基于原子模拟的金属Fe晶界能与晶界取向相关性分析  

Analysis of the Correlation Between the Energy and Crystallographic Orientation of Grain Boundaries in Fe Based on Atomistic Simulations

作　　者：黄曾鑫 蒋逸航 赖春明 吴庆捷 刘大海[2] 杨亮 HUANG Zengxin;JIANG Yihang;LAI Chunming;WU Qingjie;LIU Dahai;YANG Liang(Engineering Training Center,Nanchang Hangkong University,Nanchang 330063,China;School of Aeronautical Manufacturing Engineering,Nanchang Hangkong University,Nanchang 330063,China;School of Mechanical and Electrical Engineering,Hunan Chemical Vocational Technology College,Zhuzhou 412000,China)

机构地区：[1]南昌航空大学工程训练中心,南昌330063 [2]南昌航空大学航空制造工程学院,南昌330063 [3]湖南化工职业技术学院机电工程学院,株洲412000

出　　处：《金属学报》2024年第9期1289-1298,共10页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目No.52065045;江西省杰出青年人才计划项目No.20192BCBL23002。

摘　　要：晶界能(γ)会显著影响金属材料的诸多物理和力学性能,然而bcc金属内γ与晶界取向间相关性特征的认识仍非常有限。为揭示这些潜在特征,本研究采用截断球状双晶分子动力学模型,计算了bcc金属Fe内涵盖0°~180°取向差角(θ)、40个取向差轴(O)共1568组倾斜晶界的能量,统计性分析了γ与晶界取向参数的相关性并揭示了相关机理。结果表明,对于具有不同O的晶界,γ随θ的变化趋势在大角度范围内会存在显著差异;从统计性角度来看,γ在θ和偏转角较小时整体上随这2类角度的增大而提高,随后整体保持平稳。非重位点阵晶界的能量并不高于重位点阵(coincidence site lattice,CSL)晶界,在较小θ范围内随θ的变化趋势与CSL晶界相同。当O从取向投影三角形的内部向边部再向顶点变化时,倾斜晶界结构的对称性整体上逐渐升高从而对应能量逐渐降低,<111>顶点附近的能量整体最低。具有低Miller指数或高密排晶界面的晶界并不一定具有较低能量,γ整体上随晶界面对应表面能的增大而升高直至整体保持平稳。γ与重位因子(Σ)整体上无可见相关性,但固定O下γ(θ)曲线上的能量低谷一般都位于具有极小Σ的晶界。此外,还发现bcc金属中γ与晶界取向之间潜在的相关性及规律与fcc金属部分相似或相同。The grain boundary(GB)energy is one of the fundamental structure-dependent properties of GB and plays a crucial role in the GB-related behaviors and properties of polycrystalline materials.An in-depth understanding of GB energy will help to explore the corresponding mechanisms and provide significant guidance for tailoring material properties based on GB engineering.The crystallographic orientation of GB strongly dominates the GB energy.However,a relatively comprehensive understanding of the orientation dependence of the GB energy is still lacking,especially for bcc materials.In this study,the energies of 1568 tilt GBs in bcc Fe,which covers the misorientation angle(θ)of 0°-180°and 40 distinct misorientation axes(O),were computed using the cutoff sphere bicrystal molecular dynamics model.The energy dataset was used to statistically analyze the correlation between GB energy(γ)and GB crystallographic orientation,thereby revealing the underlying mechanisms.The results show that the tendencies ofγ-θcorrelation can be considerably different in the high-angle range for GBs with distinct O.Statistically,GB energies increase withθand disorientation angle in the low-angle range and then level off for higher angles.The energies for noncoincident site lattice(non-CSL)GBs are not necessarily higher than those of CSL GBs and follow the same trend in the low-θrange as CSL GBs.The energies of the tilt GBs decrease with the variation of O from the central regions to the edge and then the corners of the stereographic triangle due to the increasing tendency of the symmetry of the boundary structure.Therefore,the lowest energies are observed for GBs with O close to<111>.Relatively low energies are not observed for GBs terminated by low-index or dense planes.The GB energy shows an overall increasing trend with the surface energy of the boundary plane until a plateau in the GB energy is reached.No distinct correlation is observed between the GB energy and coincidence index(Σ)value.However,the cusp in theγ(θ)curve for GBs w

关 键 词：晶界 晶界能 晶体取向 BCC 原子模拟 

分 类 号：TG111[金属学及工艺—物理冶金]