scholarly journals Exciton-induced lattice defect formation

2003 ◽  
Vol 29 (3) ◽  
pp. 270-273 ◽  
Author(s):  
E. V. Savchenko ◽  
A. N. Ogurtsov ◽  
G. Zimmerer
Keyword(s):  
Defect Formation ◽  
Lattice Defect

scholarly journals Enhanced Lattice Defect Formation Associated with Hydrogen and Hydrogen Embrittlement under Elastic Stress of a Tempered Martensitic Steel

2012 ◽  
Vol 98 (5) ◽  
pp. 197-206 ◽  
Author(s):  
Tomoki Doshida ◽  
Hiroshi Suzuki ◽  
Kenichi Takai ◽  
Nagayasu Oshima ◽  
Tetsuya Hirade
Keyword(s):  
Hydrogen Embrittlement ◽  
Defect Formation ◽  
Elastic Stress ◽  
Martensitic Steel ◽  
Lattice Defect

scholarly journals Enhanced Lattice Defect Formation Associated with Hydrogen and Hydrogen Embrittlement under Elastic Stress of a Tempered Martensitic Steel

2012 ◽  
Vol 52 (2) ◽  
pp. 198-207 ◽  
Author(s):  
Tomoki Doshida ◽  
Hiroshi Suzuki ◽  
Kenichi Takai ◽  
Nagayasu Oshima ◽  
Tetsuya Hirade
Keyword(s):  
Hydrogen Embrittlement ◽  
Defect Formation ◽  
Elastic Stress ◽  
Martensitic Steel ◽  
Lattice Defect

scholarly journals Structure Refinement and Fragmentation of Precipitates under Severe Plastic Deformation: A Review

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 601
Author(s):  
Boris B. Straumal ◽  
Roman Kulagin ◽  
Leonid Klinger ◽  
Eugen Rabkin ◽  
Petr B. Straumal ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Steady State ◽  
Severe Plastic Deformation ◽  
Defect Formation ◽  
Dynamic Equilibrium ◽  
Lattice Defect ◽  
Structure Refinement ◽  
Second Phase ◽  
Different Strains ◽  
State Saturation

During severe plastic deformation (SPD), the processes of lattice defect formation as well as their relaxation (annihilation) compete with each other. As a result, a dynamic equilibrium is established, and a steady state is reached after a certain strain value. Simultaneously, other kinetic processes act in opposite directions and also compete with each other during SPD, such as grain refinement/growth, mechanical strengthening/softening, formation/decomposition of solid solution, etc. These competing processes also lead to dynamic equilibrium and result in a steady state (saturation), albeit after different strains. Among these steady-state phenomena, particle fragmentation during the second phase of SPD has received little attention. Available data indicate that precipitate fragmentation slows down with increasing strain, though saturation is achieved at higher strains than in the case of hardness or grain size. Moreover, one can consider the SPD-driven nanocrystallization in the amorphous phase as a process that is opposite to the fragmentation of precipitates. The size of these crystalline nanoprecipitates also saturates after a certain strain. The fragmentation of precipitates during SPD is the topic of this review.

The effect of substitutional elements (Al, Co) in LaNi4.5M0.5 on the lattice defect formation in the initial hydrogenation and dehydrogenation

2009 ◽  
Vol 473 (1-2) ◽  
pp. 87-93 ◽  
Author(s):  
Kouji Sakaki ◽  
Etsuo Akiba ◽  
Masataka Mizuno ◽  
Hideki Araki ◽  
Yasuharu Shirai
Keyword(s):  
Defect Formation ◽  
Lattice Defect

Hydrogen-enhanced lattice defect formation and hydrogen embrittlement of cyclically prestressed tempered martensitic steel

2013 ◽  
Vol 61 (20) ◽  
pp. 7755-7766 ◽  
Author(s):  
T. Doshida ◽  
M. Nakamura ◽  
H. Saito ◽  
T. Sawada ◽  
K. Takai
Keyword(s):  
Hydrogen Embrittlement ◽  
Defect Formation ◽  
Martensitic Steel ◽  
Lattice Defect

Oxygen Ionic Transport in Brownmillerite-Type Ca2Fe2O5-δ and Calcium Ferrite-Based Composite Membranes

2013 ◽  
Vol 200 ◽  
pp. 286-292 ◽  
Author(s):  
Aliaksandr L. Shaula ◽  
Vladislav A. Kolotygin ◽  
Eugene N. Naumovich ◽  
Yevheniy V. Pivak ◽  
Vladislav V. Kharton
Keyword(s):  
Activation Energy ◽  
Defect Formation ◽  
Lattice Defect ◽  
Ionic Transport ◽  
Composite Membranes ◽  
Oxygen Permeation ◽  
Calcium Ferrite ◽  
Equal Weight ◽  
Model Composite ◽  
Oxygen Ionic Transport

