scholarly journals Effect of electron irradiation on the 3C-4H transformation in a Co-Fe alloy

1996 ◽  
Vol 54 ◽  
pp. 992-993
Author(s):  
Charles W. Allen ◽  
Hirotaro Mori
Keyword(s):  
Martensitic Transformation ◽  
Electron Irradiation ◽  
Structural Damage ◽  
Terminal Solid Solution ◽  
Martensitic Transformations ◽  
High Energy ◽  
Transformation Mechanism ◽  
Intermediate Phases ◽  
High Energy Electrons ◽  
Kinetics Of

In general, irradiation of materials by high energy electrons, protons or neutrons has been shown to stabilize the existing microstructure against subsequent martensitic transformation. Alloys which have been studied include the binary intermediate phases NiTi and Ni63Al37 and ternary phases between Cu37,5Al62.5 and CU63.6Al36.4 as well as the intermetallic Cu69.01Al17.92 Zn12.17. In these materials, the martensitic transformations are known to be sensitive to small changes in chemical composition and to the degree of long range order. In addition, one should expect the kinetics of martensitic transformations to be sensitive to other forms of structural damage introduced during irradiation also. This spectrum of irradiation-induced phenomena renders the interpretation of results in studies of such concentrated binary and ternary phases rather complicated, therefore.We present here the preliminary results of a study of the effect of electron irradiation on the character of the martensitic transformation in a relatively dilute terminal solid solution of Co+5.75 wt pet Fe, similar in composition to that employed for studies of the transformation mechanism itself.

An Interpretation on Kinetics of Martensitic Transformation

2011 ◽  
Vol 172-174 ◽  
pp. 90-98 ◽  
Author(s):  
Tomoyuki Kakeshita ◽  
Takashi Fukuda ◽  
Yong-Hee Lee
Keyword(s):  
Magnetic Field ◽  
Hydrostatic Pressure ◽  
Martensitic Transformation ◽  
Magnetic Fields ◽  
Martensitic Transformations ◽  
Phenomenological Theory ◽  
Time Dependent ◽  
Isothermal Process ◽  
Kinetics Of ◽  
Transformation Processes

We have investigated athermal and isothermal martensitic transformations (typical displacive transformations) in Fe–Ni, Fe–Ni–Cr, and Ni-Co-Mn-In alloys under magnetic fields and hydrostatic pressures in order to understand the time-dependent nature of martensitic transformation, that is, the kinetics of martensitic transformation. We have confirmed that the two transformation processes are closely related to each other, that is, the athermal process changes to the isothermal process and the isothermal process changes to the athermal one under a hydrostatic pressure or a magnetic field. These findings can be explained by the phenomenological theory, which gives a unified explanation for the two transformation processes previously proposed by our group.

Crosslinking of Oriented Rubber

1958 ◽  
Vol 31 (1) ◽  
pp. 98-104 ◽  
Author(s):  
A. Charlesby ◽  
E. von Arnim
Keyword(s):  
Elastic Modulus ◽  
Stress Relaxation ◽  
Elastic Properties ◽  
Electron Irradiation ◽  
Main Chain ◽  
High Energy ◽  
Elongation At Break ◽  
High Energy Electrons ◽  
Anisotropic Elastic ◽  
G Value

Abstract Smoked sheet rubber, previously oriented in the calendering process, was crosslinked by exposure to 2 Mev high energy electrons in the absence of vulcanizing agents. Even after annealing, the resultant rubber showed anisotropic elastic properties, having a high elastic modulus and a low elongation at break in the direction of orientation. It is suggested that radiation in addition to crosslinking causes main chain fracture and stress relaxation in stressed molecular chains. The G value for crosslinking (1.05) by electron irradiation agrees well with that (1.1) previously found by elastic measurements of pile irradiated rubber.

scholarly journals Effects of Electron Irradiation on Optical Properties of Bismuth-Doped Phosphosilicate Fiber

2020 ◽  
Author(s):  
Alexander V. Kir’yanov ◽  
Arindam Halder
Keyword(s):  
Optical Properties ◽  
Electron Irradiation ◽  
Near Infrared ◽  
Stokes Shift ◽  
High Energy ◽  
Active Centers ◽  
Laser Applications ◽  
High Energy Electrons ◽  
Phosphosilicate Fiber ◽  
Overall Resistance

The basic optical properties of yttrium-phosphosilicate fiber doped with bismuth (Bi) are assessed in both pristine state and that established after bombardment by a beam of high-energy electrons. The fiber has been developed and fabricated with a target to use it for laser applications in visible/near-infrared (VIS/NIR) domain. In this chapter, the main attention is paid to the dramatic changes in absorption spectra of the fiber under electron irradiation. Meanwhile, we reveal its overall resistance to irradiation in terms of emissive potential and bleaching contrast at excitation into the absorption bands of bismuth-related active centers. Besides, we report a new effect of large dose-dependent Stokes shift, experienced by the fiber’s cutoff wavelength, which arises due to refractive index rise in its core area. The laws obeyed by the fiber’s characteristics vs. dose are examined for possible applications in dosimetry.

Microstructural Changes to Xenon Naonoclusters in Aluminum under 1 MeV Electron Irradiation.

