scholarly journals Extracting the Grain Boundary Character/Free Energy Relationship from the Microstructure: Pure and Tilt Boundaries

1997 ◽  
Vol 472 ◽  
Author(s):  
B. Adams ◽  
D. Kinderlehrer ◽  
S. Ta'asan ◽  
W.W. Mullins ◽  
S. Costiner
Keyword(s):  
Free Energy ◽  
Grain Boundary ◽  
Excess Free Energy ◽  
Free Energy Function ◽  
Triple Junctions ◽  
Grain Boundary Character ◽  
Classical Work ◽  
Tilt Boundaries ◽  
Lattice Misorientation ◽  
Two Parameter

ABSTRACTAnalysis is described to extract the excess free energy of grain boundaries from the mesotexture of well-equilibrated polycrystalline samples. The approach is based upon the force and torque balances at triple junctions described in the classical work of Herring [1]. The main advantage of the approach is that the free energy function is obtained over the full fundamental zone of grain boundary types. For the purposes of exposition, the method is described for specified two-parameter hypersurfaces in the fundamental zone for cubic polycrystals (the sets of pure <100> and <111> tilt boundaries) and the free energy is assumed to depend only upon the lattice misorientation. Results from testbed simulations are presented.

Five-Parameter Grain Boundary Character Distribution in Fe-1%Si

2004 ◽  
Vol 467-470 ◽  
pp. 727-732 ◽  
Author(s):  
Tricia A. Bennett ◽  
Chang Soo Kim ◽  
Gregory S. Rohrer ◽  
Anthony D. Rollett
Keyword(s):  
Grain Boundary ◽  
Grain Boundary Character Distribution ◽  
Crystalline Materials ◽  
Boundary Character ◽  
Grain Boundary Character ◽  
Symmetric Tilt ◽  
Character Distribution ◽  
Tilt Boundaries ◽  
Boundary Character Distribution ◽  
Lattice Misorientation

The grain boundary character distribution in an Fe-1%Si steel has been measured as a function of lattice misorientation and boundary plane orientation. There is a weak texture in the space of grain boundary planes that favors the {110} orientation. At specific misorientations, the anisotropy is larger. For example, when the lattice misorientation is 60° around [111], symmetric tilt boundaries comprised of two {110} planes on either side of the interface dominate the population. The results are consistent with observations suggesting that in a range of crystalline materials, the low energy, low index surface planes are found to dominate the distribution of internal interfaces.

Predictive Theory for the Grain Boundary Character Distribution

2012 ◽  
Vol 715-716 ◽  
pp. 279-285 ◽  
Author(s):  
Katayun Barmak ◽  
Eva Eggeling ◽  
M. Emelianenko ◽  
Y. Epshteyn ◽  
David Kinderlehrer ◽  
...  
Keyword(s):  
Steady State ◽  
Grain Boundary ◽  
Relative Length ◽  
Boltzmann Distribution ◽  
Grain Boundary Character Distribution ◽  
Boundary Character ◽  
Grain Boundary Character ◽  
Character Distribution ◽  
Boundary Character Distribution ◽  
Lattice Misorientation

Mesoscale experiment and simulation permit harvesting information about both geometric featuresand texture in material microstructures. The grain boundary character distribution (GBCD) is an em-pirical distribution of the relative length (in 2D) or area (in 3D) of interface with a given lattice misori-entation and grain boundary normal. During the growth process, an initially random texture distribu-tion reaches a steady state that is strongly correlated to the interfacial energy density [9]. In simulation,it is found that if the given energy depends only on lattice misorientation, then the steady state GBCDand the energy are related by a Boltzmann distribution. This is among the simplest non-random dis-tributions, corresponding to independent trials with respect to the energy. Why does such a simpledistribution arise from such a complex system?.

scholarly journals Effect of excess free energy of solvents on the oxidation of methionine by quinolinium fluorochromate: A kinetic study

