INTERACTION BETWEEN LATTICE DISLOCATIONS AND GRAIN BOUNDARIES IN FCC METALS AND ORDERED COMPOUNDS

1990 ◽  
Vol 51 (C1) ◽  
pp. C1-311-C1-316 ◽  
Author(s):  
B. J. PESTMAN ◽  
J. Th. M. DE HOSSON ◽  
V. VITEK ◽  
F. W. SCHAPINK
Keyword(s):  
Grain Boundaries ◽  
Fcc Metals

Survey of Grain Boundary Energies in Four Elemental Metals

2012 ◽  
Vol 715-716 ◽  
pp. 179-179
Author(s):  
David L. Olmsted ◽  
Elizabeth A. Holm ◽  
Stephen M. Foiles
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Energy Minimization ◽  
Boundary Energy ◽  
Atomic Scale ◽  
Energy Structure ◽  
Grain Boundary Energy ◽  
Fcc Metals ◽  
Composition And Structure ◽  
Boundary Properties

Grain boundary properties depend on both composition and structure. To test the relative contributions of composition and structure to the grain boundary energy, we calculated the energy of 388 grain boundaries in four elemental, fcc metals: Ni, Al, Au and Cu. We constructed atomic-scale bicrystals of each boundary and subjected them to a rigorous energy minimization process to determine the lowest energy structure. Typically, several thousand boundary configurations were examined for each boundary in each element.

Understanding the Threshold Conditions for Dislocation Transmission from Tilt Grain Boundaries in FCC Metals under Uniaxial Loading

2014 ◽  
Vol 553 ◽  
pp. 28-34 ◽  
Author(s):  
Nathaniel James Burbery ◽  
Raj Das ◽  
Giacomo Po ◽  
Nasr Ghoniem
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Strain Analysis ◽  
Dislocation Slip ◽  
Shear Stresses ◽  
Dislocation Dynamic ◽  
Dynamic Simulations ◽  
Fcc Metals ◽  
Grain Boundary Characteristics ◽  
Meso Scale

Plastic deformation in face-centred cubic (or ‘FCC’) metals involves multi-scale phenomena which are initiated at atomic length and time scales (on order of 1.0e-15seconds). Understanding the fundamental thresholds for plasticity at atomic and nano/meso scales requires rigorous testing, which cannot be feasibly achieved with current experimental methods. Hence, computer simulation-based investigations are extremely valuable. However, meso-scale simulations cannot yet accommodate atomically-informed grain boundary (or ‘GB’) effects and dislocation interactions. This study will provide a stress - strain analysis based on molecular dynamics simulations of a series of metastable grain boundaries with identical crystal orientations but unique grain boundary characteristics. Relationships between dislocation slip systems, resolved shear stresses and additional thermo-mechanical conditions of the system will be considered in the analysis of dislocation-grain boundary interactions, including GB penetration. This study will form the basis of new phenomenological relationships in an effort to enable accommodation of grain boundaries into meso scale dislocation dynamic simulations.

scholarly journals Dislocation Behavior in the Vicinity of Grain Boundaries in FCC Metals and Alloys

1983 ◽  
Vol 24 (4) ◽  
pp. 195-204 ◽  
Author(s):  
Hiroshi Fujita ◽  
Katsuyuki Toyoda ◽  
Takeshi Mori ◽  
Teiz\={o} Tabata ◽  
Tatuo Ono ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
Metals And Alloys ◽  
Fcc Metals ◽  
Dislocation Behavior

Molecular Dynamics Simulations of Nanocrystalline Nickel and Copper Revealing Different Failure Model of FCC Metals

2009 ◽  
Vol 633-634 ◽  
pp. 31-38
Author(s):  
Ajing Cao
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Grain Boundaries ◽  
Large Scale ◽  
Uniaxial Tensile ◽  
Face Centered Cubic ◽  
Triple Junctions ◽  
Fcc Metals ◽  
Face Centered ◽  
Dynamics Simulations

We have previously reported that the fracture behavior of nanocrystalline (NC) Ni is via the nucleation and coalescence of nano-voids at grain boundaries and triple junctions, resulting in intergranular failure mode. Here we show in large-scale molecular dynamics simulations that partial-dislocation-mediated plasticity is dominant in NC Cu with grain size as small as ~ 10 nanometers. The simulated results show that NC Cu can accommodate large plastic strains without cracking or creating damage in the grain interior or grain boundaries, revealing their intrinsic ductile properties compared with NC Ni. These results point out different failure mechanisms of the two face-centered-cubic (FCC) metals subject to uniaxial tensile loading. The insight gained in the computational experiments could explain the good plasticity found in NC Cu not seen in Ni so far.

Structure and Properties of Polycrystalline Materials From Simulation: An Interfacial Perspective

1999 ◽  
Vol 586 ◽  
Author(s):  
S. R. Phillpot ◽  
P. Keblinski ◽  
D. Wolf ◽  
F. Cleri
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Boundary Diffusion ◽  
Simulation Method ◽  
High Energy ◽  
Grain Boundary Diffusion ◽  
Dynamics Simulation ◽  
Polycrystalline Materials ◽  
Diffusion Creep ◽  
Fcc Metals

ABSTRACTWe have recently developed a novel molecular-dynamics simulation method to grow polycrystals from a melt containing randomly oriented crystalline seeds. The resulting microstructures contain only randomly oriented (i.e., high-energy) grain boundaries. We find that these grain boundaries, which are highly constrained by their close proximity to grain junctions, are highly disordered in fcc metals and amorphous in silicon. From simulations of infinitely extended high-energy grain boundaries in bicrystals, we find that such highly disordered and amorphous grain boundaries are actually the thermodynamic ground state; by contrast, low-energy grain boundaries are crystalline. High-energy grain boundaries in diamond, however, are structurally ordered at the expense of a significant amount of graphite-like bonding. We show that these complex grain boundary structures have important effects on properties including grain boundary diffusion (fcc metals and silicon), grain boundary diffusion creep (silicon) and grain boundary electrical activity and strength (diamond). The implications for engineering materials with prescribed properties are discussed.

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.

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