Investigation on Dissolving and Strain Induced Precipitation Behavior in Nb-Bearing Microalloyed Steel

2011 ◽  
Vol 109 ◽  
pp. 3-6
Author(s):  
Shao Qiang Yuan ◽  
Guo Li Liang ◽  
Hui Bin Wu
Keyword(s):  
Relaxation Time ◽  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Microalloyed Steel ◽  
Thermal Simulation ◽  
Holding Time ◽  
The Other ◽  
Precipitation Behavior ◽  
Simulation Test ◽  
Transmission Electron

Thermal simulation test, TEM(Transmission Electron Microscope) and nanobeam EDS techniques were used to investigate the dissolving and precipitation behavior in Nb-bearing mciroalloyed steel. The experimental results indicate that: there are two families of precipitates in the as forged samples. The larger precipitates of Nb(C,N) disappear after being held for 2h at 1300°C,while the inclusions of MnS formed from the solidification even remain for 48h held at that temperature. After 30% of predeformtion at 850°C and 900°C, the strain-induced precipitation occurs, that is, the other tiny precipitates. Compared with the samples relaxed at 850°C, the ones that are held at 900°C show larger particles by same holding time but demonstrate the same size when the relaxation time reaches 1000s.

Reconstruction of electron holograms recorded in a non-FEG, non-biprism TEM

1995 ◽  
Vol 53 ◽  
pp. 618-619
Author(s):  
Z.L. Wang
Keyword(s):  
Electron Microscope ◽  
Single Crystal ◽  
Experimental Technique ◽  
Transmission Electron Microscope ◽  
The Other ◽  
Electron Holography ◽  
Transmission Electron ◽  
Coherent Sources ◽  
Imaging Theory ◽  
Normal Specimen

An experimental technique for performing electron holography using a non-FEG, non-biprism transmission electron microscope (TEM) has been introduced by Ru et al. A double stacked specimens, one being a single crystal foil and the other the specimen, are loaded in the normal specimen position in TEM. The single crystal, which is placed onto the specimen, is responsible to produce two beams that are equivalent to two virtual coherent sources illuminating the specimen beneath, thus, permitting electron holography of the specimen. In this paper, the imaging theory of this technique is described. Procedures are introduced for digitally reconstructing the holograms.

scholarly journals Some Reflections On How Much Information la There On A Piece Of Film, On How Film Compares With CCD Cameras And What Features A Scanner Would Meed To Digitize TEM Negatives

1998 ◽  
Vol 6 (9) ◽  
pp. 18-21
Author(s):  
Alwyn Eades
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
The Other ◽  
Ccd Cameras ◽  
Know How ◽  
Transmission Electron ◽  
The World ◽  
Digital Methods

The world of electron microscopy is in a period of transition from acquiring images on film to acquiring images digitally, using CCD cameras, for example. It would be useful to knew how much information there is on a piece of film, in order to know how film compares with digital methods and to be able to make good judgements on the optimum moment to change from one technology to the other.This is an attempt to use simple arguments to estimate just how much information there is in an image exposed on film in the transmission electron microscope, the main reason for addressing this issue Is that, while many people are affected by it there seems to be little agreement on the answer.

scholarly journals Effect of Niobium and Titanium Addition on Formation of Second Phase Particles in CHQ Steel Using Transmission Electron Microscope

2021 ◽  
Vol 40 (1) ◽  
pp. 31-37
Author(s):  
Shahid Hussain Abro
Keyword(s):  
Heat Treatment ◽  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Weight Percent ◽  
Holding Time ◽  
Second Phase ◽  
Steel Matrix ◽  
Ehlers Danlos Syndrome ◽  
Transmission Electron ◽  
Second Phase Particles

