Fibre-Matrix Reaction Zones in Model Silicon Carbide-Titanium Aluminide Metal-Matrix Composites

1989 ◽  
Vol 170 ◽  
Author(s):  
D. R. Baker ◽  
P. J. Doorbar ◽  
M. H. Loretto
Keyword(s):  
Electron Microscopy ◽  
Titanium Aluminide ◽  
Chemical Information ◽  
Matrix Composites ◽  
Reaction Products ◽  
Transmission Electron ◽  
Complex Carbides ◽  
Reaction Zones ◽  
Electron Energy Loss ◽  
Fibre Matrix

AbstractThe reactions between coated SiC continuous fibres and TiAl, Ti3A1, or Ti3A1 + β matrices, have been investigated using optical metallography, scanning electron microscopy (SEM), and transmission electron microscopy (TEM), with chemical information obtained by energy dispersive x-ray analysis (EDX) and electron energy loss spectroscopy (EELS).Similar sequences of phases were found in all the composites; carbides based on TiC and TixAIC (x=2,3) and titanium silicides based on Ti5Si3 forming in narrow bands outside of the complex carbides. The occurrence of individual phases can be related to published phase diagram information. However, the sequences in which the reaction products occur within the reaction zones cannot be fully rationalised from the present results.

Characterization of Fiber/Matrix Interfaces by Transmission Electron Microscopy in Titanium Aluminide/Sic Composites

1992 ◽  
Vol 273 ◽  
Author(s):  
Cecil G. Rhodes
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Titanium Aluminide ◽  
Matrix Composition ◽  
Matrix Composites ◽  
Reaction Products ◽  
Alloy Matrix ◽  
Transmission Electron ◽  
Matrix Reinforcement ◽  
Sic Composites

ABSTRACTThis paper presents examples of the use of transmission electron microscopy to characterize matrix/reinforcement interaction in titanium aluminide matrix composites reinforced with continuous SCS-6 type SiC. As a result of the high temperature required for consolidating this type composite, reaction products form in the interface. Using diffraction and x-ray energy dispersive spectroscopy techniques, reaction products in Ti3Al and Ti2AINb alloy matrix composites have been identified. TiC1 –x and Ti5 Si3 compounds are common in these composites, with AlTi3C also present depending on consolidation temperature and matrix composition. Residual stress calculations indicate that these reaction products may be subject to cracking during cooling from consolidationtemperatures.

Applications of High Spatial Resolution Analytical Electron Microscopy to the Process Development of Silicon Devices

1997 ◽  
Vol 3 (S2) ◽  
pp. 471-472
Author(s):  
B. Ameirhekmat ◽  
L.Y. Tsung ◽  
H.L. Tsai ◽  
J.P. Lu
Keyword(s):  
Electron Microscopy ◽  
Thin Layer ◽  
Silicon Oxide ◽  
Process Development ◽  
Analytical Electron Microscopy ◽  
Chemical Information ◽  
Silicon Devices ◽  
Transmission Electron ◽  
Incomplete Removal ◽  
Electron Energy Loss

Analytical transmission electron microscopy (AEM) equipped with a field emission gun has made it possible to analyze chemical information at local spots or interfaces with a very small electron probe. This technique has been applied to assist in process development and addressing certain reliability issues in silicon devices.Figure 1 shows an example of applications of AEM to a 0.5 μm transistor. An oxide bump is found to be located in the middle of a transistor. A very thin layer (20 Å) is on the top of the oxide bump. Using EDS, the bump is determined to be a silicon oxide, but EDS failed to analyze the thin layer. Electron energy loss spectroscopy detects nitrogen in this residual layer (Fig. la), suggesting that the residue is a thin nitride. This residual nitride is caused by the incomplete removal of the nitride mask after field oxidation. This nitride residue blocks the subsequent removal of the buffer oxide between the nitride mask and the substrate.

scholarly journals Formation of Buried Oxide in Mev Oxygen Implanted Silicon

1987 ◽  
Vol 107 ◽  
Author(s):  
C.W. Nieh ◽  
F. Xiong ◽  
C. C. Ahn ◽  
Z. Zhou ◽  
D. N. Jamieson ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution Electron Microscopy ◽  
Chemical Information ◽  
Cross Sectional ◽  
Buried Oxide ◽  
Implantation Temperature ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Electron Energy Loss

AbstractWe have studied the formation of buried oxide in MeV oxygen implanted Si. A continuous oxide layer is formed in the samples implanted with 2x1018/cm2 oxygen and annealed at 1300° C. The microstructures are studied by cross-sectional transmission electron microscopy and high resolution electron microscopy. Chemical information was obtained by electron energy loss spectroscopy. The effects of implantation temperature are studied. Implantation at a low substrate temperature leads to a well-defined buried SiO2 layer, inhibits the formation of oxide precipitates in the silicon, and reduces silicon inclusions in the SiO2.

