The Experts below are selected from a list of 180 Experts worldwide ranked by ideXlab platform
Weimin Mao - One of the best experts on this subject based on the ideXlab platform.
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Study on Texture and Grain Orientation Evolution in Cold-Rolled BCC Steel by Reaction Stress Model
Crystals, 2020Co-Authors: Ning Zhang, Li Meng, Wenkang Zhang, Weimin MaoAbstract:The evolution of texture and grain orientations in a cold-rolled steel of BCC structure was simulated by a Reaction Stress (RS) model. The results show that cold-rolled texture could be assessed based on a RS model because the Stress and strain are considered to remain consistent in the deformation process. The strain consistency is actualized by the cooperation of two plastic strains and an elastic strain. The accumulation range of each Reaction Stress and different activation abilities of {110} and {112} slip systems strongly affect the calculated deformation textures. The values of Reaction Stress are influenced by elastic anisotropy; however, the effects are greatly reduced because its corresponding Reaction Stress accumulation is limited. Typical α-fiber and γ-fiber textures are achieved when the Reaction Stress accumulation coefficients αijs are chosen suitably. Furthermore, the αij values that are selected based on statistically calculated textures can also be used to simulate the orientation change of multiple orientations. The existence of Reaction Stress is able to stabilize crystallographically symmetrical orientations under rolling deformation, in which the Schmid factors of several slip systems are identical.
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Study on the cold rolling deformation behavior of polycrystalline tungsten
International Journal of Refractory Metals and Hard Materials, 2019Co-Authors: Ning Zhang, Weimin MaoAbstract:Abstract Tungsten is paid special attention due to its superior properties, especially in nuclear field. Meanwhile it is suitable for texture simulation investigation of BCC metals and alloys as it's near elastically isotropic. This study investigates the cold rolling deformation texture of polycrystalline tungsten using RS model, in which the Stress and strain consistence is realized simultaneously. The texture evolution and effects of deformation parameters, including external as well as internal Reaction Stress, strain and activation of different slip, on texture during rolling are discussed by comparing the simulated results and reported experimental results in literatures. The results show that, the cold rolling deformation texture could be simulated statistically based on RS model. The accumulation of each Reaction Stress is different. The up-limit of Reaction Stress σ'12 is found to be medium, meaning that σ'12 exerts important effect on texture evolution. Much lower accumulation level of σ'13 as well σ'23 is displayed, each of which within certain range contributes to the increase of different γ-fiber texture components. The effect of σ'22 can't be ignored during rolling, especially in the case of obtaining {111} texture. Regarding the deformation textures of tungsten rolled to true strains of −1.7 and −2.91, {001} texture is strengthened with the increasing strain and becomes dominant, implying the easier activation of {112} slip systems; γ-fiber texture is weakened at higher strain, and the formation of {111} texture shows significant effect of surface shear Stress σ13, which is due to the nonnegligible surface friction when rolling at high temperature.
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On the Taylor principles for plastic deformation of polycrystalline metals
Frontiers of Materials Science, 2016Co-Authors: Weimin MaoAbstract:Grain orientation evolutions and texture formation based on the Taylor principles offer important references to reveal crystallographic mechanisms of deformation behaviors. Strain equilibrium between grains is achieved in Taylor theory, however, Stress equilibrium has not yet been reached perfectly even in many modifications of the theory though the textures predicted become very close to those of experimental observations. A Reaction Stress model is proposed, in which mechanical interactions between grains are considered in details and grain deformation is conducted by penetrating and non-penetrating slips. The new model offers both of the Stress and strain equilibria and predicts the same textures indicated by Taylor theory. The rolling texture simulated comes very close to the experimental observations if the relaxation effect of the non-penetrating slips on the up-limits of Reaction Stresses is included. The Reaction Stress principles open theoretically a new field of vision to consider deformation behaviors of polycrystalline materials, whereas the Taylor principles become unnecessary both theoretically and practically. Detailed engineering conditions have to be included in simulations if the deformation textures of industrial products should be predicted.
