位错及掺杂对球铁冲击韧性影响的电子机理

计算物理 ›› 2015, Vol. 32 ›› Issue (4): 482-486.

位错及掺杂对球铁冲击韧性影响的电子机理

杨忠华^1,2, 刘贵立¹, 曲迎东², 李荣德²

1. 沈阳工业大学建筑工程学院, 沈阳 110870;
2. 沈阳工业大学材料工程学院, 沈阳 110870

收稿日期:2014-06-25 修回日期:2014-10-16 出版日期:2015-07-25 发布日期:2015-07-25
作者简介:杨忠华(1985-),男,辽宁大连人,博士生,研究方向:材料的晶体结构,E-mail:331808017@qq.com
基金资助:
国家自然科学基金(51274142)资助项目

Electronic Mechanism of Dislocation and Doping for Impact Toughness of Ductile Cast Iron

YANG Zhonghua^1,2, LIU Guili¹, QU Yingdong², LI Rongde²

1. School of Architecture Engineering Shenyang University of Technology, Shenyang 110870, China;
2. School of Material Engineering Shenyang University of Technology, Shenyang 110570, China

Received:2014-06-25 Revised:2014-10-16 Online:2015-07-25 Published:2015-07-25

摘要/Abstract

摘要： 在球墨铸铁金属基体中建立α-Fe[100](010)刃型位错原子模型,利用基于密度泛函理论的CASTEP目的计算C原子在位错芯区的埋置能、亲和能、电荷布居数等电子参数.结果表明:α-Fe[100](010)刃型位错芯区局域效应集中范围较小并具有C_2v点群对称性.位错芯区的能量低谷吸引轻质杂质C原子偏聚,C原子的2p轨道与刃型位错尖端Fe原子的4s价轨道之间发生电荷转移,具有较强的相互作用,使位错运动受阻.Fe-C原子间布居数较大、原子间距离较小表明,Fe-C原子间有生成渗碳体化合物的倾向.Si原子掺杂渗碳体的结合能及各原子轨道分波态密度表明,Si原子能够促使渗碳体分解,析出碳硅化合物成为石墨球化的核心,从而改善球墨铸铁的冲击韧性.

关键词: 球墨铸铁, 原子结构, CASTEP, 冲击韧性

Abstract: Atom module of α-Fe [100](010) edge dislocation is built in metallic matrix of ductile cast iron. Density functional theory CASTEP method is employed to calculate energy parameters of carbon doping edge dislocation system including atom embedded energy,affinity energy and Mulliken population. It shows that there exist C_2v symmetry group in structure of α-Fe [100](010) edge dislocation and localized effect of dislocation happens in limited range. Energy valley attracts light impurity carbon which forms atom clusters in dislocation corn. Interaction between C and Fe atoms is strengthened with charge transportation between C-4s and Fe-2p obtains which pins dislocation slipping. Mulliken population of Fe atom and C atom is high. Length is short. Iron carbide could be produced. Binding energy and PDOS of carbon doping cementite system show that silicon promotes cementite decomposing and nicalon becomes corn of graphite ball,which improve impact toughness of ductile cast iron.

Key words: ductile cast iron, atom structure, CASTEP, impact toughness

中图分类号:

杨忠华, 刘贵立, 曲迎东, 李荣德. 位错及掺杂对球铁冲击韧性影响的电子机理[J]. 计算物理, 2015, 32(4): 482-486.

YANG Zhonghua, LIU Guili, QU Yingdong, LI Rongde. Electronic Mechanism of Dislocation and Doping for Impact Toughness of Ductile Cast Iron[J]. CHINESE JOURNAL OF COMPUTATIONAL PHYSICS, 2015, 32(4): 482-486.

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