In Situ Tem Analysis of TiSi2 C49-C54 Transformations During Annealing

1996 ◽  
Vol 441 ◽  
Author(s):  
L. M. Gignac ◽  
V. Svilan ◽  
L. A. Clevenger ◽  
C. Cabral ◽  
C. Lavoie
Keyword(s):  
Nucleation Density ◽  
In Situ Tem ◽  
Video Tape ◽  
X Ray Diffraction ◽  
Tem Analysis ◽  
Transmission Electron ◽  
Varying Length ◽  
Transformation Front ◽  
Individual Line

AbstractIn situ transmission electron microscope (TEM) observations of TiSi2 C49-to-C54 phase transformations were recorded on video tape and photographic negatives, and transformation front velocities (vTF) were measured from the data. The samples studied in this work include: C49-TiSi2 blanket films and 0.2 μm wide, 7 mm long lines on undoped poly-Si and 0.13 μm wide, 10 μm long lines on either B- or As-doped poly-Si. The in situ TEM analysis showed that blanket TiSi2 films on undoped poly-Si fully transformed at 830°C and had an average vTF of 0.5 ± 0.2 μm/s. The transformation occurred from a sparse nucleation density of ˜0.1 site/μm2. The 0.2 μm wide lines transformed at temperatures greater than 885°C, and the average vTF was 1.1 ± 0.2 μm/sec. Agglomeration started for both the blanket film and the 0.2 μm wide lines at temperatures above 900°C. In situ x-ray diffraction (XRD) analyses of C49-TiSi2 on B- and As-doped poly-Si showed that blanket films completely transformed to C54-TiSi2 at T = 835–843°C, but 0.13 μm wide, varying length lines did not fully transform, even when rapid thermal annealed to 1025°C. From in situ TEM analysis of 0.13 μm wide, 10 μm long C49-TiSi2 lines on B-doped poly-Si, a distinct transformation was not observed. Instead, the lines slowly agglomerated, and electron diffraction of the agglomerated regions showed that the film had transformed to C54-TiSi2. An individual line either 1) completely transformed and agglomerated or 2) remained as C49-TiSi2 and did not agglomerate. Approximately 85% of all lines transformed. In situ TEM analysis of 0.13 μm wide, 10 μm long lines of C49-TiSi2 on As-doped poly-Si also showed an indistinct transformation to the C54 phase along with agglomeration, and 100% of the lines transformed.

scholarly journals Fracture in Bulk Amorphous Alloys

1998 ◽  
Vol 554 ◽  
Author(s):  
J. A. Horton ◽  
J. L. Wright ◽  
J. H. Schneibel
Keyword(s):  
Crack Propagation ◽  
Crack Growth ◽  
Shear Bands ◽  
Bulk Amorphous Alloy ◽  
In Situ Tem ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Crack Tips ◽  
Temperature Fracture

AbstractThe fracture behavior of a Zr-based bulk amorphous alloy, Zr-10 Al-5 Ti-17.9 Cu-14.6Ni (at.%), was examined by transmission electron microscopy (TEM) and x-ray diffraction forany evidence of crystallization preceding crack propagation. No evidence for crystallizationwas found in shear bands in compression specimens or at the fracture surface in tensile specimens.In- situ TEM deformation experiments were performed to more closely examine actualcrack tip regions. During the in-situ deformation experiment, controlled crack growth occurredto the point where the specimen was approximately 20 μm thick at which point uncontrolledcrack growth occurred. No evidence of any crystallization was found at the crack tips or thecrack flanks. Subsequent scanning microscope examination showed that the uncontrolledcrack growth region exhibited ridges and veins that appeared to have resulted from melting. Performing the deformations, both bulk and in-situ TEM, at liquid nitrogen temperatures (LN2) resulted in an increase in the amount of controlled crack growth. The surface roughness of the bulk regions fractured at LN2 temperatures corresponded with the roughness of the crack propagation observed during the in-situ TEM experiment, suggesting that the smooth-appearing room temperature fracture surfaces may also be a result of localized melting.