Oxygen ionic transport in mixed-conducting Ca2Fe2O5-δ brownmillerite was analyzed in light of potential applications in the composite materials for oxygen separation membranes and solid oxide fuel cell cathodes. The lattice defect formation and oxygen diffusion mechanisms were assessed by the computer simulations employing molecular dynamics and static lattice modeling. The most energetically favorable oxygen-vacancy location is in the octahedral layers of the brownmillerite structure, which provide a maximum contribution to the ionic migration in comparison with the structural blocks comprising iron-oxygen tetrahedra. The activation energies for the vacancy and interstitial diffusion in the tetrahedral layers, and also between the octahedral and tetrahedral sheets, are several times higher. The calculated values were found comparable to the experimental activation energy for ionic conduction in Ca2Fe2O5-δ, 147 kJ/mol, determined by the steady-state oxygen permeation measurements. The dense membranes of model composite Ca2Fe2O5-δ - Ce0.9Gd0.1O2-δ with equal weight fractions of the components (CGCF5) were sintered and characterized. No critical interdiffusion of the composite constituents, leading to their decomposition, was found by X-ray diffraction and electron microscopic analyses. The electrical conductivity of this composite, with an activation energy of 37 kJ/mol, is intermediate between two parent compounds and is dominantly p-type electronic as for Ca2Fe2O5-δ. Since the ion- and electron-conducting phases are well percolated in the composite ceramics, the oxygen permeation fluxes through CGCF5 are considerably higher than those of both constituents.

A Comparison of Intrinsic Point Defect Properties in Si and Ge

2008 ◽  
Vol 1070 ◽  
Author(s):  
Jan Vanhellemont ◽  
Piotr Spiewak ◽  
Koji Sueoka ◽  
Eddy Simoen ◽  
Igor Romandic
Keyword(s):  
Crystal Growth ◽  
Point Defect ◽  
Point Defects ◽  
Defect Formation ◽  
Lattice Defect ◽  
Intrinsic Point Defect ◽  
Thermal Treatments ◽  
Intrinsic Point Defects ◽  
Device Processing ◽  
Processing Point

ABSTRACTIntrinsic point defects determine to a large extent the semiconductor crystal quality both mechanically and electrically not only during crystal growth or when tuning polished wafer properties by thermal treatments, but also and not the least during device processing. Point defects play e.g. a crucial role in dopant diffusion and activation, in gettering processes and in extended lattice defect formation.Available experimental data and results of numerical calculation of the formation energy and diffusivity of the intrinsic point defects in Si and Ge are compared and discussed. Intrinsic point defect clustering is illustrated by defect formation during Czochralski crystal growth.

Hydrogen Dragging by Moving Dislocation and Enhanced Lattice Defect Formation in 316L and 304 Stainless Steels

2013 ◽  
Author(s):  
Kenichi Takai ◽  
Megumi Kitamura
Keyword(s):  
Plastic Deformation ◽  
Stainless Steel ◽  
Stainless Steels ◽  
Defect Formation ◽  
Lattice Defect ◽  
Hydrogen Desorption ◽  
Lattice Defects ◽  
304 Stainless Steel ◽  
Face Centered Cubic ◽  
Vacancy Clusters

Little is known about an enhanced lattice defect formation due to an interaction between hydrogen and dislocation in face-centered cubic (fcc) metals such as stainless steels. In the present study, hydrogen spectra evolved from Type 316L and 304 stainless steels during elastic and plastic deformation were detected using a quadrupole mass spectrometer. The amount of lattice defect enhanced by hydrogen and strain was measured using thermal desorption analysis. For 316L stainless steel, hydrogen desorption increased rapidly when plastic deformation began, since the dislocation dragged hydrogen to the surface of the specimen. In contrast, hydrogen desorption increased with applying strain for 304 stainless steel, because of phase transformation from austenite into martensite with larger hydrogen diffusivity. And the amount of desorbed hydrogen increased with decreasing strain rate. These results indicate that dislocation can drag and transport large amounts of hydrogen when the dislocation velocity approaches the hydrogen diffusion rate. The amount of lattice defects in stainless steels was enhanced by hydrogen and applied strain. The most probable reason for the increase in the amount of lattice defects can be ascribed to the increase in the amount of vacancy clusters. These findings lead to the conclusion that the interaction between dislocation and hydrogen enhances the formation of vacancy clusters, as a result, causes hydrogen embrittlement.

Sign in / Sign up

Export Citation Format

Share Document