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Intergranular mechanical equilibrium during the rolling deformation of polycrystalline metals based on Taylor principles
Materials Science and Engineering: A, 2016Co-Authors: Weimin MaoAbstract:Abstract Taylor principles indicate that the Taylor strain tensor is identical to the macroscopic strain tensor during plastic deformation and prevails everywhere inside polycrystalline aggregates, in which real grain behaviors generally differ. These principles have been modified in many deformation models while considering strain and Stress equilibria in local areas, e.g., grains, grain pairs or grain clusters. However, the Taylor strain tensor is still valid in the surrounding matrix of local areas. In this paper, a Reaction Stress model based on intergranular mechanical interactions is proposed for rolling deformation caused by penetrating slips and additional local slips while keeping Reaction shear Stresses below certain top limits. Both Stress and strain equilibria are reached in entire rolling sheets in the model, and the same Taylor texture is predicted without the Taylor strain tensor anywhere inside the polycrystalline matrix, regardless if the isotropic matrix is rigid or elastic. Rolling-texture formation in experimental polycrystalline metals could be simulated based on the model if the relaxation effects of additional slips on reducing the top limits of Reaction shear Stresses are included.
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Rolling Texture Simulation of Aluminium Sheets Based on the Mechanism of Intergranule Reaction Stresses
Materials Science Forum, 2016Co-Authors: Weimin MaoAbstract:Many efforts have been made to simulate the rolling texture evolution in polycrystalline Al for which strain and Stress equilibrium of grains need to be considered. The conventional Taylor theory and its modifications, such as current VPSC, ALAMEL, GIA, fail to solve the problem of Stress incompatibility between grains and their surrounding matrix properly. A Reaction Stress model is suggested for rolling deformation, which accounts both for Stress and strain equilibrium and predicts similar textures as those by the Taylor theory. The corresponding detailed modification could reproduced the real rolling texture formation if the industrial rolling Stress condition is included.
David Rodney - One of the best experts on this subject based on the ideXlab platform.
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atomic scale simulation of screw dislocation coherent twin boundary interaction in al au cu and ni
Acta Materialia, 2011Co-Authors: M Chassagne, Marc Legros, David RodneyAbstract:Abstract The influence of material and choice of interatomic potential on the interaction between an a /2〈1 1 0〉{1 1 1} screw dislocation and a Σ3{1 1 1}〈1 1 0〉 coherent twin boundary (CTB) is determined by simulating this process in a range of face-centered cubic metals modeled with a total of 10 embedded-atom method (EAM) potentials. Generalized stacking fault energies are computed, showing a linear relation between the stacking faut ( γ S ) and twin energies, as well as between the unstable stacking fault ( γ US ) and unstable twinning ( γ UT ) energies. We show that the Reaction mechanism (absorption of the dislocation into the CTB or transmission into the twinned region) and Reaction Stress depend strongly on the potential used, even for a given material and are controlled by the material parameter γ S / μb P (where μ is the shear modulus and b P the Shockley partial Burgers vector), rather than the sign of the ratio ( γ US − γ S )/( γ UT − γ S ), as proposed recently by Jin et al. [1] . Moreover, there exists a critical Reaction Stress, close to 400 MPa, independent of the potential, below which the dislocation is absorbed in the CTB and above which the dislocation is transmitted into the twinned region. The simulations are discussed with respect to in situ transmission electron microscopy straining experiments in Cu that highlight the importance of thermally activated cross-slip in the interaction process and show that transmission across a twin boundary is possible but is most likely an indirect process.