2008 ◽  
Vol 73 (7) ◽  
pp. 735-744 ◽  
Author(s):  
D.S. Bhuvaneshwari ◽  
K.P. Elango
Keyword(s):  
Free Energy ◽  
Excess Free Energy ◽  
Activation Parameters ◽  
Chloroacetic Acid ◽  
Reaction Rates ◽  
Solvent Mixtures ◽  
Free Energy Function ◽  
Different Temperatures ◽  
Oxidation Of Methionine ◽  
Quinolinium Fluorochromate

The oxidation of methionine by quinolinium fluorochromate (QFC) was studied in the presence of chloroacetic acid, in water/organic solvent mixtures of varying excess molar free energy function. The reaction is first order with respect to both QFC and acid. The reaction rates were determined at different temperatures and the activation parameters computed. The rate data was correlated with different solvent parameters using linear multiple regression analysis. From the results, information on the solvent-reactants and the solvent-transition state interactions was obtained. .

Structural Dependence of Grain Boundary Energy in Fe-Based Polycrystals Identified by OIM Measurements

2007 ◽  
Vol 550 ◽  
pp. 411-416
Author(s):  
Patricia Gobernado ◽  
Leo Kestens
Keyword(s):  
Grain Boundary ◽  
Boundary Energy ◽  
Initial Boundary ◽  
Geometrical Configuration ◽  
Grain Boundary Energy ◽  
Triple Junctions ◽  
High Angle ◽  
Orientation Contrast ◽  
Contrast Microscopy ◽  
Two Parameter

The (relative) grain boundary energy of random high angle boundaries has been measured in several Fe-based polycrystals. Crystallographic data obtained by orientation contrast microscopy (OIM) are combined with the geometrical configuration of grain boundaries at triple junctions. A two-parameter representation of the relative grain boundary energy in terms of misorientation angle and misorientation axis is presented. In the applied procedure a variation of the energy values assigned to one boundary was observed depending on the triangulation path chosen by the operator to connect the arbitrary initial boundary with the boundary under consideration. Results show no evidence of correspondence between the observed energy cusps and the presence of CSL boundaries.

Two-Dimensional Grain Growth Simulation by Local Curvature Multi-Vertex Model

2012 ◽  
Vol 715-716 ◽  
pp. 551-556 ◽  
Author(s):  
Teruyuki Tamaki ◽  
Kenichi Murakami ◽  
Hotaka Homma ◽  
Kohsaku Ushioda
Keyword(s):  
Grain Boundary ◽  
Boundary Energy ◽  
Two Dimensional ◽  
Vertex Model ◽  
Triple Junctions ◽  
Local Curvature ◽  
Misorientation Distribution ◽  
Grain Boundary Character ◽  
Random Microstructure ◽  
Physical Principles

A local curvature multi-vertex model was developed. This model is the straightforward two-dimensional topological network model based on the physical principles which are the curvatures of grain boundaries and the grain boundary tensions at triple junctions. The model was applied to the artificial random microstructure under some conditions of grain boundary characters. The misorientation distribution was changed very little under constant grain boundary energy and mobility, but it was change much under grain boundary character dependent on misorientation. Therefore, in order to discuss actual textures, it is important to take grain boundary characters into account.

Mesoscale Simulation of the Evolution of the Grain Boundary Character Distribution

2004 ◽  
Vol 467-470 ◽  
pp. 1063-1068 ◽  
Author(s):  
D. Kinderlehrer ◽  
Irene Livshits ◽  
Gregory S. Rohrer ◽  
Shlomo Ta'asan ◽  
Peng Yu
Keyword(s):  
Steady State ◽  
Grain Boundary ◽  
Boundary Energy ◽  
Grain Boundary Character Distribution ◽  
Grain Boundary Energy ◽  
Boundary Character ◽  
Grain Boundary Character ◽  
Character Distribution ◽  
Boundary Character Distribution ◽  
Lattice Misorientation

A mesoscale, variational simulation of grain growth in two-dimensions has been used to explore the effects of grain boundary properties on the grain boundary character distribution. Anisotropy in the grain boundary energy has a stronger influence on the grain boundary character distribution than anisotropy in the grain boundary mobility. As grain growth proceeds from an initially random distribution, the grain boundary character distribution reaches a steady state that depends on the grain boundary energy. If the energy depends only on the lattice misorientation, then the population and energy are related by the Boltzmann distribution. When the energy depends on both lattice misorientation and boundary orientation, the steady state grain boundary character distribution is more complex and depends on both the energy and changes in the gradient of the energy with respect to orientation.

