THE STUDY OF FORMATION OF EXCESS FREE VOLUME IN THE TRIPLE JUNCTIONS OF TILT BOUNDARIES IN NICKEL AT CRYSTALLIZATION BY THE METHOD OF MOLECULAR DYNAMICS

2016 ◽  
Vol 21 (3) ◽  
pp. 1191-1194
Author(s):  
D.V. Novoselova ◽  
◽  
G.M. Poletaev ◽  
V.M. Kaygorodova ◽  
E.S. Medvedeva ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Free Volume ◽  
Triple Junctions ◽  
Excess Free Volume ◽  
Method Of Molecular Dynamics ◽  
Tilt Boundaries

The Causes of Formation of the Triple Junctions of Grain Boundaries Containing Excess Free Volume in fcc Metals at Crystallization

2016 ◽  
Vol 247 ◽  
pp. 3-8 ◽  
Author(s):  
Gennady M. Poletaev ◽  
Darya V. Novoselova ◽  
Valentina M. Kaygorodova
Keyword(s):  
Molecular Dynamics ◽  
Grain Boundaries ◽  
Free Volume ◽  
Crystallization Process ◽  
Triple Junctions ◽  
Phase Density ◽  
Fcc Metals ◽  
Excess Free Volume ◽  
Method Of Molecular Dynamics ◽  
Formation Conditions

The formation conditions of strained (non-equilibrium) triple junctions of grain boundaries were studied by the method of molecular dynamics. It is shown that strained triple junctions, containing excess free volume, mainly forms during crystallization process in the result of "locking" of the liquid phase density at a meeting of the three crystallization fronts and, as a consequence, of the concentration of excess free volume in the triple junction after solidification.

scholarly journals Исследование формирования избыточного свободного объема в тройных стыках границ зерен при кристаллизации на примере никеля

2018 ◽  
Vol 60 (5) ◽  
pp. 846
Author(s):  
Г.М. Полетаев ◽  
Д.В. Новоселова ◽  
И.В. Зоря ◽  
М.Д. Старостенков
Keyword(s):  
Molecular Dynamics ◽  
Liquid Phase ◽  
Free Volume ◽  
Triple Junctions ◽  
Phase Volume ◽  
Extended State ◽  
Dynamics Model ◽  
Excess Free Volume ◽  
High Fraction

AbstractThe formation of an excess free volume in triple junctions during crystallization has been studied by the molecular dynamics model using nickel as an example. It is shown that an excess free volume that forms during nickel crystallization in triple junctions predominantly forms as a result of the fixation of the liquid phase volume when contacting three crystallization fronts that contains, after crystallization, a high fraction of the free volume. In some cases, as the free volume is concentrated in triple junctions, a comparatively small crystalline subgrain (from one to several nanometers in diameter) forms, and the subgrain has the orientation different from those of contacting grains and exists in the extended state.

scholarly journals The formation of excess free volume in triple junctions of and tilt boundaries in Ni at crystallization

2016 ◽  
Author(s):  
Gennady Poletaev ◽  
Darya Novoselova ◽  
Valentina Kaygorodova ◽  
Mikhail Starostenkov
Keyword(s):  
Free Volume ◽  
Triple Junctions ◽  
Excess Free Volume ◽  
Tilt Boundaries

Excess Free Volume of High Angle Grain Boundaries in Aluminium

2006 ◽  
Vol 519-521 ◽  
pp. 1557-1562 ◽  
Author(s):  
V.A. Ivanov ◽  
Dmitri A. Molodov ◽  
Lasar S. Shvindlerman ◽  
Günter Gottstein ◽  
D. Kolesnikov ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
Free Volume ◽  
Pressure Range ◽  
Boundary Energy ◽  
Tilt Boundary ◽  
Triple Junctions ◽  
High Angle ◽  
Absolute Value ◽  
Excess Free Volume ◽  
Tilt Boundaries

A new method is introduced to determine the absolute value of the boundary excess free volume. Along with the boundary energy the excess free volume belongs to the major thermodynamic properties of grain boundaries. The method utilizes the dependence of the contact angle at triple junctions of grain boundaries in Al-tricrystals on hydrostatic pressure. We investigated <111> tilt boundaries in the pressure range up to 14 kbar. In particular, for a 40° <111> tilt boundary with 2° twist component the boundary free volume was found to be equal to 5.03×10-11 m3/m2.

scholarly journals Молекулярно-динамическое исследование влияния концентрации вакансий на скорость миграции границ наклона в никеле