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Atomic-scale simulation of screw dislocation/coherent twin boundary interaction in Al, Au, Cu and Ni
Acta Materialia, 2011Co-Authors: M Chassagne, Marc Legros, David RodneyAbstract:Abstract The influence of material and choice of interatomic potential on the interaction between an a /2〈1 1 0〉{1 1 1} screw dislocation and a Σ3{1 1 1}〈1 1 0〉 coherent twin boundary (CTB) is determined by simulating this process in a range of face-centered cubic metals modeled with a total of 10 embedded-atom method (EAM) potentials. Generalized stacking fault energies are computed, showing a linear relation between the stacking faut ( γ S ) and twin energies, as well as between the unstable stacking fault ( γ US ) and unstable twinning ( γ UT ) energies. We show that the Reaction mechanism (absorption of the dislocation into the CTB or transmission into the twinned region) and Reaction Stress depend strongly on the potential used, even for a given material and are controlled by the material parameter γ S / μb P (where μ is the shear modulus and b P the Shockley partial Burgers vector), rather than the sign of the ratio ( γ US − γ S )/( γ UT − γ S ), as proposed recently by Jin et al. [1] . Moreover, there exists a critical Reaction Stress, close to 400 MPa, independent of the potential, below which the dislocation is absorbed in the CTB and above which the dislocation is transmitted into the twinned region. The simulations are discussed with respect to in situ transmission electron microscopy straining experiments in Cu that highlight the importance of thermally activated cross-slip in the interaction process and show that transmission across a twin boundary is possible but is most likely an indirect process.
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Atomic-scale simulation of screw dislocation/coherent twin boundary interaction in Al, Au, Cu and Ni
Acta Materialia, 2011Co-Authors: M Chassagne, Marc Legros, David RodneyAbstract:The influence of material and choice of interatomic potential on the interaction between an a/2 < 1 1 0 >{1 1 1} screw dislocation and a Sigma 3{111} < 1 1 0 > coherent twin boundary (CTB) is determined by simulating this process in a range of face-centered cubic metals modeled with a total of 10 embedded-atom method (EAM) potentials. Generalized stacking fault energies are computed, showing a linear relation between the stacking faut (gamma(S)) and twin energies, as well as between the unstable stacking fault (gamma(US)) and unstable twinning (gamma(UT)) energies. We show that the Reaction mechanism (absorption of the dislocation into the CTB or transmission into the twinned region) and Reaction Stress depend strongly on the potential used, even for a given material and are controlled by the material parameter gamma(S)/mu b(P) (where mu is the shear modulus and b(p) the Shockley partial Burgers vector), rather than the sign of the ratio (gamma(US) - gamma(S))/(gamma(UT) - gamma(S)), as proposed recently by Jin et al. [1]. Moreover, there exists a critical Reaction Stress, close to 400 MPa, independent of the potential, below which the dislocation is absorbed in the CTB and above which the dislocation is transmitted into the twinned region. The simulations are discussed with respect to in situ transmission electron microscopy straining experiments in Cu that highlight the importance of thermally activated cross-slip in the interaction process and show that transmission across a twin boundary is possible but is most likely an indirect process. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
M Chassagne - One of the best experts on this subject based on the ideXlab platform.
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atomic scale simulation of screw dislocation coherent twin boundary interaction in al au cu and ni
Acta Materialia, 2011Co-Authors: M Chassagne, Marc Legros, David RodneyAbstract:Abstract The influence of material and choice of interatomic potential on the interaction between an a /2〈1 1 0〉{1 1 1} screw dislocation and a Σ3{1 1 1}〈1 1 0〉 coherent twin boundary (CTB) is determined by simulating this process in a range of face-centered cubic metals modeled with a total of 10 embedded-atom method (EAM) potentials. Generalized stacking fault energies are computed, showing a linear relation between the stacking faut ( γ S ) and twin energies, as well as between the unstable stacking fault ( γ US ) and unstable twinning ( γ UT ) energies. We show that the Reaction mechanism (absorption of the dislocation into the CTB or transmission into the twinned region) and Reaction Stress depend strongly on the potential used, even for a given material and are controlled by the material parameter γ S / μb P (where μ is the shear modulus and b P the Shockley partial Burgers vector), rather than the sign of the ratio ( γ US − γ S )/( γ UT − γ S ), as proposed recently by Jin et al. [1] . Moreover, there exists a critical Reaction Stress, close to 400 MPa, independent of the potential, below which the dislocation is absorbed in the CTB and above which the dislocation is transmitted into the twinned region. The simulations are discussed with respect to in situ transmission electron microscopy straining experiments in Cu that highlight the importance of thermally activated cross-slip in the interaction process and show that transmission across a twin boundary is possible but is most likely an indirect process.
