Study on Recrystallization Behavior of Nb-1Zr-0.1C Alloy

2011 ◽  
Vol 702-703 ◽  
pp. 631-634 ◽  
Author(s):  
B. Vishwanadh ◽  
K.V. Mirji ◽  
K. Vaibha ◽  
S.K. Jha ◽  
R. Ajay Kumar ◽  
...  
Keyword(s):  
High Temperature ◽  
Orientation Imaging Microscopy ◽  
Chemical Compositions ◽  
Orientation Imaging ◽  
Transmission Electron ◽  
Structural Applications ◽  
The Matrix ◽  
High Temperature Reactor ◽  
Microscopy Techniques ◽  
Refractory Metal Alloys

The Nb-1%Zr-0.1%C (wt%) alloy is one of the most promising refractory metal alloys having an excellent combination of high temperature properties. Such a combination of properties makes it suitable for several structural applications in the Compact High Temperature Reactor (CHTR). In order to produce the alloy in different shape and sizes a new thermo-mechanical route has been established. The central idea behind the development of such thermo-mechanical route is to reduce the working temperature and provide suitable intermediate annealing treatments to develop desired microstructures. The present paper reports about the application of orientation imaging microscopy in optimizing annealing parameters like temperature and time as a function of the extent of deformation. Samples were also characterized by optical microscopy and transmission electron microscopy techniques. It has been shown that a heat treatment of 1300°C for 3 hour could produce nearly full-recrystallized microstructure. This paper also discusses about the carbide precipitation, their morphologies, chemical compositions and orientations with the matrix phase.

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.

Microstructure and Microchemistry of Y-Doped a-Al203

1998 ◽  
Vol 4 (S2) ◽  
pp. 546-547
Author(s):  
M. A. Giilgiin ◽  
M. L. Mulvihill ◽  
V. Putlayev ◽  
M. Riihle
Keyword(s):  
Electron Microscopy ◽  
Large Scale ◽  
Analytical Electron Microscopy ◽  
Orientation Imaging Microscopy ◽  
Second Phase ◽  
Polycrystalline Alumina ◽  
Orientation Imaging ◽  
Transmission Electron ◽  
Scale Range ◽  
Microscopy Techniques

A thorough microstructural study of common ceramics requires analysis at various length scales. Yttrium doped, polycrystalline α-Al203 was studied using a broad selection of microscopy techniques over a scale range covering seven-orders of magnitude (i.e. from mm to Å).Yttrium doped, (1000 (Y/Al) atomic ppm) polycrystalline alumina samples were prepared by hot pressing at 1450°C at 50 MPa. Some were subsequently crept in tension. Microstructure of these samples was studied by optical microscopy, scanning electron/orientation imaging microscopy (OIM™), conventional and high resolution transmission electron microscopy. Analytical electron microscopy was performed on a VG HB501 FEG-STEM equipped with an EDS and PEELS.On a large scale, the microstructure often consisted of bimodal sized alumina grains and second phase YAG (Y3A15012) precipitates. YAG precipitates at grain boundaries (GB) and triple points caused clusters (50μm to 1mm) of small equi-axed alumina grains (0.5-2 μm) randomly distributed over 40 area% of the sample.

scholarly journals Coating Reactions on Vanadium and V-Si-B Alloys during Powder Pack-Cementation

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4099
Author(s):  
Georg Hasemann ◽  
Chad Harris ◽  
Manja Krüger ◽  
John H. Perepezko
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Refractory Metal ◽  
Pack Cementation ◽  
Solid Solution Phase ◽  
Major Drawback ◽  
Three Phase ◽  
Structural Applications ◽  
New Type ◽  
Refractory Metal Alloys

Alloys in the V-Si-B system are a new and promising class of light-weight refractory metal materials for high temperature applications. Presently, the main attention is focused on three-phase alloy compositions that consist of a vanadium solid solution phase and the two intermetallic phases V3Si and V5SiB2. Similar to other refractory metal alloys, a major drawback is the poor oxidation resistance. In this study, initial pack-cementation experiments were performed on commercially available pure vanadium and a three-phase alloy V-9Si-5B to achieve an oxidation protection for this new type of high temperature material. This advance in oxidation resistance now enables the attractive mechanical properties of V-Si-B alloys to be used for high temperature structural applications.

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.

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.

Nickel oxide–silica and nickel–silica aerogel and xerogel nanocomposite materials

2000 ◽  
Vol 15 (10) ◽  
pp. 2187-2194 ◽  
Author(s):  
M. F. Casula ◽  
A. Corrias ◽  
G. Paschina
Keyword(s):  
Nickel Oxide ◽  
Sol Gel ◽  
Supercritical Drying ◽  
Nanocomposite Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
The Matrix ◽  
Drying Conditions ◽  
Microscopy Techniques

The sol-gel method was used to prepare nickel oxide–silica and nickel–silica nanocomposite materials and the corresponding silica matrices. Different drying conditions were used to obtain aerogel and xerogel materials. The samples were characterized by thermal analysis, x-ray diffraction, N2–physisorption, transmission electron microscopy techniques, and infrared spectroscopy. Aerogel samples had a much higher surface area than the xerogel samples; moreover, different supercritical drying conditions gave rise to a different porous structure, which influenced the size and distribution of the nanoparticles in the matrix.