2021 ◽  
Vol 63 (5) ◽  
pp. 582
Author(s):  
Г.М. Полетаев ◽  
Р.Ю. Ракитин
Keyword(s):  
Free Volume ◽  
Driving Force ◽  
Migration Rate ◽  
Vacancy Concentration ◽  
High Angle ◽  
Vacancy Clusters ◽  
Method Of Molecular Dynamics ◽  
Initial Stage ◽  
Tilt Boundaries ◽  
Mobile Vacancy

The influence of vacancy concentration on the migration rate of high-angle tilt boundaries with misorientation axes <111> and <100> in nickel was studied by the method of molecular dynamics. It is shown that the dependence of the migration rate on the concentration of vacancies introduced at the initial stage of modeling has a maximum near 1%. The decrease in the migration rate with a further increase in the free volume is mainly due to the deceleration of the boundary by low-mobile vacancy clusters, which at high vacancy concentrations the boundary is no longer capable of sorbing. The second reason for the decrease in the migration rate with an increase in the concentration of vacancies above 1% is a decrease in the surface tension of grain boundaries and, accordingly, the driving force of their migration due to the finite sorption capacity of the boundaries with respect to the excess free volume.

Size Effect in the Shear-Coupled Migration of Grain Boundaries Pinned by Triple Junctions

2009 ◽  
Vol 1224 ◽  
Author(s):  
Javier Gil Sevillano ◽  
Aitor Luque ◽  
Javier Aldazabal ◽  
José Manuel Martinez-Esnaola
Keyword(s):  
Molecular Dynamics ◽  
Simple Model ◽  
Low Temperature ◽  
Size Effect ◽  
Model Structure ◽  
Triple Junctions ◽  
Columnar Grains ◽  
Tilt Boundaries ◽  
Relationship Breakdown ◽  
Dynamics Simulations

AbstractThis paper presents molecular dynamics simulations of shear-coupled migration of tilt boundaries pinned by triple junctions in a simple model structure of columnar grains of different sizes. Simulations are for copper at 300 K. The phenomenon is of interest as a possible explanation of the Hall-Petch relationship breakdown in nano-grained polycrystals deformed at high or moderate strain rate and low-temperature.

Determination of the Radius of Triple Junctions of Tilt Boundaries: A Molecular Dynamics Simulation

2019 ◽  
Vol 62 (4) ◽  
pp. 680-686
Author(s):  
G. M. Poletaev ◽  
M. D. Starostenkov ◽  
R. Yu. Rakitin ◽  
V. Ya. Tsellermaer ◽  
M. A. Ilyina
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Dynamics Simulation ◽  
Triple Junctions ◽  
Tilt Boundaries

scholarly journals Влияние концентрации вакансий на скорость миграции границ наклона в никеле: молекулярно-динамическое моделирование

2021 ◽  
Vol 47 (8) ◽  
pp. 29
Author(s):  
Г.М. Полетаев ◽  
Р.Ю. Ракитин
Keyword(s):  
Molecular Dynamics ◽  
Grain Boundaries ◽  
Migration Rate ◽  
Vacancy Concentration ◽  
High Angle ◽  
Vacancy Clusters ◽  
Method Of Molecular Dynamics ◽  
Initial Stage ◽  
Tilt Boundaries ◽  
Small Clusters

The effect of vacancy concentration on the migration rate of high-angle tilt boundaries with misorientation axes <111> and <100> in nickel was studied by the method of molecular dynamics. It is shown that the dependence of the migration rate of grain boundaries on the vacancy concentration is nonmonotonic and has a maximum at a concentration of vacancies introduced at the initial stage of about 1%. With a further increase in concentration, especially above 4%, the migration rate of the considered boundaries decreased as a result of deceleration of boundaries by low-mobility vacancy clusters attached to it, which the boundary could no longer sorb, as in the case of relatively small clusters.

scholarly journals MOLECULAR-DYNAMICS RESEARCH OF STRUCTURE OF TRIPLE JUNCTIONS OF TILT BOUNDARIES AND MIXED-TYPE GRAIN BOUNDARIES IN NICKEL

2015 ◽  
Vol 56 (4) ◽  
pp. 46
Author(s):  
G. M. Poletaev ◽  
D. V. Dmitrienko ◽  
V. V. Diabdenkov ◽  
V. R. Mikrukov ◽  
M. D. Starostenkov
Keyword(s):  
Molecular Dynamics ◽  
Grain Boundaries ◽  
Mixed Type ◽  
Triple Junctions ◽  
Tilt Boundaries
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