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Atomic-scale simulation of screw dislocation/coherent twin boundary interaction in Al, Au, Cu and Ni
Acta Materialia, 2011Co-Authors: M Chassagne, Marc Legros, David RodneyAbstract:Abstract The influence of material and choice of interatomic potential on the interaction between an a /2〈1 1 0〉{1 1 1} screw dislocation and a Σ3{1 1 1}〈1 1 0〉 coherent twin boundary (CTB) is determined by simulating this process in a range of face-centered cubic metals modeled with a total of 10 embedded-atom method (EAM) potentials. Generalized stacking fault energies are computed, showing a linear relation between the stacking faut ( γ S ) and twin energies, as well as between the unstable stacking fault ( γ US ) and unstable twinning ( γ UT ) energies. We show that the Reaction mechanism (absorption of the dislocation into the CTB or transmission into the twinned region) and Reaction Stress depend strongly on the potential used, even for a given material and are controlled by the material parameter γ S / μb P (where μ is the shear modulus and b P the Shockley partial Burgers vector), rather than the sign of the ratio ( γ US − γ S )/( γ UT − γ S ), as proposed recently by Jin et al. [1] . Moreover, there exists a critical Reaction Stress, close to 400 MPa, independent of the potential, below which the dislocation is absorbed in the CTB and above which the dislocation is transmitted into the twinned region. The simulations are discussed with respect to in situ transmission electron microscopy straining experiments in Cu that highlight the importance of thermally activated cross-slip in the interaction process and show that transmission across a twin boundary is possible but is most likely an indirect process.
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Atomic-scale simulation of screw dislocation/coherent twin boundary interaction in Al, Au, Cu and Ni
Acta Materialia, 2011Co-Authors: M Chassagne, Marc Legros, David RodneyAbstract:The influence of material and choice of interatomic potential on the interaction between an a/2 < 1 1 0 >{1 1 1} screw dislocation and a Sigma 3{111} < 1 1 0 > coherent twin boundary (CTB) is determined by simulating this process in a range of face-centered cubic metals modeled with a total of 10 embedded-atom method (EAM) potentials. Generalized stacking fault energies are computed, showing a linear relation between the stacking faut (gamma(S)) and twin energies, as well as between the unstable stacking fault (gamma(US)) and unstable twinning (gamma(UT)) energies. We show that the Reaction mechanism (absorption of the dislocation into the CTB or transmission into the twinned region) and Reaction Stress depend strongly on the potential used, even for a given material and are controlled by the material parameter gamma(S)/mu b(P) (where mu is the shear modulus and b(p) the Shockley partial Burgers vector), rather than the sign of the ratio (gamma(US) - gamma(S))/(gamma(UT) - gamma(S)), as proposed recently by Jin et al. [1]. Moreover, there exists a critical Reaction Stress, close to 400 MPa, independent of the potential, below which the dislocation is absorbed in the CTB and above which the dislocation is transmitted into the twinned region. The simulations are discussed with respect to in situ transmission electron microscopy straining experiments in Cu that highlight the importance of thermally activated cross-slip in the interaction process and show that transmission across a twin boundary is possible but is most likely an indirect process. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Marc Legros - One of the best experts on this subject based on the ideXlab platform.
