A Microstruciure Investigation on Rapidly Solidified Ni3Al Containing Boron

1983 ◽  
Vol 28 ◽  
Author(s):  
K.M. Ciiang ◽  
S.C. Huang ◽  
A.I. Taub
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Room Temperature ◽  
Martensitic Phase ◽  
Boron Addition ◽  
Transmission Electron ◽  
Melt Spun ◽  
Rapidly Solidified ◽  
Room Temperature Strength ◽  
Strength And Ductility

ABSTRACTA small amount of boron addition in rapidly solidified Ni3 Al has been found to yield remarkable improvements in bolh room-temperature strength and ductility. In this study, the microstructure of melt-spun Ni3Al ribbons with various boron modifications ranging from 0 to 6.0 at% was investigated in detail by using transmission electron microscopy. All alloy compositions studied reveal a completely ordered fcc L12 matrix phase, in which polygonized dislocation networks and subgrain boundaries are observed. The boron-free Ni3 Al contains a dispersion of an Al-rich martensitic phase consisting of alternate twins. The boron addition tends to suppress the formation of the martensitic phase, but excessive boron (≥ 2.0 at%) causes the precipitation of M23B6 type borides.

Enhanced Strength and Ductility at a Cryogenic Temperature in a Nanostructured Ni-Fe Alloy

2007 ◽  
Vol 539-543 ◽  
pp. 2828-2833
Author(s):  
Hong Qi Li ◽  
Kai Xiang Tao ◽  
Hahn Choo ◽  
Peter K. Liaw
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cryogenic Temperature ◽  
Room Temperature ◽  
Liquid Nitrogen Temperature ◽  
Compressive Behavior ◽  
Grain Sizes ◽  
Transmission Electron ◽  
Before And After ◽  
Strength And Ductility

The compressive behavior was investigated on an electrodeposited nanocrystalline Ni-20%Fe alloy with a grain size of about 22 nm at room temperature (RT), 298 K, and the liquid nitrogen temperature (LN2T), 77 K. The sensitivity of the yield strength and plastic strain to the test temperature at different grain sizes was discussed. Moreover, through the Transmission Electron Microscopy (TEM) examination and microhardness measurement, the microstructures before and after the compression test at RT and LN2T were studied.

Scanning and Transmission Electron Microscopy of Human Red Blood Cells

1969 ◽  
Vol 27 ◽  
pp. 44-45
Author(s):  
A.J. Tousimis ◽  
T.R. Padden
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Blood Cells ◽  
Room Temperature ◽  
Type Specimen ◽  
New Combination ◽  
Human Red Blood Cells ◽  
Transmission Electron ◽  
Microscope Slides ◽  
Scanning Electron

The size, shape and surface morphology of human erythrocytes (RBC) were examined by scanning electron microscopy (SEM), of the fixed material directly and by transmission electron microscopy (TEM) of surface replicas to compare the relative merits of these two observational procedures for this type specimen.A sample of human blood was fixed in glutaraldehyde and washed in distilled water by centrifugation. The washed RBC's were spread on freshly cleaved mica and on aluminum coated microscope slides and then air dried at room temperature. The SEM specimens were rotary coated with 150Å of 60:40- gold:palladium alloy in a vacuum evaporator using a new combination spinning and tilting device. The TEM specimens were preshadowed with platinum and then rotary coated with carbon in the same device. After stripping the RBC-Pt-C composite film, the RBC's were dissolved in 2.5N HNO3 followed by 0.2N NaOH leaving the preshadowed surface replicas showing positive topography.

Formation of Dislocation Channels in Neutron Irradiated Molybdenum

1972 ◽  
Vol 30 ◽  
pp. 672-673
Author(s):  
S. Mahajan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ambient Temperature ◽  
Room Temperature ◽  
Channel Formation ◽  
Early Stages ◽  
Transmission Electron ◽  
Three Stages ◽  
Two Stages ◽  
Polycrystalline Molybdenum

The evolution of dislocation channels in irradiated metals during deformation can be envisaged to occur in three stages: (i) formation of embryonic cluster free regions, (ii) growth of these regions into microscopically observable channels and (iii) termination of their growth due to the accumulation of dislocation damage. The first two stages are particularly intriguing, and we have attempted to follow the early stages of channel formation in polycrystalline molybdenum, irradiated to 5×1019 n. cm−2 (E > 1 Mev) at the reactor ambient temperature (∼ 60°C), using transmission electron microscopy. The irradiated samples were strained, at room temperature, up to the macroscopic yield point.Figure 1 illustrates the early stages of channel formation. The observations suggest that the cluster free regions, such as A, B and C, form in isolated packets, which could subsequently link-up to evolve a channel.