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.

Transmission electron microscopy on Zr- and Hf-borides with MoSi2 addition: Densification mechanisms

2010 ◽  
Vol 25 (5) ◽  
pp. 828-834 ◽  
Author(s):  
Laura Silvestroni ◽  
Hans-Joachim Kleebe ◽  
Stefan Lauterbach ◽  
Mathis Müller ◽  
Diletta Sciti
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Temperature ◽  
Liquid Phase ◽  
Core Shell ◽  
Electron Microscopies ◽  
Partial Wetting ◽  
Transmission Electron ◽  
The Matrix ◽  
Core Shell Structure

The microstructures of two pressureless sintered ceramics, ZrB2 and HfB2 with 20 vol% MoSi2 added, were analyzed by scanning and transmission electron microscopies. Carbides and oxides of the transition metals and MoB were observed to be well dispersed within the boride matrix. Mo5Si3 and Mo5SiB2, with Zr or Hf impurities, were observed at triple grain junctions and showed a partial wetting of the matrix. It was also noticed that the borides had a core-shell structure, which was especially pronounced in the ZrB2-based composite. The experimental results suggest the formation of a Mo–Si–B liquid phase at high temperature, which strongly promoted the densification. The densification mechanisms are discussed in light of the microstructure evolution on sintering, thermodynamic considerations, and the phase diagrams of the species involved.

Effect of Mg Content on the Precipitation in Al-Mg-Ge Alloys

2007 ◽  
Vol 561-565 ◽  
pp. 2049-2052 ◽  
Author(s):  
Kenji Matsuda ◽  
Teruyoshi Munekata ◽  
Susumu Ikeno
Keyword(s):  
Cross Sections ◽  
Base Alloy ◽  
Lattice Parameter ◽  
Chemical Compositions ◽  
Crystal Lattices ◽  
Β Phase ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
The Matrix ◽  
Mg Content

Rod-shaped precipitates in Al -1.1 mass% Mg2Ge (balanced) and Al -1.0 mass% Mg2Ge – 0.5 mass% Mg (excess Mg) alloys aged at 523 K were observed by high-resolution transmission electron microscope (HRTEM) to understand their crystal lattices and chemical compositions. Rod-shaped precipitates were parallel to <100> directions of the matrix. There were 2 groups for rod-shaped precipitates in the base alloy, namely, small cross sections about 10 nm and large ones over 20nm in diameter. Small precipitates showed a hexagonal network of bright dots in their HRTEM images, and its crystal lattice was estimated as a hexagonal having a= 0.72 and c= 0.405 nm based on analysis of HRTEM images and selected area electron diffraction (SAED) patterns. This lattice parameter was slight larger than that of the β’-phase in Al-Mg-Si alloy.

Recovery and Recrystallization Study after Low Deformation Amount by Cold Rolling in an IF-Ti Steel

2004 ◽  
Vol 467-470 ◽  
pp. 183-188 ◽  
Author(s):  
Amel Samet-Meziou ◽  
Anne Laure Etter ◽  
Thierry Baudin ◽  
Richard Penelle
Keyword(s):  
Cold Rolling ◽  
Boundary Migration ◽  
Orientation Imaging Microscopy ◽  
Continuous Growth ◽  
Orientation Imaging ◽  
Transmission Electron ◽  
Deformation Amount ◽  
Deformed State ◽  
Electron Back Scattered Diffraction

The first steps of recovery and recrystallization in an IF-Ti steel after 40% cold rolling have been studied using the Electron Back Scattered Diffraction (EBSD), Orientation Imaging Microscopy(™) (OIM) and the Transmission Electron Microscopy (TEM). As it is well known, for low deformation amounts by cold rolling, recrystallization texture exhibits the g fiber (ND // <111>) with a reinforcement of the {111}<110> orientation. In order to understand this {111}<110> development during recrystallization, characterization of the deformed state was performed. Different microstructures were distinguished: lamellar bands for the {111}<112> grains of the g fiber and coarse elongated cells for the {111}<110> orientation that belongs to the a and g fibers. Whatever the initial dislocation structure, the recovery step seems to be characterized by coalescence and growth of existing cells in the recovered matrix. Then nucleus growth seems to occur by sub-boundary migration. The first steps of recrystallization mainly take place by continuous growth of subgrains including or not the bulging of grain boundaries.

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