Phosphorus-induced relaxation in an iron grain boundary: A cluster-model study

Shaoping Tang, Arthur J Freeman, G. B. Olson

Research output: Contribution to journalArticle

54 Citations (Scopus)

Abstract

The DMol molecular-cluster method, based on local density-functional theory, is employed to study the electronic structure and structural relaxation of a P impurity in the Fe 3[11̄0](111) grain boundary (GB). Large clusters (53 and 91 atoms) are used to simulate the local environment of the Fe grain boundary; by calculating the force on the nearby Fe atoms around the impurity and minimizing the total energy of the cluster, an optimized atomic geometry with minimum energy is obtained. In the pure grain boundary, the center Fe atoms above the GB core have the tendency to move toward each other keeping a bond length very close to the Fe bulk bond length. From the 91-atom cluster, the P-induced relaxation of the Fe GB extends to at least eight Fe layers and the bond length between P and the nearest vertical Fe is 2.34, which is 3.5% larger than that in bulk Fe3P. Although the nearest Fe-P distance is the same in the vertical and horizontal directions, we found a stronger bonding between P and the in-plane Fe than in the vertical direction, which may contribute to the P embrittlement of Fe. A lesson from the present study with two cluster models is that even a cluster as large as 53 atoms does not provide the correct bonding picture around the impurity. This is due to the large relaxation induced by the P atom, which cannot be treated by a 53-atom cluster.

Original languageEnglish
Pages (from-to)2441-2445
Number of pages5
JournalPhysical Review B
Volume47
Issue number5
DOIs
Publication statusPublished - 1993

Fingerprint

Phosphorus
phosphorus
Grain boundaries
Iron
grain boundaries
iron
Atoms
Bond length
atoms
Impurities
impurities
Structural relaxation
embrittlement
molecular clusters
Embrittlement
Electronic structure
Density functional theory
tendencies
density functional theory
electronic structure

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

Phosphorus-induced relaxation in an iron grain boundary : A cluster-model study. / Tang, Shaoping; Freeman, Arthur J; Olson, G. B.

In: Physical Review B, Vol. 47, No. 5, 1993, p. 2441-2445.

Research output: Contribution to journalArticle

@article{a94b384558f64b3293f37649f2982b1d,
title = "Phosphorus-induced relaxation in an iron grain boundary: A cluster-model study",
abstract = "The DMol molecular-cluster method, based on local density-functional theory, is employed to study the electronic structure and structural relaxation of a P impurity in the Fe 3[11̄0](111) grain boundary (GB). Large clusters (53 and 91 atoms) are used to simulate the local environment of the Fe grain boundary; by calculating the force on the nearby Fe atoms around the impurity and minimizing the total energy of the cluster, an optimized atomic geometry with minimum energy is obtained. In the pure grain boundary, the center Fe atoms above the GB core have the tendency to move toward each other keeping a bond length very close to the Fe bulk bond length. From the 91-atom cluster, the P-induced relaxation of the Fe GB extends to at least eight Fe layers and the bond length between P and the nearest vertical Fe is 2.34, which is 3.5{\%} larger than that in bulk Fe3P. Although the nearest Fe-P distance is the same in the vertical and horizontal directions, we found a stronger bonding between P and the in-plane Fe than in the vertical direction, which may contribute to the P embrittlement of Fe. A lesson from the present study with two cluster models is that even a cluster as large as 53 atoms does not provide the correct bonding picture around the impurity. This is due to the large relaxation induced by the P atom, which cannot be treated by a 53-atom cluster.",
author = "Shaoping Tang and Freeman, {Arthur J} and Olson, {G. B.}",
year = "1993",
doi = "10.1103/PhysRevB.47.2441",
language = "English",
volume = "47",
pages = "2441--2445",
journal = "Physical Review B-Condensed Matter",
issn = "1098-0121",
publisher = "American Physical Society",
number = "5",

}

TY - JOUR

T1 - Phosphorus-induced relaxation in an iron grain boundary

T2 - A cluster-model study

AU - Tang, Shaoping

AU - Freeman, Arthur J

AU - Olson, G. B.

PY - 1993

Y1 - 1993

N2 - The DMol molecular-cluster method, based on local density-functional theory, is employed to study the electronic structure and structural relaxation of a P impurity in the Fe 3[11̄0](111) grain boundary (GB). Large clusters (53 and 91 atoms) are used to simulate the local environment of the Fe grain boundary; by calculating the force on the nearby Fe atoms around the impurity and minimizing the total energy of the cluster, an optimized atomic geometry with minimum energy is obtained. In the pure grain boundary, the center Fe atoms above the GB core have the tendency to move toward each other keeping a bond length very close to the Fe bulk bond length. From the 91-atom cluster, the P-induced relaxation of the Fe GB extends to at least eight Fe layers and the bond length between P and the nearest vertical Fe is 2.34, which is 3.5% larger than that in bulk Fe3P. Although the nearest Fe-P distance is the same in the vertical and horizontal directions, we found a stronger bonding between P and the in-plane Fe than in the vertical direction, which may contribute to the P embrittlement of Fe. A lesson from the present study with two cluster models is that even a cluster as large as 53 atoms does not provide the correct bonding picture around the impurity. This is due to the large relaxation induced by the P atom, which cannot be treated by a 53-atom cluster.

AB - The DMol molecular-cluster method, based on local density-functional theory, is employed to study the electronic structure and structural relaxation of a P impurity in the Fe 3[11̄0](111) grain boundary (GB). Large clusters (53 and 91 atoms) are used to simulate the local environment of the Fe grain boundary; by calculating the force on the nearby Fe atoms around the impurity and minimizing the total energy of the cluster, an optimized atomic geometry with minimum energy is obtained. In the pure grain boundary, the center Fe atoms above the GB core have the tendency to move toward each other keeping a bond length very close to the Fe bulk bond length. From the 91-atom cluster, the P-induced relaxation of the Fe GB extends to at least eight Fe layers and the bond length between P and the nearest vertical Fe is 2.34, which is 3.5% larger than that in bulk Fe3P. Although the nearest Fe-P distance is the same in the vertical and horizontal directions, we found a stronger bonding between P and the in-plane Fe than in the vertical direction, which may contribute to the P embrittlement of Fe. A lesson from the present study with two cluster models is that even a cluster as large as 53 atoms does not provide the correct bonding picture around the impurity. This is due to the large relaxation induced by the P atom, which cannot be treated by a 53-atom cluster.

UR - http://www.scopus.com/inward/record.url?scp=0000311367&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0000311367&partnerID=8YFLogxK

U2 - 10.1103/PhysRevB.47.2441

DO - 10.1103/PhysRevB.47.2441

M3 - Article

AN - SCOPUS:0000311367

VL - 47

SP - 2441

EP - 2445

JO - Physical Review B-Condensed Matter

JF - Physical Review B-Condensed Matter

SN - 1098-0121

IS - 5

ER -