Interfacial Reactions in Metal-Matrix Composites

1995 ◽  
Vol 398 ◽  
Author(s):  
J. R. Heffelfinger ◽  
R. R. Kieschke ◽  
C. B. Carter
Keyword(s):  
Electron Microscopy ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Ti Alloy ◽  
Matrix Composites ◽  
Reaction Products ◽  
Alloy Matrix ◽  
Β Phase ◽  
Transmission Electron ◽  
The Matrix

ABSTRACTThe interfacial reaction between Al2O3 (alumina) and a β-Ti alloy has been characterized by transmission electron microscopy, scanning electron microscopy, and X-ray energy-dispersive spectroscopy. Diffusion bonding single-crystal alumina and a β-Ti alloy was found to produce three interfacial regions: a region of intermetallics (Tl3Al and TiAl) located near the alumina interface, an α-Ti region, and a β-Ti region (rich in Mo, the β-phase stabilizer). Of the intermetallics to form, Ti3Al was found to form first and have an aligned, planar interface with the alumina. TiAl formed second and was found to separate grains of Ti3Al and the alumina. Reaction products observed in the diffusion-bonded alumina/β-Ti couples are compared with those observed in metal-matrix composites (MMCs), where a β-Ti alloy matrix is reinforced with alumina fibers. Different coatings used in MMCs are investigated for their ability to prevent the reaction between the matrix and fibers.

Transmission Electron Microscopy (TEM) Studies of Interfaces in TiB2-ZrO2 Composites

1996 ◽  
Vol 458 ◽  
Author(s):  
S. Stemmer ◽  
J. Vleugels ◽  
O. Van Der Biest
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Transmission Electron Microscopy ◽  
Chemical Reactions ◽  
Reaction Products ◽  
Transformation Toughening ◽  
Transmission Electron ◽  
Interphase Boundaries ◽  
Reaction Zones

ABSTRACTTEM studies of the microstructure and of chemical reactions at interfaces in TiB2-ZrO2 composites are presented. Samples with 70 vol% of Y2O3-stabilized ZrO sintered at 1700 °C showed reaction zones around the TiB2 grains, that consisted of a solid-solution of TiO2 and ZrO2(Y2O3). In addition, nontransformable, tetragonal t'-ZrO2 was observed in these samples. In contrast, the interphase boundaries in composites sintered at 1450 °C contained no reaction products, and the ZrO2 matrix consisted of small, transformable tetragonal grains, as required for transformation toughening of the composites.

Investigation of Switching Mechanism in HfO2-Based Oxide Resistive Memories by In-Situ Transmission Electron Microscopy and Electron Energy Loss Spectroscopy

2017 ◽  
Author(s):  
T. Dewolf ◽  
D. Cooper ◽  
N. Bernier ◽  
V. Delaye ◽  
A. Grenier ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Hafnium Dioxide ◽  
Switching Mechanism ◽  
Transmission Electron ◽  
Electron Energy Loss

Abstract Forming and breaking a nanometer-sized conductive area are commonly accepted as the physical phenomenon involved in the switching mechanism of oxide resistive random access memories (OxRRAM). This study investigates a state-of-the-art OxRRAM device by in-situ transmission electron microscopy (TEM). Combining high spatial resolution obtained with a very small probe scanned over the area of interest of the sample and chemical analyses with electron energy loss spectroscopy, the local chemical state of the device can be compared before and after applying an electrical bias. This in-situ approach allows simultaneous TEM observation and memory cell operation. After the in-situ forming, a filamentary migration of titanium within the dielectric hafnium dioxide layer has been evidenced. This migration may be at the origin of the conductive path responsible for the low and high resistive states of the memory.

Microtexture of shock reaction products of niobium and silica mixtures

1999 ◽  
Vol 14 (7) ◽  
pp. 3169-3174 ◽  
Author(s):  
Reiko Murao ◽  
Masae Kikuchi ◽  
Kiyoto Fukuoka ◽  
Eiji Aoyagi ◽  
Toshiyuki Atou ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Microscope ◽  
Shock Compression ◽  
Pressure Range ◽  
Reaction Products ◽  
Small Particles ◽  
Powder Mixtures ◽  
X Ray ◽  
Transmission Electron

Shock compression experiments on powder mixtures of niobium metal and quartz were conducted for the pressure range of 30–40 GPa by a 25-mm single-stage propellant gun. Chemical reaction occurred above 35 GPa, and products were found to be mainly so-called “Cu3Au-type” Nb3Si, which contained a small amount of oxygen. Microtextures of the specimen were examined by scanning and transmission electron microscopy. A field-emission transmission electron microscope was used for energy-dispersive x-ray analysis of microtextures in small particles found in the SiO2 matrix, and various species with different Nb/Si ratio and oxygen content were shown to be produced through the nonequilibrium process of shock compression.

Synthesis and Forming of Titanium Matrix Composites by Casting Route

2007 ◽  
Vol 334-335 ◽  
pp. 297-300
Author(s):  
Si Young Sung ◽  
Bong Jae Choi ◽  
Young Jig Kim
Keyword(s):  
Electron Microscopy ◽  
Melting Furnace ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Matrix Composites ◽  
Titanium Matrix ◽  
Titanium Matrix Composites ◽  
Electron Probe Micro Analyzer ◽  
Transmission Electron

The aim of this study is to evaluated the possibility of the in-situ synthesized (TiC+TiB) reinforced titanium matrix composites (TMCs) for the application of structural materials. In-situ synthesis and casting of TMCs were carried out in a vacuum induction melting furnace with Ti and B4C. The synthesized TMCs were characterized using scanning electron microscopy, an electron probe micro-analyzer and transmission electron microscopy, and evaluated through thermodynamic calculations. The spherical TiC plus needle-like and large, many-angled facet TiB reinforced TMCs can be synthesized with Ti and B4C by a melting route.

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