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atomic scale simulation of screw dislocation coherent twin boundary interaction in al au cu and ni
Acta Materialia, 2011Co-Authors: M Chassagne, Marc Legros, David RodneyAbstract:Abstract The influence of material and choice of interatomic potential on the interaction between an a /2〈1 1 0〉{1 1 1} screw dislocation and a Σ3{1 1 1}〈1 1 0〉 coherent twin boundary (CTB) is determined by simulating this process in a range of face-centered cubic metals modeled with a total of 10 embedded-atom method (EAM) potentials. Generalized stacking fault energies are computed, showing a linear relation between the stacking faut ( γ S ) and twin energies, as well as between the unstable stacking fault ( γ US ) and unstable twinning ( γ UT ) energies. We show that the Reaction mechanism (absorption of the dislocation into the CTB or transmission into the twinned region) and Reaction Stress depend strongly on the potential used, even for a given material and are controlled by the material parameter γ S / μb P (where μ is the shear modulus and b P the Shockley partial Burgers vector), rather than the sign of the ratio ( γ US − γ S )/( γ UT − γ S ), as proposed recently by Jin et al. [1] . Moreover, there exists a critical Reaction Stress, close to 400 MPa, independent of the potential, below which the dislocation is absorbed in the CTB and above which the dislocation is transmitted into the twinned region. The simulations are discussed with respect to in situ transmission electron microscopy straining experiments in Cu that highlight the importance of thermally activated cross-slip in the interaction process and show that transmission across a twin boundary is possible but is most likely an indirect process.
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Atomic-scale simulation of screw dislocation/coherent twin boundary interaction in Al, Au, Cu and Ni
Acta Materialia, 2011Co-Authors: M Chassagne, Marc Legros, David RodneyAbstract:Abstract The influence of material and choice of interatomic potential on the interaction between an a /2〈1 1 0〉{1 1 1} screw dislocation and a Σ3{1 1 1}〈1 1 0〉 coherent twin boundary (CTB) is determined by simulating this process in a range of face-centered cubic metals modeled with a total of 10 embedded-atom method (EAM) potentials. Generalized stacking fault energies are computed, showing a linear relation between the stacking faut ( γ S ) and twin energies, as well as between the unstable stacking fault ( γ US ) and unstable twinning ( γ UT ) energies. We show that the Reaction mechanism (absorption of the dislocation into the CTB or transmission into the twinned region) and Reaction Stress depend strongly on the potential used, even for a given material and are controlled by the material parameter γ S / μb P (where μ is the shear modulus and b P the Shockley partial Burgers vector), rather than the sign of the ratio ( γ US − γ S )/( γ UT − γ S ), as proposed recently by Jin et al. [1] . Moreover, there exists a critical Reaction Stress, close to 400 MPa, independent of the potential, below which the dislocation is absorbed in the CTB and above which the dislocation is transmitted into the twinned region. The simulations are discussed with respect to in situ transmission electron microscopy straining experiments in Cu that highlight the importance of thermally activated cross-slip in the interaction process and show that transmission across a twin boundary is possible but is most likely an indirect process.
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Atomic-scale simulation of screw dislocation/coherent twin boundary interaction in Al, Au, Cu and Ni
Acta Materialia, 2011Co-Authors: M Chassagne, Marc Legros, David RodneyAbstract:The influence of material and choice of interatomic potential on the interaction between an a/2 < 1 1 0 >{1 1 1} screw dislocation and a Sigma 3{111} < 1 1 0 > coherent twin boundary (CTB) is determined by simulating this process in a range of face-centered cubic metals modeled with a total of 10 embedded-atom method (EAM) potentials. Generalized stacking fault energies are computed, showing a linear relation between the stacking faut (gamma(S)) and twin energies, as well as between the unstable stacking fault (gamma(US)) and unstable twinning (gamma(UT)) energies. We show that the Reaction mechanism (absorption of the dislocation into the CTB or transmission into the twinned region) and Reaction Stress depend strongly on the potential used, even for a given material and are controlled by the material parameter gamma(S)/mu b(P) (where mu is the shear modulus and b(p) the Shockley partial Burgers vector), rather than the sign of the ratio (gamma(US) - gamma(S))/(gamma(UT) - gamma(S)), as proposed recently by Jin et al. [1]. Moreover, there exists a critical Reaction Stress, close to 400 MPa, independent of the potential, below which the dislocation is absorbed in the CTB and above which the dislocation is transmitted into the twinned region. The simulations are discussed with respect to in situ transmission electron microscopy straining experiments in Cu that highlight the importance of thermally activated cross-slip in the interaction process and show that transmission across a twin boundary is possible but is most likely an indirect process. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Ning Zhang - One of the best experts on this subject based on the ideXlab platform.