Grain Boundary Character Evolution during Grain Growth in a Zr Alloy

2007 ◽  
Vol 558-559 ◽  
pp. 863-868 ◽  
Author(s):  
Nathalie Bozzolo ◽  
Grzegorz Sawina ◽  
Francois Gerspach ◽  
Krzystof Sztwiertnia ◽  
Anthony D. Rollett ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Grain Growth ◽  
Misorientation Distribution ◽  
Boundary Character ◽  
Rotation Axes ◽  
Grain Boundary Character ◽  
Two Samples ◽  
Different Temperatures ◽  
Lattice Misorientation ◽  
Zr Alloy

Grain boundary character in samples of Zr701 annealed at two different temperatures has been investigated in terms of lattice misorientation. The main difference between the two samples was the extent of grain growth post-recrystallization. The textures were typical for the material. Differences between the texture-based misorientation distribution function (T-MDF) and the microstructure-based MDF (M-MDF) revealed significant preferences for certain grain boundary types, notably those with <11-20> rotation axes.

DISTRIBUTION AND CORROSION BEHAVIORS OF THE TRIPLE JUNCTIONS IN A GRAIN BOUNDARY ENGINEERED 304 STAINLESS STEEL

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1110-1115 ◽  
Author(s):  
XIAOYING FANG ◽  
WEIGUO WANG ◽  
HONG GUO ◽  
CONGXIANG QIN ◽  
BANGXIN ZHOU
Keyword(s):  
Stainless Steel ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Intergranular Corrosion ◽  
Electron Back Scatter Diffraction ◽  
304 Stainless Steel ◽  
Grain Boundary Character Distribution ◽  
Triple Junctions ◽  
Grain Boundary Character ◽  
Character Distribution

Grain boundary character distribution (GBCD) and triple junction character distribution (TJCD) in a 304 stainless steel cold rolled with the thickness reduction of 6% and then annealed at 1323K for 5 minutes(GBE process) were analyzed by electron back scatter diffraction (EBSD). The intergranular corrosion (IGC) resistance of various triple junctions and grain boundaries were evaluated after sensitization treatment at 1073K for 30 minutes. The results showed special TJ containing 2 or 3 CSL boundaries exhibit higher resistance to IGC than other TJs. In addition, the {411} and {221} symmetrical tilt grain boundaries (STGBs) are more resistant to intergranular corrosion for Σ9 boundaries.

Finite temperature structure and thermodynamics of the Au Σ5 (001) twist boundary

1990 ◽  
Vol 5 (11) ◽  
pp. 2663-2676 ◽  
Author(s):  
R. Najafabadi ◽  
D. J. Srolovitz ◽  
R. LeSar
Keyword(s):  
Free Energy ◽  
Grain Boundary ◽  
Specific Heat ◽  
Excess Volume ◽  
Coefficient Of Thermal Expansion ◽  
Excess Free Energy ◽  
Boundary Structure ◽  
Temperature Structure ◽  
Twist Boundary ◽  
Eam Potential

The structure and thermodynamic properties of a Σ5 (001) twist boundary in gold are studied as a function of temperature. This study was performed within the framework of the Local Harmonic (LH) model and employed an Embedded Atom Method (EAM) potential for gold. We find that for the Σ5 (001) twist boundary in gold, a distorted CSL structure is stable at low temperatures, but undergoes a phase transformation to a DSC related structure near room temperature. This transformation is shown to be first order. The temperature dependences of the excess grain boundary free energy, enthalpy, entropy, specific heat, and excess volume are calculated. Discontinuities are observed in the slope of the grain boundary excess free energy (versus temperature), in the value of the grain boundary excess specific heat and excess volume. The stable high temperature grain boundary structure has a smaller excess volume than does the lower temperature structure, and both structures have a coefficient of thermal expansion which is in excess of that for the perfect crystal.

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