A crystallographic analysis of the CoSi/Si(111) interface using Transmission Electron Microscopy

1990 ◽  
Vol 48 (4) ◽  
pp. 574-575
Author(s):  
A.C. Daykin ◽  
C.J. Kiely ◽  
R.C. Pond ◽  
J.L. Batstone
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Defect Structure ◽  
Room Temperature ◽  
Theoretical Method ◽  
Crystallographic Analysis ◽  
Si Substrate ◽  
Transmission Electron ◽  
Theoretical Predictions

When CoSi2 is grown onto a Si(111) surface it can form in two distinct orientations. A-type CoSi2 has the same orientation as the Si substrate and B-type is rotated by 180° degrees about the [111] surface normal.One method of producing epitaxial CoSi2 is to deposit Co at room temperature and anneal to 650°C.If greater than 10Å of Co is deposited then both A and B-type CoSi2 form via a number of intermediate silicides .The literature suggests that the co-existence of A and B-type CoSi2 is in some way linked to these intermediate silicides analogous to the NiSi2/Si(111) system. The phase which forms prior to complete CoSi2 formation is CoSi. This paper is a crystallographic analysis of the CoSi2/Si(l11) bicrystal using a theoretical method developed by Pond. Transmission electron microscopy (TEM) has been used to verify the theoretical predictions and to characterise the defect structure at the interface.

Synthesis and TEM study of Ag–In–(Eu, Ce) ternary approximants

2009 ◽  
Vol 224 (1-2) ◽  
Author(s):  
Kazue Nishimoto ◽  
Miki Muraki ◽  
Ryuji Tamura
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Room Temperature ◽  
Transmission Electron

AbstractTernary Ag–In–(Eu, Ce) 1/1 approximants are synthesized and their structures are studied by transmission electron microscopy (TEM). For both the approximants, superlattice spots are clearly observed at room temperature, and the superstructures of the Ag–In–(Eu, Ce) approximants are found to be similar to those of Cd

Preparation of Straight and Orderly Polypyrrole Microrods through Soft Template Methods

2011 ◽  
Vol 306-307 ◽  
pp. 679-683
Author(s):  
Li Bo Sun ◽  
Yuan Chang Shi ◽  
Lin Ya Chu ◽  
Bing Chang Zhang ◽  
Jiu Rong Liu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cetyltrimethylammonium Bromide ◽  
Growth Process ◽  
Room Temperature ◽  
Oxidative Polymerization ◽  
Soft Template ◽  
Microemulsion System ◽  
Transmission Electron ◽  
The Impact

The straight and orderly microrods of polypyrrole(PPy) was synthesized in a microemulsion system consisted of cetyltrimethylammonium bromide(CTAB), n-pentanol, water and pyrrole by chemical oxidative polymerization, in which CTAB was used as soft templates and APS was used as the oxidant. Fourier-transform infrared spectroscopy (FTIR) was used to characterize the structure of the PPy microrods. Transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM) was used to characterize the morphology of the samples. We discussed the impact of temperature, the adding way of the oxidant, the amount of cosurfactant n-pentanol to the morphology of PPy microrods. The results showed that straight and orderly PPy microrods with a diameter about 300nm and a length up to 20μm were synthesized when the temperature was kept at room temperature (25°C), the dropping time of APS was more than 1.5h, the ratio of CTAB to n-pentanol was 0.6:1, and the polymerization time was about 24h. We studied the growth process of PPy microrods by HTEM analysis. HTEM images revealed that the growth process of PPy changed from hollow microrods, semi-hollow microrods, and finally solid microrods.

Nanotwinned Surface on a Ternary Titanium Alloy with Increased Hardness Induced under Nanoindentations

2016 ◽  
Vol 874 ◽  
pp. 323-327
Author(s):  
Hong Xiu Zhou ◽  
Ming Lei Li ◽  
Neng Dong Duan ◽  
Bo Wang ◽  
Zhi Feng Shi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Surface Roughness ◽  
Titanium Alloy ◽  
Chemical Mechanical Polishing ◽  
Material Removal ◽  
Room Temperature ◽  
Chemical Reagents ◽  
Transmission Electron ◽  
High Temperature High Pressure

A nanotwinned surface is formed on a titanium alloy under nanoindentations. Prior to nanoindentation, blocks of a ternary titanium alloy are machined by chemical mechanical polishing. The surface roughness Ra and peak-to-valley values are 1.135 nm and 8.82 nm, respectively. The hardness in the indented surface is greatly increased, indicated from the load-displacement curves compared to the polished surfaces. Nanotwins are confirmed using transmission electron microscopy. The nanotwinned surface is uniformly generated by nanoindentations at room temperature, which is different from previous findings, in which high temperature, high pressure, or chemical reagents are usually used. The nanotwinned surface is produced by pure mechanical stress, neither material removal nor addition.

New method for the production of bulk amorphous materials of Nd–Fe–B alloys

2005 ◽  
Vol 20 (3) ◽  
pp. 563-566 ◽  
Author(s):  
Tetsuji Saito ◽  
Hiroyuku Takeishi ◽  
Noboru Nakayama
Keyword(s):  
Electron Microscopy ◽  
Amorphous Materials ◽  
Room Temperature ◽  
Amorphous Structure ◽  
X Ray Diffraction ◽  
Bulk Materials ◽  
X Ray ◽  
Transmission Electron ◽  
Melt Spun ◽  
Melt Spun Ribbons

We report a new compression shearing method for the production of bulk amorphous materials. In this study, amorphous Nd–Fe–B melt-spun ribbons were successfully consolidated into bulk form at room temperature by the compression shearing method. X-ray diffraction and transmission electron microscopy studies revealed that the amorphous structure was well maintained in the bulk materials. The resultant bulk materials exhibited the same magnetic properties as the original amorphous Nd–Fe–B materials.

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