A Facile Synthesis of Poly(3-octylthiophene)-Titanium Dioxide Nanocomposite Particles in Supercritical CO2

2008 ◽  
Vol 8 (9) ◽  
pp. 4743-4746 ◽  
Author(s):  
Haldorai Yuvaraj ◽  
Min Hee Woo ◽  
Eun Ju Park ◽  
Yeong-Soon Gal ◽  
Kwon Taek Lim
Keyword(s):  
Titanium Dioxide ◽  
Oxidative Polymerization ◽  
X Ray Diffraction ◽  
Photoluminescence Quenching ◽  
Tem Analysis ◽  
Ir Studies ◽  
Transmission Electron ◽  
Ft Ir ◽  
Synthesized Materials

Poly(3-octylthiophene) (P3OT)-titanium dioxide (TiO2) nanocomposite powder where TiO2 was embedded with homogeneous dispersion was synthesized by in-situ chemical oxidative polymerization of 3-octylthiophene in the presence of TiO2 nanoparticles in supercritical carbon dioxide (scCO2), using ferric chloride as the oxidant. The synthesized materials could be obtained as dry powder upon venting of CO2 after the polymerization. The composites were subsequently characterized by FT-IR spectroscopy, transmission electron microscopy (TEM), X-ray diffraction studies (XRD), thermogravimetric analysis (TGA) and photoluminescence (PL). The incorporation of TiO2 in the composite was endorsed by FT-IR studies. TGA revealed enhanced thermal stability of P3OT/TiO2 nanocomposite compared to 3-octylthiophene. TEM analysis showed that well dispersed TiO2 nanoparticles in the polymer matrix. Photoluminescence quenching increased with increasing TiO2 concentration in the composite.

In situ tEM observation of C49 to C54 TiSi2 transformation

1992 ◽  
Vol 50 (2) ◽  
pp. 1356-1357
Author(s):  
K. Barmak ◽  
L.E. Levine ◽  
D.A. Smith ◽  
Y. Komemt
Keyword(s):  
High Resistivity ◽  
In Situ Tem ◽  
Video Tape ◽  
Furnace Annealing ◽  
Plan View ◽  
Transmission Electron ◽  
In Situ Heating ◽  
Face Centered ◽  
Si Wafer

The reaction of thin films of Ti with Si results in the formation of the high resistivity (≃150 μΩcm) base-centered orthorhombic C49 phase prior to the low resistivity (≃15-20 μΩcm) face-centered orthorhombic C54 phase. In our experiments, 30 nm of Ti was evaporated onto a < 100 > oriented Si wafer cleaned in a 10:1 H2O:HF solution. The wafer had been previously implanted with As to a dose of 5×l015 cm−2. Mixed C49/C54 phase films were obtained by furnace annealing at 700°C for 10 min. Plan view transmission electron microscopy (TEM) specimens were prepared by dimpling and etching in a 10:6:6 HNO3:HF:CH3COOH solution. The sample was initially studied in a JEOL 4000FX and in situ heating experiments were carried out in a Philips 430 operating at 300 kV. The progress of the transformation was recorded on video tape. The temperature was raised relatively quickly to 700°C and then more slowly to 750°C.

