A Phenomenological Micromechanical Model of FCC Metals under Radiation Induced Crystal Defects

2012 ◽  
pp. 269-287
Author(s):  
Yoshiteru Aoyagi ◽  
Tomohito Tsuru ◽  
Yoshiyuki Kaji
Keyword(s):  
Micromechanical Model ◽  
Crystal Defects ◽  
Fcc Metals ◽  
Radiation Induced

Correlation between the Radiation Induced Colours and the OH-stretching Vibrations of Amazonite

1993 ◽  
Vol 48 (10) ◽  
pp. 1041-1042
Author(s):  
A. Banerjee
Keyword(s):  
Crystal Defects ◽  
Radiation Induced ◽  
Stretching Vibrations

Abstract The changes of colour and the OH-stretching vibrations of amazonites (K-Feldspar) on irradiation have been investigated. It is concluded that the changes are caused by radiation induced crystal defects.

Resonant phonon scattering by radiation-induced crystal defects inCaF2

1993 ◽  
Vol 70 (22) ◽  
pp. 3451-3454 ◽  
Author(s):  
C. Wurster ◽  
K. Lassmann ◽  
W. Eisenmenger
Keyword(s):  
Phonon Scattering ◽  
Crystal Defects ◽  
Radiation Induced

Radiation-induced crystal defects in PTFE

1993 ◽  
Vol 40 (1) ◽  
pp. 97-100 ◽  
Author(s):  
Xiaoguang Zhong ◽  
Li Yu ◽  
Wenwei Zhao ◽  
Jiazhen Sun ◽  
Yuefang Zhang
Keyword(s):  
Crystal Defects ◽  
Radiation Induced

Correlation of Optical Luminescence with Radiation Hardness in Doped LiNbO3 Crystals

2004 ◽  
Vol 851 ◽  
Author(s):  
William J. Thomes ◽  
Kelly Simmons-Potter ◽  
Barrett G. Potter ◽  
Louis S. Weichman
Keyword(s):  
Optical Loss ◽  
Crystal Defects ◽  
Mg Doping ◽  
Radiation Fields ◽  
Optical Luminescence ◽  
High Gamma ◽  
Radiation Induced ◽  
Gamma Field ◽  
Radiation Hard ◽  
Selection Of

ABSTRACTTransient ionizing radiation fields have been observed to cause substantial optical loss in undoped LiNbO3 crystals operating at 1.06 microns. This loss is slow to recover and makes the selection of this material for Q-switch applications in radiation environments unfeasible. We have studied the effects of Mg doping on the radiation response of LiNbO3 crystals and have investigated the optical luminescence of doped and undoped samples. Our results indicate a strong correlation between crystal defects, formed primarily during crystal growth, and the radiation-induced optical loss exhibited by these materials. These findings have enabled us to produce radiation-hard LiNbO3 crystals for use in high gamma-field environments.

scholarly journals Complexity and Anisotropy of Plastic Flow of α-Ti Probed by Acoustic Emission and Local Extensometry

2018 ◽  
Author(s):  
Mikhail Lebyodkin ◽  
Kékéli Amouzou ◽  
Tatiana Lebedkina ◽  
Thiebaud Richeton ◽  
Amandine Roth
Keyword(s):  
Acoustic Emission ◽  
Plastic Flow ◽  
Micromechanical Model ◽  
Local Strain ◽  
Simultaneous Recording ◽  
Distribution Functions ◽  
Crystal Defects ◽  
Dislocation Dynamics ◽  
Dislocation Glide ◽  
Deformation Curves

Current progress in the prediction of mechanical behavior of solids requires understanding of spatiotemporal complexity of plastic flow caused by self-organization of crystal defects. It may be particularly important in hexagonal materials because of their strong anisotropy and combination of different mechanisms of plasticity, such as dislocation glide and twinning. These materials often display complex behavior even on the macroscopic scale of deformation curves, e.g., a peculiar three-stage elastoplastic transition, the origin of which is a matter of debates. The present work is devoted to a multiscale study of plastic flow in α-Ti, based on simultaneous recording of deformation curves, 1D local strain field, and acoustic emission (AE). It is found that the average AE activity also reveals three-stage behavior, but in a qualitatively different way depending on the crystallographic orientation of the sample axis. On the finer scale, the statistical analysis of AE events and local strain rates testifies to an avalanche-like character of dislocation processes, reflected in power-law probability distribution functions. The results are discussed from the viewpoint of collective dislocation dynamics and are confronted to predictions of a recent micromechanical model of Ti strain hardening.

The Imaging of Crystal Structures and Crystal Defects

1978 ◽  
Vol 36 (3) ◽  
pp. 207-217
Author(s):  
J.M. Cowley
Keyword(s):  
Electron Microscope ◽  
Crystal Structures ◽  
Phase Contrast ◽  
Crystal Defects ◽  
Atom Density ◽  
Lack Of Information ◽  
Spatial Frequencies

The problem of "understandinq" electron microscope imaqes becomes more acute as the resolution is improved. The naive interpretation of an imaqe as representinq the projection of an atom density becomes less and less appropriate. We are increasinqly forced to face the complexities of coherent imaqinq of what are essentially phase objects. Most electron microscopists are now aware that, for very thin weakly scatterinq objects such as thin unstained bioloqical specimens, hiqh resolution imaqes are best obtained near the optimum defocus, as prescribed by Scherzer, where the phase contrast imaqe qives a qood representation of the projected potential, apart from a lack of information on the lower spatial frequencies. But phase contrast imaqinq is never simple except in idealized limitinq cases.

Radiation-Induced Precipitation at Thin Foil Surfaces in Ni-Be Alloys

1982 ◽  
Vol 40 ◽  
pp. 598-599
Author(s):  
T. Mukai ◽  
T. E. Mitchell
Keyword(s):  
Electron Microscopy ◽  
High Voltage ◽  
Electron Irradiation ◽  
High Vacuum ◽  
Thin Foil ◽  
Homogeneous Precipitation ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
High Voltage Electron ◽  
Radiation Induced

Radiation-induced homogeneous precipitation in Ni-Be alloys was recently observed by high voltage electron microscopy. A coupling of interstitial flux with solute Be atoms is responsible for the precipitation. The present investigation further shows that precipitation is also induced at thin foil surfaces by electron irradiation under a high vacuum.

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