It is common practice that formation of second phase particles such as nitrides or carbides in the steel matrix has significant role to control the grain size of steel. An attempt is made in the present research work to find out the role of nitrogen to form the nitride particles either with Al, Ti, B, Cr or Si. Two steel samples Steel-A and Steel-B with same titanium and aluminum weight percent in the chemical composition were obtained in hot rolled conditions from international market with only the difference of presence of Niobium in Steel-A. Solution heat treatment was performed at 1350°C with 60 minutes holding time in protherm heat treatment furnace available locally was used to dissolve the particles and then steel samples were reheat treated at 800°C with holding time of 60 minutes and water quenched and microstructure was revealed. Transmission electron microscope connected with Ehlers-Danlos Syndrome (EDS) was used to reveal the morphology of second phase particles. Both samples for a high resolution power Transmission Electron Microscopy (TEM) (Jeol JEM 3010) analysis were prepared by using carbon extraction replica method in 5% Nital solution as an etching technique. Both samples were then caught in copper grid of 3mm for using TEM analysis. TEM micrographs clearly revealed the second phase particles in the matrix of steel. The EDS peaks were studied and it was found that the peaks showed the titanium peaks in both the samples A and B and surprisingly there was no any peak found for aluminum. Stoichiometric calculations were carried out and it was found that weight percent nitrogen required for forming TiN is 0.0073, however the total nitrogen present in both the steels A and B is 0.0058 and 0.0061 respectively. That means that all the nitrogen present in the steel matrix was consumed by titanium to form the Titanium Nitride (TiN) so there was no nitrogen remain to fulfil the requirement of aluminum to form the Aluminum Nitride (AlN) particles.

Threading dislocations with edge components in GaN epilayers grown on Al2O3 substrates

2001 ◽  
Vol 16 (9) ◽  
pp. 2550-2555 ◽  
Author(s):  
Junyong Kang ◽  
Tomoya Ogawa
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Transmission Electron Microscope ◽  
The Other ◽  
Threading Dislocations ◽  
Line Segments ◽  
Bright Line ◽  
Transmission Electron ◽  
Dislocation Interactions

Two types of threading dislocations with edge components were investigated by a high-resolution transmission electron microscope in undoped GaN epilayers grown on Al2O3 substrates. One is a fully filled core with regular contraction and stretch of bright dots, and the other is incompletely filled with one bright dot less and irregular contraction and stretch of bright dots. The bright dots were distorted and degenerated into bright line segments at cores in areas with smaller local dislocation intervals. The calculated results suggested that the distorted bright regions are attributable to the glide and/or climb caused by nearby dislocation interactions.

Transmission electron microscope observations of rectangular dislocation networks in an Al70Co15Ni15 decagonal quasicrystal

1993 ◽  
Vol 8 (2) ◽  
pp. 286-290 ◽  
Author(s):  
Yanfa Yan ◽  
Renhui Wang
Keyword(s):  
Electron Microscope ◽  
Electron Diffraction ◽  
Transmission Electron Microscope ◽  
The Other ◽  
Dislocation Network ◽  
Decagonal Quasicrystal ◽  
Twofold Axis ◽  
Decagonal Phase ◽  
Diffraction Contrast ◽  
Transmission Electron

The electron diffraction contrast of two types of rectangular dislocation networks in an Al70Co15Ni15 decagonal quasicrystal has been analyzed. One type of dislocation network consists of two dislocation sets whose Burgers vectors are parallel to the tenfold axis A10 and a twofold axis A2D. The other type of dislocation network consists of two dislocation sets whose Burgers vectors are parallel to the A10 and the other twofold axis of A2P. The characteristics of the diffraction contrast of the dislocation networks in the Al–Co–Ni decagonal phase are similar to those in conventional crystals.

Ultrastructurally different hemocytes in a spider

1973 ◽  
Vol 51 (11) ◽  
pp. 1155-1159 ◽  
Author(s):  
R. G. Sherman
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
The Other ◽  
Transmission Electron ◽  
Insect Hemocytes

Hemocytes found, in association with the heart of the tarantula spider, Eurypelma marxi Simon, were examined with a transmission electron microscope. Three main ultrastructural types were described. These were designated as granular, oenocytoid, and plasmatocytoid on the basis of similarities to insect hemocytes. In addition, two presumed transitional hemocytes were found. One showed characteristics of both plasmatocytoids and granular hemocytes; the other possessed features common to both plasmato-cytoids and oenocytoids.

scholarly journals Some Reflections on How Much Information is there on a Piece of Film, on How Film Compares with CCD Cameras and what Features a Scanner would need to Digitize TEM Negatives

1996 ◽  
Vol 4 (1) ◽  
pp. 24-27
Author(s):  
Alwyn Eades
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
The Other ◽  
Ccd Cameras ◽  
Know How ◽  
Transmission Electron ◽  
The World ◽  
Digital Methods

The world of electron microscopy is in a period of transition from acquiring images on film to acquiring images digitally, using CCD cameras, for example. It would be useful to know how much information there is on a piece of film, in order to know how film compares with digital methods and to be able to make good judgements on the optimum moment to change from one technology to the other.This is an attempt to use simple arguments to estimate just how much information there is in an image exposed on film in the transmission electron microscope. The main reason for addressing this issue is that, while many people are affected by it, there seems to be little agreement on the answer.