In situ TEM studies of deformation and fracture

1989 ◽  
Vol 47 ◽  
pp. 622-623
Author(s):  
I.M. Robertson ◽  
T.C. Lee ◽  
D.K. Dewald ◽  
H.K. Birnbaum
Keyword(s):  
Grain Boundary ◽  
Video Camera ◽  
In Situ Tem ◽  
Video Tape ◽  
Slip Systems ◽  
Camera System ◽  
Dynamic Events ◽  
Transmission Electron ◽  
Deformation And Fracture

The in-situ TEM straining technique has been used to investigate the micromechanisms of deformation and fracture in several ductile and semi-brittle systems. Attention has been focussed on the dislocation structures ahead of advancing cracks and on the interaction between lattice dislocations and grain boundaries.The deformation experiments were performed in-situ in a transmission electron microscope equipped with a video camera system. The dynamic events were recorded on video tape with a time resolution of l/30th of a second. Static interactions were recorded using the regular microscope plate system. The straining stage deforms the samples in Mode I and can operate at a displacement rate of 4 in sec-1.An example of one of the possible interactions between lattice dislocations and a ∑- 3 ([ll)/60°) grain boundary in 310 stainless steel is shown in the micrograph in Figure 1. The dislocations on slip systems A (a/2[110)1 (ll) 1 ) and B (a/2[101] (11) 1 ) impinge on the grain boundary, generating slip systems C (a/2[l0) 2/(111) 2) and D (a/2[l0) 2/(111) 2). To understand this effect three conditions were considered:

In-Situ TEM Observations of Different Growth Modes of Small Iron Particles on Sapphire

1980 ◽  
Vol 38 ◽  
pp. 402-403
Author(s):  
R. Anton ◽  
K. Heinemann
Keyword(s):  
Electron Beam ◽  
Width Ratio ◽  
In Situ Tem ◽  
Video Tape ◽  
Growth Modes ◽  
Transmission Electron ◽  
Special Direction ◽  
Substrate Temperatures ◽  
Kinetics Of

An in-situ study was performed of the growth kinetics of individual crystallites during the deposition of iron onto electron-transparent singlecrystalline α-Al2O3 (sapphire) substrates. Clean sapphire films were produced in-situ under UHV conditions by electron-beam induced crystallization of amorphous Al2O3 (1). Iron was electron-beam vapor-deposited at constant rates (0.2-0.5 nm/min) and elevated substrate temperatures (750 – 900°C) immediately following the crystallization. The nucleation, growth, and eventual coalescence of the metal particles were observed in-situ by transmission electron microscopy and recorded on video tape at 30 frames per second. In fig. 1, a growth and coalescence sequence of several Fe-particles on [100]-α-Al2O3 is shown. The images were selected and photographed from the TV monitor during video playback. The particles marked with letters were analyzed in detail. Noteworthy is that particle A (after about 30 min. of growth) started a rapid increase of its length-to-width ratio. Particle H, formed in a coalescence event, exhibited a preferred growth in a special direction, presumably in order to develop a certain crystallographic habit. Particle K developed a fast lateral growth ab-initio and remained a thin platelet until it coalesced with a neighboring particle about 25 min. after the beginning of the deposition.

Formation of Pb Inclusions in Si by Ion Implantation

1997 ◽  
Vol 504 ◽  
Author(s):  
V. S. Touboltsev ◽  
E. Johnson ◽  
U. Dahmen ◽  
A. Johansen ◽  
L. Sarholt ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Average Concentration ◽  
Supersaturated Solution ◽  
In Situ Tem ◽  
Tem Analysis ◽  
Host Matrix ◽  
Transmission Electron ◽  
Main Fraction ◽  
20 Nm

AbstracrSi<110> single crystals were implanted at a temperature of 835 K with 150 keV Pb+ ions to a fluence of 1·1020 m−2 corresponding to an average concentration of 2–3 at%. The implanted samples have been studied by Rutherford Backscattering (RBS)/channeling and transmission electron microscopy (TEM) techniques. In as-implanted samples the main fraction of implanted Pb was located on substitutional sites in the Si matrix thus providing a highly supersaturated solution of Pb in Si. Spontaneous precipitation of Pb, giving rise to formation of nanosized Pb inclusions, was found to take place only in the peak region of the implantation. TEM analysis showed that the Pb precipitates had sizes from about 2 to 20 nm and that they grew in parallel cube orientation relationship with the host matrix. The shape of the inclusions was found to be approximately cuboctahedral with poorly developed {111} and {100} facets.In-situ RBS/channeling heating/cooling experiments on both as-implanted samples and samples previously furnace-annealed at 1175 K showed a distinct melting/solidification hysteresis of the Pb inclusions around the bulk melting point for Pb at 600 K. These results were verified by in-situ TEM heating/cooling experiments on as-implanted samples.