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Study on Texture and Grain Orientation Evolution in Cold-Rolled BCC Steel by Reaction Stress Model
Crystals, 2020Co-Authors: Ning Zhang, Li Meng, Wenkang Zhang, Weimin MaoAbstract:The evolution of texture and grain orientations in a cold-rolled steel of BCC structure was simulated by a Reaction Stress (RS) model. The results show that cold-rolled texture could be assessed based on a RS model because the Stress and strain are considered to remain consistent in the deformation process. The strain consistency is actualized by the cooperation of two plastic strains and an elastic strain. The accumulation range of each Reaction Stress and different activation abilities of {110} and {112} slip systems strongly affect the calculated deformation textures. The values of Reaction Stress are influenced by elastic anisotropy; however, the effects are greatly reduced because its corresponding Reaction Stress accumulation is limited. Typical α-fiber and γ-fiber textures are achieved when the Reaction Stress accumulation coefficients αijs are chosen suitably. Furthermore, the αij values that are selected based on statistically calculated textures can also be used to simulate the orientation change of multiple orientations. The existence of Reaction Stress is able to stabilize crystallographically symmetrical orientations under rolling deformation, in which the Schmid factors of several slip systems are identical.
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Study on the cold rolling deformation behavior of polycrystalline tungsten
International Journal of Refractory Metals and Hard Materials, 2019Co-Authors: Ning Zhang, Weimin MaoAbstract:Abstract Tungsten is paid special attention due to its superior properties, especially in nuclear field. Meanwhile it is suitable for texture simulation investigation of BCC metals and alloys as it's near elastically isotropic. This study investigates the cold rolling deformation texture of polycrystalline tungsten using RS model, in which the Stress and strain consistence is realized simultaneously. The texture evolution and effects of deformation parameters, including external as well as internal Reaction Stress, strain and activation of different slip, on texture during rolling are discussed by comparing the simulated results and reported experimental results in literatures. The results show that, the cold rolling deformation texture could be simulated statistically based on RS model. The accumulation of each Reaction Stress is different. The up-limit of Reaction Stress σ'12 is found to be medium, meaning that σ'12 exerts important effect on texture evolution. Much lower accumulation level of σ'13 as well σ'23 is displayed, each of which within certain range contributes to the increase of different γ-fiber texture components. The effect of σ'22 can't be ignored during rolling, especially in the case of obtaining {111} texture. Regarding the deformation textures of tungsten rolled to true strains of −1.7 and −2.91, {001} texture is strengthened with the increasing strain and becomes dominant, implying the easier activation of {112} slip systems; γ-fiber texture is weakened at higher strain, and the formation of {111} texture shows significant effect of surface shear Stress σ13, which is due to the nonnegligible surface friction when rolling at high temperature.
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formation of cube texture affected by neighboring grains in a transverse directionally aligned columnar grained electrical steel
Materials Letters, 2013Co-Authors: Ning Zhang, Ping YangAbstract:Abstract The formation of stronger cube recrystallization texture in a transverse-directionally aligned columnar-grained electrical steel than columnar-grained ND and RD samples with initial columnar grains' longitudinal axis being along normal and rolling direction respectively was analyzed experimentally and theoretically, and cube texture was indicated to be attributed to the specific deformation and recrystallization behaviors of cube oriented columnar grains. The specific deformation behaviors of cube oriented grains were revealed focusing on the interactions of specially aligned columnar grains in comparison with {001}〈100〉 single crystal and other two kinds of samples. In addition, Reaction Stress model was selected to simulate the orientation evolution of {001}〈100〉 orientation by cold rolling, and the modeled result coincided with the experimental results and confirmed the effects of neighboring grains.