Asbestos Fibers in Sake

1988 ◽  
Vol 51 (9) ◽  
pp. 737-739 ◽  
Author(s):  
SHUZO OGINO ◽  
NOBUTAKA FUKUMORI ◽  
TETSUKO YASUNO ◽  
MASAMICHI KOSEKI ◽  
MASAYOSHI KAZAMA
Keyword(s):  
Electron Microscope ◽  
Detection Limit ◽  
Transmission Electron Microscope ◽  
Detection Limits ◽  
The Body ◽  
The Other ◽  
Filtration Process ◽  
Asbestos Fibers ◽  
Transmission Electron ◽  
High Concentrations

Asbestos filters have been widely used to clear beverages in many countries including Japan, and despite warnings from the authorities, some Japanese sake companies have continued using such filters until recently. Forty-seven Japanese sake samples were analyzed using a transmission electron microscope to detect contamination with asbestos fibers. The concentrations of fibers found in sake samples ranged from <7.8 × 103 fibers/L (the detection limit) to 1.96 × 108 fibers/L. Ten sake manufacturers provided information as to whether they had used asbestos in the filtration process and the remaining 37 did not (unknown group). Five out of the 10 manufacturers from which information was available had used asbestos (with asbestos group), and the other 5 had not (without asbestos group). The concentrations of fibers in the samples of the “with asbestos” group were more than 7.7 × 106 fibers/L while those in the “without asbestos” group did not exceed 2.8 × 105 fibers/L. The concentrations of fibers in the samples of the “unknown group” ranged from below the detection limits to 1.46 × 108 fibers/L. Some brands of sake showed extremely high concentrations of asbestos fibers, and therefore it may be necessary to investigate the fate of ingested asbestos in the body and its possible carcinogenicity.

Influence of Microstructure and Precipitates on the Strength of Container Steel

2012 ◽  
Vol 586 ◽  
pp. 225-229
Author(s):  
Jia Yan Ma ◽  
Wen Liang ◽  
Rong Dong Han ◽  
Yun Guan ◽  
Zhao Jun Deng
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Transmission Electron Microscope ◽  
Optical Microscope ◽  
The Other ◽  
Precipitation Strengthening ◽  
Strengthening Effect ◽  
Transmission Electron ◽  
Uniform Dispersion ◽  
Scanning Electron

The variation rules of strength with the microstructure and precipitates of container steel were studied by optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM). The results show that the microstructures of four kinds of test steels are all bainite and M/A island, but the number and size of islands of M/A and precipitates exist obvious difference: two kinds of test steels have fewer precipitates and more M/A islands, however, the other two kinds of steels are on the contrary. As for the former two kinds steels, the number of M/A islands is larger, and the size is smaller, the strength of steel is higher; For the later two kinds steels, the number of precipitates less than 30nm is larger, and distribution is more uniform dispersion, the strength is higher, precipitation strengthening effect is better. Getting lots of small and uniform M/A islands or precipitates is an effective way of improving the performance of steel.

Strain-Induced Precipitation in Nb-Bearing Low Carbon Multi-Microalloyed Steel

2010 ◽  
Vol 97-101 ◽  
pp. 560-564 ◽  
Author(s):  
Shao Qiang Yuan ◽  
Guo Li Liang ◽  
Xiao Juan Zhang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Relaxation Process ◽  
Microalloyed Steel ◽  
Low Carbon ◽  
Precipitation Behavior ◽  
Simulation Test ◽  
Transmission Electron

Thermo-simulation test, transmission electron microscopy(TEM) and nanobeam EDS technique were used to investigate the strain induced precipitation behavior during relaxation process after deformed austenite in Mn-Mo-Nb-B low carbon multi-microalloyed Steel. The experiment results indicate that during isothermal held at 850 °Cand 900 °C after predeformation, the size of precipitates occurred in the Mn-Mo-Nb-B steel at different stage is smaller than that happened in the only Nb and Ti-bearing microalloyed steel. The ratio of Nb/Ti to precipitates increased with the relaxing time. After being held longer, Mo atoms would enter the lattice of (Nb,Ti)(C,N) precipitates and the amount in the precipitates increased with the relaxation as time prolonged.

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