Preparation of TiB2/TiN Nanocomposites by SP

2013 ◽  
Vol 745-746 ◽  
pp. 551-554 ◽  
Author(s):  
Ming Hui Wang ◽  
Hua Jian Li ◽  
Wan Jiang
Keyword(s):  
X Ray Diffraction ◽  
Tem Analysis ◽  
X Ray ◽  
Plasma Sintering ◽  
Transmission Electron ◽  
Average Grain Size ◽  
High Resolution Tem ◽  
Spark Plasma ◽  
Xrd Techniques

TiB2/TiN nanocomposites were in-situ fabricated by spark plasma sintering (SPS) technique using Ti and BN powders as starting materials. The phase constituents and microstructures of the samples were analyzed by X-ray diffraction (XRD) techniques, scanning electron microscopy (SEM) and transmission electron microscope (TEM), respectively. The results showed that the average grain size of TiB2 and TiN was 1m and 300nm respectively. Furthermore, high resolution TEM analysis indicated that the as-prepared TiB2/TiN nanocomposites had very clean grain boundaries, and no amorphous phase or oxide layer was observed.

In Situ Tem Study of Amorphous to Crystalline Transformation in R-Fe-B Ribbons

1991 ◽  
Vol 232 ◽  
Author(s):  
Y. J. Zhang ◽  
Y. Z. Wang ◽  
G. C. Hadjipanayis
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Building Blocks ◽  
In Situ Tem ◽  
Local Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Unit Structure ◽  
Transmission Electron

ABSTRACTThe amorphous-crystalline transformation in R-Fe-B ribbons was studied in situ in a transmission electron microscope (TEM) and with X-ray diffraction. Metastable phases of α-Fe(R) and Fe3B were found to form during crystallization before the final R2Fe14B phase is formed. The Fe3B phase is believed to be important for the formation of the 2:14:1 phase because its “local unit structure” is one of the basic building blocks in the 2:14:1 unit cell.

scholarly journals Direct observation of dislocation plasticity in high-Mn lightweight steel by in-situ TEM

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Sung-Dae Kim ◽  
Jun Young Park ◽  
Seong-Jun Park ◽  
Jae hoon Jang ◽  
Joonoh Moon ◽  
...  
Keyword(s):  
Slip Band ◽  
In Situ Tem ◽  
Tem Analysis ◽  
Premature Failure ◽  
Slip Bands ◽  
Dislocation Plasticity ◽  
Transmission Electron ◽  
Enhanced Strain ◽  
Planar Dislocation

Abstract To gain the fundamental understanding of deformation mechanisms in an aluminum-containing austenitic high-Mn steel (Fe-32Mn-8.9Al-0.78 C (wt.%)), in-situ straining transmission electron microscopy (TEM) analysis is conducted. The in-situ observation during the deformation demonstrates that the plastic deformation is accommodated by the pronounced planar dislocation gliding followed by the formation of slip bands (SBs) and highly dense dislocation walls (HDDWs). Experimental evidences of the glide plane softening can be obtained from the interaction between the gliding perfect dislocations and the L’12 ordered precipitates in the austenite matrix. Furthermore, the observation of the localized cross-slip of dislocations at the slip band intersections enables to understand why slip bands are extensively developed without mutual obstructions between the slip bands. The enhanced strain hardening rate of the aluminum-containing austenitic high-Mn steels can be attributed to the pronounced planar dislocation glides followed by formation of extensive slip band which prevent premature failure by suppressing strain localization.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

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