2000 ◽  
Vol 650 ◽  
Author(s):  
S. E. Donnelly ◽  
R. C. Birtcher ◽  
C. W. Allen ◽  
K. Furuya ◽  
M. Song ◽  
...  
Keyword(s):  
Electron Irradiation ◽  
High Energy ◽  
Extended Defects ◽  
Aluminum Films ◽  
Voltage Electron ◽  
Video Recordings ◽  
High Energy Electrons ◽  
High Resolution Images ◽  
Small Clusters ◽  
Shape Changes

ABSTRACTAluminum films containing solid Xe precipitates have been subjected to 1 MeV electron irradiation in a high-voltage electron microscope. High-resolution images have been recorded on videotape in order to monitor the changes to the system resulting from the passage of electrons through the film. Inspection of the video recordings reveals that complex, rapid processes occur under the electron beam. These include shape changes, the creation and movement of extended defects within the Xe lattice, movement of small clusters, coalescence of neighboring clusters and the apparent melting and resolidification of the Xe. An interpretation of many of the observations is presented in terms of the interaction of the nanoclusters with defects created in the aluminum by the high-energy electrons.

Evaluation of single-electron movies of glutamine synthetase molecules

1983 ◽  
Vol 41 ◽  
pp. 280-281
Author(s):  
W. Kunath ◽  
E. Zeitler ◽  
M. Kessel
Keyword(s):  
Electron Microscope ◽  
Glutamine Synthetase ◽  
Electron Irradiation ◽  
Structural Damage ◽  
Structural Changes ◽  
Single Electron ◽  
Continuous Series ◽  
Digital Recording ◽  
Recording Device ◽  
Low Exposure

The features of digital recording of a continuous series (movie) of singleelectron TV frames are reported. The technique is used to investigate structural changes in negatively stained glutamine synthetase molecules (GS) during electron irradiation and, as an ultimate goal, to look for the molecules' “undamaged” structure, say, after a 1 e/Å2 dose.The TV frame of fig. la shows an image of 5 glutamine synthetase molecules exposed to 1/150 e/Å2. Every single electron is recorded as a unit signal in a 256 ×256 field. The extremely low exposure of a single TV frame as dictated by the single-electron recording device including the electron microscope requires accumulation of 150 TV frames into one frame (fig. lb) thus achieving a reasonable compromise between the conflicting aspects of exposure time per frame of 3 sec. vs. object drift of less than 1 Å, and exposure per frame of 1 e/Å2 vs. rate of structural damage.

Void-Lattice Formation in Natural Fluorite by Electron Irradiation

1976 ◽  
Vol 34 ◽  
pp. 614-615 ◽  
Author(s):  
L.E. Murr
Keyword(s):  
Electron Microscope ◽  
Electron Irradiation ◽  
Heavy Ion ◽  
High Energy ◽  
Stoichiometric Ratio ◽  
Direct Observations ◽  
Transmission Electron ◽  
Anion Vacancies ◽  
Cation And Anion Vacancies ◽  
Lattice Formation

The production of void lattices in metals as a result of displacement damage associated with high energy and heavy ion bombardment is now well documented. More recently, Murr has shown that a void lattice can be developed in natural (colored) fluorites observed in the transmission electron microscope. These were the first observations of a void lattice in an irradiated nonmetal, and the first, direct observations of color-center aggregates. Clinard, et al. have also recently observed a void lattice (described as a high density of aligned "pores") in neutron irradiated Al2O3 and Y2O3. In this latter work, itwas pointed out that in order that a cavity be formed,a near-stoichiometric ratio of cation and anion vacancies must aggregate. It was reasoned that two other alternatives to explain the pores were cation metal colloids and highpressure anion gas bubbles.Evans has proposed that void lattices result from the presence of a pre-existing impurity lattice, and predicted that the formation of a void lattice should restrict swelling in irradiated materials because it represents a state of saturation.

In situ observation of the martensitic transformation in (Mg,Y)-PSZ

1986 ◽  
Vol 44 ◽  
pp. 500-501
Author(s):  
R-R. Lee
Keyword(s):  
Martensitic Transformation ◽  
High Strength ◽  
Nucleation And Growth ◽  
In Situ Observation ◽  
Considerable Potential ◽  
Transmission Electron ◽  
Structural Applications ◽  
Applied Stresses ◽  
Kinetics Of

Partially-stabilized ZrO2 (PSZ) ceramics have considerable potential for advanced structural applications because of their high strength and toughness. These properties derive from small tetragonal ZrO2 (t-ZrO2) precipitates in a cubic (c) ZrO2 matrix, which transform martensitically to monoclinic (m) symmetry under applied stresses. The kinetics of the martensitic transformation is believed to be nucleation controlled and the nucleation is always stress induced. In situ observation of the martensitic transformation using transmission electron microscopy provides considerable information about the nucleation and growth aspects of the transformation.

The kinetics of lath martensitic transformation

2003 ◽  
Vol 112 ◽  
pp. 139-142 ◽  
Author(s):  
G. Ghosh ◽  
G. B. Olson
Keyword(s):  
Martensitic Transformation ◽  
Kinetics Of
Sign in / Sign up

Export Citation Format

Share Document