by observing the diffraction patterns.

In situ TEM observations of melting in nanosized eutectic Pb-Cd inclusions embedded in Al

1996 ◽  
Vol 54 ◽  
pp. 986-987
Author(s):  
S. Hagège ◽  
U. Dahmen ◽  
E. Johnson ◽  
A. Johansen ◽  
V.S. Tuboltsev
Keyword(s):  
Electron Microscope ◽  
Melt Spinning ◽  
Ternary Alloys ◽  
Solid Matrix ◽  
Eutectic System ◽  
In Situ Tem ◽  
In Situ Observation ◽  
Orientation Relationships ◽  
Transmission Electron

Small particles of a low-melting phase embedded in a solid matrix with a higher melting point offer the possibility of studying the mechanisms of melting and solidification directly by in-situ observation in a transmission electron microscope. Previous studies of Pb, Cd and other low-melting inclusions embedded in an Al matrix have shown well-defined orientation relationships, strongly faceted shapes, and an unusual size-dependent superheating before melting.[e.g. 1,2].In the present study we have examined the shapes and thermal behavior of eutectic Pb-Cd inclusions in Al. Pb and Cd form a simple eutectic system with each other, but both elements are insoluble in solid Al. Ternary alloys of Al (Pb,Cd) were prepared from high purity elements by melt spinning or by sequential ion implantation of the two alloying additions to achieve a total alloying addition of up to lat%. TEM observations were made using a heating stage in a 200kV electron microscope equipped with a video system for recording dynamic behavior.

Postmortem and in situ TEM methods to study the mechanism of failure in controlled-morphology high-impact polystrene resin

1996 ◽  
Vol 54 ◽  
pp. 178-179
Author(s):  
R. C. Cieslinski ◽  
M. T. Dineen ◽  
J. L. Hahnfeld
Keyword(s):  
Poisson Ratio ◽  
Acrylonitrile Butadiene Styrene ◽  
High Impact ◽  
In Situ Tem ◽  
Styrene Copolymers ◽  
Controlled Morphology ◽  
Point Bend ◽  
Mechanism Of Failure ◽  
Impact Energies

Advanced Styrenic resins are being developed throughout the industry to bridge the properties gap between traditional HIPS (High Impact Polystyrene) and ABS (Acrylonitrile-Butadiene-Styrene copolymers) resins. These new resins have an unprecedented balance of high gloss and high impact energies. Dow Chemical's contribution to this area is based on a unique combination of rubber morphologies including labyrinth, onion skin, and core-shell rubber particles. This new resin, referred as a controlled morphology resin (CMR), was investigated to determine the toughening mechanism of this unique rubber morphology. This poster will summarize the initial studies of these resins using the double-notch four-point bend test of Su and Yee, tensile stage electron microscopy, and Poisson Ratio analysis of the fracture mechanism.

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